fs/nfs/delegation.c

   1 /*
   2  * linux/fs/nfs/delegation.c
   3  *
   4  * Copyright (C) 2004 Trond Myklebust
   5  *
   6  * NFS file delegation management
   7  *
   8  */
   9 #include <linux/completion.h>
  10 #include <linux/kthread.h>
  11 #include <linux/module.h>
  12 #include <linux/sched.h>
  13 #include <linux/slab.h>
  14 #include <linux/smp_lock.h>
  15 #include <linux/spinlock.h>
  16
  17 #include <linux/nfs4.h>
  18 #include <linux/nfs_fs.h>
  19 #include <linux/nfs_xdr.h>
  20
  21 #include "nfs4_fs.h"
  22 #include "delegation.h"
  23 #include "internal.h"
  24
  25 static void nfs_do_free_delegation(struct nfs_delegation *delegation)
  26 {
  27         kfree(delegation);
  28 }
  29
  30 static void nfs_free_delegation_callback(struct rcu_head *head)
  31 {
  32         struct nfs_delegation *delegation = container_of(head, struct nfs_delegation, rcu);
  33
  34         nfs_do_free_delegation(delegation);
  35 }
  36
  37 static void nfs_free_delegation(struct nfs_delegation *delegation)
  38 {
  39         if (delegation->cred) {
  40                 put_rpccred(delegation->cred);
  41                 delegation->cred = NULL;
  42         }
  43         call_rcu(&delegation->rcu, nfs_free_delegation_callback);
  44 }
  45
  46 void nfs_mark_delegation_referenced(struct nfs_delegation *delegation)
  47 {
  48         set_bit(NFS_DELEGATION_REFERENCED, &delegation->flags);
  49 }
  50
  51 int nfs_have_delegation(struct inode *inode, fmode_t flags)
  52 {
  53         struct nfs_delegation *delegation;
  54         int ret = 0;
  55
  56         flags &= FMODE_READ|FMODE_WRITE;
  57         rcu_read_lock();
  58         delegation = rcu_dereference(NFS_I(inode)->delegation);
  59         if (delegation != NULL && (delegation->type & flags) == flags) {
  60                 nfs_mark_delegation_referenced(delegation);
  61                 ret = 1;
  62         }
  63         rcu_read_unlock();
  64         return ret;
  65 }
  66
  67 static int nfs_delegation_claim_locks(struct nfs_open_context *ctx, struct nfs4_state *state)
  68 {
  69         struct inode *inode = state->inode;
  70         struct file_lock *fl;
  71         int status = 0;
  72
  73         if (inode->i_flock == NULL)
  74                 goto out;
  75
  76         /* Protect inode->i_flock using the BKL */
  77         lock_kernel();
  78         for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
  79                 if (!(fl->fl_flags & (FL_POSIX|FL_FLOCK)))
  80                         continue;
  81                 if (nfs_file_open_context(fl->fl_file) != ctx)
  82                         continue;
  83                 unlock_kernel();
  84                 status = nfs4_lock_delegation_recall(state, fl);
  85                 if (status < 0)
  86                         goto out;
  87                 lock_kernel();
  88         }
  89         unlock_kernel();
  90 out:
  91         return status;
  92 }
  93
  94 static int nfs_delegation_claim_opens(struct inode *inode, const nfs4_stateid *stateid)
  95 {
  96         struct nfs_inode *nfsi = NFS_I(inode);
  97         struct nfs_open_context *ctx;
  98         struct nfs4_state *state;
  99         int err;
 100
 101 again:
 102         spin_lock(&inode->i_lock);
 103         list_for_each_entry(ctx, &nfsi->open_files, list) {
 104                 state = ctx->state;
 105                 if (state == NULL)
 106                         continue;
 107                 if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
 108                         continue;
 109                 if (memcmp(state->stateid.data, stateid->data, sizeof(state->stateid.data)) != 0)
 110                         continue;
 111                 get_nfs_open_context(ctx);
 112                 spin_unlock(&inode->i_lock);
 113                 err = nfs4_open_delegation_recall(ctx, state, stateid);
 114                 if (err >= 0)
 115                         err = nfs_delegation_claim_locks(ctx, state);
 116                 put_nfs_open_context(ctx);
 117                 if (err != 0)
 118                         return err;
 119                 goto again;
 120         }
 121         spin_unlock(&inode->i_lock);
 122         return 0;
 123 }
 124
 125 /*
 126  * Set up a delegation on an inode
 127  */
 128 void nfs_inode_reclaim_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
 129 {
 130         struct nfs_delegation *delegation;
 131         struct rpc_cred *oldcred = NULL;
 132
 133         rcu_read_lock();
 134         delegation = rcu_dereference(NFS_I(inode)->delegation);
 135         if (delegation != NULL) {
 136                 spin_lock(&delegation->lock);
 137                 if (delegation->inode != NULL) {
 138                         memcpy(delegation->stateid.data, res->delegation.data,
 139                                sizeof(delegation->stateid.data));
 140                         delegation->type = res->delegation_type;
 141                         delegation->maxsize = res->maxsize;
 142                         oldcred = delegation->cred;
 143                         delegation->cred = get_rpccred(cred);
 144                         clear_bit(NFS_DELEGATION_NEED_RECLAIM,
 145                                   &delegation->flags);
 146                         NFS_I(inode)->delegation_state = delegation->type;
 147                         spin_unlock(&delegation->lock);
 148                         put_rpccred(oldcred);
 149                         rcu_read_unlock();
 150                 } else {
 151                         /* We appear to have raced with a delegation return. */
 152                         spin_unlock(&delegation->lock);
 153                         rcu_read_unlock();
 154                         nfs_inode_set_delegation(inode, cred, res);
 155                 }
 156         } else {
 157                 rcu_read_unlock();
 158         }
 159 }
 160
 161 static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
 162 {
 163         int res = 0;
 164
 165         res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid, issync);
 166         nfs_free_delegation(delegation);
 167         return res;
 168 }
 169
 170 static struct inode *nfs_delegation_grab_inode(struct nfs_delegation *delegation)
 171 {
 172         struct inode *inode = NULL;
 173
 174         spin_lock(&delegation->lock);
 175         if (delegation->inode != NULL)
 176                 inode = igrab(delegation->inode);
 177         spin_unlock(&delegation->lock);
 178         return inode;
 179 }
 180
 181 static struct nfs_delegation *nfs_detach_delegation_locked(struct nfs_inode *nfsi,
 182                                                            const nfs4_stateid *stateid,
 183                                                            struct nfs_client *clp)
 184 {
 185         struct nfs_delegation *delegation =
 186                 rcu_dereference_protected(nfsi->delegation,
 187                                           lockdep_is_held(&clp->cl_lock));
 188
 189         if (delegation == NULL)
 190                 goto nomatch;
 191         spin_lock(&delegation->lock);
 192         if (stateid != NULL && memcmp(delegation->stateid.data, stateid->data,
 193                                 sizeof(delegation->stateid.data)) != 0)
 194                 goto nomatch_unlock;
 195         list_del_rcu(&delegation->super_list);
 196         delegation->inode = NULL;
 197         nfsi->delegation_state = 0;
 198         rcu_assign_pointer(nfsi->delegation, NULL);
 199         spin_unlock(&delegation->lock);
 200         return delegation;
 201 nomatch_unlock:
 202         spin_unlock(&delegation->lock);
 203 nomatch:
 204         return NULL;
 205 }
 206
 207 /*
 208  * Set up a delegation on an inode
 209  */
 210 int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
 211 {
 212         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 213         struct nfs_inode *nfsi = NFS_I(inode);
 214         struct nfs_delegation *delegation, *old_delegation;
 215         struct nfs_delegation *freeme = NULL;
 216         int status = 0;
 217
 218         delegation = kmalloc(sizeof(*delegation), GFP_NOFS);
 219         if (delegation == NULL)
 220                 return -ENOMEM;
 221         memcpy(delegation->stateid.data, res->delegation.data,
 222                         sizeof(delegation->stateid.data));
 223         delegation->type = res->delegation_type;
 224         delegation->maxsize = res->maxsize;
 225         delegation->change_attr = nfsi->change_attr;
 226         delegation->cred = get_rpccred(cred);
 227         delegation->inode = inode;
 228         delegation->flags = 1<<NFS_DELEGATION_REFERENCED;
 229         spin_lock_init(&delegation->lock);
 230
 231         spin_lock(&clp->cl_lock);
 232         old_delegation = rcu_dereference_protected(nfsi->delegation,
 233                                                    lockdep_is_held(&clp->cl_lock));
 234         if (old_delegation != NULL) {
 235                 if (memcmp(&delegation->stateid, &old_delegation->stateid,
 236                                         sizeof(old_delegation->stateid)) == 0 &&
 237                                 delegation->type == old_delegation->type) {
 238                         goto out;
 239                 }
 240                 /*
 241                  * Deal with broken servers that hand out two
 242                  * delegations for the same file.
 243                  */
 244                 dfprintk(FILE, "%s: server %s handed out "
 245                                 "a duplicate delegation!\n",
 246                                 __func__, clp->cl_hostname);
 247                 if (delegation->type <= old_delegation->type) {
 248                         freeme = delegation;
 249                         delegation = NULL;
 250                         goto out;
 251                 }
 252                 freeme = nfs_detach_delegation_locked(nfsi, NULL, clp);
 253         }
 254         list_add_rcu(&delegation->super_list, &clp->cl_delegations);
 255         nfsi->delegation_state = delegation->type;
 256         rcu_assign_pointer(nfsi->delegation, delegation);
 257         delegation = NULL;
 258
 259         /* Ensure we revalidate the attributes and page cache! */
 260         spin_lock(&inode->i_lock);
 261         nfsi->cache_validity |= NFS_INO_REVAL_FORCED;
 262         spin_unlock(&inode->i_lock);
 263
 264 out:
 265         spin_unlock(&clp->cl_lock);
 266         if (delegation != NULL)
 267                 nfs_free_delegation(delegation);
 268         if (freeme != NULL)
 269                 nfs_do_return_delegation(inode, freeme, 0);
 270         return status;
 271 }
 272
 273 /*
 274  * Basic procedure for returning a delegation to the server
 275  */
 276 static int __nfs_inode_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
 277 {
 278         struct nfs_inode *nfsi = NFS_I(inode);
 279         int err;
 280
 281         /*
 282          * Guard against new delegated open/lock/unlock calls and against
 283          * state recovery
 284          */
 285         down_write(&nfsi->rwsem);
 286         err = nfs_delegation_claim_opens(inode, &delegation->stateid);
 287         up_write(&nfsi->rwsem);
 288         if (err)
 289                 goto out;
 290
 291         err = nfs_do_return_delegation(inode, delegation, issync);
 292 out:
 293         return err;
 294 }
 295
 296 /*
 297  * Return all delegations that have been marked for return
 298  */
 299 int nfs_client_return_marked_delegations(struct nfs_client *clp)
 300 {
 301         struct nfs_delegation *delegation;
 302         struct inode *inode;
 303         int err = 0;
 304
 305 restart:
 306         rcu_read_lock();
 307         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 308                 if (!test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
 309                         continue;
 310                 inode = nfs_delegation_grab_inode(delegation);
 311                 if (inode == NULL)
 312                         continue;
 313                 spin_lock(&clp->cl_lock);
 314                 delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL, clp);
 315                 spin_unlock(&clp->cl_lock);
 316                 rcu_read_unlock();
 317                 if (delegation != NULL) {
 318                         filemap_flush(inode->i_mapping);
 319                         err = __nfs_inode_return_delegation(inode, delegation, 0);
 320                 }
 321                 iput(inode);
 322                 if (!err)
 323                         goto restart;
 324                 set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
 325                 return err;
 326         }
 327         rcu_read_unlock();
 328         return 0;
 329 }
 330
 331 /*
 332  * This function returns the delegation without reclaiming opens
 333  * or protecting against delegation reclaims.
 334  * It is therefore really only safe to be called from
 335  * nfs4_clear_inode()
 336  */
 337 void nfs_inode_return_delegation_noreclaim(struct inode *inode)
 338 {
 339         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 340         struct nfs_inode *nfsi = NFS_I(inode);
 341         struct nfs_delegation *delegation;
 342
 343         if (rcu_access_pointer(nfsi->delegation) != NULL) {
 344                 spin_lock(&clp->cl_lock);
 345                 delegation = nfs_detach_delegation_locked(nfsi, NULL, clp);
 346                 spin_unlock(&clp->cl_lock);
 347                 if (delegation != NULL)
 348                         nfs_do_return_delegation(inode, delegation, 0);
 349         }
 350 }
 351
 352 int nfs_inode_return_delegation(struct inode *inode)
 353 {
 354         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 355         struct nfs_inode *nfsi = NFS_I(inode);
 356         struct nfs_delegation *delegation;
 357         int err = 0;
 358
 359         if (rcu_access_pointer(nfsi->delegation) != NULL) {
 360                 spin_lock(&clp->cl_lock);
 361                 delegation = nfs_detach_delegation_locked(nfsi, NULL, clp);
 362                 spin_unlock(&clp->cl_lock);
 363                 if (delegation != NULL) {
 364                         nfs_wb_all(inode);
 365                         err = __nfs_inode_return_delegation(inode, delegation, 1);
 366                 }
 367         }
 368         return err;
 369 }
 370
 371 static void nfs_mark_return_delegation(struct nfs_client *clp, struct nfs_delegation *delegation)
 372 {
 373         set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
 374         set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
 375 }
 376
 377 /*
 378  * Return all delegations associated to a super block
 379  */
 380 void nfs_super_return_all_delegations(struct super_block *sb)
 381 {
 382         struct nfs_client *clp = NFS_SB(sb)->nfs_client;
 383         struct nfs_delegation *delegation;
 384
 385         if (clp == NULL)
 386                 return;
 387         rcu_read_lock();
 388         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 389                 spin_lock(&delegation->lock);
 390                 if (delegation->inode != NULL && delegation->inode->i_sb == sb)
 391                         set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
 392                 spin_unlock(&delegation->lock);
 393         }
 394         rcu_read_unlock();
 395         if (nfs_client_return_marked_delegations(clp) != 0)
 396                 nfs4_schedule_state_manager(clp);
 397 }
 398
 399 static
 400 void nfs_client_mark_return_all_delegation_types(struct nfs_client *clp, fmode_t flags)
 401 {
 402         struct nfs_delegation *delegation;
 403
 404         rcu_read_lock();
 405         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 406                 if ((delegation->type == (FMODE_READ|FMODE_WRITE)) && !(flags & FMODE_WRITE))
 407                         continue;
 408                 if (delegation->type & flags)
 409                         nfs_mark_return_delegation(clp, delegation);
 410         }
 411         rcu_read_unlock();
 412 }
 413
 414 static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
 415 {
 416         nfs_client_mark_return_all_delegation_types(clp, FMODE_READ|FMODE_WRITE);
 417 }
 418
 419 static void nfs_delegation_run_state_manager(struct nfs_client *clp)
 420 {
 421         if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
 422                 nfs4_schedule_state_manager(clp);
 423 }
 424
 425 void nfs_expire_all_delegation_types(struct nfs_client *clp, fmode_t flags)
 426 {
 427         nfs_client_mark_return_all_delegation_types(clp, flags);
 428         nfs_delegation_run_state_manager(clp);
 429 }
 430
 431 void nfs_expire_all_delegations(struct nfs_client *clp)
 432 {
 433         nfs_expire_all_delegation_types(clp, FMODE_READ|FMODE_WRITE);
 434 }
 435
 436 /*
 437  * Return all delegations following an NFS4ERR_CB_PATH_DOWN error.
 438  */
 439 void nfs_handle_cb_pathdown(struct nfs_client *clp)
 440 {
 441         if (clp == NULL)
 442                 return;
 443         nfs_client_mark_return_all_delegations(clp);
 444 }
 445
 446 static void nfs_client_mark_return_unreferenced_delegations(struct nfs_client *clp)
 447 {
 448         struct nfs_delegation *delegation;
 449
 450         rcu_read_lock();
 451         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 452                 if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags))
 453                         continue;
 454                 nfs_mark_return_delegation(clp, delegation);
 455         }
 456         rcu_read_unlock();
 457 }
 458
 459 void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
 460 {
 461         nfs_client_mark_return_unreferenced_delegations(clp);
 462         nfs_delegation_run_state_manager(clp);
 463 }
 464
 465 /*
 466  * Asynchronous delegation recall!
 467  */
 468 int nfs_async_inode_return_delegation(struct inode *inode, const nfs4_stateid *stateid)
 469 {
 470         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 471         struct nfs_delegation *delegation;
 472
 473         rcu_read_lock();
 474         delegation = rcu_dereference(NFS_I(inode)->delegation);
 475
 476         if (!clp->cl_mvops->validate_stateid(delegation, stateid)) {
 477                 rcu_read_unlock();
 478                 return -ENOENT;
 479         }
 480
 481         nfs_mark_return_delegation(clp, delegation);
 482         rcu_read_unlock();
 483         nfs_delegation_run_state_manager(clp);
 484         return 0;
 485 }
 486
 487 /*
 488  * Retrieve the inode associated with a delegation
 489  */
 490 struct inode *nfs_delegation_find_inode(struct nfs_client *clp, const struct nfs_fh *fhandle)
 491 {
 492         struct nfs_delegation *delegation;
 493         struct inode *res = NULL;
 494         rcu_read_lock();
 495         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 496                 spin_lock(&delegation->lock);
 497                 if (delegation->inode != NULL &&
 498                     nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
 499                         res = igrab(delegation->inode);
 500                 }
 501                 spin_unlock(&delegation->lock);
 502                 if (res != NULL)
 503                         break;
 504         }
 505         rcu_read_unlock();
 506         return res;
 507 }
 508
 509 /*
 510  * Mark all delegations as needing to be reclaimed
 511  */
 512 void nfs_delegation_mark_reclaim(struct nfs_client *clp)
 513 {
 514         struct nfs_delegation *delegation;
 515         rcu_read_lock();
 516         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list)
 517                 set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
 518         rcu_read_unlock();
 519 }
 520
 521 /*
 522  * Reap all unclaimed delegations after reboot recovery is done
 523  */
 524 void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
 525 {
 526         struct nfs_delegation *delegation;
 527         struct inode *inode;
 528 restart:
 529         rcu_read_lock();
 530         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 531                 if (test_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags) == 0)
 532                         continue;
 533                 inode = nfs_delegation_grab_inode(delegation);
 534                 if (inode == NULL)
 535                         continue;
 536                 spin_lock(&clp->cl_lock);
 537                 delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL, clp);
 538                 spin_unlock(&clp->cl_lock);
 539                 rcu_read_unlock();
 540                 if (delegation != NULL)
 541                         nfs_free_delegation(delegation);
 542                 iput(inode);
 543                 goto restart;
 544         }
 545         rcu_read_unlock();
 546 }
 547
 548 int nfs4_copy_delegation_stateid(nfs4_stateid *dst, struct inode *inode)
 549 {
 550         struct nfs_inode *nfsi = NFS_I(inode);
 551         struct nfs_delegation *delegation;
 552         int ret = 0;
 553
 554         rcu_read_lock();
 555         delegation = rcu_dereference(nfsi->delegation);
 556         if (delegation != NULL) {
 557                 memcpy(dst->data, delegation->stateid.data, sizeof(dst->data));
 558                 ret = 1;
 559         }
 560         rcu_read_unlock();
 561         return ret;
 562 }