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   1 /*
   2  *  fs/nfs/nfs4state.c
   3  *
   4  *  Client-side XDR for NFSv4.
   5  *
   6  *  Copyright (c) 2002 The Regents of the University of Michigan.
   7  *  All rights reserved.
   8  *
   9  *  Kendrick Smith <kmsmith@umich.edu>
  10  *
  11  *  Redistribution and use in source and binary forms, with or without
  12  *  modification, are permitted provided that the following conditions
  13  *  are met:
  14  *
  15  *  1. Redistributions of source code must retain the above copyright
  16  *     notice, this list of conditions and the following disclaimer.
  17  *  2. Redistributions in binary form must reproduce the above copyright
  18  *     notice, this list of conditions and the following disclaimer in the
  19  *     documentation and/or other materials provided with the distribution.
  20  *  3. Neither the name of the University nor the names of its
  21  *     contributors may be used to endorse or promote products derived
  22  *     from this software without specific prior written permission.
  23  *
  24  *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
  25  *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  26  *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  27  *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  29  *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  30  *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
  31  *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  32  *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  33  *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  34  *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  35  *
  36  * Implementation of the NFSv4 state model.  For the time being,
  37  * this is minimal, but will be made much more complex in a
  38  * subsequent patch.
  39  */
  40
  41 #include <linux/kernel.h>
  42 #include <linux/slab.h>
  43 #include <linux/smp_lock.h>
  44 #include <linux/nfs_fs.h>
  45 #include <linux/nfs_idmap.h>
  46 #include <linux/kthread.h>
  47 #include <linux/module.h>
  48 #include <linux/random.h>
  49 #include <linux/workqueue.h>
  50 #include <linux/bitops.h>
  51
  52 #include "nfs4_fs.h"
  53 #include "callback.h"
  54 #include "delegation.h"
  55 #include "internal.h"
  56
  57 #define OPENOWNER_POOL_SIZE     8
  58
  59 const nfs4_stateid zero_stateid;
  60
  61 static LIST_HEAD(nfs4_clientid_list);
  62
  63 static int nfs4_init_client(struct nfs_client *clp, struct rpc_cred *cred)
  64 {
  65         int status = nfs4_proc_setclientid(clp, NFS4_CALLBACK,
  66                         nfs_callback_tcpport, cred);
  67         if (status == 0)
  68                 status = nfs4_proc_setclientid_confirm(clp, cred);
  69         if (status == 0)
  70                 nfs4_schedule_state_renewal(clp);
  71         return status;
  72 }
  73
  74 struct rpc_cred *nfs4_get_renew_cred(struct nfs_client *clp)
  75 {
  76         struct nfs4_state_owner *sp;
  77         struct rb_node *pos;
  78         struct rpc_cred *cred = NULL;
  79
  80         for (pos = rb_first(&clp->cl_state_owners); pos != NULL; pos = rb_next(pos)) {
  81                 sp = rb_entry(pos, struct nfs4_state_owner, so_client_node);
  82                 if (list_empty(&sp->so_states))
  83                         continue;
  84                 cred = get_rpccred(sp->so_cred);
  85                 break;
  86         }
  87         return cred;
  88 }
  89
  90 static struct rpc_cred *nfs4_get_setclientid_cred(struct nfs_client *clp)
  91 {
  92         struct nfs4_state_owner *sp;
  93         struct rb_node *pos;
  94
  95         pos = rb_first(&clp->cl_state_owners);
  96         if (pos != NULL) {
  97                 sp = rb_entry(pos, struct nfs4_state_owner, so_client_node);
  98                 return get_rpccred(sp->so_cred);
  99         }
 100         return NULL;
 101 }
 102
 103 static void nfs_alloc_unique_id(struct rb_root *root, struct nfs_unique_id *new,
 104                 __u64 minval, int maxbits)
 105 {
 106         struct rb_node **p, *parent;
 107         struct nfs_unique_id *pos;
 108         __u64 mask = ~0ULL;
 109
 110         if (maxbits < 64)
 111                 mask = (1ULL << maxbits) - 1ULL;
 112
 113         /* Ensure distribution is more or less flat */
 114         get_random_bytes(&new->id, sizeof(new->id));
 115         new->id &= mask;
 116         if (new->id < minval)
 117                 new->id += minval;
 118 retry:
 119         p = &root->rb_node;
 120         parent = NULL;
 121
 122         while (*p != NULL) {
 123                 parent = *p;
 124                 pos = rb_entry(parent, struct nfs_unique_id, rb_node);
 125
 126                 if (new->id < pos->id)
 127                         p = &(*p)->rb_left;
 128                 else if (new->id > pos->id)
 129                         p = &(*p)->rb_right;
 130                 else
 131                         goto id_exists;
 132         }
 133         rb_link_node(&new->rb_node, parent, p);
 134         rb_insert_color(&new->rb_node, root);
 135         return;
 136 id_exists:
 137         for (;;) {
 138                 new->id++;
 139                 if (new->id < minval || (new->id & mask) != new->id) {
 140                         new->id = minval;
 141                         break;
 142                 }
 143                 parent = rb_next(parent);
 144                 if (parent == NULL)
 145                         break;
 146                 pos = rb_entry(parent, struct nfs_unique_id, rb_node);
 147                 if (new->id < pos->id)
 148                         break;
 149         }
 150         goto retry;
 151 }
 152
 153 static void nfs_free_unique_id(struct rb_root *root, struct nfs_unique_id *id)
 154 {
 155         rb_erase(&id->rb_node, root);
 156 }
 157
 158 static struct nfs4_state_owner *
 159 nfs4_find_state_owner(struct nfs_server *server, struct rpc_cred *cred)
 160 {
 161         struct nfs_client *clp = server->nfs_client;
 162         struct rb_node **p = &clp->cl_state_owners.rb_node,
 163                        *parent = NULL;
 164         struct nfs4_state_owner *sp, *res = NULL;
 165
 166         while (*p != NULL) {
 167                 parent = *p;
 168                 sp = rb_entry(parent, struct nfs4_state_owner, so_client_node);
 169
 170                 if (server < sp->so_server) {
 171                         p = &parent->rb_left;
 172                         continue;
 173                 }
 174                 if (server > sp->so_server) {
 175                         p = &parent->rb_right;
 176                         continue;
 177                 }
 178                 if (cred < sp->so_cred)
 179                         p = &parent->rb_left;
 180                 else if (cred > sp->so_cred)
 181                         p = &parent->rb_right;
 182                 else {
 183                         atomic_inc(&sp->so_count);
 184                         res = sp;
 185                         break;
 186                 }
 187         }
 188         return res;
 189 }
 190
 191 static struct nfs4_state_owner *
 192 nfs4_insert_state_owner(struct nfs_client *clp, struct nfs4_state_owner *new)
 193 {
 194         struct rb_node **p = &clp->cl_state_owners.rb_node,
 195                        *parent = NULL;
 196         struct nfs4_state_owner *sp;
 197
 198         while (*p != NULL) {
 199                 parent = *p;
 200                 sp = rb_entry(parent, struct nfs4_state_owner, so_client_node);
 201
 202                 if (new->so_server < sp->so_server) {
 203                         p = &parent->rb_left;
 204                         continue;
 205                 }
 206                 if (new->so_server > sp->so_server) {
 207                         p = &parent->rb_right;
 208                         continue;
 209                 }
 210                 if (new->so_cred < sp->so_cred)
 211                         p = &parent->rb_left;
 212                 else if (new->so_cred > sp->so_cred)
 213                         p = &parent->rb_right;
 214                 else {
 215                         atomic_inc(&sp->so_count);
 216                         return sp;
 217                 }
 218         }
 219         nfs_alloc_unique_id(&clp->cl_openowner_id, &new->so_owner_id, 1, 64);
 220         rb_link_node(&new->so_client_node, parent, p);
 221         rb_insert_color(&new->so_client_node, &clp->cl_state_owners);
 222         return new;
 223 }
 224
 225 static void
 226 nfs4_remove_state_owner(struct nfs_client *clp, struct nfs4_state_owner *sp)
 227 {
 228         if (!RB_EMPTY_NODE(&sp->so_client_node))
 229                 rb_erase(&sp->so_client_node, &clp->cl_state_owners);
 230         nfs_free_unique_id(&clp->cl_openowner_id, &sp->so_owner_id);
 231 }
 232
 233 /*
 234  * nfs4_alloc_state_owner(): this is called on the OPEN or CREATE path to
 235  * create a new state_owner.
 236  *
 237  */
 238 static struct nfs4_state_owner *
 239 nfs4_alloc_state_owner(void)
 240 {
 241         struct nfs4_state_owner *sp;
 242
 243         sp = kzalloc(sizeof(*sp),GFP_KERNEL);
 244         if (!sp)
 245                 return NULL;
 246         spin_lock_init(&sp->so_lock);
 247         INIT_LIST_HEAD(&sp->so_states);
 248         INIT_LIST_HEAD(&sp->so_delegations);
 249         rpc_init_wait_queue(&sp->so_sequence.wait, "Seqid_waitqueue");
 250         sp->so_seqid.sequence = &sp->so_sequence;
 251         spin_lock_init(&sp->so_sequence.lock);
 252         INIT_LIST_HEAD(&sp->so_sequence.list);
 253         atomic_set(&sp->so_count, 1);
 254         return sp;
 255 }
 256
 257 void
 258 nfs4_drop_state_owner(struct nfs4_state_owner *sp)
 259 {
 260         if (!RB_EMPTY_NODE(&sp->so_client_node)) {
 261                 struct nfs_client *clp = sp->so_client;
 262
 263                 spin_lock(&clp->cl_lock);
 264                 rb_erase(&sp->so_client_node, &clp->cl_state_owners);
 265                 RB_CLEAR_NODE(&sp->so_client_node);
 266                 spin_unlock(&clp->cl_lock);
 267         }
 268 }
 269
 270 /*
 271  * Note: must be called with clp->cl_sem held in order to prevent races
 272  *       with reboot recovery!
 273  */
 274 struct nfs4_state_owner *nfs4_get_state_owner(struct nfs_server *server, struct rpc_cred *cred)
 275 {
 276         struct nfs_client *clp = server->nfs_client;
 277         struct nfs4_state_owner *sp, *new;
 278
 279         spin_lock(&clp->cl_lock);
 280         sp = nfs4_find_state_owner(server, cred);
 281         spin_unlock(&clp->cl_lock);
 282         if (sp != NULL)
 283                 return sp;
 284         new = nfs4_alloc_state_owner();
 285         if (new == NULL)
 286                 return NULL;
 287         new->so_client = clp;
 288         new->so_server = server;
 289         new->so_cred = cred;
 290         spin_lock(&clp->cl_lock);
 291         sp = nfs4_insert_state_owner(clp, new);
 292         spin_unlock(&clp->cl_lock);
 293         if (sp == new)
 294                 get_rpccred(cred);
 295         else {
 296                 rpc_destroy_wait_queue(&new->so_sequence.wait);
 297                 kfree(new);
 298         }
 299         return sp;
 300 }
 301
 302 /*
 303  * Must be called with clp->cl_sem held in order to avoid races
 304  * with state recovery...
 305  */
 306 void nfs4_put_state_owner(struct nfs4_state_owner *sp)
 307 {
 308         struct nfs_client *clp = sp->so_client;
 309         struct rpc_cred *cred = sp->so_cred;
 310
 311         if (!atomic_dec_and_lock(&sp->so_count, &clp->cl_lock))
 312                 return;
 313         nfs4_remove_state_owner(clp, sp);
 314         spin_unlock(&clp->cl_lock);
 315         rpc_destroy_wait_queue(&sp->so_sequence.wait);
 316         put_rpccred(cred);
 317         kfree(sp);
 318 }
 319
 320 static struct nfs4_state *
 321 nfs4_alloc_open_state(void)
 322 {
 323         struct nfs4_state *state;
 324
 325         state = kzalloc(sizeof(*state), GFP_KERNEL);
 326         if (!state)
 327                 return NULL;
 328         atomic_set(&state->count, 1);
 329         INIT_LIST_HEAD(&state->lock_states);
 330         spin_lock_init(&state->state_lock);
 331         seqlock_init(&state->seqlock);
 332         return state;
 333 }
 334
 335 void
 336 nfs4_state_set_mode_locked(struct nfs4_state *state, mode_t mode)
 337 {
 338         if (state->state == mode)
 339                 return;
 340         /* NB! List reordering - see the reclaim code for why.  */
 341         if ((mode & FMODE_WRITE) != (state->state & FMODE_WRITE)) {
 342                 if (mode & FMODE_WRITE)
 343                         list_move(&state->open_states, &state->owner->so_states);
 344                 else
 345                         list_move_tail(&state->open_states, &state->owner->so_states);
 346         }
 347         state->state = mode;
 348 }
 349
 350 static struct nfs4_state *
 351 __nfs4_find_state_byowner(struct inode *inode, struct nfs4_state_owner *owner)
 352 {
 353         struct nfs_inode *nfsi = NFS_I(inode);
 354         struct nfs4_state *state;
 355
 356         list_for_each_entry(state, &nfsi->open_states, inode_states) {
 357                 if (state->owner != owner)
 358                         continue;
 359                 if (atomic_inc_not_zero(&state->count))
 360                         return state;
 361         }
 362         return NULL;
 363 }
 364
 365 static void
 366 nfs4_free_open_state(struct nfs4_state *state)
 367 {
 368         kfree(state);
 369 }
 370
 371 struct nfs4_state *
 372 nfs4_get_open_state(struct inode *inode, struct nfs4_state_owner *owner)
 373 {
 374         struct nfs4_state *state, *new;
 375         struct nfs_inode *nfsi = NFS_I(inode);
 376
 377         spin_lock(&inode->i_lock);
 378         state = __nfs4_find_state_byowner(inode, owner);
 379         spin_unlock(&inode->i_lock);
 380         if (state)
 381                 goto out;
 382         new = nfs4_alloc_open_state();
 383         spin_lock(&owner->so_lock);
 384         spin_lock(&inode->i_lock);
 385         state = __nfs4_find_state_byowner(inode, owner);
 386         if (state == NULL && new != NULL) {
 387                 state = new;
 388                 state->owner = owner;
 389                 atomic_inc(&owner->so_count);
 390                 list_add(&state->inode_states, &nfsi->open_states);
 391                 state->inode = igrab(inode);
 392                 spin_unlock(&inode->i_lock);
 393                 /* Note: The reclaim code dictates that we add stateless
 394                  * and read-only stateids to the end of the list */
 395                 list_add_tail(&state->open_states, &owner->so_states);
 396                 spin_unlock(&owner->so_lock);
 397         } else {
 398                 spin_unlock(&inode->i_lock);
 399                 spin_unlock(&owner->so_lock);
 400                 if (new)
 401                         nfs4_free_open_state(new);
 402         }
 403 out:
 404         return state;
 405 }
 406
 407 /*
 408  * Beware! Caller must be holding exactly one
 409  * reference to clp->cl_sem!
 410  */
 411 void nfs4_put_open_state(struct nfs4_state *state)
 412 {
 413         struct inode *inode = state->inode;
 414         struct nfs4_state_owner *owner = state->owner;
 415
 416         if (!atomic_dec_and_lock(&state->count, &owner->so_lock))
 417                 return;
 418         spin_lock(&inode->i_lock);
 419         list_del(&state->inode_states);
 420         list_del(&state->open_states);
 421         spin_unlock(&inode->i_lock);
 422         spin_unlock(&owner->so_lock);
 423         iput(inode);
 424         nfs4_free_open_state(state);
 425         nfs4_put_state_owner(owner);
 426 }
 427
 428 /*
 429  * Close the current file.
 430  */
 431 static void __nfs4_close(struct path *path, struct nfs4_state *state, mode_t mode, int wait)
 432 {
 433         struct nfs4_state_owner *owner = state->owner;
 434         int call_close = 0;
 435         int newstate;
 436
 437         atomic_inc(&owner->so_count);
 438         /* Protect against nfs4_find_state() */
 439         spin_lock(&owner->so_lock);
 440         switch (mode & (FMODE_READ | FMODE_WRITE)) {
 441                 case FMODE_READ:
 442                         state->n_rdonly--;
 443                         break;
 444                 case FMODE_WRITE:
 445                         state->n_wronly--;
 446                         break;
 447                 case FMODE_READ|FMODE_WRITE:
 448                         state->n_rdwr--;
 449         }
 450         newstate = FMODE_READ|FMODE_WRITE;
 451         if (state->n_rdwr == 0) {
 452                 if (state->n_rdonly == 0) {
 453                         newstate &= ~FMODE_READ;
 454                         call_close |= test_bit(NFS_O_RDONLY_STATE, &state->flags);
 455                         call_close |= test_bit(NFS_O_RDWR_STATE, &state->flags);
 456                 }
 457                 if (state->n_wronly == 0) {
 458                         newstate &= ~FMODE_WRITE;
 459                         call_close |= test_bit(NFS_O_WRONLY_STATE, &state->flags);
 460                         call_close |= test_bit(NFS_O_RDWR_STATE, &state->flags);
 461                 }
 462                 if (newstate == 0)
 463                         clear_bit(NFS_DELEGATED_STATE, &state->flags);
 464         }
 465         nfs4_state_set_mode_locked(state, newstate);
 466         spin_unlock(&owner->so_lock);
 467
 468         if (!call_close) {
 469                 nfs4_put_open_state(state);
 470                 nfs4_put_state_owner(owner);
 471         } else
 472                 nfs4_do_close(path, state, wait);
 473 }
 474
 475 void nfs4_close_state(struct path *path, struct nfs4_state *state, mode_t mode)
 476 {
 477         __nfs4_close(path, state, mode, 0);
 478 }
 479
 480 void nfs4_close_sync(struct path *path, struct nfs4_state *state, mode_t mode)
 481 {
 482         __nfs4_close(path, state, mode, 1);
 483 }
 484
 485 /*
 486  * Search the state->lock_states for an existing lock_owner
 487  * that is compatible with current->files
 488  */
 489 static struct nfs4_lock_state *
 490 __nfs4_find_lock_state(struct nfs4_state *state, fl_owner_t fl_owner)
 491 {
 492         struct nfs4_lock_state *pos;
 493         list_for_each_entry(pos, &state->lock_states, ls_locks) {
 494                 if (pos->ls_owner != fl_owner)
 495                         continue;
 496                 atomic_inc(&pos->ls_count);
 497                 return pos;
 498         }
 499         return NULL;
 500 }
 501
 502 /*
 503  * Return a compatible lock_state. If no initialized lock_state structure
 504  * exists, return an uninitialized one.
 505  *
 506  */
 507 static struct nfs4_lock_state *nfs4_alloc_lock_state(struct nfs4_state *state, fl_owner_t fl_owner)
 508 {
 509         struct nfs4_lock_state *lsp;
 510         struct nfs_client *clp = state->owner->so_client;
 511
 512         lsp = kzalloc(sizeof(*lsp), GFP_KERNEL);
 513         if (lsp == NULL)
 514                 return NULL;
 515         rpc_init_wait_queue(&lsp->ls_sequence.wait, "lock_seqid_waitqueue");
 516         spin_lock_init(&lsp->ls_sequence.lock);
 517         INIT_LIST_HEAD(&lsp->ls_sequence.list);
 518         lsp->ls_seqid.sequence = &lsp->ls_sequence;
 519         atomic_set(&lsp->ls_count, 1);
 520         lsp->ls_owner = fl_owner;
 521         spin_lock(&clp->cl_lock);
 522         nfs_alloc_unique_id(&clp->cl_lockowner_id, &lsp->ls_id, 1, 64);
 523         spin_unlock(&clp->cl_lock);
 524         INIT_LIST_HEAD(&lsp->ls_locks);
 525         return lsp;
 526 }
 527
 528 static void nfs4_free_lock_state(struct nfs4_lock_state *lsp)
 529 {
 530         struct nfs_client *clp = lsp->ls_state->owner->so_client;
 531
 532         spin_lock(&clp->cl_lock);
 533         nfs_free_unique_id(&clp->cl_lockowner_id, &lsp->ls_id);
 534         spin_unlock(&clp->cl_lock);
 535         rpc_destroy_wait_queue(&lsp->ls_sequence.wait);
 536         kfree(lsp);
 537 }
 538
 539 /*
 540  * Return a compatible lock_state. If no initialized lock_state structure
 541  * exists, return an uninitialized one.
 542  *
 543  * The caller must be holding clp->cl_sem
 544  */
 545 static struct nfs4_lock_state *nfs4_get_lock_state(struct nfs4_state *state, fl_owner_t owner)
 546 {
 547         struct nfs4_lock_state *lsp, *new = NULL;
 548
 549         for(;;) {
 550                 spin_lock(&state->state_lock);
 551                 lsp = __nfs4_find_lock_state(state, owner);
 552                 if (lsp != NULL)
 553                         break;
 554                 if (new != NULL) {
 555                         new->ls_state = state;
 556                         list_add(&new->ls_locks, &state->lock_states);
 557                         set_bit(LK_STATE_IN_USE, &state->flags);
 558                         lsp = new;
 559                         new = NULL;
 560                         break;
 561                 }
 562                 spin_unlock(&state->state_lock);
 563                 new = nfs4_alloc_lock_state(state, owner);
 564                 if (new == NULL)
 565                         return NULL;
 566         }
 567         spin_unlock(&state->state_lock);
 568         if (new != NULL)
 569                 nfs4_free_lock_state(new);
 570         return lsp;
 571 }
 572
 573 /*
 574  * Release reference to lock_state, and free it if we see that
 575  * it is no longer in use
 576  */
 577 void nfs4_put_lock_state(struct nfs4_lock_state *lsp)
 578 {
 579         struct nfs4_state *state;
 580
 581         if (lsp == NULL)
 582                 return;
 583         state = lsp->ls_state;
 584         if (!atomic_dec_and_lock(&lsp->ls_count, &state->state_lock))
 585                 return;
 586         list_del(&lsp->ls_locks);
 587         if (list_empty(&state->lock_states))
 588                 clear_bit(LK_STATE_IN_USE, &state->flags);
 589         spin_unlock(&state->state_lock);
 590         nfs4_free_lock_state(lsp);
 591 }
 592
 593 static void nfs4_fl_copy_lock(struct file_lock *dst, struct file_lock *src)
 594 {
 595         struct nfs4_lock_state *lsp = src->fl_u.nfs4_fl.owner;
 596
 597         dst->fl_u.nfs4_fl.owner = lsp;
 598         atomic_inc(&lsp->ls_count);
 599 }
 600
 601 static void nfs4_fl_release_lock(struct file_lock *fl)
 602 {
 603         nfs4_put_lock_state(fl->fl_u.nfs4_fl.owner);
 604 }
 605
 606 static struct file_lock_operations nfs4_fl_lock_ops = {
 607         .fl_copy_lock = nfs4_fl_copy_lock,
 608         .fl_release_private = nfs4_fl_release_lock,
 609 };
 610
 611 int nfs4_set_lock_state(struct nfs4_state *state, struct file_lock *fl)
 612 {
 613         struct nfs4_lock_state *lsp;
 614
 615         if (fl->fl_ops != NULL)
 616                 return 0;
 617         lsp = nfs4_get_lock_state(state, fl->fl_owner);
 618         if (lsp == NULL)
 619                 return -ENOMEM;
 620         fl->fl_u.nfs4_fl.owner = lsp;
 621         fl->fl_ops = &nfs4_fl_lock_ops;
 622         return 0;
 623 }
 624
 625 /*
 626  * Byte-range lock aware utility to initialize the stateid of read/write
 627  * requests.
 628  */
 629 void nfs4_copy_stateid(nfs4_stateid *dst, struct nfs4_state *state, fl_owner_t fl_owner)
 630 {
 631         struct nfs4_lock_state *lsp;
 632         int seq;
 633
 634         do {
 635                 seq = read_seqbegin(&state->seqlock);
 636                 memcpy(dst, &state->stateid, sizeof(*dst));
 637         } while (read_seqretry(&state->seqlock, seq));
 638         if (test_bit(LK_STATE_IN_USE, &state->flags) == 0)
 639                 return;
 640
 641         spin_lock(&state->state_lock);
 642         lsp = __nfs4_find_lock_state(state, fl_owner);
 643         if (lsp != NULL && (lsp->ls_flags & NFS_LOCK_INITIALIZED) != 0)
 644                 memcpy(dst, &lsp->ls_stateid, sizeof(*dst));
 645         spin_unlock(&state->state_lock);
 646         nfs4_put_lock_state(lsp);
 647 }
 648
 649 struct nfs_seqid *nfs_alloc_seqid(struct nfs_seqid_counter *counter)
 650 {
 651         struct nfs_seqid *new;
 652
 653         new = kmalloc(sizeof(*new), GFP_KERNEL);
 654         if (new != NULL) {
 655                 new->sequence = counter;
 656                 INIT_LIST_HEAD(&new->list);
 657         }
 658         return new;
 659 }
 660
 661 void nfs_free_seqid(struct nfs_seqid *seqid)
 662 {
 663         if (!list_empty(&seqid->list)) {
 664                 struct rpc_sequence *sequence = seqid->sequence->sequence;
 665
 666                 spin_lock(&sequence->lock);
 667                 list_del(&seqid->list);
 668                 spin_unlock(&sequence->lock);
 669                 rpc_wake_up(&sequence->wait);
 670         }
 671         kfree(seqid);
 672 }
 673
 674 /*
 675  * Increment the seqid if the OPEN/OPEN_DOWNGRADE/CLOSE succeeded, or
 676  * failed with a seqid incrementing error -
 677  * see comments nfs_fs.h:seqid_mutating_error()
 678  */
 679 static void nfs_increment_seqid(int status, struct nfs_seqid *seqid)
 680 {
 681         BUG_ON(list_first_entry(&seqid->sequence->sequence->list, struct nfs_seqid, list) != seqid);
 682         switch (status) {
 683                 case 0:
 684                         break;
 685                 case -NFS4ERR_BAD_SEQID:
 686                         if (seqid->sequence->flags & NFS_SEQID_CONFIRMED)
 687                                 return;
 688                         printk(KERN_WARNING "NFS: v4 server returned a bad"
 689                                         " sequence-id error on an"
 690                                         " unconfirmed sequence %p!\n",
 691                                         seqid->sequence);
 692                 case -NFS4ERR_STALE_CLIENTID:
 693                 case -NFS4ERR_STALE_STATEID:
 694                 case -NFS4ERR_BAD_STATEID:
 695                 case -NFS4ERR_BADXDR:
 696                 case -NFS4ERR_RESOURCE:
 697                 case -NFS4ERR_NOFILEHANDLE:
 698                         /* Non-seqid mutating errors */
 699                         return;
 700         };
 701         /*
 702          * Note: no locking needed as we are guaranteed to be first
 703          * on the sequence list
 704          */
 705         seqid->sequence->counter++;
 706 }
 707
 708 void nfs_increment_open_seqid(int status, struct nfs_seqid *seqid)
 709 {
 710         if (status == -NFS4ERR_BAD_SEQID) {
 711                 struct nfs4_state_owner *sp = container_of(seqid->sequence,
 712                                 struct nfs4_state_owner, so_seqid);
 713                 nfs4_drop_state_owner(sp);
 714         }
 715         nfs_increment_seqid(status, seqid);
 716 }
 717
 718 /*
 719  * Increment the seqid if the LOCK/LOCKU succeeded, or
 720  * failed with a seqid incrementing error -
 721  * see comments nfs_fs.h:seqid_mutating_error()
 722  */
 723 void nfs_increment_lock_seqid(int status, struct nfs_seqid *seqid)
 724 {
 725         nfs_increment_seqid(status, seqid);
 726 }
 727
 728 int nfs_wait_on_sequence(struct nfs_seqid *seqid, struct rpc_task *task)
 729 {
 730         struct rpc_sequence *sequence = seqid->sequence->sequence;
 731         int status = 0;
 732
 733         spin_lock(&sequence->lock);
 734         if (list_empty(&seqid->list))
 735                 list_add_tail(&seqid->list, &sequence->list);
 736         if (list_first_entry(&sequence->list, struct nfs_seqid, list) == seqid)
 737                 goto unlock;
 738         rpc_sleep_on(&sequence->wait, task, NULL);
 739         status = -EAGAIN;
 740 unlock:
 741         spin_unlock(&sequence->lock);
 742         return status;
 743 }
 744
 745 static int reclaimer(void *);
 746
 747 static inline void nfs4_clear_recover_bit(struct nfs_client *clp)
 748 {
 749         smp_mb__before_clear_bit();
 750         clear_bit(NFS4CLNT_STATE_RECOVER, &clp->cl_state);
 751         smp_mb__after_clear_bit();
 752         wake_up_bit(&clp->cl_state, NFS4CLNT_STATE_RECOVER);
 753         rpc_wake_up(&clp->cl_rpcwaitq);
 754 }
 755
 756 /*
 757  * State recovery routine
 758  */
 759 static void nfs4_recover_state(struct nfs_client *clp)
 760 {
 761         struct task_struct *task;
 762
 763         __module_get(THIS_MODULE);
 764         atomic_inc(&clp->cl_count);
 765         task = kthread_run(reclaimer, clp, "%s-reclaim",
 766                                 rpc_peeraddr2str(clp->cl_rpcclient,
 767                                                         RPC_DISPLAY_ADDR));
 768         if (!IS_ERR(task))
 769                 return;
 770         nfs4_clear_recover_bit(clp);
 771         nfs_put_client(clp);
 772         module_put(THIS_MODULE);
 773 }
 774
 775 /*
 776  * Schedule a state recovery attempt
 777  */
 778 void nfs4_schedule_state_recovery(struct nfs_client *clp)
 779 {
 780         if (!clp)
 781                 return;
 782         if (test_and_set_bit(NFS4CLNT_STATE_RECOVER, &clp->cl_state) == 0)
 783                 nfs4_recover_state(clp);
 784 }
 785
 786 static int nfs4_reclaim_locks(struct nfs4_state_recovery_ops *ops, struct nfs4_state *state)
 787 {
 788         struct inode *inode = state->inode;
 789         struct file_lock *fl;
 790         int status = 0;
 791
 792         for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
 793                 if (!(fl->fl_flags & (FL_POSIX|FL_FLOCK)))
 794                         continue;
 795                 if (nfs_file_open_context(fl->fl_file)->state != state)
 796                         continue;
 797                 status = ops->recover_lock(state, fl);
 798                 if (status >= 0)
 799                         continue;
 800                 switch (status) {
 801                         default:
 802                                 printk(KERN_ERR "%s: unhandled error %d. Zeroing state\n",
 803                                                 __FUNCTION__, status);
 804                         case -NFS4ERR_EXPIRED:
 805                         case -NFS4ERR_NO_GRACE:
 806                         case -NFS4ERR_RECLAIM_BAD:
 807                         case -NFS4ERR_RECLAIM_CONFLICT:
 808                                 /* kill_proc(fl->fl_pid, SIGLOST, 1); */
 809                                 break;
 810                         case -NFS4ERR_STALE_CLIENTID:
 811                                 goto out_err;
 812                 }
 813         }
 814         return 0;
 815 out_err:
 816         return status;
 817 }
 818
 819 static int nfs4_reclaim_open_state(struct nfs4_state_recovery_ops *ops, struct nfs4_state_owner *sp)
 820 {
 821         struct nfs4_state *state;
 822         struct nfs4_lock_state *lock;
 823         int status = 0;
 824
 825         /* Note: we rely on the sp->so_states list being ordered
 826          * so that we always reclaim open(O_RDWR) and/or open(O_WRITE)
 827          * states first.
 828          * This is needed to ensure that the server won't give us any
 829          * read delegations that we have to return if, say, we are
 830          * recovering after a network partition or a reboot from a
 831          * server that doesn't support a grace period.
 832          */
 833         list_for_each_entry(state, &sp->so_states, open_states) {
 834                 if (state->state == 0)
 835                         continue;
 836                 status = ops->recover_open(sp, state);
 837                 if (status >= 0) {
 838                         status = nfs4_reclaim_locks(ops, state);
 839                         if (status < 0)
 840                                 goto out_err;
 841                         list_for_each_entry(lock, &state->lock_states, ls_locks) {
 842                                 if (!(lock->ls_flags & NFS_LOCK_INITIALIZED))
 843                                         printk("%s: Lock reclaim failed!\n",
 844                                                         __FUNCTION__);
 845                         }
 846                         continue;
 847                 }
 848                 switch (status) {
 849                         default:
 850                                 printk(KERN_ERR "%s: unhandled error %d. Zeroing state\n",
 851                                                 __FUNCTION__, status);
 852                         case -ENOENT:
 853                         case -NFS4ERR_RECLAIM_BAD:
 854                         case -NFS4ERR_RECLAIM_CONFLICT:
 855                                 /*
 856                                  * Open state on this file cannot be recovered
 857                                  * All we can do is revert to using the zero stateid.
 858                                  */
 859                                 memset(state->stateid.data, 0,
 860                                         sizeof(state->stateid.data));
 861                                 /* Mark the file as being 'closed' */
 862                                 state->state = 0;
 863                                 break;
 864                         case -NFS4ERR_EXPIRED:
 865                         case -NFS4ERR_NO_GRACE:
 866                         case -NFS4ERR_STALE_CLIENTID:
 867                                 goto out_err;
 868                 }
 869         }
 870         return 0;
 871 out_err:
 872         return status;
 873 }
 874
 875 static void nfs4_state_mark_reclaim(struct nfs_client *clp)
 876 {
 877         struct nfs4_state_owner *sp;
 878         struct rb_node *pos;
 879         struct nfs4_state *state;
 880         struct nfs4_lock_state *lock;
 881
 882         /* Reset all sequence ids to zero */
 883         for (pos = rb_first(&clp->cl_state_owners); pos != NULL; pos = rb_next(pos)) {
 884                 sp = rb_entry(pos, struct nfs4_state_owner, so_client_node);
 885                 sp->so_seqid.counter = 0;
 886                 sp->so_seqid.flags = 0;
 887                 spin_lock(&sp->so_lock);
 888                 list_for_each_entry(state, &sp->so_states, open_states) {
 889                         clear_bit(NFS_DELEGATED_STATE, &state->flags);
 890                         clear_bit(NFS_O_RDONLY_STATE, &state->flags);
 891                         clear_bit(NFS_O_WRONLY_STATE, &state->flags);
 892                         clear_bit(NFS_O_RDWR_STATE, &state->flags);
 893                         list_for_each_entry(lock, &state->lock_states, ls_locks) {
 894                                 lock->ls_seqid.counter = 0;
 895                                 lock->ls_seqid.flags = 0;
 896                                 lock->ls_flags &= ~NFS_LOCK_INITIALIZED;
 897                         }
 898                 }
 899                 spin_unlock(&sp->so_lock);
 900         }
 901 }
 902
 903 static int reclaimer(void *ptr)
 904 {
 905         struct nfs_client *clp = ptr;
 906         struct nfs4_state_owner *sp;
 907         struct rb_node *pos;
 908         struct nfs4_state_recovery_ops *ops;
 909         struct rpc_cred *cred;
 910         int status = 0;
 911
 912         allow_signal(SIGKILL);
 913
 914         /* Ensure exclusive access to NFSv4 state */
 915         lock_kernel();
 916         down_write(&clp->cl_sem);
 917         /* Are there any NFS mounts out there? */
 918         if (list_empty(&clp->cl_superblocks))
 919                 goto out;
 920 restart_loop:
 921         ops = &nfs4_network_partition_recovery_ops;
 922         /* Are there any open files on this volume? */
 923         cred = nfs4_get_renew_cred(clp);
 924         if (cred != NULL) {
 925                 /* Yes there are: try to renew the old lease */
 926                 status = nfs4_proc_renew(clp, cred);
 927                 switch (status) {
 928                         case 0:
 929                         case -NFS4ERR_CB_PATH_DOWN:
 930                                 put_rpccred(cred);
 931                                 goto out;
 932                         case -NFS4ERR_STALE_CLIENTID:
 933                         case -NFS4ERR_LEASE_MOVED:
 934                                 ops = &nfs4_reboot_recovery_ops;
 935                 }
 936         } else {
 937                 /* "reboot" to ensure we clear all state on the server */
 938                 clp->cl_boot_time = CURRENT_TIME;
 939                 cred = nfs4_get_setclientid_cred(clp);
 940         }
 941         /* We're going to have to re-establish a clientid */
 942         nfs4_state_mark_reclaim(clp);
 943         status = -ENOENT;
 944         if (cred != NULL) {
 945                 status = nfs4_init_client(clp, cred);
 946                 put_rpccred(cred);
 947         }
 948         if (status)
 949                 goto out_error;
 950         /* Mark all delegations for reclaim */
 951         nfs_delegation_mark_reclaim(clp);
 952         /* Note: list is protected by exclusive lock on cl->cl_sem */
 953         for (pos = rb_first(&clp->cl_state_owners); pos != NULL; pos = rb_next(pos)) {
 954                 sp = rb_entry(pos, struct nfs4_state_owner, so_client_node);
 955                 status = nfs4_reclaim_open_state(ops, sp);
 956                 if (status < 0) {
 957                         if (status == -NFS4ERR_NO_GRACE) {
 958                                 ops = &nfs4_network_partition_recovery_ops;
 959                                 status = nfs4_reclaim_open_state(ops, sp);
 960                         }
 961                         if (status == -NFS4ERR_STALE_CLIENTID)
 962                                 goto restart_loop;
 963                         if (status == -NFS4ERR_EXPIRED)
 964                                 goto restart_loop;
 965                 }
 966         }
 967         nfs_delegation_reap_unclaimed(clp);
 968 out:
 969         up_write(&clp->cl_sem);
 970         unlock_kernel();
 971         if (status == -NFS4ERR_CB_PATH_DOWN)
 972                 nfs_handle_cb_pathdown(clp);
 973         nfs4_clear_recover_bit(clp);
 974         nfs_put_client(clp);
 975         module_put_and_exit(0);
 976         return 0;
 977 out_error:
 978         printk(KERN_WARNING "Error: state recovery failed on NFSv4 server %s"
 979                         " with error %d\n", clp->cl_hostname, -status);
 980         set_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state);
 981         goto out;
 982 }
 983
 984 /*
 985  * Local variables:
 986  *  c-basic-offset: 8
 987  * End:
 988  */