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/gfp.h>
   7 #include <linux/sched.h>
   8 #include <linux/debugfs.h>
   9 #include <linux/seq_file.h>
  10
  11 #include "super.h"
  12 #include "mds_client.h"
  13
  14 #include <linux/ceph/ceph_features.h>
  15 #include <linux/ceph/messenger.h>
  16 #include <linux/ceph/decode.h>
  17 #include <linux/ceph/pagelist.h>
  18 #include <linux/ceph/auth.h>
  19 #include <linux/ceph/debugfs.h>
  20
  21 /*
  22  * A cluster of MDS (metadata server) daemons is responsible for
  23  * managing the file system namespace (the directory hierarchy and
  24  * inodes) and for coordinating shared access to storage.  Metadata is
  25  * partitioning hierarchically across a number of servers, and that
  26  * partition varies over time as the cluster adjusts the distribution
  27  * in order to balance load.
  28  *
  29  * The MDS client is primarily responsible to managing synchronous
  30  * metadata requests for operations like open, unlink, and so forth.
  31  * If there is a MDS failure, we find out about it when we (possibly
  32  * request and) receive a new MDS map, and can resubmit affected
  33  * requests.
  34  *
  35  * For the most part, though, we take advantage of a lossless
  36  * communications channel to the MDS, and do not need to worry about
  37  * timing out or resubmitting requests.
  38  *
  39  * We maintain a stateful "session" with each MDS we interact with.
  40  * Within each session, we sent periodic heartbeat messages to ensure
  41  * any capabilities or leases we have been issues remain valid.  If
  42  * the session times out and goes stale, our leases and capabilities
  43  * are no longer valid.
  44  */
  45
  46 struct ceph_reconnect_state {
  47         int nr_caps;
  48         struct ceph_pagelist *pagelist;
  49         bool flock;
  50 };
  51
  52 static void __wake_requests(struct ceph_mds_client *mdsc,
  53                             struct list_head *head);
  54
  55 static const struct ceph_connection_operations mds_con_ops;
  56
  57
  58 /*
  59  * mds reply parsing
  60  */
  61
  62 /*
  63  * parse individual inode info
  64  */
  65 static int parse_reply_info_in(void **p, void *end,
  66                                struct ceph_mds_reply_info_in *info,
  67                                u64 features)
  68 {
  69         int err = -EIO;
  70
  71         info->in = *p;
  72         *p += sizeof(struct ceph_mds_reply_inode) +
  73                 sizeof(*info->in->fragtree.splits) *
  74                 le32_to_cpu(info->in->fragtree.nsplits);
  75
  76         ceph_decode_32_safe(p, end, info->symlink_len, bad);
  77         ceph_decode_need(p, end, info->symlink_len, bad);
  78         info->symlink = *p;
  79         *p += info->symlink_len;
  80
  81         if (features & CEPH_FEATURE_DIRLAYOUTHASH)
  82                 ceph_decode_copy_safe(p, end, &info->dir_layout,
  83                                       sizeof(info->dir_layout), bad);
  84         else
  85                 memset(&info->dir_layout, 0, sizeof(info->dir_layout));
  86
  87         ceph_decode_32_safe(p, end, info->xattr_len, bad);
  88         ceph_decode_need(p, end, info->xattr_len, bad);
  89         info->xattr_data = *p;
  90         *p += info->xattr_len;
  91         return 0;
  92 bad:
  93         return err;
  94 }
  95
  96 /*
  97  * parse a normal reply, which may contain a (dir+)dentry and/or a
  98  * target inode.
  99  */
 100 static int parse_reply_info_trace(void **p, void *end,
 101                                   struct ceph_mds_reply_info_parsed *info,
 102                                   u64 features)
 103 {
 104         int err;
 105
 106         if (info->head->is_dentry) {
 107                 err = parse_reply_info_in(p, end, &info->diri, features);
 108                 if (err < 0)
 109                         goto out_bad;
 110
 111                 if (unlikely(*p + sizeof(*info->dirfrag) > end))
 112                         goto bad;
 113                 info->dirfrag = *p;
 114                 *p += sizeof(*info->dirfrag) +
 115                         sizeof(u32)*le32_to_cpu(info->dirfrag->ndist);
 116                 if (unlikely(*p > end))
 117                         goto bad;
 118
 119                 ceph_decode_32_safe(p, end, info->dname_len, bad);
 120                 ceph_decode_need(p, end, info->dname_len, bad);
 121                 info->dname = *p;
 122                 *p += info->dname_len;
 123                 info->dlease = *p;
 124                 *p += sizeof(*info->dlease);
 125         }
 126
 127         if (info->head->is_target) {
 128                 err = parse_reply_info_in(p, end, &info->targeti, features);
 129                 if (err < 0)
 130                         goto out_bad;
 131         }
 132
 133         if (unlikely(*p != end))
 134                 goto bad;
 135         return 0;
 136
 137 bad:
 138         err = -EIO;
 139 out_bad:
 140         pr_err("problem parsing mds trace %d\n", err);
 141         return err;
 142 }
 143
 144 /*
 145  * parse readdir results
 146  */
 147 static int parse_reply_info_dir(void **p, void *end,
 148                                 struct ceph_mds_reply_info_parsed *info,
 149                                 u64 features)
 150 {
 151         u32 num, i = 0;
 152         int err;
 153
 154         info->dir_dir = *p;
 155         if (*p + sizeof(*info->dir_dir) > end)
 156                 goto bad;
 157         *p += sizeof(*info->dir_dir) +
 158                 sizeof(u32)*le32_to_cpu(info->dir_dir->ndist);
 159         if (*p > end)
 160                 goto bad;
 161
 162         ceph_decode_need(p, end, sizeof(num) + 2, bad);
 163         num = ceph_decode_32(p);
 164         info->dir_end = ceph_decode_8(p);
 165         info->dir_complete = ceph_decode_8(p);
 166         if (num == 0)
 167                 goto done;
 168
 169         BUG_ON(!info->dir_in);
 170         info->dir_dname = (void *)(info->dir_in + num);
 171         info->dir_dname_len = (void *)(info->dir_dname + num);
 172         info->dir_dlease = (void *)(info->dir_dname_len + num);
 173         if ((unsigned long)(info->dir_dlease + num) >
 174             (unsigned long)info->dir_in + info->dir_buf_size) {
 175                 pr_err("dir contents are larger than expected\n");
 176                 WARN_ON(1);
 177                 goto bad;
 178         }
 179
 180         info->dir_nr = num;
 181         while (num) {
 182                 /* dentry */
 183                 ceph_decode_need(p, end, sizeof(u32)*2, bad);
 184                 info->dir_dname_len[i] = ceph_decode_32(p);
 185                 ceph_decode_need(p, end, info->dir_dname_len[i], bad);
 186                 info->dir_dname[i] = *p;
 187                 *p += info->dir_dname_len[i];
 188                 dout("parsed dir dname '%.*s'\n", info->dir_dname_len[i],
 189                      info->dir_dname[i]);
 190                 info->dir_dlease[i] = *p;
 191                 *p += sizeof(struct ceph_mds_reply_lease);
 192
 193                 /* inode */
 194                 err = parse_reply_info_in(p, end, &info->dir_in[i], features);
 195                 if (err < 0)
 196                         goto out_bad;
 197                 i++;
 198                 num--;
 199         }
 200
 201 done:
 202         if (*p != end)
 203                 goto bad;
 204         return 0;
 205
 206 bad:
 207         err = -EIO;
 208 out_bad:
 209         pr_err("problem parsing dir contents %d\n", err);
 210         return err;
 211 }
 212
 213 /*
 214  * parse fcntl F_GETLK results
 215  */
 216 static int parse_reply_info_filelock(void **p, void *end,
 217                                      struct ceph_mds_reply_info_parsed *info,
 218                                      u64 features)
 219 {
 220         if (*p + sizeof(*info->filelock_reply) > end)
 221                 goto bad;
 222
 223         info->filelock_reply = *p;
 224         *p += sizeof(*info->filelock_reply);
 225
 226         if (unlikely(*p != end))
 227                 goto bad;
 228         return 0;
 229
 230 bad:
 231         return -EIO;
 232 }
 233
 234 /*
 235  * parse create results
 236  */
 237 static int parse_reply_info_create(void **p, void *end,
 238                                   struct ceph_mds_reply_info_parsed *info,
 239                                   u64 features)
 240 {
 241         if (features & CEPH_FEATURE_REPLY_CREATE_INODE) {
 242                 if (*p == end) {
 243                         info->has_create_ino = false;
 244                 } else {
 245                         info->has_create_ino = true;
 246                         info->ino = ceph_decode_64(p);
 247                 }
 248         }
 249
 250         if (unlikely(*p != end))
 251                 goto bad;
 252         return 0;
 253
 254 bad:
 255         return -EIO;
 256 }
 257
 258 /*
 259  * parse extra results
 260  */
 261 static int parse_reply_info_extra(void **p, void *end,
 262                                   struct ceph_mds_reply_info_parsed *info,
 263                                   u64 features)
 264 {
 265         if (info->head->op == CEPH_MDS_OP_GETFILELOCK)
 266                 return parse_reply_info_filelock(p, end, info, features);
 267         else if (info->head->op == CEPH_MDS_OP_READDIR ||
 268                  info->head->op == CEPH_MDS_OP_LSSNAP)
 269                 return parse_reply_info_dir(p, end, info, features);
 270         else if (info->head->op == CEPH_MDS_OP_CREATE)
 271                 return parse_reply_info_create(p, end, info, features);
 272         else
 273                 return -EIO;
 274 }
 275
 276 /*
 277  * parse entire mds reply
 278  */
 279 static int parse_reply_info(struct ceph_msg *msg,
 280                             struct ceph_mds_reply_info_parsed *info,
 281                             u64 features)
 282 {
 283         void *p, *end;
 284         u32 len;
 285         int err;
 286
 287         info->head = msg->front.iov_base;
 288         p = msg->front.iov_base + sizeof(struct ceph_mds_reply_head);
 289         end = p + msg->front.iov_len - sizeof(struct ceph_mds_reply_head);
 290
 291         /* trace */
 292         ceph_decode_32_safe(&p, end, len, bad);
 293         if (len > 0) {
 294                 ceph_decode_need(&p, end, len, bad);
 295                 err = parse_reply_info_trace(&p, p+len, info, features);
 296                 if (err < 0)
 297                         goto out_bad;
 298         }
 299
 300         /* extra */
 301         ceph_decode_32_safe(&p, end, len, bad);
 302         if (len > 0) {
 303                 ceph_decode_need(&p, end, len, bad);
 304                 err = parse_reply_info_extra(&p, p+len, info, features);
 305                 if (err < 0)
 306                         goto out_bad;
 307         }
 308
 309         /* snap blob */
 310         ceph_decode_32_safe(&p, end, len, bad);
 311         info->snapblob_len = len;
 312         info->snapblob = p;
 313         p += len;
 314
 315         if (p != end)
 316                 goto bad;
 317         return 0;
 318
 319 bad:
 320         err = -EIO;
 321 out_bad:
 322         pr_err("mds parse_reply err %d\n", err);
 323         return err;
 324 }
 325
 326 static void destroy_reply_info(struct ceph_mds_reply_info_parsed *info)
 327 {
 328         if (!info->dir_in)
 329                 return;
 330         free_pages((unsigned long)info->dir_in, get_order(info->dir_buf_size));
 331 }
 332
 333
 334 /*
 335  * sessions
 336  */
 337 static const char *session_state_name(int s)
 338 {
 339         switch (s) {
 340         case CEPH_MDS_SESSION_NEW: return "new";
 341         case CEPH_MDS_SESSION_OPENING: return "opening";
 342         case CEPH_MDS_SESSION_OPEN: return "open";
 343         case CEPH_MDS_SESSION_HUNG: return "hung";
 344         case CEPH_MDS_SESSION_CLOSING: return "closing";
 345         case CEPH_MDS_SESSION_RESTARTING: return "restarting";
 346         case CEPH_MDS_SESSION_RECONNECTING: return "reconnecting";
 347         default: return "???";
 348         }
 349 }
 350
 351 static struct ceph_mds_session *get_session(struct ceph_mds_session *s)
 352 {
 353         if (atomic_inc_not_zero(&s->s_ref)) {
 354                 dout("mdsc get_session %p %d -> %d\n", s,
 355                      atomic_read(&s->s_ref)-1, atomic_read(&s->s_ref));
 356                 return s;
 357         } else {
 358                 dout("mdsc get_session %p 0 -- FAIL", s);
 359                 return NULL;
 360         }
 361 }
 362
 363 void ceph_put_mds_session(struct ceph_mds_session *s)
 364 {
 365         dout("mdsc put_session %p %d -> %d\n", s,
 366              atomic_read(&s->s_ref), atomic_read(&s->s_ref)-1);
 367         if (atomic_dec_and_test(&s->s_ref)) {
 368                 if (s->s_auth.authorizer)
 369                         ceph_auth_destroy_authorizer(
 370                                 s->s_mdsc->fsc->client->monc.auth,
 371                                 s->s_auth.authorizer);
 372                 kfree(s);
 373         }
 374 }
 375
 376 /*
 377  * called under mdsc->mutex
 378  */
 379 struct ceph_mds_session *__ceph_lookup_mds_session(struct ceph_mds_client *mdsc,
 380                                                    int mds)
 381 {
 382         struct ceph_mds_session *session;
 383
 384         if (mds >= mdsc->max_sessions || mdsc->sessions[mds] == NULL)
 385                 return NULL;
 386         session = mdsc->sessions[mds];
 387         dout("lookup_mds_session %p %d\n", session,
 388              atomic_read(&session->s_ref));
 389         get_session(session);
 390         return session;
 391 }
 392
 393 static bool __have_session(struct ceph_mds_client *mdsc, int mds)
 394 {
 395         if (mds >= mdsc->max_sessions)
 396                 return false;
 397         return mdsc->sessions[mds];
 398 }
 399
 400 static int __verify_registered_session(struct ceph_mds_client *mdsc,
 401                                        struct ceph_mds_session *s)
 402 {
 403         if (s->s_mds >= mdsc->max_sessions ||
 404             mdsc->sessions[s->s_mds] != s)
 405                 return -ENOENT;
 406         return 0;
 407 }
 408
 409 /*
 410  * create+register a new session for given mds.
 411  * called under mdsc->mutex.
 412  */
 413 static struct ceph_mds_session *register_session(struct ceph_mds_client *mdsc,
 414                                                  int mds)
 415 {
 416         struct ceph_mds_session *s;
 417
 418         if (mds >= mdsc->mdsmap->m_max_mds)
 419                 return ERR_PTR(-EINVAL);
 420
 421         s = kzalloc(sizeof(*s), GFP_NOFS);
 422         if (!s)
 423                 return ERR_PTR(-ENOMEM);
 424         s->s_mdsc = mdsc;
 425         s->s_mds = mds;
 426         s->s_state = CEPH_MDS_SESSION_NEW;
 427         s->s_ttl = 0;
 428         s->s_seq = 0;
 429         mutex_init(&s->s_mutex);
 430
 431         ceph_con_init(&s->s_con, s, &mds_con_ops, &mdsc->fsc->client->msgr);
 432
 433         spin_lock_init(&s->s_gen_ttl_lock);
 434         s->s_cap_gen = 0;
 435         s->s_cap_ttl = jiffies - 1;
 436
 437         spin_lock_init(&s->s_cap_lock);
 438         s->s_renew_requested = 0;
 439         s->s_renew_seq = 0;
 440         INIT_LIST_HEAD(&s->s_caps);
 441         s->s_nr_caps = 0;
 442         s->s_trim_caps = 0;
 443         atomic_set(&s->s_ref, 1);
 444         INIT_LIST_HEAD(&s->s_waiting);
 445         INIT_LIST_HEAD(&s->s_unsafe);
 446         s->s_num_cap_releases = 0;
 447         s->s_cap_reconnect = 0;
 448         s->s_cap_iterator = NULL;
 449         INIT_LIST_HEAD(&s->s_cap_releases);
 450         INIT_LIST_HEAD(&s->s_cap_releases_done);
 451         INIT_LIST_HEAD(&s->s_cap_flushing);
 452         INIT_LIST_HEAD(&s->s_cap_snaps_flushing);
 453
 454         dout("register_session mds%d\n", mds);
 455         if (mds >= mdsc->max_sessions) {
 456                 int newmax = 1 << get_count_order(mds+1);
 457                 struct ceph_mds_session **sa;
 458
 459                 dout("register_session realloc to %d\n", newmax);
 460                 sa = kcalloc(newmax, sizeof(void *), GFP_NOFS);
 461                 if (sa == NULL)
 462                         goto fail_realloc;
 463                 if (mdsc->sessions) {
 464                         memcpy(sa, mdsc->sessions,
 465                                mdsc->max_sessions * sizeof(void *));
 466                         kfree(mdsc->sessions);
 467                 }
 468                 mdsc->sessions = sa;
 469                 mdsc->max_sessions = newmax;
 470         }
 471         mdsc->sessions[mds] = s;
 472         atomic_inc(&s->s_ref);  /* one ref to sessions[], one to caller */
 473
 474         ceph_con_open(&s->s_con, CEPH_ENTITY_TYPE_MDS, mds,
 475                       ceph_mdsmap_get_addr(mdsc->mdsmap, mds));
 476
 477         return s;
 478
 479 fail_realloc:
 480         kfree(s);
 481         return ERR_PTR(-ENOMEM);
 482 }
 483
 484 /*
 485  * called under mdsc->mutex
 486  */
 487 static void __unregister_session(struct ceph_mds_client *mdsc,
 488                                struct ceph_mds_session *s)
 489 {
 490         dout("__unregister_session mds%d %p\n", s->s_mds, s);
 491         BUG_ON(mdsc->sessions[s->s_mds] != s);
 492         mdsc->sessions[s->s_mds] = NULL;
 493         ceph_con_close(&s->s_con);
 494         ceph_put_mds_session(s);
 495 }
 496
 497 /*
 498  * drop session refs in request.
 499  *
 500  * should be last request ref, or hold mdsc->mutex
 501  */
 502 static void put_request_session(struct ceph_mds_request *req)
 503 {
 504         if (req->r_session) {
 505                 ceph_put_mds_session(req->r_session);
 506                 req->r_session = NULL;
 507         }
 508 }
 509
 510 void ceph_mdsc_release_request(struct kref *kref)
 511 {
 512         struct ceph_mds_request *req = container_of(kref,
 513                                                     struct ceph_mds_request,
 514                                                     r_kref);
 515         destroy_reply_info(&req->r_reply_info);
 516         if (req->r_request)
 517                 ceph_msg_put(req->r_request);
 518         if (req->r_reply)
 519                 ceph_msg_put(req->r_reply);
 520         if (req->r_inode) {
 521                 ceph_put_cap_refs(ceph_inode(req->r_inode), CEPH_CAP_PIN);
 522                 iput(req->r_inode);
 523         }
 524         if (req->r_locked_dir)
 525                 ceph_put_cap_refs(ceph_inode(req->r_locked_dir), CEPH_CAP_PIN);
 526         if (req->r_target_inode)
 527                 iput(req->r_target_inode);
 528         if (req->r_dentry)
 529                 dput(req->r_dentry);
 530         if (req->r_old_dentry)
 531                 dput(req->r_old_dentry);
 532         if (req->r_old_dentry_dir) {
 533                 /*
 534                  * track (and drop pins for) r_old_dentry_dir
 535                  * separately, since r_old_dentry's d_parent may have
 536                  * changed between the dir mutex being dropped and
 537                  * this request being freed.
 538                  */
 539                 ceph_put_cap_refs(ceph_inode(req->r_old_dentry_dir),
 540                                   CEPH_CAP_PIN);
 541                 iput(req->r_old_dentry_dir);
 542         }
 543         kfree(req->r_path1);
 544         kfree(req->r_path2);
 545         put_request_session(req);
 546         ceph_unreserve_caps(req->r_mdsc, &req->r_caps_reservation);
 547         kfree(req);
 548 }
 549
 550 /*
 551  * lookup session, bump ref if found.
 552  *
 553  * called under mdsc->mutex.
 554  */
 555 static struct ceph_mds_request *__lookup_request(struct ceph_mds_client *mdsc,
 556                                              u64 tid)
 557 {
 558         struct ceph_mds_request *req;
 559         struct rb_node *n = mdsc->request_tree.rb_node;
 560
 561         while (n) {
 562                 req = rb_entry(n, struct ceph_mds_request, r_node);
 563                 if (tid < req->r_tid)
 564                         n = n->rb_left;
 565                 else if (tid > req->r_tid)
 566                         n = n->rb_right;
 567                 else {
 568                         ceph_mdsc_get_request(req);
 569                         return req;
 570                 }
 571         }
 572         return NULL;
 573 }
 574
 575 static void __insert_request(struct ceph_mds_client *mdsc,
 576                              struct ceph_mds_request *new)
 577 {
 578         struct rb_node **p = &mdsc->request_tree.rb_node;
 579         struct rb_node *parent = NULL;
 580         struct ceph_mds_request *req = NULL;
 581
 582         while (*p) {
 583                 parent = *p;
 584                 req = rb_entry(parent, struct ceph_mds_request, r_node);
 585                 if (new->r_tid < req->r_tid)
 586                         p = &(*p)->rb_left;
 587                 else if (new->r_tid > req->r_tid)
 588                         p = &(*p)->rb_right;
 589                 else
 590                         BUG();
 591         }
 592
 593         rb_link_node(&new->r_node, parent, p);
 594         rb_insert_color(&new->r_node, &mdsc->request_tree);
 595 }
 596
 597 /*
 598  * Register an in-flight request, and assign a tid.  Link to directory
 599  * are modifying (if any).
 600  *
 601  * Called under mdsc->mutex.
 602  */
 603 static void __register_request(struct ceph_mds_client *mdsc,
 604                                struct ceph_mds_request *req,
 605                                struct inode *dir)
 606 {
 607         req->r_tid = ++mdsc->last_tid;
 608         if (req->r_num_caps)
 609                 ceph_reserve_caps(mdsc, &req->r_caps_reservation,
 610                                   req->r_num_caps);
 611         dout("__register_request %p tid %lld\n", req, req->r_tid);
 612         ceph_mdsc_get_request(req);
 613         __insert_request(mdsc, req);
 614
 615         req->r_uid = current_fsuid();
 616         req->r_gid = current_fsgid();
 617
 618         if (dir) {
 619                 struct ceph_inode_info *ci = ceph_inode(dir);
 620
 621                 ihold(dir);
 622                 spin_lock(&ci->i_unsafe_lock);
 623                 req->r_unsafe_dir = dir;
 624                 list_add_tail(&req->r_unsafe_dir_item, &ci->i_unsafe_dirops);
 625                 spin_unlock(&ci->i_unsafe_lock);
 626         }
 627 }
 628
 629 static void __unregister_request(struct ceph_mds_client *mdsc,
 630                                  struct ceph_mds_request *req)
 631 {
 632         dout("__unregister_request %p tid %lld\n", req, req->r_tid);
 633         rb_erase(&req->r_node, &mdsc->request_tree);
 634         RB_CLEAR_NODE(&req->r_node);
 635
 636         if (req->r_unsafe_dir) {
 637                 struct ceph_inode_info *ci = ceph_inode(req->r_unsafe_dir);
 638
 639                 spin_lock(&ci->i_unsafe_lock);
 640                 list_del_init(&req->r_unsafe_dir_item);
 641                 spin_unlock(&ci->i_unsafe_lock);
 642
 643                 iput(req->r_unsafe_dir);
 644                 req->r_unsafe_dir = NULL;
 645         }
 646
 647         complete_all(&req->r_safe_completion);
 648
 649         ceph_mdsc_put_request(req);
 650 }
 651
 652 /*
 653  * Choose mds to send request to next.  If there is a hint set in the
 654  * request (e.g., due to a prior forward hint from the mds), use that.
 655  * Otherwise, consult frag tree and/or caps to identify the
 656  * appropriate mds.  If all else fails, choose randomly.
 657  *
 658  * Called under mdsc->mutex.
 659  */
 660 static struct dentry *get_nonsnap_parent(struct dentry *dentry)
 661 {
 662         /*
 663          * we don't need to worry about protecting the d_parent access
 664          * here because we never renaming inside the snapped namespace
 665          * except to resplice to another snapdir, and either the old or new
 666          * result is a valid result.
 667          */
 668         while (!IS_ROOT(dentry) && ceph_snap(dentry->d_inode) != CEPH_NOSNAP)
 669                 dentry = dentry->d_parent;
 670         return dentry;
 671 }
 672
 673 static int __choose_mds(struct ceph_mds_client *mdsc,
 674                         struct ceph_mds_request *req)
 675 {
 676         struct inode *inode;
 677         struct ceph_inode_info *ci;
 678         struct ceph_cap *cap;
 679         int mode = req->r_direct_mode;
 680         int mds = -1;
 681         u32 hash = req->r_direct_hash;
 682         bool is_hash = req->r_direct_is_hash;
 683
 684         /*
 685          * is there a specific mds we should try?  ignore hint if we have
 686          * no session and the mds is not up (active or recovering).
 687          */
 688         if (req->r_resend_mds >= 0 &&
 689             (__have_session(mdsc, req->r_resend_mds) ||
 690              ceph_mdsmap_get_state(mdsc->mdsmap, req->r_resend_mds) > 0)) {
 691                 dout("choose_mds using resend_mds mds%d\n",
 692                      req->r_resend_mds);
 693                 return req->r_resend_mds;
 694         }
 695
 696         if (mode == USE_RANDOM_MDS)
 697                 goto random;
 698
 699         inode = NULL;
 700         if (req->r_inode) {
 701                 inode = req->r_inode;
 702         } else if (req->r_dentry) {
 703                 /* ignore race with rename; old or new d_parent is okay */
 704                 struct dentry *parent = req->r_dentry->d_parent;
 705                 struct inode *dir = parent->d_inode;
 706
 707                 if (dir->i_sb != mdsc->fsc->sb) {
 708                         /* not this fs! */
 709                         inode = req->r_dentry->d_inode;
 710                 } else if (ceph_snap(dir) != CEPH_NOSNAP) {
 711                         /* direct snapped/virtual snapdir requests
 712                          * based on parent dir inode */
 713                         struct dentry *dn = get_nonsnap_parent(parent);
 714                         inode = dn->d_inode;
 715                         dout("__choose_mds using nonsnap parent %p\n", inode);
 716                 } else {
 717                         /* dentry target */
 718                         inode = req->r_dentry->d_inode;
 719                         if (!inode || mode == USE_AUTH_MDS) {
 720                                 /* dir + name */
 721                                 inode = dir;
 722                                 hash = ceph_dentry_hash(dir, req->r_dentry);
 723                                 is_hash = true;
 724                         }
 725                 }
 726         }
 727
 728         dout("__choose_mds %p is_hash=%d (%d) mode %d\n", inode, (int)is_hash,
 729              (int)hash, mode);
 730         if (!inode)
 731                 goto random;
 732         ci = ceph_inode(inode);
 733
 734         if (is_hash && S_ISDIR(inode->i_mode)) {
 735                 struct ceph_inode_frag frag;
 736                 int found;
 737
 738                 ceph_choose_frag(ci, hash, &frag, &found);
 739                 if (found) {
 740                         if (mode == USE_ANY_MDS && frag.ndist > 0) {
 741                                 u8 r;
 742
 743                                 /* choose a random replica */
 744                                 get_random_bytes(&r, 1);
 745                                 r %= frag.ndist;
 746                                 mds = frag.dist[r];
 747                                 dout("choose_mds %p %llx.%llx "
 748                                      "frag %u mds%d (%d/%d)\n",
 749                                      inode, ceph_vinop(inode),
 750                                      frag.frag, mds,
 751                                      (int)r, frag.ndist);
 752                                 if (ceph_mdsmap_get_state(mdsc->mdsmap, mds) >=
 753                                     CEPH_MDS_STATE_ACTIVE)
 754                                         return mds;
 755                         }
 756
 757                         /* since this file/dir wasn't known to be
 758                          * replicated, then we want to look for the
 759                          * authoritative mds. */
 760                         mode = USE_AUTH_MDS;
 761                         if (frag.mds >= 0) {
 762                                 /* choose auth mds */
 763                                 mds = frag.mds;
 764                                 dout("choose_mds %p %llx.%llx "
 765                                      "frag %u mds%d (auth)\n",
 766                                      inode, ceph_vinop(inode), frag.frag, mds);
 767                                 if (ceph_mdsmap_get_state(mdsc->mdsmap, mds) >=
 768                                     CEPH_MDS_STATE_ACTIVE)
 769                                         return mds;
 770                         }
 771                 }
 772         }
 773
 774         spin_lock(&ci->i_ceph_lock);
 775         cap = NULL;
 776         if (mode == USE_AUTH_MDS)
 777                 cap = ci->i_auth_cap;
 778         if (!cap && !RB_EMPTY_ROOT(&ci->i_caps))
 779                 cap = rb_entry(rb_first(&ci->i_caps), struct ceph_cap, ci_node);
 780         if (!cap) {
 781                 spin_unlock(&ci->i_ceph_lock);
 782                 goto random;
 783         }
 784         mds = cap->session->s_mds;
 785         dout("choose_mds %p %llx.%llx mds%d (%scap %p)\n",
 786              inode, ceph_vinop(inode), mds,
 787              cap == ci->i_auth_cap ? "auth " : "", cap);
 788         spin_unlock(&ci->i_ceph_lock);
 789         return mds;
 790
 791 random:
 792         mds = ceph_mdsmap_get_random_mds(mdsc->mdsmap);
 793         dout("choose_mds chose random mds%d\n", mds);
 794         return mds;
 795 }
 796
 797
 798 /*
 799  * session messages
 800  */
 801 static struct ceph_msg *create_session_msg(u32 op, u64 seq)
 802 {
 803         struct ceph_msg *msg;
 804         struct ceph_mds_session_head *h;
 805
 806         msg = ceph_msg_new(CEPH_MSG_CLIENT_SESSION, sizeof(*h), GFP_NOFS,
 807                            false);
 808         if (!msg) {
 809                 pr_err("create_session_msg ENOMEM creating msg\n");
 810                 return NULL;
 811         }
 812         h = msg->front.iov_base;
 813         h->op = cpu_to_le32(op);
 814         h->seq = cpu_to_le64(seq);
 815         return msg;
 816 }
 817
 818 /*
 819  * send session open request.
 820  *
 821  * called under mdsc->mutex
 822  */
 823 static int __open_session(struct ceph_mds_client *mdsc,
 824                           struct ceph_mds_session *session)
 825 {
 826         struct ceph_msg *msg;
 827         int mstate;
 828         int mds = session->s_mds;
 829
 830         /* wait for mds to go active? */
 831         mstate = ceph_mdsmap_get_state(mdsc->mdsmap, mds);
 832         dout("open_session to mds%d (%s)\n", mds,
 833              ceph_mds_state_name(mstate));
 834         session->s_state = CEPH_MDS_SESSION_OPENING;
 835         session->s_renew_requested = jiffies;
 836
 837         /* send connect message */
 838         msg = create_session_msg(CEPH_SESSION_REQUEST_OPEN, session->s_seq);
 839         if (!msg)
 840                 return -ENOMEM;
 841         ceph_con_send(&session->s_con, msg);
 842         return 0;
 843 }
 844
 845 /*
 846  * open sessions for any export targets for the given mds
 847  *
 848  * called under mdsc->mutex
 849  */
 850 static struct ceph_mds_session *
 851 __open_export_target_session(struct ceph_mds_client *mdsc, int target)
 852 {
 853         struct ceph_mds_session *session;
 854
 855         session = __ceph_lookup_mds_session(mdsc, target);
 856         if (!session) {
 857                 session = register_session(mdsc, target);
 858                 if (IS_ERR(session))
 859                         return session;
 860         }
 861         if (session->s_state == CEPH_MDS_SESSION_NEW ||
 862             session->s_state == CEPH_MDS_SESSION_CLOSING)
 863                 __open_session(mdsc, session);
 864
 865         return session;
 866 }
 867
 868 struct ceph_mds_session *
 869 ceph_mdsc_open_export_target_session(struct ceph_mds_client *mdsc, int target)
 870 {
 871         struct ceph_mds_session *session;
 872
 873         dout("open_export_target_session to mds%d\n", target);
 874
 875         mutex_lock(&mdsc->mutex);
 876         session = __open_export_target_session(mdsc, target);
 877         mutex_unlock(&mdsc->mutex);
 878
 879         return session;
 880 }
 881
 882 static void __open_export_target_sessions(struct ceph_mds_client *mdsc,
 883                                           struct ceph_mds_session *session)
 884 {
 885         struct ceph_mds_info *mi;
 886         struct ceph_mds_session *ts;
 887         int i, mds = session->s_mds;
 888
 889         if (mds >= mdsc->mdsmap->m_max_mds)
 890                 return;
 891
 892         mi = &mdsc->mdsmap->m_info[mds];
 893         dout("open_export_target_sessions for mds%d (%d targets)\n",
 894              session->s_mds, mi->num_export_targets);
 895
 896         for (i = 0; i < mi->num_export_targets; i++) {
 897                 ts = __open_export_target_session(mdsc, mi->export_targets[i]);
 898                 if (!IS_ERR(ts))
 899                         ceph_put_mds_session(ts);
 900         }
 901 }
 902
 903 void ceph_mdsc_open_export_target_sessions(struct ceph_mds_client *mdsc,
 904                                            struct ceph_mds_session *session)
 905 {
 906         mutex_lock(&mdsc->mutex);
 907         __open_export_target_sessions(mdsc, session);
 908         mutex_unlock(&mdsc->mutex);
 909 }
 910
 911 /*
 912  * session caps
 913  */
 914
 915 /*
 916  * Free preallocated cap messages assigned to this session
 917  */
 918 static void cleanup_cap_releases(struct ceph_mds_session *session)
 919 {
 920         struct ceph_msg *msg;
 921
 922         spin_lock(&session->s_cap_lock);
 923         while (!list_empty(&session->s_cap_releases)) {
 924                 msg = list_first_entry(&session->s_cap_releases,
 925                                        struct ceph_msg, list_head);
 926                 list_del_init(&msg->list_head);
 927                 ceph_msg_put(msg);
 928         }
 929         while (!list_empty(&session->s_cap_releases_done)) {
 930                 msg = list_first_entry(&session->s_cap_releases_done,
 931                                        struct ceph_msg, list_head);
 932                 list_del_init(&msg->list_head);
 933                 ceph_msg_put(msg);
 934         }
 935         spin_unlock(&session->s_cap_lock);
 936 }
 937
 938 /*
 939  * Helper to safely iterate over all caps associated with a session, with
 940  * special care taken to handle a racing __ceph_remove_cap().
 941  *
 942  * Caller must hold session s_mutex.
 943  */
 944 static int iterate_session_caps(struct ceph_mds_session *session,
 945                                  int (*cb)(struct inode *, struct ceph_cap *,
 946                                             void *), void *arg)
 947 {
 948         struct list_head *p;
 949         struct ceph_cap *cap;
 950         struct inode *inode, *last_inode = NULL;
 951         struct ceph_cap *old_cap = NULL;
 952         int ret;
 953
 954         dout("iterate_session_caps %p mds%d\n", session, session->s_mds);
 955         spin_lock(&session->s_cap_lock);
 956         p = session->s_caps.next;
 957         while (p != &session->s_caps) {
 958                 cap = list_entry(p, struct ceph_cap, session_caps);
 959                 inode = igrab(&cap->ci->vfs_inode);
 960                 if (!inode) {
 961                         p = p->next;
 962                         continue;
 963                 }
 964                 session->s_cap_iterator = cap;
 965                 spin_unlock(&session->s_cap_lock);
 966
 967                 if (last_inode) {
 968                         iput(last_inode);
 969                         last_inode = NULL;
 970                 }
 971                 if (old_cap) {
 972                         ceph_put_cap(session->s_mdsc, old_cap);
 973                         old_cap = NULL;
 974                 }
 975
 976                 ret = cb(inode, cap, arg);
 977                 last_inode = inode;
 978
 979                 spin_lock(&session->s_cap_lock);
 980                 p = p->next;
 981                 if (cap->ci == NULL) {
 982                         dout("iterate_session_caps  finishing cap %p removal\n",
 983                              cap);
 984                         BUG_ON(cap->session != session);
 985                         list_del_init(&cap->session_caps);
 986                         session->s_nr_caps--;
 987                         cap->session = NULL;
 988                         old_cap = cap;  /* put_cap it w/o locks held */
 989                 }
 990                 if (ret < 0)
 991                         goto out;
 992         }
 993         ret = 0;
 994 out:
 995         session->s_cap_iterator = NULL;
 996         spin_unlock(&session->s_cap_lock);
 997
 998         if (last_inode)
 999                 iput(last_inode);
1000         if (old_cap)
1001                 ceph_put_cap(session->s_mdsc, old_cap);
1002
1003         return ret;
1004 }
1005
1006 static int remove_session_caps_cb(struct inode *inode, struct ceph_cap *cap,
1007                                   void *arg)
1008 {
1009         struct ceph_inode_info *ci = ceph_inode(inode);
1010         int drop = 0;
1011
1012         dout("removing cap %p, ci is %p, inode is %p\n",
1013              cap, ci, &ci->vfs_inode);
1014         spin_lock(&ci->i_ceph_lock);
1015         __ceph_remove_cap(cap, false);
1016         if (!__ceph_is_any_real_caps(ci)) {
1017                 struct ceph_mds_client *mdsc =
1018                         ceph_sb_to_client(inode->i_sb)->mdsc;
1019
1020                 spin_lock(&mdsc->cap_dirty_lock);
1021                 if (!list_empty(&ci->i_dirty_item)) {
1022                         pr_info(" dropping dirty %s state for %p %lld\n",
1023                                 ceph_cap_string(ci->i_dirty_caps),
1024                                 inode, ceph_ino(inode));
1025                         ci->i_dirty_caps = 0;
1026                         list_del_init(&ci->i_dirty_item);
1027                         drop = 1;
1028                 }
1029                 if (!list_empty(&ci->i_flushing_item)) {
1030                         pr_info(" dropping dirty+flushing %s state for %p %lld\n",
1031                                 ceph_cap_string(ci->i_flushing_caps),
1032                                 inode, ceph_ino(inode));
1033                         ci->i_flushing_caps = 0;
1034                         list_del_init(&ci->i_flushing_item);
1035                         mdsc->num_cap_flushing--;
1036                         drop = 1;
1037                 }
1038                 if (drop && ci->i_wrbuffer_ref) {
1039                         pr_info(" dropping dirty data for %p %lld\n",
1040                                 inode, ceph_ino(inode));
1041                         ci->i_wrbuffer_ref = 0;
1042                         ci->i_wrbuffer_ref_head = 0;
1043                         drop++;
1044                 }
1045                 spin_unlock(&mdsc->cap_dirty_lock);
1046         }
1047         spin_unlock(&ci->i_ceph_lock);
1048         while (drop--)
1049                 iput(inode);
1050         return 0;
1051 }
1052
1053 /*
1054  * caller must hold session s_mutex
1055  */
1056 static void remove_session_caps(struct ceph_mds_session *session)
1057 {
1058         dout("remove_session_caps on %p\n", session);
1059         iterate_session_caps(session, remove_session_caps_cb, NULL);
1060
1061         spin_lock(&session->s_cap_lock);
1062         if (session->s_nr_caps > 0) {
1063                 struct super_block *sb = session->s_mdsc->fsc->sb;
1064                 struct inode *inode;
1065                 struct ceph_cap *cap, *prev = NULL;
1066                 struct ceph_vino vino;
1067                 /*
1068                  * iterate_session_caps() skips inodes that are being
1069                  * deleted, we need to wait until deletions are complete.
1070                  * __wait_on_freeing_inode() is designed for the job,
1071                  * but it is not exported, so use lookup inode function
1072                  * to access it.
1073                  */
1074                 while (!list_empty(&session->s_caps)) {
1075                         cap = list_entry(session->s_caps.next,
1076                                          struct ceph_cap, session_caps);
1077                         if (cap == prev)
1078                                 break;
1079                         prev = cap;
1080                         vino = cap->ci->i_vino;
1081                         spin_unlock(&session->s_cap_lock);
1082
1083                         inode = ceph_find_inode(sb, vino);
1084                         iput(inode);
1085
1086                         spin_lock(&session->s_cap_lock);
1087                 }
1088         }
1089         spin_unlock(&session->s_cap_lock);
1090
1091         BUG_ON(session->s_nr_caps > 0);
1092         BUG_ON(!list_empty(&session->s_cap_flushing));
1093         cleanup_cap_releases(session);
1094 }
1095
1096 /*
1097  * wake up any threads waiting on this session's caps.  if the cap is
1098  * old (didn't get renewed on the client reconnect), remove it now.
1099  *
1100  * caller must hold s_mutex.
1101  */
1102 static int wake_up_session_cb(struct inode *inode, struct ceph_cap *cap,
1103                               void *arg)
1104 {
1105         struct ceph_inode_info *ci = ceph_inode(inode);
1106
1107         wake_up_all(&ci->i_cap_wq);
1108         if (arg) {
1109                 spin_lock(&ci->i_ceph_lock);
1110                 ci->i_wanted_max_size = 0;
1111                 ci->i_requested_max_size = 0;
1112                 spin_unlock(&ci->i_ceph_lock);
1113         }
1114         return 0;
1115 }
1116
1117 static void wake_up_session_caps(struct ceph_mds_session *session,
1118                                  int reconnect)
1119 {
1120         dout("wake_up_session_caps %p mds%d\n", session, session->s_mds);
1121         iterate_session_caps(session, wake_up_session_cb,
1122                              (void *)(unsigned long)reconnect);
1123 }
1124
1125 /*
1126  * Send periodic message to MDS renewing all currently held caps.  The
1127  * ack will reset the expiration for all caps from this session.
1128  *
1129  * caller holds s_mutex
1130  */
1131 static int send_renew_caps(struct ceph_mds_client *mdsc,
1132                            struct ceph_mds_session *session)
1133 {
1134         struct ceph_msg *msg;
1135         int state;
1136
1137         if (time_after_eq(jiffies, session->s_cap_ttl) &&
1138             time_after_eq(session->s_cap_ttl, session->s_renew_requested))
1139                 pr_info("mds%d caps stale\n", session->s_mds);
1140         session->s_renew_requested = jiffies;
1141
1142         /* do not try to renew caps until a recovering mds has reconnected
1143          * with its clients. */
1144         state = ceph_mdsmap_get_state(mdsc->mdsmap, session->s_mds);
1145         if (state < CEPH_MDS_STATE_RECONNECT) {
1146                 dout("send_renew_caps ignoring mds%d (%s)\n",
1147                      session->s_mds, ceph_mds_state_name(state));
1148                 return 0;
1149         }
1150
1151         dout("send_renew_caps to mds%d (%s)\n", session->s_mds,
1152                 ceph_mds_state_name(state));
1153         msg = create_session_msg(CEPH_SESSION_REQUEST_RENEWCAPS,
1154                                  ++session->s_renew_seq);
1155         if (!msg)
1156                 return -ENOMEM;
1157         ceph_con_send(&session->s_con, msg);
1158         return 0;
1159 }
1160
1161 static int send_flushmsg_ack(struct ceph_mds_client *mdsc,
1162                              struct ceph_mds_session *session, u64 seq)
1163 {
1164         struct ceph_msg *msg;
1165
1166         dout("send_flushmsg_ack to mds%d (%s)s seq %lld\n",
1167              session->s_mds, session_state_name(session->s_state), seq);
1168         msg = create_session_msg(CEPH_SESSION_FLUSHMSG_ACK, seq);
1169         if (!msg)
1170                 return -ENOMEM;
1171         ceph_con_send(&session->s_con, msg);
1172         return 0;
1173 }
1174
1175
1176 /*
1177  * Note new cap ttl, and any transition from stale -> not stale (fresh?).
1178  *
1179  * Called under session->s_mutex
1180  */
1181 static void renewed_caps(struct ceph_mds_client *mdsc,
1182                          struct ceph_mds_session *session, int is_renew)
1183 {
1184         int was_stale;
1185         int wake = 0;
1186
1187         spin_lock(&session->s_cap_lock);
1188         was_stale = is_renew && time_after_eq(jiffies, session->s_cap_ttl);
1189
1190         session->s_cap_ttl = session->s_renew_requested +
1191                 mdsc->mdsmap->m_session_timeout*HZ;
1192
1193         if (was_stale) {
1194                 if (time_before(jiffies, session->s_cap_ttl)) {
1195                         pr_info("mds%d caps renewed\n", session->s_mds);
1196                         wake = 1;
1197                 } else {
1198                         pr_info("mds%d caps still stale\n", session->s_mds);
1199                 }
1200         }
1201         dout("renewed_caps mds%d ttl now %lu, was %s, now %s\n",
1202              session->s_mds, session->s_cap_ttl, was_stale ? "stale" : "fresh",
1203              time_before(jiffies, session->s_cap_ttl) ? "stale" : "fresh");
1204         spin_unlock(&session->s_cap_lock);
1205
1206         if (wake)
1207                 wake_up_session_caps(session, 0);
1208 }
1209
1210 /*
1211  * send a session close request
1212  */
1213 static int request_close_session(struct ceph_mds_client *mdsc,
1214                                  struct ceph_mds_session *session)
1215 {
1216         struct ceph_msg *msg;
1217
1218         dout("request_close_session mds%d state %s seq %lld\n",
1219              session->s_mds, session_state_name(session->s_state),
1220              session->s_seq);
1221         msg = create_session_msg(CEPH_SESSION_REQUEST_CLOSE, session->s_seq);
1222         if (!msg)
1223                 return -ENOMEM;
1224         ceph_con_send(&session->s_con, msg);
1225         return 0;
1226 }
1227
1228 /*
1229  * Called with s_mutex held.
1230  */
1231 static int __close_session(struct ceph_mds_client *mdsc,
1232                          struct ceph_mds_session *session)
1233 {
1234         if (session->s_state >= CEPH_MDS_SESSION_CLOSING)
1235                 return 0;
1236         session->s_state = CEPH_MDS_SESSION_CLOSING;
1237         return request_close_session(mdsc, session);
1238 }
1239
1240 /*
1241  * Trim old(er) caps.
1242  *
1243  * Because we can't cache an inode without one or more caps, we do
1244  * this indirectly: if a cap is unused, we prune its aliases, at which
1245  * point the inode will hopefully get dropped to.
1246  *
1247  * Yes, this is a bit sloppy.  Our only real goal here is to respond to
1248  * memory pressure from the MDS, though, so it needn't be perfect.
1249  */
1250 static int trim_caps_cb(struct inode *inode, struct ceph_cap *cap, void *arg)
1251 {
1252         struct ceph_mds_session *session = arg;
1253         struct ceph_inode_info *ci = ceph_inode(inode);
1254         int used, wanted, oissued, mine;
1255
1256         if (session->s_trim_caps <= 0)
1257                 return -1;
1258
1259         spin_lock(&ci->i_ceph_lock);
1260         mine = cap->issued | cap->implemented;
1261         used = __ceph_caps_used(ci);
1262         wanted = __ceph_caps_file_wanted(ci);
1263         oissued = __ceph_caps_issued_other(ci, cap);
1264
1265         dout("trim_caps_cb %p cap %p mine %s oissued %s used %s wanted %s\n",
1266              inode, cap, ceph_cap_string(mine), ceph_cap_string(oissued),
1267              ceph_cap_string(used), ceph_cap_string(wanted));
1268         if (cap == ci->i_auth_cap) {
1269                 if (ci->i_dirty_caps | ci->i_flushing_caps)
1270                         goto out;
1271                 if ((used | wanted) & CEPH_CAP_ANY_WR)
1272                         goto out;
1273         }
1274         if ((used | wanted) & ~oissued & mine)
1275                 goto out;   /* we need these caps */
1276
1277         session->s_trim_caps--;
1278         if (oissued) {
1279                 /* we aren't the only cap.. just remove us */
1280                 __ceph_remove_cap(cap, true);
1281         } else {
1282                 /* try to drop referring dentries */
1283                 spin_unlock(&ci->i_ceph_lock);
1284                 d_prune_aliases(inode);
1285                 dout("trim_caps_cb %p cap %p  pruned, count now %d\n",
1286                      inode, cap, atomic_read(&inode->i_count));
1287                 return 0;
1288         }
1289
1290 out:
1291         spin_unlock(&ci->i_ceph_lock);
1292         return 0;
1293 }
1294
1295 /*
1296  * Trim session cap count down to some max number.
1297  */
1298 static int trim_caps(struct ceph_mds_client *mdsc,
1299                      struct ceph_mds_session *session,
1300                      int max_caps)
1301 {
1302         int trim_caps = session->s_nr_caps - max_caps;
1303
1304         dout("trim_caps mds%d start: %d / %d, trim %d\n",
1305              session->s_mds, session->s_nr_caps, max_caps, trim_caps);
1306         if (trim_caps > 0) {
1307                 session->s_trim_caps = trim_caps;
1308                 iterate_session_caps(session, trim_caps_cb, session);
1309                 dout("trim_caps mds%d done: %d / %d, trimmed %d\n",
1310                      session->s_mds, session->s_nr_caps, max_caps,
1311                         trim_caps - session->s_trim_caps);
1312                 session->s_trim_caps = 0;
1313         }
1314
1315         ceph_add_cap_releases(mdsc, session);
1316         ceph_send_cap_releases(mdsc, session);
1317         return 0;
1318 }
1319
1320 /*
1321  * Allocate cap_release messages.  If there is a partially full message
1322  * in the queue, try to allocate enough to cover it's remainder, so that
1323  * we can send it immediately.
1324  *
1325  * Called under s_mutex.
1326  */
1327 int ceph_add_cap_releases(struct ceph_mds_client *mdsc,
1328                           struct ceph_mds_session *session)
1329 {
1330         struct ceph_msg *msg, *partial = NULL;
1331         struct ceph_mds_cap_release *head;
1332         int err = -ENOMEM;
1333         int extra = mdsc->fsc->mount_options->cap_release_safety;
1334         int num;
1335
1336         dout("add_cap_releases %p mds%d extra %d\n", session, session->s_mds,
1337              extra);
1338
1339         spin_lock(&session->s_cap_lock);
1340
1341         if (!list_empty(&session->s_cap_releases)) {
1342                 msg = list_first_entry(&session->s_cap_releases,
1343                                        struct ceph_msg,
1344                                  list_head);
1345                 head = msg->front.iov_base;
1346                 num = le32_to_cpu(head->num);
1347                 if (num) {
1348                         dout(" partial %p with (%d/%d)\n", msg, num,
1349                              (int)CEPH_CAPS_PER_RELEASE);
1350                         extra += CEPH_CAPS_PER_RELEASE - num;
1351                         partial = msg;
1352                 }
1353         }
1354         while (session->s_num_cap_releases < session->s_nr_caps + extra) {
1355                 spin_unlock(&session->s_cap_lock);
1356                 msg = ceph_msg_new(CEPH_MSG_CLIENT_CAPRELEASE, PAGE_CACHE_SIZE,
1357                                    GFP_NOFS, false);
1358                 if (!msg)
1359                         goto out_unlocked;
1360                 dout("add_cap_releases %p msg %p now %d\n", session, msg,
1361                      (int)msg->front.iov_len);
1362                 head = msg->front.iov_base;
1363                 head->num = cpu_to_le32(0);
1364                 msg->front.iov_len = sizeof(*head);
1365                 spin_lock(&session->s_cap_lock);
1366                 list_add(&msg->list_head, &session->s_cap_releases);
1367                 session->s_num_cap_releases += CEPH_CAPS_PER_RELEASE;
1368         }
1369
1370         if (partial) {
1371                 head = partial->front.iov_base;
1372                 num = le32_to_cpu(head->num);
1373                 dout(" queueing partial %p with %d/%d\n", partial, num,
1374                      (int)CEPH_CAPS_PER_RELEASE);
1375                 list_move_tail(&partial->list_head,
1376                                &session->s_cap_releases_done);
1377                 session->s_num_cap_releases -= CEPH_CAPS_PER_RELEASE - num;
1378         }
1379         err = 0;
1380         spin_unlock(&session->s_cap_lock);
1381 out_unlocked:
1382         return err;
1383 }
1384
1385 /*
1386  * flush all dirty inode data to disk.
1387  *
1388  * returns true if we've flushed through want_flush_seq
1389  */
1390 static int check_cap_flush(struct ceph_mds_client *mdsc, u64 want_flush_seq)
1391 {
1392         int mds, ret = 1;
1393
1394         dout("check_cap_flush want %lld\n", want_flush_seq);
1395         mutex_lock(&mdsc->mutex);
1396         for (mds = 0; ret && mds < mdsc->max_sessions; mds++) {
1397                 struct ceph_mds_session *session = mdsc->sessions[mds];
1398
1399                 if (!session)
1400                         continue;
1401                 get_session(session);
1402                 mutex_unlock(&mdsc->mutex);
1403
1404                 mutex_lock(&session->s_mutex);
1405                 if (!list_empty(&session->s_cap_flushing)) {
1406                         struct ceph_inode_info *ci =
1407                                 list_entry(session->s_cap_flushing.next,
1408                                            struct ceph_inode_info,
1409                                            i_flushing_item);
1410                         struct inode *inode = &ci->vfs_inode;
1411
1412                         spin_lock(&ci->i_ceph_lock);
1413                         if (ci->i_cap_flush_seq <= want_flush_seq) {
1414                                 dout("check_cap_flush still flushing %p "
1415                                      "seq %lld <= %lld to mds%d\n", inode,
1416                                      ci->i_cap_flush_seq, want_flush_seq,
1417                                      session->s_mds);
1418                                 ret = 0;
1419                         }
1420                         spin_unlock(&ci->i_ceph_lock);
1421                 }
1422                 mutex_unlock(&session->s_mutex);
1423                 ceph_put_mds_session(session);
1424
1425                 if (!ret)
1426                         return ret;
1427                 mutex_lock(&mdsc->mutex);
1428         }
1429
1430         mutex_unlock(&mdsc->mutex);
1431         dout("check_cap_flush ok, flushed thru %lld\n", want_flush_seq);
1432         return ret;
1433 }
1434
1435 /*
1436  * called under s_mutex
1437  */
1438 void ceph_send_cap_releases(struct ceph_mds_client *mdsc,
1439                             struct ceph_mds_session *session)
1440 {
1441         struct ceph_msg *msg;
1442
1443         dout("send_cap_releases mds%d\n", session->s_mds);
1444         spin_lock(&session->s_cap_lock);
1445         while (!list_empty(&session->s_cap_releases_done)) {
1446                 msg = list_first_entry(&session->s_cap_releases_done,
1447                                  struct ceph_msg, list_head);
1448                 list_del_init(&msg->list_head);
1449                 spin_unlock(&session->s_cap_lock);
1450                 msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
1451                 dout("send_cap_releases mds%d %p\n", session->s_mds, msg);
1452                 ceph_con_send(&session->s_con, msg);
1453                 spin_lock(&session->s_cap_lock);
1454         }
1455         spin_unlock(&session->s_cap_lock);
1456 }
1457
1458 static void discard_cap_releases(struct ceph_mds_client *mdsc,
1459                                  struct ceph_mds_session *session)
1460 {
1461         struct ceph_msg *msg;
1462         struct ceph_mds_cap_release *head;
1463         unsigned num;
1464
1465         dout("discard_cap_releases mds%d\n", session->s_mds);
1466
1467         if (!list_empty(&session->s_cap_releases)) {
1468                 /* zero out the in-progress message */
1469                 msg = list_first_entry(&session->s_cap_releases,
1470                                         struct ceph_msg, list_head);
1471                 head = msg->front.iov_base;
1472                 num = le32_to_cpu(head->num);
1473                 dout("discard_cap_releases mds%d %p %u\n",
1474                      session->s_mds, msg, num);
1475                 head->num = cpu_to_le32(0);
1476                 msg->front.iov_len = sizeof(*head);
1477                 session->s_num_cap_releases += num;
1478         }
1479
1480         /* requeue completed messages */
1481         while (!list_empty(&session->s_cap_releases_done)) {
1482                 msg = list_first_entry(&session->s_cap_releases_done,
1483                                  struct ceph_msg, list_head);
1484                 list_del_init(&msg->list_head);
1485
1486                 head = msg->front.iov_base;
1487                 num = le32_to_cpu(head->num);
1488                 dout("discard_cap_releases mds%d %p %u\n", session->s_mds, msg,
1489                      num);
1490                 session->s_num_cap_releases += num;
1491                 head->num = cpu_to_le32(0);
1492                 msg->front.iov_len = sizeof(*head);
1493                 list_add(&msg->list_head, &session->s_cap_releases);
1494         }
1495 }
1496
1497 /*
1498  * requests
1499  */
1500
1501 int ceph_alloc_readdir_reply_buffer(struct ceph_mds_request *req,
1502                                     struct inode *dir)
1503 {
1504         struct ceph_inode_info *ci = ceph_inode(dir);
1505         struct ceph_mds_reply_info_parsed *rinfo = &req->r_reply_info;
1506         struct ceph_mount_options *opt = req->r_mdsc->fsc->mount_options;
1507         size_t size = sizeof(*rinfo->dir_in) + sizeof(*rinfo->dir_dname_len) +
1508                       sizeof(*rinfo->dir_dname) + sizeof(*rinfo->dir_dlease);
1509         int order, num_entries;
1510
1511         spin_lock(&ci->i_ceph_lock);
1512         num_entries = ci->i_files + ci->i_subdirs;
1513         spin_unlock(&ci->i_ceph_lock);
1514         num_entries = max(num_entries, 1);
1515         num_entries = min(num_entries, opt->max_readdir);
1516
1517         order = get_order(size * num_entries);
1518         while (order >= 0) {
1519                 rinfo->dir_in = (void*)__get_free_pages(GFP_NOFS | __GFP_NOWARN,
1520                                                         order);
1521                 if (rinfo->dir_in)
1522                         break;
1523                 order--;
1524         }
1525         if (!rinfo->dir_in)
1526                 return -ENOMEM;
1527
1528         num_entries = (PAGE_SIZE << order) / size;
1529         num_entries = min(num_entries, opt->max_readdir);
1530
1531         rinfo->dir_buf_size = PAGE_SIZE << order;
1532         req->r_num_caps = num_entries + 1;
1533         req->r_args.readdir.max_entries = cpu_to_le32(num_entries);
1534         req->r_args.readdir.max_bytes = cpu_to_le32(opt->max_readdir_bytes);
1535         return 0;
1536 }
1537
1538 /*
1539  * Create an mds request.
1540  */
1541 struct ceph_mds_request *
1542 ceph_mdsc_create_request(struct ceph_mds_client *mdsc, int op, int mode)
1543 {
1544         struct ceph_mds_request *req = kzalloc(sizeof(*req), GFP_NOFS);
1545
1546         if (!req)
1547                 return ERR_PTR(-ENOMEM);
1548
1549         mutex_init(&req->r_fill_mutex);
1550         req->r_mdsc = mdsc;
1551         req->r_started = jiffies;
1552         req->r_resend_mds = -1;
1553         INIT_LIST_HEAD(&req->r_unsafe_dir_item);
1554         req->r_fmode = -1;
1555         kref_init(&req->r_kref);
1556         INIT_LIST_HEAD(&req->r_wait);
1557         init_completion(&req->r_completion);
1558         init_completion(&req->r_safe_completion);
1559         INIT_LIST_HEAD(&req->r_unsafe_item);
1560
1561         req->r_stamp = CURRENT_TIME;
1562
1563         req->r_op = op;
1564         req->r_direct_mode = mode;
1565         return req;
1566 }
1567
1568 /*
1569  * return oldest (lowest) request, tid in request tree, 0 if none.
1570  *
1571  * called under mdsc->mutex.
1572  */
1573 static struct ceph_mds_request *__get_oldest_req(struct ceph_mds_client *mdsc)
1574 {
1575         if (RB_EMPTY_ROOT(&mdsc->request_tree))
1576                 return NULL;
1577         return rb_entry(rb_first(&mdsc->request_tree),
1578                         struct ceph_mds_request, r_node);
1579 }
1580
1581 static u64 __get_oldest_tid(struct ceph_mds_client *mdsc)
1582 {
1583         struct ceph_mds_request *req = __get_oldest_req(mdsc);
1584
1585         if (req)
1586                 return req->r_tid;
1587         return 0;
1588 }
1589
1590 /*
1591  * Build a dentry's path.  Allocate on heap; caller must kfree.  Based
1592  * on build_path_from_dentry in fs/cifs/dir.c.
1593  *
1594  * If @stop_on_nosnap, generate path relative to the first non-snapped
1595  * inode.
1596  *
1597  * Encode hidden .snap dirs as a double /, i.e.
1598  *   foo/.snap/bar -> foo//bar
1599  */
1600 char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *base,
1601                            int stop_on_nosnap)
1602 {
1603         struct dentry *temp;
1604         char *path;
1605         int len, pos;
1606         unsigned seq;
1607
1608         if (dentry == NULL)
1609                 return ERR_PTR(-EINVAL);
1610
1611 retry:
1612         len = 0;
1613         seq = read_seqbegin(&rename_lock);
1614         rcu_read_lock();
1615         for (temp = dentry; !IS_ROOT(temp);) {
1616                 struct inode *inode = temp->d_inode;
1617                 if (inode && ceph_snap(inode) == CEPH_SNAPDIR)
1618                         len++;  /* slash only */
1619                 else if (stop_on_nosnap && inode &&
1620                          ceph_snap(inode) == CEPH_NOSNAP)
1621                         break;
1622                 else
1623                         len += 1 + temp->d_name.len;
1624                 temp = temp->d_parent;
1625         }
1626         rcu_read_unlock();
1627         if (len)
1628                 len--;  /* no leading '/' */
1629
1630         path = kmalloc(len+1, GFP_NOFS);
1631         if (path == NULL)
1632                 return ERR_PTR(-ENOMEM);
1633         pos = len;
1634         path[pos] = 0;  /* trailing null */
1635         rcu_read_lock();
1636         for (temp = dentry; !IS_ROOT(temp) && pos != 0; ) {
1637                 struct inode *inode;
1638
1639                 spin_lock(&temp->d_lock);
1640                 inode = temp->d_inode;
1641                 if (inode && ceph_snap(inode) == CEPH_SNAPDIR) {
1642                         dout("build_path path+%d: %p SNAPDIR\n",
1643                              pos, temp);
1644                 } else if (stop_on_nosnap && inode &&
1645                            ceph_snap(inode) == CEPH_NOSNAP) {
1646                         spin_unlock(&temp->d_lock);
1647                         break;
1648                 } else {
1649                         pos -= temp->d_name.len;
1650                         if (pos < 0) {
1651                                 spin_unlock(&temp->d_lock);
1652                                 break;
1653                         }
1654                         strncpy(path + pos, temp->d_name.name,
1655                                 temp->d_name.len);
1656                 }
1657                 spin_unlock(&temp->d_lock);
1658                 if (pos)
1659                         path[--pos] = '/';
1660                 temp = temp->d_parent;
1661         }
1662         rcu_read_unlock();
1663         if (pos != 0 || read_seqretry(&rename_lock, seq)) {
1664                 pr_err("build_path did not end path lookup where "
1665                        "expected, namelen is %d, pos is %d\n", len, pos);
1666                 /* presumably this is only possible if racing with a
1667                    rename of one of the parent directories (we can not
1668                    lock the dentries above us to prevent this, but
1669                    retrying should be harmless) */
1670                 kfree(path);
1671                 goto retry;
1672         }
1673
1674         *base = ceph_ino(temp->d_inode);
1675         *plen = len;
1676         dout("build_path on %p %d built %llx '%.*s'\n",
1677              dentry, d_count(dentry), *base, len, path);
1678         return path;
1679 }
1680
1681 static int build_dentry_path(struct dentry *dentry,
1682                              const char **ppath, int *ppathlen, u64 *pino,
1683                              int *pfreepath)
1684 {
1685         char *path;
1686
1687         if (ceph_snap(dentry->d_parent->d_inode) == CEPH_NOSNAP) {
1688                 *pino = ceph_ino(dentry->d_parent->d_inode);
1689                 *ppath = dentry->d_name.name;
1690                 *ppathlen = dentry->d_name.len;
1691                 return 0;
1692         }
1693         path = ceph_mdsc_build_path(dentry, ppathlen, pino, 1);
1694         if (IS_ERR(path))
1695                 return PTR_ERR(path);
1696         *ppath = path;
1697         *pfreepath = 1;
1698         return 0;
1699 }
1700
1701 static int build_inode_path(struct inode *inode,
1702                             const char **ppath, int *ppathlen, u64 *pino,
1703                             int *pfreepath)
1704 {
1705         struct dentry *dentry;
1706         char *path;
1707
1708         if (ceph_snap(inode) == CEPH_NOSNAP) {
1709                 *pino = ceph_ino(inode);
1710                 *ppathlen = 0;
1711                 return 0;
1712         }
1713         dentry = d_find_alias(inode);
1714         path = ceph_mdsc_build_path(dentry, ppathlen, pino, 1);
1715         dput(dentry);
1716         if (IS_ERR(path))
1717                 return PTR_ERR(path);
1718         *ppath = path;
1719         *pfreepath = 1;
1720         return 0;
1721 }
1722
1723 /*
1724  * request arguments may be specified via an inode *, a dentry *, or
1725  * an explicit ino+path.
1726  */
1727 static int set_request_path_attr(struct inode *rinode, struct dentry *rdentry,
1728                                   const char *rpath, u64 rino,
1729                                   const char **ppath, int *pathlen,
1730                                   u64 *ino, int *freepath)
1731 {
1732         int r = 0;
1733
1734         if (rinode) {
1735                 r = build_inode_path(rinode, ppath, pathlen, ino, freepath);
1736                 dout(" inode %p %llx.%llx\n", rinode, ceph_ino(rinode),
1737                      ceph_snap(rinode));
1738         } else if (rdentry) {
1739                 r = build_dentry_path(rdentry, ppath, pathlen, ino, freepath);
1740                 dout(" dentry %p %llx/%.*s\n", rdentry, *ino, *pathlen,
1741                      *ppath);
1742         } else if (rpath || rino) {
1743                 *ino = rino;
1744                 *ppath = rpath;
1745                 *pathlen = rpath ? strlen(rpath) : 0;
1746                 dout(" path %.*s\n", *pathlen, rpath);
1747         }
1748
1749         return r;
1750 }
1751
1752 /*
1753  * called under mdsc->mutex
1754  */
1755 static struct ceph_msg *create_request_message(struct ceph_mds_client *mdsc,
1756                                                struct ceph_mds_request *req,
1757                                                int mds)
1758 {
1759         struct ceph_msg *msg;
1760         struct ceph_mds_request_head *head;
1761         const char *path1 = NULL;
1762         const char *path2 = NULL;
1763         u64 ino1 = 0, ino2 = 0;
1764         int pathlen1 = 0, pathlen2 = 0;
1765         int freepath1 = 0, freepath2 = 0;
1766         int len;
1767         u16 releases;
1768         void *p, *end;
1769         int ret;
1770
1771         ret = set_request_path_attr(req->r_inode, req->r_dentry,
1772                               req->r_path1, req->r_ino1.ino,
1773                               &path1, &pathlen1, &ino1, &freepath1);
1774         if (ret < 0) {
1775                 msg = ERR_PTR(ret);
1776                 goto out;
1777         }
1778
1779         ret = set_request_path_attr(NULL, req->r_old_dentry,
1780                               req->r_path2, req->r_ino2.ino,
1781                               &path2, &pathlen2, &ino2, &freepath2);
1782         if (ret < 0) {
1783                 msg = ERR_PTR(ret);
1784                 goto out_free1;
1785         }
1786
1787         len = sizeof(*head) +
1788                 pathlen1 + pathlen2 + 2*(1 + sizeof(u32) + sizeof(u64)) +
1789                 sizeof(struct timespec);
1790
1791         /* calculate (max) length for cap releases */
1792         len += sizeof(struct ceph_mds_request_release) *
1793                 (!!req->r_inode_drop + !!req->r_dentry_drop +
1794                  !!req->r_old_inode_drop + !!req->r_old_dentry_drop);
1795         if (req->r_dentry_drop)
1796                 len += req->r_dentry->d_name.len;
1797         if (req->r_old_dentry_drop)
1798                 len += req->r_old_dentry->d_name.len;
1799
1800         msg = ceph_msg_new(CEPH_MSG_CLIENT_REQUEST, len, GFP_NOFS, false);
1801         if (!msg) {
1802                 msg = ERR_PTR(-ENOMEM);
1803                 goto out_free2;
1804         }
1805
1806         msg->hdr.version = 2;
1807         msg->hdr.tid = cpu_to_le64(req->r_tid);
1808
1809         head = msg->front.iov_base;
1810         p = msg->front.iov_base + sizeof(*head);
1811         end = msg->front.iov_base + msg->front.iov_len;
1812
1813         head->mdsmap_epoch = cpu_to_le32(mdsc->mdsmap->m_epoch);
1814         head->op = cpu_to_le32(req->r_op);
1815         head->caller_uid = cpu_to_le32(from_kuid(&init_user_ns, req->r_uid));
1816         head->caller_gid = cpu_to_le32(from_kgid(&init_user_ns, req->r_gid));
1817         head->args = req->r_args;
1818
1819         ceph_encode_filepath(&p, end, ino1, path1);
1820         ceph_encode_filepath(&p, end, ino2, path2);
1821
1822         /* make note of release offset, in case we need to replay */
1823         req->r_request_release_offset = p - msg->front.iov_base;
1824
1825         /* cap releases */
1826         releases = 0;
1827         if (req->r_inode_drop)
1828                 releases += ceph_encode_inode_release(&p,
1829                       req->r_inode ? req->r_inode : req->r_dentry->d_inode,
1830                       mds, req->r_inode_drop, req->r_inode_unless, 0);
1831         if (req->r_dentry_drop)
1832                 releases += ceph_encode_dentry_release(&p, req->r_dentry,
1833                        mds, req->r_dentry_drop, req->r_dentry_unless);
1834         if (req->r_old_dentry_drop)
1835                 releases += ceph_encode_dentry_release(&p, req->r_old_dentry,
1836                        mds, req->r_old_dentry_drop, req->r_old_dentry_unless);
1837         if (req->r_old_inode_drop)
1838                 releases += ceph_encode_inode_release(&p,
1839                       req->r_old_dentry->d_inode,
1840                       mds, req->r_old_inode_drop, req->r_old_inode_unless, 0);
1841         head->num_releases = cpu_to_le16(releases);
1842
1843         /* time stamp */
1844         ceph_encode_copy(&p, &req->r_stamp, sizeof(req->r_stamp));
1845
1846         BUG_ON(p > end);
1847         msg->front.iov_len = p - msg->front.iov_base;
1848         msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
1849
1850         if (req->r_data_len) {
1851                 /* outbound data set only by ceph_sync_setxattr() */
1852                 BUG_ON(!req->r_pages);
1853                 ceph_msg_data_add_pages(msg, req->r_pages, req->r_data_len, 0);
1854         }
1855
1856         msg->hdr.data_len = cpu_to_le32(req->r_data_len);
1857         msg->hdr.data_off = cpu_to_le16(0);
1858
1859 out_free2:
1860         if (freepath2)
1861                 kfree((char *)path2);
1862 out_free1:
1863         if (freepath1)
1864                 kfree((char *)path1);
1865 out:
1866         return msg;
1867 }
1868
1869 /*
1870  * called under mdsc->mutex if error, under no mutex if
1871  * success.
1872  */
1873 static void complete_request(struct ceph_mds_client *mdsc,
1874                              struct ceph_mds_request *req)
1875 {
1876         if (req->r_callback)
1877                 req->r_callback(mdsc, req);
1878         else
1879                 complete_all(&req->r_completion);
1880 }
1881
1882 /*
1883  * called under mdsc->mutex
1884  */
1885 static int __prepare_send_request(struct ceph_mds_client *mdsc,
1886                                   struct ceph_mds_request *req,
1887                                   int mds)
1888 {
1889         struct ceph_mds_request_head *rhead;
1890         struct ceph_msg *msg;
1891         int flags = 0;
1892
1893         req->r_attempts++;
1894         if (req->r_inode) {
1895                 struct ceph_cap *cap =
1896                         ceph_get_cap_for_mds(ceph_inode(req->r_inode), mds);
1897
1898                 if (cap)
1899                         req->r_sent_on_mseq = cap->mseq;
1900                 else
1901                         req->r_sent_on_mseq = -1;
1902         }
1903         dout("prepare_send_request %p tid %lld %s (attempt %d)\n", req,
1904              req->r_tid, ceph_mds_op_name(req->r_op), req->r_attempts);
1905
1906         if (req->r_got_unsafe) {
1907                 void *p;
1908                 /*
1909                  * Replay.  Do not regenerate message (and rebuild
1910                  * paths, etc.); just use the original message.
1911                  * Rebuilding paths will break for renames because
1912                  * d_move mangles the src name.
1913                  */
1914                 msg = req->r_request;
1915                 rhead = msg->front.iov_base;
1916
1917                 flags = le32_to_cpu(rhead->flags);
1918                 flags |= CEPH_MDS_FLAG_REPLAY;
1919                 rhead->flags = cpu_to_le32(flags);
1920
1921                 if (req->r_target_inode)
1922                         rhead->ino = cpu_to_le64(ceph_ino(req->r_target_inode));
1923
1924                 rhead->num_retry = req->r_attempts - 1;
1925
1926                 /* remove cap/dentry releases from message */
1927                 rhead->num_releases = 0;
1928
1929                 /* time stamp */
1930                 p = msg->front.iov_base + req->r_request_release_offset;
1931                 ceph_encode_copy(&p, &req->r_stamp, sizeof(req->r_stamp));
1932
1933                 msg->front.iov_len = p - msg->front.iov_base;
1934                 msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
1935                 return 0;
1936         }
1937
1938         if (req->r_request) {
1939                 ceph_msg_put(req->r_request);
1940                 req->r_request = NULL;
1941         }
1942         msg = create_request_message(mdsc, req, mds);
1943         if (IS_ERR(msg)) {
1944                 req->r_err = PTR_ERR(msg);
1945                 complete_request(mdsc, req);
1946                 return PTR_ERR(msg);
1947         }
1948         req->r_request = msg;
1949
1950         rhead = msg->front.iov_base;
1951         rhead->oldest_client_tid = cpu_to_le64(__get_oldest_tid(mdsc));
1952         if (req->r_got_unsafe)
1953                 flags |= CEPH_MDS_FLAG_REPLAY;
1954         if (req->r_locked_dir)
1955                 flags |= CEPH_MDS_FLAG_WANT_DENTRY;
1956         rhead->flags = cpu_to_le32(flags);
1957         rhead->num_fwd = req->r_num_fwd;
1958         rhead->num_retry = req->r_attempts - 1;
1959         rhead->ino = 0;
1960
1961         dout(" r_locked_dir = %p\n", req->r_locked_dir);
1962         return 0;
1963 }
1964
1965 /*
1966  * send request, or put it on the appropriate wait list.
1967  */
1968 static int __do_request(struct ceph_mds_client *mdsc,
1969                         struct ceph_mds_request *req)
1970 {
1971         struct ceph_mds_session *session = NULL;
1972         int mds = -1;
1973         int err = -EAGAIN;
1974
1975         if (req->r_err || req->r_got_result) {
1976                 if (req->r_aborted)
1977                         __unregister_request(mdsc, req);
1978                 goto out;
1979         }
1980
1981         if (req->r_timeout &&
1982             time_after_eq(jiffies, req->r_started + req->r_timeout)) {
1983                 dout("do_request timed out\n");
1984                 err = -EIO;
1985                 goto finish;
1986         }
1987
1988         put_request_session(req);
1989
1990         mds = __choose_mds(mdsc, req);
1991         if (mds < 0 ||
1992             ceph_mdsmap_get_state(mdsc->mdsmap, mds) < CEPH_MDS_STATE_ACTIVE) {
1993                 dout("do_request no mds or not active, waiting for map\n");
1994                 list_add(&req->r_wait, &mdsc->waiting_for_map);
1995                 goto out;
1996         }
1997
1998         /* get, open session */
1999         session = __ceph_lookup_mds_session(mdsc, mds);
2000         if (!session) {
2001                 session = register_session(mdsc, mds);
2002                 if (IS_ERR(session)) {
2003                         err = PTR_ERR(session);
2004                         goto finish;
2005                 }
2006         }
2007         req->r_session = get_session(session);
2008
2009         dout("do_request mds%d session %p state %s\n", mds, session,
2010              session_state_name(session->s_state));
2011         if (session->s_state != CEPH_MDS_SESSION_OPEN &&
2012             session->s_state != CEPH_MDS_SESSION_HUNG) {
2013                 if (session->s_state == CEPH_MDS_SESSION_NEW ||
2014                     session->s_state == CEPH_MDS_SESSION_CLOSING)
2015                         __open_session(mdsc, session);
2016                 list_add(&req->r_wait, &session->s_waiting);
2017                 goto out_session;
2018         }
2019
2020         /* send request */
2021         req->r_resend_mds = -1;   /* forget any previous mds hint */
2022
2023         if (req->r_request_started == 0)   /* note request start time */
2024                 req->r_request_started = jiffies;
2025
2026         err = __prepare_send_request(mdsc, req, mds);
2027         if (!err) {
2028                 ceph_msg_get(req->r_request);
2029                 ceph_con_send(&session->s_con, req->r_request);
2030         }
2031
2032 out_session:
2033         ceph_put_mds_session(session);
2034 out:
2035         return err;
2036
2037 finish:
2038         req->r_err = err;
2039         complete_request(mdsc, req);
2040         goto out;
2041 }
2042
2043 /*
2044  * called under mdsc->mutex
2045  */
2046 static void __wake_requests(struct ceph_mds_client *mdsc,
2047                             struct list_head *head)
2048 {
2049         struct ceph_mds_request *req;
2050         LIST_HEAD(tmp_list);
2051
2052         list_splice_init(head, &tmp_list);
2053
2054         while (!list_empty(&tmp_list)) {
2055                 req = list_entry(tmp_list.next,
2056                                  struct ceph_mds_request, r_wait);
2057                 list_del_init(&req->r_wait);
2058                 dout(" wake request %p tid %llu\n", req, req->r_tid);
2059                 __do_request(mdsc, req);
2060         }
2061 }
2062
2063 /*
2064  * Wake up threads with requests pending for @mds, so that they can
2065  * resubmit their requests to a possibly different mds.
2066  */
2067 static void kick_requests(struct ceph_mds_client *mdsc, int mds)
2068 {
2069         struct ceph_mds_request *req;
2070         struct rb_node *p = rb_first(&mdsc->request_tree);
2071
2072         dout("kick_requests mds%d\n", mds);
2073         while (p) {
2074                 req = rb_entry(p, struct ceph_mds_request, r_node);
2075                 p = rb_next(p);
2076                 if (req->r_got_unsafe)
2077                         continue;
2078                 if (req->r_session &&
2079                     req->r_session->s_mds == mds) {
2080                         dout(" kicking tid %llu\n", req->r_tid);
2081                         __do_request(mdsc, req);
2082                 }
2083         }
2084 }
2085
2086 void ceph_mdsc_submit_request(struct ceph_mds_client *mdsc,
2087                               struct ceph_mds_request *req)
2088 {
2089         dout("submit_request on %p\n", req);
2090         mutex_lock(&mdsc->mutex);
2091         __register_request(mdsc, req, NULL);
2092         __do_request(mdsc, req);
2093         mutex_unlock(&mdsc->mutex);
2094 }
2095
2096 /*
2097  * Synchrously perform an mds request.  Take care of all of the
2098  * session setup, forwarding, retry details.
2099  */
2100 int ceph_mdsc_do_request(struct ceph_mds_client *mdsc,
2101                          struct inode *dir,
2102                          struct ceph_mds_request *req)
2103 {
2104         int err;
2105
2106         dout("do_request on %p\n", req);
2107
2108         /* take CAP_PIN refs for r_inode, r_locked_dir, r_old_dentry */
2109         if (req->r_inode)
2110                 ceph_get_cap_refs(ceph_inode(req->r_inode), CEPH_CAP_PIN);
2111         if (req->r_locked_dir)
2112                 ceph_get_cap_refs(ceph_inode(req->r_locked_dir), CEPH_CAP_PIN);
2113         if (req->r_old_dentry_dir)
2114                 ceph_get_cap_refs(ceph_inode(req->r_old_dentry_dir),
2115                                   CEPH_CAP_PIN);
2116
2117         /* issue */
2118         mutex_lock(&mdsc->mutex);
2119         __register_request(mdsc, req, dir);
2120         __do_request(mdsc, req);
2121
2122         if (req->r_err) {
2123                 err = req->r_err;
2124                 __unregister_request(mdsc, req);
2125                 dout("do_request early error %d\n", err);
2126                 goto out;
2127         }
2128
2129         /* wait */
2130         mutex_unlock(&mdsc->mutex);
2131         dout("do_request waiting\n");
2132         if (req->r_timeout) {
2133                 err = (long)wait_for_completion_killable_timeout(
2134                         &req->r_completion, req->r_timeout);
2135                 if (err == 0)
2136                         err = -EIO;
2137         } else {
2138                 err = wait_for_completion_killable(&req->r_completion);
2139         }
2140         dout("do_request waited, got %d\n", err);
2141         mutex_lock(&mdsc->mutex);
2142
2143         /* only abort if we didn't race with a real reply */
2144         if (req->r_got_result) {
2145                 err = le32_to_cpu(req->r_reply_info.head->result);
2146         } else if (err < 0) {
2147                 dout("aborted request %lld with %d\n", req->r_tid, err);
2148
2149                 /*
2150                  * ensure we aren't running concurrently with
2151                  * ceph_fill_trace or ceph_readdir_prepopulate, which
2152                  * rely on locks (dir mutex) held by our caller.
2153                  */
2154                 mutex_lock(&req->r_fill_mutex);
2155                 req->r_err = err;
2156                 req->r_aborted = true;
2157                 mutex_unlock(&req->r_fill_mutex);
2158
2159                 if (req->r_locked_dir &&
2160                     (req->r_op & CEPH_MDS_OP_WRITE))
2161                         ceph_invalidate_dir_request(req);
2162         } else {
2163                 err = req->r_err;
2164         }
2165
2166 out:
2167         mutex_unlock(&mdsc->mutex);
2168         dout("do_request %p done, result %d\n", req, err);
2169         return err;
2170 }
2171
2172 /*
2173  * Invalidate dir's completeness, dentry lease state on an aborted MDS
2174  * namespace request.
2175  */
2176 void ceph_invalidate_dir_request(struct ceph_mds_request *req)
2177 {
2178         struct inode *inode = req->r_locked_dir;
2179
2180         dout("invalidate_dir_request %p (complete, lease(s))\n", inode);
2181
2182         ceph_dir_clear_complete(inode);
2183         if (req->r_dentry)
2184                 ceph_invalidate_dentry_lease(req->r_dentry);
2185         if (req->r_old_dentry)
2186                 ceph_invalidate_dentry_lease(req->r_old_dentry);
2187 }
2188
2189 /*
2190  * Handle mds reply.
2191  *
2192  * We take the session mutex and parse and process the reply immediately.
2193  * This preserves the logical ordering of replies, capabilities, etc., sent
2194  * by the MDS as they are applied to our local cache.
2195  */
2196 static void handle_reply(struct ceph_mds_session *session, struct ceph_msg *msg)
2197 {
2198         struct ceph_mds_client *mdsc = session->s_mdsc;
2199         struct ceph_mds_request *req;
2200         struct ceph_mds_reply_head *head = msg->front.iov_base;
2201         struct ceph_mds_reply_info_parsed *rinfo;  /* parsed reply info */
2202         u64 tid;
2203         int err, result;
2204         int mds = session->s_mds;
2205
2206         if (msg->front.iov_len < sizeof(*head)) {
2207                 pr_err("mdsc_handle_reply got corrupt (short) reply\n");
2208                 ceph_msg_dump(msg);
2209                 return;
2210         }
2211
2212         /* get request, session */
2213         tid = le64_to_cpu(msg->hdr.tid);
2214         mutex_lock(&mdsc->mutex);
2215         req = __lookup_request(mdsc, tid);
2216         if (!req) {
2217                 dout("handle_reply on unknown tid %llu\n", tid);
2218                 mutex_unlock(&mdsc->mutex);
2219                 return;
2220         }
2221         dout("handle_reply %p\n", req);
2222
2223         /* correct session? */
2224         if (req->r_session != session) {
2225                 pr_err("mdsc_handle_reply got %llu on session mds%d"
2226                        " not mds%d\n", tid, session->s_mds,
2227                        req->r_session ? req->r_session->s_mds : -1);
2228                 mutex_unlock(&mdsc->mutex);
2229                 goto out;
2230         }
2231
2232         /* dup? */
2233         if ((req->r_got_unsafe && !head->safe) ||
2234             (req->r_got_safe && head->safe)) {
2235                 pr_warn("got a dup %s reply on %llu from mds%d\n",
2236                            head->safe ? "safe" : "unsafe", tid, mds);
2237                 mutex_unlock(&mdsc->mutex);
2238                 goto out;
2239         }
2240         if (req->r_got_safe && !head->safe) {
2241                 pr_warn("got unsafe after safe on %llu from mds%d\n",
2242                            tid, mds);
2243                 mutex_unlock(&mdsc->mutex);
2244                 goto out;
2245         }
2246
2247         result = le32_to_cpu(head->result);
2248
2249         /*
2250          * Handle an ESTALE
2251          * if we're not talking to the authority, send to them
2252          * if the authority has changed while we weren't looking,
2253          * send to new authority
2254          * Otherwise we just have to return an ESTALE
2255          */
2256         if (result == -ESTALE) {
2257                 dout("got ESTALE on request %llu", req->r_tid);
2258                 req->r_resend_mds = -1;
2259                 if (req->r_direct_mode != USE_AUTH_MDS) {
2260                         dout("not using auth, setting for that now");
2261                         req->r_direct_mode = USE_AUTH_MDS;
2262                         __do_request(mdsc, req);
2263                         mutex_unlock(&mdsc->mutex);
2264                         goto out;
2265                 } else  {
2266                         int mds = __choose_mds(mdsc, req);
2267                         if (mds >= 0 && mds != req->r_session->s_mds) {
2268                                 dout("but auth changed, so resending");
2269                                 __do_request(mdsc, req);
2270                                 mutex_unlock(&mdsc->mutex);
2271                                 goto out;
2272                         }
2273                 }
2274                 dout("have to return ESTALE on request %llu", req->r_tid);
2275         }
2276
2277
2278         if (head->safe) {
2279                 req->r_got_safe = true;
2280                 __unregister_request(mdsc, req);
2281
2282                 if (req->r_got_unsafe) {
2283                         /*
2284                          * We already handled the unsafe response, now do the
2285                          * cleanup.  No need to examine the response; the MDS
2286                          * doesn't include any result info in the safe
2287                          * response.  And even if it did, there is nothing
2288                          * useful we could do with a revised return value.
2289                          */
2290                         dout("got safe reply %llu, mds%d\n", tid, mds);
2291                         list_del_init(&req->r_unsafe_item);
2292
2293                         /* last unsafe request during umount? */
2294                         if (mdsc->stopping && !__get_oldest_req(mdsc))
2295                                 complete_all(&mdsc->safe_umount_waiters);
2296                         mutex_unlock(&mdsc->mutex);
2297                         goto out;
2298                 }
2299         } else {
2300                 req->r_got_unsafe = true;
2301                 list_add_tail(&req->r_unsafe_item, &req->r_session->s_unsafe);
2302         }
2303
2304         dout("handle_reply tid %lld result %d\n", tid, result);
2305         rinfo = &req->r_reply_info;
2306         err = parse_reply_info(msg, rinfo, session->s_con.peer_features);
2307         mutex_unlock(&mdsc->mutex);
2308
2309         mutex_lock(&session->s_mutex);
2310         if (err < 0) {
2311                 pr_err("mdsc_handle_reply got corrupt reply mds%d(tid:%lld)\n", mds, tid);
2312                 ceph_msg_dump(msg);
2313                 goto out_err;
2314         }
2315
2316         /* snap trace */
2317         if (rinfo->snapblob_len) {
2318                 down_write(&mdsc->snap_rwsem);
2319                 ceph_update_snap_trace(mdsc, rinfo->snapblob,
2320                                rinfo->snapblob + rinfo->snapblob_len,
2321                                le32_to_cpu(head->op) == CEPH_MDS_OP_RMSNAP);
2322                 downgrade_write(&mdsc->snap_rwsem);
2323         } else {
2324                 down_read(&mdsc->snap_rwsem);
2325         }
2326
2327         /* insert trace into our cache */
2328         mutex_lock(&req->r_fill_mutex);
2329         err = ceph_fill_trace(mdsc->fsc->sb, req, req->r_session);
2330         if (err == 0) {
2331                 if (result == 0 && (req->r_op == CEPH_MDS_OP_READDIR ||
2332                                     req->r_op == CEPH_MDS_OP_LSSNAP))
2333                         ceph_readdir_prepopulate(req, req->r_session);
2334                 ceph_unreserve_caps(mdsc, &req->r_caps_reservation);
2335         }
2336         mutex_unlock(&req->r_fill_mutex);
2337
2338         up_read(&mdsc->snap_rwsem);
2339 out_err:
2340         mutex_lock(&mdsc->mutex);
2341         if (!req->r_aborted) {
2342                 if (err) {
2343                         req->r_err = err;
2344                 } else {
2345                         req->r_reply = msg;
2346                         ceph_msg_get(msg);
2347                         req->r_got_result = true;
2348                 }
2349         } else {
2350                 dout("reply arrived after request %lld was aborted\n", tid);
2351         }
2352         mutex_unlock(&mdsc->mutex);
2353
2354         ceph_add_cap_releases(mdsc, req->r_session);
2355         mutex_unlock(&session->s_mutex);
2356
2357         /* kick calling process */
2358         complete_request(mdsc, req);
2359 out:
2360         ceph_mdsc_put_request(req);
2361         return;
2362 }
2363
2364
2365
2366 /*
2367  * handle mds notification that our request has been forwarded.
2368  */
2369 static void handle_forward(struct ceph_mds_client *mdsc,
2370                            struct ceph_mds_session *session,
2371                            struct ceph_msg *msg)
2372 {
2373         struct ceph_mds_request *req;
2374         u64 tid = le64_to_cpu(msg->hdr.tid);
2375         u32 next_mds;
2376         u32 fwd_seq;
2377         int err = -EINVAL;
2378         void *p = msg->front.iov_base;
2379         void *end = p + msg->front.iov_len;
2380
2381         ceph_decode_need(&p, end, 2*sizeof(u32), bad);
2382         next_mds = ceph_decode_32(&p);
2383         fwd_seq = ceph_decode_32(&p);
2384
2385         mutex_lock(&mdsc->mutex);
2386         req = __lookup_request(mdsc, tid);
2387         if (!req) {
2388                 dout("forward tid %llu to mds%d - req dne\n", tid, next_mds);
2389                 goto out;  /* dup reply? */
2390         }
2391
2392         if (req->r_aborted) {
2393                 dout("forward tid %llu aborted, unregistering\n", tid);
2394                 __unregister_request(mdsc, req);
2395         } else if (fwd_seq <= req->r_num_fwd) {
2396                 dout("forward tid %llu to mds%d - old seq %d <= %d\n",
2397                      tid, next_mds, req->r_num_fwd, fwd_seq);
2398         } else {
2399                 /* resend. forward race not possible; mds would drop */
2400                 dout("forward tid %llu to mds%d (we resend)\n", tid, next_mds);
2401                 BUG_ON(req->r_err);
2402                 BUG_ON(req->r_got_result);
2403                 req->r_num_fwd = fwd_seq;
2404                 req->r_resend_mds = next_mds;
2405                 put_request_session(req);
2406                 __do_request(mdsc, req);
2407         }
2408         ceph_mdsc_put_request(req);
2409 out:
2410         mutex_unlock(&mdsc->mutex);
2411         return;
2412
2413 bad:
2414         pr_err("mdsc_handle_forward decode error err=%d\n", err);
2415 }
2416
2417 /*
2418  * handle a mds session control message
2419  */
2420 static void handle_session(struct ceph_mds_session *session,
2421                            struct ceph_msg *msg)
2422 {
2423         struct ceph_mds_client *mdsc = session->s_mdsc;
2424         u32 op;
2425         u64 seq;
2426         int mds = session->s_mds;
2427         struct ceph_mds_session_head *h = msg->front.iov_base;
2428         int wake = 0;
2429
2430         /* decode */
2431         if (msg->front.iov_len != sizeof(*h))
2432                 goto bad;
2433         op = le32_to_cpu(h->op);
2434         seq = le64_to_cpu(h->seq);
2435
2436         mutex_lock(&mdsc->mutex);
2437         if (op == CEPH_SESSION_CLOSE)
2438                 __unregister_session(mdsc, session);
2439         /* FIXME: this ttl calculation is generous */
2440         session->s_ttl = jiffies + HZ*mdsc->mdsmap->m_session_autoclose;
2441         mutex_unlock(&mdsc->mutex);
2442
2443         mutex_lock(&session->s_mutex);
2444
2445         dout("handle_session mds%d %s %p state %s seq %llu\n",
2446              mds, ceph_session_op_name(op), session,
2447              session_state_name(session->s_state), seq);
2448
2449         if (session->s_state == CEPH_MDS_SESSION_HUNG) {
2450                 session->s_state = CEPH_MDS_SESSION_OPEN;
2451                 pr_info("mds%d came back\n", session->s_mds);
2452         }
2453
2454         switch (op) {
2455         case CEPH_SESSION_OPEN:
2456                 if (session->s_state == CEPH_MDS_SESSION_RECONNECTING)
2457                         pr_info("mds%d reconnect success\n", session->s_mds);
2458                 session->s_state = CEPH_MDS_SESSION_OPEN;
2459                 renewed_caps(mdsc, session, 0);
2460                 wake = 1;
2461                 if (mdsc->stopping)
2462                         __close_session(mdsc, session);
2463                 break;
2464
2465         case CEPH_SESSION_RENEWCAPS:
2466                 if (session->s_renew_seq == seq)
2467                         renewed_caps(mdsc, session, 1);
2468                 break;
2469
2470         case CEPH_SESSION_CLOSE:
2471                 if (session->s_state == CEPH_MDS_SESSION_RECONNECTING)
2472                         pr_info("mds%d reconnect denied\n", session->s_mds);
2473                 remove_session_caps(session);
2474                 wake = 1; /* for good measure */
2475                 wake_up_all(&mdsc->session_close_wq);
2476                 kick_requests(mdsc, mds);
2477                 break;
2478
2479         case CEPH_SESSION_STALE:
2480                 pr_info("mds%d caps went stale, renewing\n",
2481                         session->s_mds);
2482                 spin_lock(&session->s_gen_ttl_lock);
2483                 session->s_cap_gen++;
2484                 session->s_cap_ttl = jiffies - 1;
2485                 spin_unlock(&session->s_gen_ttl_lock);
2486                 send_renew_caps(mdsc, session);
2487                 break;
2488
2489         case CEPH_SESSION_RECALL_STATE:
2490                 trim_caps(mdsc, session, le32_to_cpu(h->max_caps));
2491                 break;
2492
2493         case CEPH_SESSION_FLUSHMSG:
2494                 send_flushmsg_ack(mdsc, session, seq);
2495                 break;
2496
2497         default:
2498                 pr_err("mdsc_handle_session bad op %d mds%d\n", op, mds);
2499                 WARN_ON(1);
2500         }
2501
2502         mutex_unlock(&session->s_mutex);
2503         if (wake) {
2504                 mutex_lock(&mdsc->mutex);
2505                 __wake_requests(mdsc, &session->s_waiting);
2506                 mutex_unlock(&mdsc->mutex);
2507         }
2508         return;
2509
2510 bad:
2511         pr_err("mdsc_handle_session corrupt message mds%d len %d\n", mds,
2512                (int)msg->front.iov_len);
2513         ceph_msg_dump(msg);
2514         return;
2515 }
2516
2517
2518 /*
2519  * called under session->mutex.
2520  */
2521 static void replay_unsafe_requests(struct ceph_mds_client *mdsc,
2522                                    struct ceph_mds_session *session)
2523 {
2524         struct ceph_mds_request *req, *nreq;
2525         int err;
2526
2527         dout("replay_unsafe_requests mds%d\n", session->s_mds);
2528
2529         mutex_lock(&mdsc->mutex);
2530         list_for_each_entry_safe(req, nreq, &session->s_unsafe, r_unsafe_item) {
2531                 err = __prepare_send_request(mdsc, req, session->s_mds);
2532                 if (!err) {
2533                         ceph_msg_get(req->r_request);
2534                         ceph_con_send(&session->s_con, req->r_request);
2535                 }
2536         }
2537         mutex_unlock(&mdsc->mutex);
2538 }
2539
2540 /*
2541  * Encode information about a cap for a reconnect with the MDS.
2542  */
2543 static int encode_caps_cb(struct inode *inode, struct ceph_cap *cap,
2544                           void *arg)
2545 {
2546         union {
2547                 struct ceph_mds_cap_reconnect v2;
2548                 struct ceph_mds_cap_reconnect_v1 v1;
2549         } rec;
2550         size_t reclen;
2551         struct ceph_inode_info *ci;
2552         struct ceph_reconnect_state *recon_state = arg;
2553         struct ceph_pagelist *pagelist = recon_state->pagelist;
2554         char *path;
2555         int pathlen, err;
2556         u64 pathbase;
2557         struct dentry *dentry;
2558
2559         ci = cap->ci;
2560
2561         dout(" adding %p ino %llx.%llx cap %p %lld %s\n",
2562              inode, ceph_vinop(inode), cap, cap->cap_id,
2563              ceph_cap_string(cap->issued));
2564         err = ceph_pagelist_encode_64(pagelist, ceph_ino(inode));
2565         if (err)
2566                 return err;
2567
2568         dentry = d_find_alias(inode);
2569         if (dentry) {
2570                 path = ceph_mdsc_build_path(dentry, &pathlen, &pathbase, 0);
2571                 if (IS_ERR(path)) {
2572                         err = PTR_ERR(path);
2573                         goto out_dput;
2574                 }
2575         } else {
2576                 path = NULL;
2577                 pathlen = 0;
2578         }
2579         err = ceph_pagelist_encode_string(pagelist, path, pathlen);
2580         if (err)
2581                 goto out_free;
2582
2583         spin_lock(&ci->i_ceph_lock);
2584         cap->seq = 0;        /* reset cap seq */
2585         cap->issue_seq = 0;  /* and issue_seq */
2586         cap->mseq = 0;       /* and migrate_seq */
2587         cap->cap_gen = cap->session->s_cap_gen;
2588
2589         if (recon_state->flock) {
2590                 rec.v2.cap_id = cpu_to_le64(cap->cap_id);
2591                 rec.v2.wanted = cpu_to_le32(__ceph_caps_wanted(ci));
2592                 rec.v2.issued = cpu_to_le32(cap->issued);
2593                 rec.v2.snaprealm = cpu_to_le64(ci->i_snap_realm->ino);
2594                 rec.v2.pathbase = cpu_to_le64(pathbase);
2595                 rec.v2.flock_len = 0;
2596                 reclen = sizeof(rec.v2);
2597         } else {
2598                 rec.v1.cap_id = cpu_to_le64(cap->cap_id);
2599                 rec.v1.wanted = cpu_to_le32(__ceph_caps_wanted(ci));
2600                 rec.v1.issued = cpu_to_le32(cap->issued);
2601                 rec.v1.size = cpu_to_le64(inode->i_size);
2602                 ceph_encode_timespec(&rec.v1.mtime, &inode->i_mtime);
2603                 ceph_encode_timespec(&rec.v1.atime, &inode->i_atime);
2604                 rec.v1.snaprealm = cpu_to_le64(ci->i_snap_realm->ino);
2605                 rec.v1.pathbase = cpu_to_le64(pathbase);
2606                 reclen = sizeof(rec.v1);
2607         }
2608         spin_unlock(&ci->i_ceph_lock);
2609
2610         if (recon_state->flock) {
2611                 int num_fcntl_locks, num_flock_locks;
2612                 struct ceph_filelock *flocks;
2613
2614 encode_again:
2615                 spin_lock(&inode->i_lock);
2616                 ceph_count_locks(inode, &num_fcntl_locks, &num_flock_locks);
2617                 spin_unlock(&inode->i_lock);
2618                 flocks = kmalloc((num_fcntl_locks+num_flock_locks) *
2619                                  sizeof(struct ceph_filelock), GFP_NOFS);
2620                 if (!flocks) {
2621                         err = -ENOMEM;
2622                         goto out_free;
2623                 }
2624                 spin_lock(&inode->i_lock);
2625                 err = ceph_encode_locks_to_buffer(inode, flocks,
2626                                                   num_fcntl_locks,
2627                                                   num_flock_locks);
2628                 spin_unlock(&inode->i_lock);
2629                 if (err) {
2630                         kfree(flocks);
2631                         if (err == -ENOSPC)
2632                                 goto encode_again;
2633                         goto out_free;
2634                 }
2635                 /*
2636                  * number of encoded locks is stable, so copy to pagelist
2637                  */
2638                 rec.v2.flock_len = cpu_to_le32(2*sizeof(u32) +
2639                                     (num_fcntl_locks+num_flock_locks) *
2640                                     sizeof(struct ceph_filelock));
2641                 err = ceph_pagelist_append(pagelist, &rec, reclen);
2642                 if (!err)
2643                         err = ceph_locks_to_pagelist(flocks, pagelist,
2644                                                      num_fcntl_locks,
2645                                                      num_flock_locks);
2646                 kfree(flocks);
2647         } else {
2648                 err = ceph_pagelist_append(pagelist, &rec, reclen);
2649         }
2650
2651         recon_state->nr_caps++;
2652 out_free:
2653         kfree(path);
2654 out_dput:
2655         dput(dentry);
2656         return err;
2657 }
2658
2659
2660 /*
2661  * If an MDS fails and recovers, clients need to reconnect in order to
2662  * reestablish shared state.  This includes all caps issued through
2663  * this session _and_ the snap_realm hierarchy.  Because it's not
2664  * clear which snap realms the mds cares about, we send everything we
2665  * know about.. that ensures we'll then get any new info the
2666  * recovering MDS might have.
2667  *
2668  * This is a relatively heavyweight operation, but it's rare.
2669  *
2670  * called with mdsc->mutex held.
2671  */
2672 static void send_mds_reconnect(struct ceph_mds_client *mdsc,
2673                                struct ceph_mds_session *session)
2674 {
2675         struct ceph_msg *reply;
2676         struct rb_node *p;
2677         int mds = session->s_mds;
2678         int err = -ENOMEM;
2679         int s_nr_caps;
2680         struct ceph_pagelist *pagelist;
2681         struct ceph_reconnect_state recon_state;
2682
2683         pr_info("mds%d reconnect start\n", mds);
2684
2685         pagelist = kmalloc(sizeof(*pagelist), GFP_NOFS);
2686         if (!pagelist)
2687                 goto fail_nopagelist;
2688         ceph_pagelist_init(pagelist);
2689
2690         reply = ceph_msg_new(CEPH_MSG_CLIENT_RECONNECT, 0, GFP_NOFS, false);
2691         if (!reply)
2692                 goto fail_nomsg;
2693
2694         mutex_lock(&session->s_mutex);
2695         session->s_state = CEPH_MDS_SESSION_RECONNECTING;
2696         session->s_seq = 0;
2697
2698         ceph_con_close(&session->s_con);
2699         ceph_con_open(&session->s_con,
2700                       CEPH_ENTITY_TYPE_MDS, mds,
2701                       ceph_mdsmap_get_addr(mdsc->mdsmap, mds));
2702
2703         /* replay unsafe requests */
2704         replay_unsafe_requests(mdsc, session);
2705
2706         down_read(&mdsc->snap_rwsem);
2707
2708         dout("session %p state %s\n", session,
2709              session_state_name(session->s_state));
2710
2711         spin_lock(&session->s_gen_ttl_lock);
2712         session->s_cap_gen++;
2713         spin_unlock(&session->s_gen_ttl_lock);
2714
2715         spin_lock(&session->s_cap_lock);
2716         /*
2717          * notify __ceph_remove_cap() that we are composing cap reconnect.
2718          * If a cap get released before being added to the cap reconnect,
2719          * __ceph_remove_cap() should skip queuing cap release.
2720          */
2721         session->s_cap_reconnect = 1;
2722         /* drop old cap expires; we're about to reestablish that state */
2723         discard_cap_releases(mdsc, session);
2724         spin_unlock(&session->s_cap_lock);
2725
2726         /* traverse this session's caps */
2727         s_nr_caps = session->s_nr_caps;
2728         err = ceph_pagelist_encode_32(pagelist, s_nr_caps);
2729         if (err)
2730                 goto fail;
2731
2732         recon_state.nr_caps = 0;
2733         recon_state.pagelist = pagelist;
2734         recon_state.flock = session->s_con.peer_features & CEPH_FEATURE_FLOCK;
2735         err = iterate_session_caps(session, encode_caps_cb, &recon_state);
2736         if (err < 0)
2737                 goto fail;
2738
2739         spin_lock(&session->s_cap_lock);
2740         session->s_cap_reconnect = 0;
2741         spin_unlock(&session->s_cap_lock);
2742
2743         /*
2744          * snaprealms.  we provide mds with the ino, seq (version), and
2745          * parent for all of our realms.  If the mds has any newer info,
2746          * it will tell us.
2747          */
2748         for (p = rb_first(&mdsc->snap_realms); p; p = rb_next(p)) {
2749                 struct ceph_snap_realm *realm =
2750                         rb_entry(p, struct ceph_snap_realm, node);
2751                 struct ceph_mds_snaprealm_reconnect sr_rec;
2752
2753                 dout(" adding snap realm %llx seq %lld parent %llx\n",
2754                      realm->ino, realm->seq, realm->parent_ino);
2755                 sr_rec.ino = cpu_to_le64(realm->ino);
2756                 sr_rec.seq = cpu_to_le64(realm->seq);
2757                 sr_rec.parent = cpu_to_le64(realm->parent_ino);
2758                 err = ceph_pagelist_append(pagelist, &sr_rec, sizeof(sr_rec));
2759                 if (err)
2760                         goto fail;
2761         }
2762
2763         if (recon_state.flock)
2764                 reply->hdr.version = cpu_to_le16(2);
2765
2766         /* raced with cap release? */
2767         if (s_nr_caps != recon_state.nr_caps) {
2768                 struct page *page = list_first_entry(&pagelist->head,
2769                                                      struct page, lru);
2770                 __le32 *addr = kmap_atomic(page);
2771                 *addr = cpu_to_le32(recon_state.nr_caps);
2772                 kunmap_atomic(addr);
2773         }
2774
2775         reply->hdr.data_len = cpu_to_le32(pagelist->length);
2776         ceph_msg_data_add_pagelist(reply, pagelist);
2777         ceph_con_send(&session->s_con, reply);
2778
2779         mutex_unlock(&session->s_mutex);
2780
2781         mutex_lock(&mdsc->mutex);
2782         __wake_requests(mdsc, &session->s_waiting);
2783         mutex_unlock(&mdsc->mutex);
2784
2785         up_read(&mdsc->snap_rwsem);
2786         return;
2787
2788 fail:
2789         ceph_msg_put(reply);
2790         up_read(&mdsc->snap_rwsem);
2791         mutex_unlock(&session->s_mutex);
2792 fail_nomsg:
2793         ceph_pagelist_release(pagelist);
2794         kfree(pagelist);
2795 fail_nopagelist:
2796         pr_err("error %d preparing reconnect for mds%d\n", err, mds);
2797         return;
2798 }
2799
2800
2801 /*
2802  * compare old and new mdsmaps, kicking requests
2803  * and closing out old connections as necessary
2804  *
2805  * called under mdsc->mutex.
2806  */
2807 static void check_new_map(struct ceph_mds_client *mdsc,
2808                           struct ceph_mdsmap *newmap,
2809                           struct ceph_mdsmap *oldmap)
2810 {
2811         int i;
2812         int oldstate, newstate;
2813         struct ceph_mds_session *s;
2814
2815         dout("check_new_map new %u old %u\n",
2816              newmap->m_epoch, oldmap->m_epoch);
2817
2818         for (i = 0; i < oldmap->m_max_mds && i < mdsc->max_sessions; i++) {
2819                 if (mdsc->sessions[i] == NULL)
2820                         continue;
2821                 s = mdsc->sessions[i];
2822                 oldstate = ceph_mdsmap_get_state(oldmap, i);
2823                 newstate = ceph_mdsmap_get_state(newmap, i);
2824
2825                 dout("check_new_map mds%d state %s%s -> %s%s (session %s)\n",
2826                      i, ceph_mds_state_name(oldstate),
2827                      ceph_mdsmap_is_laggy(oldmap, i) ? " (laggy)" : "",
2828                      ceph_mds_state_name(newstate),
2829                      ceph_mdsmap_is_laggy(newmap, i) ? " (laggy)" : "",
2830                      session_state_name(s->s_state));
2831
2832                 if (i >= newmap->m_max_mds ||
2833                     memcmp(ceph_mdsmap_get_addr(oldmap, i),
2834                            ceph_mdsmap_get_addr(newmap, i),
2835                            sizeof(struct ceph_entity_addr))) {
2836                         if (s->s_state == CEPH_MDS_SESSION_OPENING) {
2837                                 /* the session never opened, just close it
2838                                  * out now */
2839                                 __wake_requests(mdsc, &s->s_waiting);
2840                                 __unregister_session(mdsc, s);
2841                         } else {
2842                                 /* just close it */
2843                                 mutex_unlock(&mdsc->mutex);
2844                                 mutex_lock(&s->s_mutex);
2845                                 mutex_lock(&mdsc->mutex);
2846                                 ceph_con_close(&s->s_con);
2847                                 mutex_unlock(&s->s_mutex);
2848                                 s->s_state = CEPH_MDS_SESSION_RESTARTING;
2849                         }
2850
2851                         /* kick any requests waiting on the recovering mds */
2852                         kick_requests(mdsc, i);
2853                 } else if (oldstate == newstate) {
2854                         continue;  /* nothing new with this mds */
2855                 }
2856
2857                 /*
2858                  * send reconnect?
2859                  */
2860                 if (s->s_state == CEPH_MDS_SESSION_RESTARTING &&
2861                     newstate >= CEPH_MDS_STATE_RECONNECT) {
2862                         mutex_unlock(&mdsc->mutex);
2863                         send_mds_reconnect(mdsc, s);
2864                         mutex_lock(&mdsc->mutex);
2865                 }
2866
2867                 /*
2868                  * kick request on any mds that has gone active.
2869                  */
2870                 if (oldstate < CEPH_MDS_STATE_ACTIVE &&
2871                     newstate >= CEPH_MDS_STATE_ACTIVE) {
2872                         if (oldstate != CEPH_MDS_STATE_CREATING &&
2873                             oldstate != CEPH_MDS_STATE_STARTING)
2874                                 pr_info("mds%d recovery completed\n", s->s_mds);
2875                         kick_requests(mdsc, i);
2876                         ceph_kick_flushing_caps(mdsc, s);
2877                         wake_up_session_caps(s, 1);
2878                 }
2879         }
2880
2881         for (i = 0; i < newmap->m_max_mds && i < mdsc->max_sessions; i++) {
2882                 s = mdsc->sessions[i];
2883                 if (!s)
2884                         continue;
2885                 if (!ceph_mdsmap_is_laggy(newmap, i))
2886                         continue;
2887                 if (s->s_state == CEPH_MDS_SESSION_OPEN ||
2888                     s->s_state == CEPH_MDS_SESSION_HUNG ||
2889                     s->s_state == CEPH_MDS_SESSION_CLOSING) {
2890                         dout(" connecting to export targets of laggy mds%d\n",
2891                              i);
2892                         __open_export_target_sessions(mdsc, s);
2893                 }
2894         }
2895 }
2896
2897
2898
2899 /*
2900  * leases
2901  */
2902
2903 /*
2904  * caller must hold session s_mutex, dentry->d_lock
2905  */
2906 void __ceph_mdsc_drop_dentry_lease(struct dentry *dentry)
2907 {
2908         struct ceph_dentry_info *di = ceph_dentry(dentry);
2909
2910         ceph_put_mds_session(di->lease_session);
2911         di->lease_session = NULL;
2912 }
2913
2914 static void handle_lease(struct ceph_mds_client *mdsc,
2915                          struct ceph_mds_session *session,
2916                          struct ceph_msg *msg)
2917 {
2918         struct super_block *sb = mdsc->fsc->sb;
2919         struct inode *inode;
2920         struct dentry *parent, *dentry;
2921         struct ceph_dentry_info *di;
2922         int mds = session->s_mds;
2923         struct ceph_mds_lease *h = msg->front.iov_base;
2924         u32 seq;
2925         struct ceph_vino vino;
2926         struct qstr dname;
2927         int release = 0;
2928
2929         dout("handle_lease from mds%d\n", mds);
2930
2931         /* decode */
2932         if (msg->front.iov_len < sizeof(*h) + sizeof(u32))
2933                 goto bad;
2934         vino.ino = le64_to_cpu(h->ino);
2935         vino.snap = CEPH_NOSNAP;
2936         seq = le32_to_cpu(h->seq);
2937         dname.name = (void *)h + sizeof(*h) + sizeof(u32);
2938         dname.len = msg->front.iov_len - sizeof(*h) - sizeof(u32);
2939         if (dname.len != get_unaligned_le32(h+1))
2940                 goto bad;
2941
2942         mutex_lock(&session->s_mutex);
2943         session->s_seq++;
2944
2945         /* lookup inode */
2946         inode = ceph_find_inode(sb, vino);
2947         dout("handle_lease %s, ino %llx %p %.*s\n",
2948              ceph_lease_op_name(h->action), vino.ino, inode,
2949              dname.len, dname.name);
2950         if (inode == NULL) {
2951                 dout("handle_lease no inode %llx\n", vino.ino);
2952                 goto release;
2953         }
2954
2955         /* dentry */
2956         parent = d_find_alias(inode);
2957         if (!parent) {
2958                 dout("no parent dentry on inode %p\n", inode);
2959                 WARN_ON(1);
2960                 goto release;  /* hrm... */
2961         }
2962         dname.hash = full_name_hash(dname.name, dname.len);
2963         dentry = d_lookup(parent, &dname);
2964         dput(parent);
2965         if (!dentry)
2966                 goto release;
2967
2968         spin_lock(&dentry->d_lock);
2969         di = ceph_dentry(dentry);
2970         switch (h->action) {
2971         case CEPH_MDS_LEASE_REVOKE:
2972                 if (di->lease_session == session) {
2973                         if (ceph_seq_cmp(di->lease_seq, seq) > 0)
2974                                 h->seq = cpu_to_le32(di->lease_seq);
2975                         __ceph_mdsc_drop_dentry_lease(dentry);
2976                 }
2977                 release = 1;
2978                 break;
2979
2980         case CEPH_MDS_LEASE_RENEW:
2981                 if (di->lease_session == session &&
2982                     di->lease_gen == session->s_cap_gen &&
2983                     di->lease_renew_from &&
2984                     di->lease_renew_after == 0) {
2985                         unsigned long duration =
2986                                 le32_to_cpu(h->duration_ms) * HZ / 1000;
2987
2988                         di->lease_seq = seq;
2989                         dentry->d_time = di->lease_renew_from + duration;
2990                         di->lease_renew_after = di->lease_renew_from +
2991                                 (duration >> 1);
2992                         di->lease_renew_from = 0;
2993                 }
2994                 break;
2995         }
2996         spin_unlock(&dentry->d_lock);
2997         dput(dentry);
2998
2999         if (!release)
3000                 goto out;
3001
3002 release:
3003         /* let's just reuse the same message */
3004         h->action = CEPH_MDS_LEASE_REVOKE_ACK;
3005         ceph_msg_get(msg);
3006         ceph_con_send(&session->s_con, msg);
3007
3008 out:
3009         iput(inode);
3010         mutex_unlock(&session->s_mutex);
3011         return;
3012
3013 bad:
3014         pr_err("corrupt lease message\n");
3015         ceph_msg_dump(msg);
3016 }
3017
3018 void ceph_mdsc_lease_send_msg(struct ceph_mds_session *session,
3019                               struct inode *inode,
3020                               struct dentry *dentry, char action,
3021                               u32 seq)
3022 {
3023         struct ceph_msg *msg;
3024         struct ceph_mds_lease *lease;
3025         int len = sizeof(*lease) + sizeof(u32);
3026         int dnamelen = 0;
3027
3028         dout("lease_send_msg inode %p dentry %p %s to mds%d\n",
3029              inode, dentry, ceph_lease_op_name(action), session->s_mds);
3030         dnamelen = dentry->d_name.len;
3031         len += dnamelen;
3032
3033         msg = ceph_msg_new(CEPH_MSG_CLIENT_LEASE, len, GFP_NOFS, false);
3034         if (!msg)
3035                 return;
3036         lease = msg->front.iov_base;
3037         lease->action = action;
3038         lease->ino = cpu_to_le64(ceph_vino(inode).ino);
3039         lease->first = lease->last = cpu_to_le64(ceph_vino(inode).snap);
3040         lease->seq = cpu_to_le32(seq);
3041         put_unaligned_le32(dnamelen, lease + 1);
3042         memcpy((void *)(lease + 1) + 4, dentry->d_name.name, dnamelen);
3043
3044         /*
3045          * if this is a preemptive lease RELEASE, no need to
3046          * flush request stream, since the actual request will
3047          * soon follow.
3048          */
3049         msg->more_to_follow = (action == CEPH_MDS_LEASE_RELEASE);
3050
3051         ceph_con_send(&session->s_con, msg);
3052 }
3053
3054 /*
3055  * Preemptively release a lease we expect to invalidate anyway.
3056  * Pass @inode always, @dentry is optional.
3057  */
3058 void ceph_mdsc_lease_release(struct ceph_mds_client *mdsc, struct inode *inode,
3059                              struct dentry *dentry)
3060 {
3061         struct ceph_dentry_info *di;
3062         struct ceph_mds_session *session;
3063         u32 seq;
3064
3065         BUG_ON(inode == NULL);
3066         BUG_ON(dentry == NULL);
3067
3068         /* is dentry lease valid? */
3069         spin_lock(&dentry->d_lock);
3070         di = ceph_dentry(dentry);
3071         if (!di || !di->lease_session ||
3072             di->lease_session->s_mds < 0 ||
3073             di->lease_gen != di->lease_session->s_cap_gen ||
3074             !time_before(jiffies, dentry->d_time)) {
3075                 dout("lease_release inode %p dentry %p -- "
3076                      "no lease\n",
3077                      inode, dentry);
3078                 spin_unlock(&dentry->d_lock);
3079                 return;
3080         }
3081
3082         /* we do have a lease on this dentry; note mds and seq */
3083         session = ceph_get_mds_session(di->lease_session);
3084         seq = di->lease_seq;
3085         __ceph_mdsc_drop_dentry_lease(dentry);
3086         spin_unlock(&dentry->d_lock);
3087
3088         dout("lease_release inode %p dentry %p to mds%d\n",
3089              inode, dentry, session->s_mds);
3090         ceph_mdsc_lease_send_msg(session, inode, dentry,
3091                                  CEPH_MDS_LEASE_RELEASE, seq);
3092         ceph_put_mds_session(session);
3093 }
3094
3095 /*
3096  * drop all leases (and dentry refs) in preparation for umount
3097  */
3098 static void drop_leases(struct ceph_mds_client *mdsc)
3099 {
3100         int i;
3101
3102         dout("drop_leases\n");
3103         mutex_lock(&mdsc->mutex);
3104         for (i = 0; i < mdsc->max_sessions; i++) {
3105                 struct ceph_mds_session *s = __ceph_lookup_mds_session(mdsc, i);
3106                 if (!s)
3107                         continue;
3108                 mutex_unlock(&mdsc->mutex);
3109                 mutex_lock(&s->s_mutex);
3110                 mutex_unlock(&s->s_mutex);
3111                 ceph_put_mds_session(s);
3112                 mutex_lock(&mdsc->mutex);
3113         }
3114         mutex_unlock(&mdsc->mutex);
3115 }
3116
3117
3118
3119 /*
3120  * delayed work -- periodically trim expired leases, renew caps with mds
3121  */
3122 static void schedule_delayed(struct ceph_mds_client *mdsc)
3123 {
3124         int delay = 5;
3125         unsigned hz = round_jiffies_relative(HZ * delay);
3126         schedule_delayed_work(&mdsc->delayed_work, hz);
3127 }
3128
3129 static void delayed_work(struct work_struct *work)
3130 {
3131         int i;
3132         struct ceph_mds_client *mdsc =
3133                 container_of(work, struct ceph_mds_client, delayed_work.work);
3134         int renew_interval;
3135         int renew_caps;
3136
3137         dout("mdsc delayed_work\n");
3138         ceph_check_delayed_caps(mdsc);
3139
3140         mutex_lock(&mdsc->mutex);
3141         renew_interval = mdsc->mdsmap->m_session_timeout >> 2;
3142         renew_caps = time_after_eq(jiffies, HZ*renew_interval +
3143                                    mdsc->last_renew_caps);
3144         if (renew_caps)
3145                 mdsc->last_renew_caps = jiffies;
3146
3147         for (i = 0; i < mdsc->max_sessions; i++) {
3148                 struct ceph_mds_session *s = __ceph_lookup_mds_session(mdsc, i);
3149                 if (s == NULL)
3150                         continue;
3151                 if (s->s_state == CEPH_MDS_SESSION_CLOSING) {
3152                         dout("resending session close request for mds%d\n",
3153                              s->s_mds);
3154                         request_close_session(mdsc, s);
3155                         ceph_put_mds_session(s);
3156                         continue;
3157                 }
3158                 if (s->s_ttl && time_after(jiffies, s->s_ttl)) {
3159                         if (s->s_state == CEPH_MDS_SESSION_OPEN) {
3160                                 s->s_state = CEPH_MDS_SESSION_HUNG;
3161                                 pr_info("mds%d hung\n", s->s_mds);
3162                         }
3163                 }
3164                 if (s->s_state < CEPH_MDS_SESSION_OPEN) {
3165                         /* this mds is failed or recovering, just wait */
3166                         ceph_put_mds_session(s);
3167                         continue;
3168                 }
3169                 mutex_unlock(&mdsc->mutex);
3170
3171                 mutex_lock(&s->s_mutex);
3172                 if (renew_caps)
3173                         send_renew_caps(mdsc, s);
3174                 else
3175                         ceph_con_keepalive(&s->s_con);
3176                 ceph_add_cap_releases(mdsc, s);
3177                 if (s->s_state == CEPH_MDS_SESSION_OPEN ||
3178                     s->s_state == CEPH_MDS_SESSION_HUNG)
3179                         ceph_send_cap_releases(mdsc, s);
3180                 mutex_unlock(&s->s_mutex);
3181                 ceph_put_mds_session(s);
3182
3183                 mutex_lock(&mdsc->mutex);
3184         }
3185         mutex_unlock(&mdsc->mutex);
3186
3187         schedule_delayed(mdsc);
3188 }
3189
3190 int ceph_mdsc_init(struct ceph_fs_client *fsc)
3191
3192 {
3193         struct ceph_mds_client *mdsc;
3194
3195         mdsc = kzalloc(sizeof(struct ceph_mds_client), GFP_NOFS);
3196         if (!mdsc)
3197                 return -ENOMEM;
3198         mdsc->fsc = fsc;
3199         fsc->mdsc = mdsc;
3200         mutex_init(&mdsc->mutex);
3201         mdsc->mdsmap = kzalloc(sizeof(*mdsc->mdsmap), GFP_NOFS);
3202         if (mdsc->mdsmap == NULL) {
3203                 kfree(mdsc);
3204                 return -ENOMEM;
3205         }
3206
3207         init_completion(&mdsc->safe_umount_waiters);
3208         init_waitqueue_head(&mdsc->session_close_wq);
3209         INIT_LIST_HEAD(&mdsc->waiting_for_map);
3210         mdsc->sessions = NULL;
3211         mdsc->max_sessions = 0;
3212         mdsc->stopping = 0;
3213         init_rwsem(&mdsc->snap_rwsem);
3214         mdsc->snap_realms = RB_ROOT;
3215         INIT_LIST_HEAD(&mdsc->snap_empty);
3216         spin_lock_init(&mdsc->snap_empty_lock);
3217         mdsc->last_tid = 0;
3218         mdsc->request_tree = RB_ROOT;
3219         INIT_DELAYED_WORK(&mdsc->delayed_work, delayed_work);
3220         mdsc->last_renew_caps = jiffies;
3221         INIT_LIST_HEAD(&mdsc->cap_delay_list);
3222         spin_lock_init(&mdsc->cap_delay_lock);
3223         INIT_LIST_HEAD(&mdsc->snap_flush_list);
3224         spin_lock_init(&mdsc->snap_flush_lock);
3225         mdsc->cap_flush_seq = 0;
3226         INIT_LIST_HEAD(&mdsc->cap_dirty);
3227         INIT_LIST_HEAD(&mdsc->cap_dirty_migrating);
3228         mdsc->num_cap_flushing = 0;
3229         spin_lock_init(&mdsc->cap_dirty_lock);
3230         init_waitqueue_head(&mdsc->cap_flushing_wq);
3231         spin_lock_init(&mdsc->dentry_lru_lock);
3232         INIT_LIST_HEAD(&mdsc->dentry_lru);
3233
3234         ceph_caps_init(mdsc);
3235         ceph_adjust_min_caps(mdsc, fsc->min_caps);
3236
3237         return 0;
3238 }
3239
3240 /*
3241  * Wait for safe replies on open mds requests.  If we time out, drop
3242  * all requests from the tree to avoid dangling dentry refs.
3243  */
3244 static void wait_requests(struct ceph_mds_client *mdsc)
3245 {
3246         struct ceph_mds_request *req;
3247         struct ceph_fs_client *fsc = mdsc->fsc;
3248
3249         mutex_lock(&mdsc->mutex);
3250         if (__get_oldest_req(mdsc)) {
3251                 mutex_unlock(&mdsc->mutex);
3252
3253                 dout("wait_requests waiting for requests\n");
3254                 wait_for_completion_timeout(&mdsc->safe_umount_waiters,
3255                                     fsc->client->options->mount_timeout * HZ);
3256
3257                 /* tear down remaining requests */
3258                 mutex_lock(&mdsc->mutex);
3259                 while ((req = __get_oldest_req(mdsc))) {
3260                         dout("wait_requests timed out on tid %llu\n",
3261                              req->r_tid);
3262                         __unregister_request(mdsc, req);
3263                 }
3264         }
3265         mutex_unlock(&mdsc->mutex);
3266         dout("wait_requests done\n");
3267 }
3268
3269 /*
3270  * called before mount is ro, and before dentries are torn down.
3271  * (hmm, does this still race with new lookups?)
3272  */
3273 void ceph_mdsc_pre_umount(struct ceph_mds_client *mdsc)
3274 {
3275         dout("pre_umount\n");
3276         mdsc->stopping = 1;
3277
3278         drop_leases(mdsc);
3279         ceph_flush_dirty_caps(mdsc);
3280         wait_requests(mdsc);
3281
3282         /*
3283          * wait for reply handlers to drop their request refs and
3284          * their inode/dcache refs
3285          */
3286         ceph_msgr_flush();
3287 }
3288
3289 /*
3290  * wait for all write mds requests to flush.
3291  */
3292 static void wait_unsafe_requests(struct ceph_mds_client *mdsc, u64 want_tid)
3293 {
3294         struct ceph_mds_request *req = NULL, *nextreq;
3295         struct rb_node *n;
3296
3297         mutex_lock(&mdsc->mutex);
3298         dout("wait_unsafe_requests want %lld\n", want_tid);
3299 restart:
3300         req = __get_oldest_req(mdsc);
3301         while (req && req->r_tid <= want_tid) {
3302                 /* find next request */
3303                 n = rb_next(&req->r_node);
3304                 if (n)
3305                         nextreq = rb_entry(n, struct ceph_mds_request, r_node);
3306                 else
3307                         nextreq = NULL;
3308                 if ((req->r_op & CEPH_MDS_OP_WRITE)) {
3309                         /* write op */
3310                         ceph_mdsc_get_request(req);
3311                         if (nextreq)
3312                                 ceph_mdsc_get_request(nextreq);
3313                         mutex_unlock(&mdsc->mutex);
3314                         dout("wait_unsafe_requests  wait on %llu (want %llu)\n",
3315                              req->r_tid, want_tid);
3316                         wait_for_completion(&req->r_safe_completion);
3317                         mutex_lock(&mdsc->mutex);
3318                         ceph_mdsc_put_request(req);
3319                         if (!nextreq)
3320                                 break;  /* next dne before, so we're done! */
3321                         if (RB_EMPTY_NODE(&nextreq->r_node)) {
3322                                 /* next request was removed from tree */
3323                                 ceph_mdsc_put_request(nextreq);
3324                                 goto restart;
3325                         }
3326                         ceph_mdsc_put_request(nextreq);  /* won't go away */
3327                 }
3328                 req = nextreq;
3329         }
3330         mutex_unlock(&mdsc->mutex);
3331         dout("wait_unsafe_requests done\n");
3332 }
3333
3334 void ceph_mdsc_sync(struct ceph_mds_client *mdsc)
3335 {
3336         u64 want_tid, want_flush;
3337
3338         if (mdsc->fsc->mount_state == CEPH_MOUNT_SHUTDOWN)
3339                 return;
3340
3341         dout("sync\n");
3342         mutex_lock(&mdsc->mutex);
3343         want_tid = mdsc->last_tid;
3344         want_flush = mdsc->cap_flush_seq;
3345         mutex_unlock(&mdsc->mutex);
3346         dout("sync want tid %lld flush_seq %lld\n", want_tid, want_flush);
3347
3348         ceph_flush_dirty_caps(mdsc);
3349
3350         wait_unsafe_requests(mdsc, want_tid);
3351         wait_event(mdsc->cap_flushing_wq, check_cap_flush(mdsc, want_flush));
3352 }
3353
3354 /*
3355  * true if all sessions are closed, or we force unmount
3356  */
3357 static bool done_closing_sessions(struct ceph_mds_client *mdsc)
3358 {
3359         int i, n = 0;
3360
3361         if (mdsc->fsc->mount_state == CEPH_MOUNT_SHUTDOWN)
3362                 return true;
3363
3364         mutex_lock(&mdsc->mutex);
3365         for (i = 0; i < mdsc->max_sessions; i++)
3366                 if (mdsc->sessions[i])
3367                         n++;
3368         mutex_unlock(&mdsc->mutex);
3369         return n == 0;
3370 }
3371
3372 /*
3373  * called after sb is ro.
3374  */
3375 void ceph_mdsc_close_sessions(struct ceph_mds_client *mdsc)
3376 {
3377         struct ceph_mds_session *session;
3378         int i;
3379         struct ceph_fs_client *fsc = mdsc->fsc;
3380         unsigned long timeout = fsc->client->options->mount_timeout * HZ;
3381
3382         dout("close_sessions\n");
3383
3384         /* close sessions */
3385         mutex_lock(&mdsc->mutex);
3386         for (i = 0; i < mdsc->max_sessions; i++) {
3387                 session = __ceph_lookup_mds_session(mdsc, i);
3388                 if (!session)
3389                         continue;
3390                 mutex_unlock(&mdsc->mutex);
3391                 mutex_lock(&session->s_mutex);
3392                 __close_session(mdsc, session);
3393                 mutex_unlock(&session->s_mutex);
3394                 ceph_put_mds_session(session);
3395                 mutex_lock(&mdsc->mutex);
3396         }
3397         mutex_unlock(&mdsc->mutex);
3398
3399         dout("waiting for sessions to close\n");
3400         wait_event_timeout(mdsc->session_close_wq, done_closing_sessions(mdsc),
3401                            timeout);
3402
3403         /* tear down remaining sessions */
3404         mutex_lock(&mdsc->mutex);
3405         for (i = 0; i < mdsc->max_sessions; i++) {
3406                 if (mdsc->sessions[i]) {
3407                         session = get_session(mdsc->sessions[i]);
3408                         __unregister_session(mdsc, session);
3409                         mutex_unlock(&mdsc->mutex);
3410                         mutex_lock(&session->s_mutex);
3411                         remove_session_caps(session);
3412                         mutex_unlock(&session->s_mutex);
3413                         ceph_put_mds_session(session);
3414                         mutex_lock(&mdsc->mutex);
3415                 }
3416         }
3417         WARN_ON(!list_empty(&mdsc->cap_delay_list));
3418         mutex_unlock(&mdsc->mutex);
3419
3420         ceph_cleanup_empty_realms(mdsc);
3421
3422         cancel_delayed_work_sync(&mdsc->delayed_work); /* cancel timer */
3423
3424         dout("stopped\n");
3425 }
3426
3427 static void ceph_mdsc_stop(struct ceph_mds_client *mdsc)
3428 {
3429         dout("stop\n");
3430         cancel_delayed_work_sync(&mdsc->delayed_work); /* cancel timer */
3431         if (mdsc->mdsmap)
3432                 ceph_mdsmap_destroy(mdsc->mdsmap);
3433         kfree(mdsc->sessions);
3434         ceph_caps_finalize(mdsc);
3435 }
3436
3437 void ceph_mdsc_destroy(struct ceph_fs_client *fsc)
3438 {
3439         struct ceph_mds_client *mdsc = fsc->mdsc;
3440
3441         dout("mdsc_destroy %p\n", mdsc);
3442         ceph_mdsc_stop(mdsc);
3443
3444         /* flush out any connection work with references to us */
3445         ceph_msgr_flush();
3446
3447         fsc->mdsc = NULL;
3448         kfree(mdsc);
3449         dout("mdsc_destroy %p done\n", mdsc);
3450 }
3451
3452
3453 /*
3454  * handle mds map update.
3455  */
3456 void ceph_mdsc_handle_map(struct ceph_mds_client *mdsc, struct ceph_msg *msg)
3457 {
3458         u32 epoch;
3459         u32 maplen;
3460         void *p = msg->front.iov_base;
3461         void *end = p + msg->front.iov_len;
3462         struct ceph_mdsmap *newmap, *oldmap;
3463         struct ceph_fsid fsid;
3464         int err = -EINVAL;
3465
3466         ceph_decode_need(&p, end, sizeof(fsid)+2*sizeof(u32), bad);
3467         ceph_decode_copy(&p, &fsid, sizeof(fsid));
3468         if (ceph_check_fsid(mdsc->fsc->client, &fsid) < 0)
3469                 return;
3470         epoch = ceph_decode_32(&p);
3471         maplen = ceph_decode_32(&p);
3472         dout("handle_map epoch %u len %d\n", epoch, (int)maplen);
3473
3474         /* do we need it? */
3475         ceph_monc_got_mdsmap(&mdsc->fsc->client->monc, epoch);
3476         mutex_lock(&mdsc->mutex);
3477         if (mdsc->mdsmap && epoch <= mdsc->mdsmap->m_epoch) {
3478                 dout("handle_map epoch %u <= our %u\n",
3479                      epoch, mdsc->mdsmap->m_epoch);
3480                 mutex_unlock(&mdsc->mutex);
3481                 return;
3482         }
3483
3484         newmap = ceph_mdsmap_decode(&p, end);
3485         if (IS_ERR(newmap)) {
3486                 err = PTR_ERR(newmap);
3487                 goto bad_unlock;
3488         }
3489
3490         /* swap into place */
3491         if (mdsc->mdsmap) {
3492                 oldmap = mdsc->mdsmap;
3493                 mdsc->mdsmap = newmap;
3494                 check_new_map(mdsc, newmap, oldmap);
3495                 ceph_mdsmap_destroy(oldmap);
3496         } else {
3497                 mdsc->mdsmap = newmap;  /* first mds map */
3498         }
3499         mdsc->fsc->sb->s_maxbytes = mdsc->mdsmap->m_max_file_size;
3500
3501         __wake_requests(mdsc, &mdsc->waiting_for_map);
3502
3503         mutex_unlock(&mdsc->mutex);
3504         schedule_delayed(mdsc);
3505         return;
3506
3507 bad_unlock:
3508         mutex_unlock(&mdsc->mutex);
3509 bad:
3510         pr_err("error decoding mdsmap %d\n", err);
3511         return;
3512 }
3513
3514 static struct ceph_connection *con_get(struct ceph_connection *con)
3515 {
3516         struct ceph_mds_session *s = con->private;
3517
3518         if (get_session(s)) {
3519                 dout("mdsc con_get %p ok (%d)\n", s, atomic_read(&s->s_ref));
3520                 return con;
3521         }
3522         dout("mdsc con_get %p FAIL\n", s);
3523         return NULL;
3524 }
3525
3526 static void con_put(struct ceph_connection *con)
3527 {
3528         struct ceph_mds_session *s = con->private;
3529
3530         dout("mdsc con_put %p (%d)\n", s, atomic_read(&s->s_ref) - 1);
3531         ceph_put_mds_session(s);
3532 }
3533
3534 /*
3535  * if the client is unresponsive for long enough, the mds will kill
3536  * the session entirely.
3537  */
3538 static void peer_reset(struct ceph_connection *con)
3539 {
3540         struct ceph_mds_session *s = con->private;
3541         struct ceph_mds_client *mdsc = s->s_mdsc;
3542
3543         pr_warn("mds%d closed our session\n", s->s_mds);
3544         send_mds_reconnect(mdsc, s);
3545 }
3546
3547 static void dispatch(struct ceph_connection *con, struct ceph_msg *msg)
3548 {
3549         struct ceph_mds_session *s = con->private;
3550         struct ceph_mds_client *mdsc = s->s_mdsc;
3551         int type = le16_to_cpu(msg->hdr.type);
3552
3553         mutex_lock(&mdsc->mutex);
3554         if (__verify_registered_session(mdsc, s) < 0) {
3555                 mutex_unlock(&mdsc->mutex);
3556                 goto out;
3557         }
3558         mutex_unlock(&mdsc->mutex);
3559
3560         switch (type) {
3561         case CEPH_MSG_MDS_MAP:
3562                 ceph_mdsc_handle_map(mdsc, msg);
3563                 break;
3564         case CEPH_MSG_CLIENT_SESSION:
3565                 handle_session(s, msg);
3566                 break;
3567         case CEPH_MSG_CLIENT_REPLY:
3568                 handle_reply(s, msg);
3569                 break;
3570         case CEPH_MSG_CLIENT_REQUEST_FORWARD:
3571                 handle_forward(mdsc, s, msg);
3572                 break;
3573         case CEPH_MSG_CLIENT_CAPS:
3574                 ceph_handle_caps(s, msg);
3575                 break;
3576         case CEPH_MSG_CLIENT_SNAP:
3577                 ceph_handle_snap(mdsc, s, msg);
3578                 break;
3579         case CEPH_MSG_CLIENT_LEASE:
3580                 handle_lease(mdsc, s, msg);
3581                 break;
3582
3583         default:
3584                 pr_err("received unknown message type %d %s\n", type,
3585                        ceph_msg_type_name(type));
3586         }
3587 out:
3588         ceph_msg_put(msg);
3589 }
3590
3591 /*
3592  * authentication
3593  */
3594
3595 /*
3596  * Note: returned pointer is the address of a structure that's
3597  * managed separately.  Caller must *not* attempt to free it.
3598  */
3599 static struct ceph_auth_handshake *get_authorizer(struct ceph_connection *con,
3600                                         int *proto, int force_new)
3601 {
3602         struct ceph_mds_session *s = con->private;
3603         struct ceph_mds_client *mdsc = s->s_mdsc;
3604         struct ceph_auth_client *ac = mdsc->fsc->client->monc.auth;
3605         struct ceph_auth_handshake *auth = &s->s_auth;
3606
3607         if (force_new && auth->authorizer) {
3608                 ceph_auth_destroy_authorizer(ac, auth->authorizer);
3609                 auth->authorizer = NULL;
3610         }
3611         if (!auth->authorizer) {
3612                 int ret = ceph_auth_create_authorizer(ac, CEPH_ENTITY_TYPE_MDS,
3613                                                       auth);
3614                 if (ret)
3615                         return ERR_PTR(ret);
3616         } else {
3617                 int ret = ceph_auth_update_authorizer(ac, CEPH_ENTITY_TYPE_MDS,
3618                                                       auth);
3619                 if (ret)
3620                         return ERR_PTR(ret);
3621         }
3622         *proto = ac->protocol;
3623
3624         return auth;
3625 }
3626
3627
3628 static int verify_authorizer_reply(struct ceph_connection *con, int len)
3629 {
3630         struct ceph_mds_session *s = con->private;
3631         struct ceph_mds_client *mdsc = s->s_mdsc;
3632         struct ceph_auth_client *ac = mdsc->fsc->client->monc.auth;
3633
3634         return ceph_auth_verify_authorizer_reply(ac, s->s_auth.authorizer, len);
3635 }
3636
3637 static int invalidate_authorizer(struct ceph_connection *con)
3638 {
3639         struct ceph_mds_session *s = con->private;
3640         struct ceph_mds_client *mdsc = s->s_mdsc;
3641         struct ceph_auth_client *ac = mdsc->fsc->client->monc.auth;
3642
3643         ceph_auth_invalidate_authorizer(ac, CEPH_ENTITY_TYPE_MDS);
3644
3645         return ceph_monc_validate_auth(&mdsc->fsc->client->monc);
3646 }
3647
3648 static struct ceph_msg *mds_alloc_msg(struct ceph_connection *con,
3649                                 struct ceph_msg_header *hdr, int *skip)
3650 {
3651         struct ceph_msg *msg;
3652         int type = (int) le16_to_cpu(hdr->type);
3653         int front_len = (int) le32_to_cpu(hdr->front_len);
3654
3655         if (con->in_msg)
3656                 return con->in_msg;
3657
3658         *skip = 0;
3659         msg = ceph_msg_new(type, front_len, GFP_NOFS, false);
3660         if (!msg) {
3661                 pr_err("unable to allocate msg type %d len %d\n",
3662                        type, front_len);
3663                 return NULL;
3664         }
3665
3666         return msg;
3667 }
3668
3669 static const struct ceph_connection_operations mds_con_ops = {
3670         .get = con_get,
3671         .put = con_put,
3672         .dispatch = dispatch,
3673         .get_authorizer = get_authorizer,
3674         .verify_authorizer_reply = verify_authorizer_reply,
3675         .invalidate_authorizer = invalidate_authorizer,
3676         .peer_reset = peer_reset,
3677         .alloc_msg = mds_alloc_msg,
3678 };
3679
3680 /* eof */