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/spinlock.h>
  14
  15 #include <linux/nfs4.h>
  16 #include <linux/nfs_fs.h>
  17 #include <linux/nfs_xdr.h>
  18
  19 #include "nfs4_fs.h"
  20 #include "delegation.h"
  21 #include "internal.h"
  22
  23 static void nfs_do_free_delegation(struct nfs_delegation *delegation)
  24 {
  25         kfree(delegation);
  26 }
  27
  28 static void nfs_free_delegation_callback(struct rcu_head *head)
  29 {
  30         struct nfs_delegation *delegation = container_of(head, struct nfs_delegation, rcu);
  31
  32         nfs_do_free_delegation(delegation);
  33 }
  34
  35 static void nfs_free_delegation(struct nfs_delegation *delegation)
  36 {
  37         struct rpc_cred *cred;
  38
  39         cred = rcu_dereference(delegation->cred);
  40         rcu_assign_pointer(delegation->cred, NULL);
  41         call_rcu(&delegation->rcu, nfs_free_delegation_callback);
  42         if (cred)
  43                 put_rpccred(cred);
  44 }
  45
  46 static int nfs_delegation_claim_locks(struct nfs_open_context *ctx, struct nfs4_state *state)
  47 {
  48         struct inode *inode = state->inode;
  49         struct file_lock *fl;
  50         int status;
  51
  52         for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
  53                 if (!(fl->fl_flags & (FL_POSIX|FL_FLOCK)))
  54                         continue;
  55                 if (nfs_file_open_context(fl->fl_file) != ctx)
  56                         continue;
  57                 status = nfs4_lock_delegation_recall(state, fl);
  58                 if (status >= 0)
  59                         continue;
  60                 switch (status) {
  61                         default:
  62                                 printk(KERN_ERR "%s: unhandled error %d.\n",
  63                                                 __func__, status);
  64                         case -NFS4ERR_EXPIRED:
  65                                 /* kill_proc(fl->fl_pid, SIGLOST, 1); */
  66                         case -NFS4ERR_STALE_CLIENTID:
  67                                 nfs4_schedule_state_recovery(NFS_SERVER(inode)->nfs_client);
  68                                 goto out_err;
  69                 }
  70         }
  71         return 0;
  72 out_err:
  73         return status;
  74 }
  75
  76 static void nfs_delegation_claim_opens(struct inode *inode, const nfs4_stateid *stateid)
  77 {
  78         struct nfs_inode *nfsi = NFS_I(inode);
  79         struct nfs_open_context *ctx;
  80         struct nfs4_state *state;
  81         int err;
  82
  83 again:
  84         spin_lock(&inode->i_lock);
  85         list_for_each_entry(ctx, &nfsi->open_files, list) {
  86                 state = ctx->state;
  87                 if (state == NULL)
  88                         continue;
  89                 if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
  90                         continue;
  91                 if (memcmp(state->stateid.data, stateid->data, sizeof(state->stateid.data)) != 0)
  92                         continue;
  93                 get_nfs_open_context(ctx);
  94                 spin_unlock(&inode->i_lock);
  95                 err = nfs4_open_delegation_recall(ctx, state, stateid);
  96                 if (err >= 0)
  97                         err = nfs_delegation_claim_locks(ctx, state);
  98                 put_nfs_open_context(ctx);
  99                 if (err != 0)
 100                         return;
 101                 goto again;
 102         }
 103         spin_unlock(&inode->i_lock);
 104 }
 105
 106 /*
 107  * Set up a delegation on an inode
 108  */
 109 void nfs_inode_reclaim_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
 110 {
 111         struct nfs_delegation *delegation = NFS_I(inode)->delegation;
 112         struct rpc_cred *oldcred;
 113
 114         if (delegation == NULL)
 115                 return;
 116         memcpy(delegation->stateid.data, res->delegation.data,
 117                         sizeof(delegation->stateid.data));
 118         delegation->type = res->delegation_type;
 119         delegation->maxsize = res->maxsize;
 120         oldcred = delegation->cred;
 121         delegation->cred = get_rpccred(cred);
 122         clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
 123         NFS_I(inode)->delegation_state = delegation->type;
 124         smp_wmb();
 125         put_rpccred(oldcred);
 126 }
 127
 128 static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
 129 {
 130         int res = 0;
 131
 132         res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid, issync);
 133         nfs_free_delegation(delegation);
 134         return res;
 135 }
 136
 137 static struct inode *nfs_delegation_grab_inode(struct nfs_delegation *delegation)
 138 {
 139         struct inode *inode = NULL;
 140
 141         spin_lock(&delegation->lock);
 142         if (delegation->inode != NULL)
 143                 inode = igrab(delegation->inode);
 144         spin_unlock(&delegation->lock);
 145         return inode;
 146 }
 147
 148 static struct nfs_delegation *nfs_detach_delegation_locked(struct nfs_inode *nfsi, const nfs4_stateid *stateid)
 149 {
 150         struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
 151
 152         if (delegation == NULL)
 153                 goto nomatch;
 154         spin_lock(&delegation->lock);
 155         if (stateid != NULL && memcmp(delegation->stateid.data, stateid->data,
 156                                 sizeof(delegation->stateid.data)) != 0)
 157                 goto nomatch_unlock;
 158         list_del_rcu(&delegation->super_list);
 159         delegation->inode = NULL;
 160         nfsi->delegation_state = 0;
 161         rcu_assign_pointer(nfsi->delegation, NULL);
 162         spin_unlock(&delegation->lock);
 163         return delegation;
 164 nomatch_unlock:
 165         spin_unlock(&delegation->lock);
 166 nomatch:
 167         return NULL;
 168 }
 169
 170 /*
 171  * Set up a delegation on an inode
 172  */
 173 int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
 174 {
 175         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 176         struct nfs_inode *nfsi = NFS_I(inode);
 177         struct nfs_delegation *delegation;
 178         struct nfs_delegation *freeme = NULL;
 179         int status = 0;
 180
 181         delegation = kmalloc(sizeof(*delegation), GFP_KERNEL);
 182         if (delegation == NULL)
 183                 return -ENOMEM;
 184         memcpy(delegation->stateid.data, res->delegation.data,
 185                         sizeof(delegation->stateid.data));
 186         delegation->type = res->delegation_type;
 187         delegation->maxsize = res->maxsize;
 188         delegation->change_attr = nfsi->change_attr;
 189         delegation->cred = get_rpccred(cred);
 190         delegation->inode = inode;
 191         spin_lock_init(&delegation->lock);
 192
 193         spin_lock(&clp->cl_lock);
 194         if (rcu_dereference(nfsi->delegation) != NULL) {
 195                 if (memcmp(&delegation->stateid, &nfsi->delegation->stateid,
 196                                         sizeof(delegation->stateid)) == 0 &&
 197                                 delegation->type == nfsi->delegation->type) {
 198                         goto out;
 199                 }
 200                 /*
 201                  * Deal with broken servers that hand out two
 202                  * delegations for the same file.
 203                  */
 204                 dfprintk(FILE, "%s: server %s handed out "
 205                                 "a duplicate delegation!\n",
 206                                 __func__, clp->cl_hostname);
 207                 if (delegation->type <= nfsi->delegation->type) {
 208                         freeme = delegation;
 209                         delegation = NULL;
 210                         goto out;
 211                 }
 212                 freeme = nfs_detach_delegation_locked(nfsi, NULL);
 213         }
 214         list_add_rcu(&delegation->super_list, &clp->cl_delegations);
 215         nfsi->delegation_state = delegation->type;
 216         rcu_assign_pointer(nfsi->delegation, delegation);
 217         delegation = NULL;
 218
 219         /* Ensure we revalidate the attributes and page cache! */
 220         spin_lock(&inode->i_lock);
 221         nfsi->cache_validity |= NFS_INO_REVAL_FORCED;
 222         spin_unlock(&inode->i_lock);
 223
 224 out:
 225         spin_unlock(&clp->cl_lock);
 226         if (delegation != NULL)
 227                 nfs_free_delegation(delegation);
 228         if (freeme != NULL)
 229                 nfs_do_return_delegation(inode, freeme, 0);
 230         return status;
 231 }
 232
 233 /* Sync all data to disk upon delegation return */
 234 static void nfs_msync_inode(struct inode *inode)
 235 {
 236         filemap_fdatawrite(inode->i_mapping);
 237         nfs_wb_all(inode);
 238         filemap_fdatawait(inode->i_mapping);
 239 }
 240
 241 /*
 242  * Basic procedure for returning a delegation to the server
 243  */
 244 static int __nfs_inode_return_delegation(struct inode *inode, struct nfs_delegation *delegation)
 245 {
 246         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 247         struct nfs_inode *nfsi = NFS_I(inode);
 248
 249         nfs_msync_inode(inode);
 250         down_read(&clp->cl_sem);
 251         /* Guard against new delegated open calls */
 252         down_write(&nfsi->rwsem);
 253         nfs_delegation_claim_opens(inode, &delegation->stateid);
 254         up_write(&nfsi->rwsem);
 255         up_read(&clp->cl_sem);
 256         nfs_msync_inode(inode);
 257
 258         return nfs_do_return_delegation(inode, delegation, 1);
 259 }
 260
 261 /*
 262  * This function returns the delegation without reclaiming opens
 263  * or protecting against delegation reclaims.
 264  * It is therefore really only safe to be called from
 265  * nfs4_clear_inode()
 266  */
 267 void nfs_inode_return_delegation_noreclaim(struct inode *inode)
 268 {
 269         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 270         struct nfs_inode *nfsi = NFS_I(inode);
 271         struct nfs_delegation *delegation;
 272
 273         if (rcu_dereference(nfsi->delegation) != NULL) {
 274                 spin_lock(&clp->cl_lock);
 275                 delegation = nfs_detach_delegation_locked(nfsi, NULL);
 276                 spin_unlock(&clp->cl_lock);
 277                 if (delegation != NULL)
 278                         nfs_do_return_delegation(inode, delegation, 0);
 279         }
 280 }
 281
 282 int nfs_inode_return_delegation(struct inode *inode)
 283 {
 284         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 285         struct nfs_inode *nfsi = NFS_I(inode);
 286         struct nfs_delegation *delegation;
 287         int err = 0;
 288
 289         if (rcu_dereference(nfsi->delegation) != NULL) {
 290                 spin_lock(&clp->cl_lock);
 291                 delegation = nfs_detach_delegation_locked(nfsi, NULL);
 292                 spin_unlock(&clp->cl_lock);
 293                 if (delegation != NULL)
 294                         err = __nfs_inode_return_delegation(inode, delegation);
 295         }
 296         return err;
 297 }
 298
 299 /*
 300  * Return all delegations associated to a super block
 301  */
 302 void nfs_return_all_delegations(struct super_block *sb)
 303 {
 304         struct nfs_client *clp = NFS_SB(sb)->nfs_client;
 305         struct nfs_delegation *delegation;
 306         struct inode *inode;
 307
 308         if (clp == NULL)
 309                 return;
 310 restart:
 311         rcu_read_lock();
 312         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 313                 inode = NULL;
 314                 spin_lock(&delegation->lock);
 315                 if (delegation->inode != NULL && delegation->inode->i_sb == sb)
 316                         inode = igrab(delegation->inode);
 317                 spin_unlock(&delegation->lock);
 318                 if (inode == NULL)
 319                         continue;
 320                 spin_lock(&clp->cl_lock);
 321                 delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
 322                 spin_unlock(&clp->cl_lock);
 323                 rcu_read_unlock();
 324                 if (delegation != NULL)
 325                         __nfs_inode_return_delegation(inode, delegation);
 326                 iput(inode);
 327                 goto restart;
 328         }
 329         rcu_read_unlock();
 330 }
 331
 332 static int nfs_do_expire_all_delegations(void *ptr)
 333 {
 334         struct nfs_client *clp = ptr;
 335         struct nfs_delegation *delegation;
 336         struct inode *inode;
 337
 338         allow_signal(SIGKILL);
 339 restart:
 340         if (test_bit(NFS4CLNT_STATE_RECOVER, &clp->cl_state) != 0)
 341                 goto out;
 342         if (test_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state) == 0)
 343                 goto out;
 344         rcu_read_lock();
 345         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 346                 inode = nfs_delegation_grab_inode(delegation);
 347                 if (inode == NULL)
 348                         continue;
 349                 spin_lock(&clp->cl_lock);
 350                 delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
 351                 spin_unlock(&clp->cl_lock);
 352                 rcu_read_unlock();
 353                 if (delegation)
 354                         __nfs_inode_return_delegation(inode, delegation);
 355                 iput(inode);
 356                 goto restart;
 357         }
 358         rcu_read_unlock();
 359 out:
 360         nfs_put_client(clp);
 361         module_put_and_exit(0);
 362 }
 363
 364 void nfs_expire_all_delegations(struct nfs_client *clp)
 365 {
 366         struct task_struct *task;
 367
 368         __module_get(THIS_MODULE);
 369         atomic_inc(&clp->cl_count);
 370         task = kthread_run(nfs_do_expire_all_delegations, clp,
 371                                 "%s-delegreturn",
 372                                 rpc_peeraddr2str(clp->cl_rpcclient,
 373                                                         RPC_DISPLAY_ADDR));
 374         if (!IS_ERR(task))
 375                 return;
 376         nfs_put_client(clp);
 377         module_put(THIS_MODULE);
 378 }
 379
 380 /*
 381  * Return all delegations following an NFS4ERR_CB_PATH_DOWN error.
 382  */
 383 void nfs_handle_cb_pathdown(struct nfs_client *clp)
 384 {
 385         struct nfs_delegation *delegation;
 386         struct inode *inode;
 387
 388         if (clp == NULL)
 389                 return;
 390 restart:
 391         rcu_read_lock();
 392         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 393                 inode = nfs_delegation_grab_inode(delegation);
 394                 if (inode == NULL)
 395                         continue;
 396                 spin_lock(&clp->cl_lock);
 397                 delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
 398                 spin_unlock(&clp->cl_lock);
 399                 rcu_read_unlock();
 400                 if (delegation != NULL)
 401                         __nfs_inode_return_delegation(inode, delegation);
 402                 iput(inode);
 403                 goto restart;
 404         }
 405         rcu_read_unlock();
 406 }
 407
 408 struct recall_threadargs {
 409         struct inode *inode;
 410         struct nfs_client *clp;
 411         const nfs4_stateid *stateid;
 412
 413         struct completion started;
 414         int result;
 415 };
 416
 417 static int recall_thread(void *data)
 418 {
 419         struct recall_threadargs *args = (struct recall_threadargs *)data;
 420         struct inode *inode = igrab(args->inode);
 421         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 422         struct nfs_inode *nfsi = NFS_I(inode);
 423         struct nfs_delegation *delegation;
 424
 425         daemonize("nfsv4-delegreturn");
 426
 427         nfs_msync_inode(inode);
 428         down_read(&clp->cl_sem);
 429         down_write(&nfsi->rwsem);
 430         spin_lock(&clp->cl_lock);
 431         delegation = nfs_detach_delegation_locked(nfsi, args->stateid);
 432         if (delegation != NULL)
 433                 args->result = 0;
 434         else
 435                 args->result = -ENOENT;
 436         spin_unlock(&clp->cl_lock);
 437         complete(&args->started);
 438         nfs_delegation_claim_opens(inode, args->stateid);
 439         up_write(&nfsi->rwsem);
 440         up_read(&clp->cl_sem);
 441         nfs_msync_inode(inode);
 442
 443         if (delegation != NULL)
 444                 nfs_do_return_delegation(inode, delegation, 1);
 445         iput(inode);
 446         module_put_and_exit(0);
 447 }
 448
 449 /*
 450  * Asynchronous delegation recall!
 451  */
 452 int nfs_async_inode_return_delegation(struct inode *inode, const nfs4_stateid *stateid)
 453 {
 454         struct recall_threadargs data = {
 455                 .inode = inode,
 456                 .stateid = stateid,
 457         };
 458         int status;
 459
 460         init_completion(&data.started);
 461         __module_get(THIS_MODULE);
 462         status = kernel_thread(recall_thread, &data, CLONE_KERNEL);
 463         if (status < 0)
 464                 goto out_module_put;
 465         wait_for_completion(&data.started);
 466         return data.result;
 467 out_module_put:
 468         module_put(THIS_MODULE);
 469         return status;
 470 }
 471
 472 /*
 473  * Retrieve the inode associated with a delegation
 474  */
 475 struct inode *nfs_delegation_find_inode(struct nfs_client *clp, const struct nfs_fh *fhandle)
 476 {
 477         struct nfs_delegation *delegation;
 478         struct inode *res = NULL;
 479         rcu_read_lock();
 480         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 481                 spin_lock(&delegation->lock);
 482                 if (delegation->inode != NULL &&
 483                     nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
 484                         res = igrab(delegation->inode);
 485                 }
 486                 spin_unlock(&delegation->lock);
 487                 if (res != NULL)
 488                         break;
 489         }
 490         rcu_read_unlock();
 491         return res;
 492 }
 493
 494 /*
 495  * Mark all delegations as needing to be reclaimed
 496  */
 497 void nfs_delegation_mark_reclaim(struct nfs_client *clp)
 498 {
 499         struct nfs_delegation *delegation;
 500         rcu_read_lock();
 501         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list)
 502                 set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
 503         rcu_read_unlock();
 504 }
 505
 506 /*
 507  * Reap all unclaimed delegations after reboot recovery is done
 508  */
 509 void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
 510 {
 511         struct nfs_delegation *delegation;
 512         struct inode *inode;
 513 restart:
 514         rcu_read_lock();
 515         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 516                 if (test_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags) == 0)
 517                         continue;
 518                 inode = nfs_delegation_grab_inode(delegation);
 519                 if (inode == NULL)
 520                         continue;
 521                 spin_lock(&clp->cl_lock);
 522                 delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
 523                 spin_unlock(&clp->cl_lock);
 524                 rcu_read_unlock();
 525                 if (delegation != NULL)
 526                         nfs_free_delegation(delegation);
 527                 iput(inode);
 528                 goto restart;
 529         }
 530         rcu_read_unlock();
 531 }
 532
 533 int nfs4_copy_delegation_stateid(nfs4_stateid *dst, struct inode *inode)
 534 {
 535         struct nfs_inode *nfsi = NFS_I(inode);
 536         struct nfs_delegation *delegation;
 537         int ret = 0;
 538
 539         rcu_read_lock();
 540         delegation = rcu_dereference(nfsi->delegation);
 541         if (delegation != NULL) {
 542                 memcpy(dst->data, delegation->stateid.data, sizeof(dst->data));
 543                 ret = 1;
 544         }
 545         rcu_read_unlock();
 546         return ret;
 547 }