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