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