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