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