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