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         delegation->flags &= ~NFS_DELEGATION_NEED_RECLAIM;
 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 nfs_delegation *nfs_detach_delegation_locked(struct nfs_inode *nfsi, const nfs4_stateid *stateid)
 138 {
 139         struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
 140
 141         if (delegation == NULL)
 142                 goto nomatch;
 143         spin_lock(&delegation->lock);
 144         if (stateid != NULL && memcmp(delegation->stateid.data, stateid->data,
 145                                 sizeof(delegation->stateid.data)) != 0)
 146                 goto nomatch_unlock;
 147         list_del_rcu(&delegation->super_list);
 148         nfsi->delegation_state = 0;
 149         rcu_assign_pointer(nfsi->delegation, NULL);
 150         spin_unlock(&delegation->lock);
 151         return delegation;
 152 nomatch_unlock:
 153         spin_unlock(&delegation->lock);
 154 nomatch:
 155         return NULL;
 156 }
 157
 158 /*
 159  * Set up a delegation on an inode
 160  */
 161 int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
 162 {
 163         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 164         struct nfs_inode *nfsi = NFS_I(inode);
 165         struct nfs_delegation *delegation;
 166         struct nfs_delegation *freeme = NULL;
 167         int status = 0;
 168
 169         delegation = kmalloc(sizeof(*delegation), GFP_KERNEL);
 170         if (delegation == NULL)
 171                 return -ENOMEM;
 172         memcpy(delegation->stateid.data, res->delegation.data,
 173                         sizeof(delegation->stateid.data));
 174         delegation->type = res->delegation_type;
 175         delegation->maxsize = res->maxsize;
 176         delegation->change_attr = nfsi->change_attr;
 177         delegation->cred = get_rpccred(cred);
 178         delegation->inode = inode;
 179         spin_lock_init(&delegation->lock);
 180
 181         spin_lock(&clp->cl_lock);
 182         if (rcu_dereference(nfsi->delegation) != NULL) {
 183                 if (memcmp(&delegation->stateid, &nfsi->delegation->stateid,
 184                                         sizeof(delegation->stateid)) == 0 &&
 185                                 delegation->type == nfsi->delegation->type) {
 186                         goto out;
 187                 }
 188                 /*
 189                  * Deal with broken servers that hand out two
 190                  * delegations for the same file.
 191                  */
 192                 dfprintk(FILE, "%s: server %s handed out "
 193                                 "a duplicate delegation!\n",
 194                                 __func__, clp->cl_hostname);
 195                 if (delegation->type <= nfsi->delegation->type) {
 196                         freeme = delegation;
 197                         delegation = NULL;
 198                         goto out;
 199                 }
 200                 freeme = nfs_detach_delegation_locked(nfsi, NULL);
 201         }
 202         list_add_rcu(&delegation->super_list, &clp->cl_delegations);
 203         nfsi->delegation_state = delegation->type;
 204         rcu_assign_pointer(nfsi->delegation, delegation);
 205         delegation = NULL;
 206
 207         /* Ensure we revalidate the attributes and page cache! */
 208         spin_lock(&inode->i_lock);
 209         nfsi->cache_validity |= NFS_INO_REVAL_FORCED;
 210         spin_unlock(&inode->i_lock);
 211
 212 out:
 213         spin_unlock(&clp->cl_lock);
 214         if (delegation != NULL)
 215                 nfs_free_delegation(delegation);
 216         if (freeme != NULL)
 217                 nfs_do_return_delegation(inode, freeme, 0);
 218         return status;
 219 }
 220
 221 /* Sync all data to disk upon delegation return */
 222 static void nfs_msync_inode(struct inode *inode)
 223 {
 224         filemap_fdatawrite(inode->i_mapping);
 225         nfs_wb_all(inode);
 226         filemap_fdatawait(inode->i_mapping);
 227 }
 228
 229 /*
 230  * Basic procedure for returning a delegation to the server
 231  */
 232 static int __nfs_inode_return_delegation(struct inode *inode, struct nfs_delegation *delegation)
 233 {
 234         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 235         struct nfs_inode *nfsi = NFS_I(inode);
 236
 237         nfs_msync_inode(inode);
 238         down_read(&clp->cl_sem);
 239         /* Guard against new delegated open calls */
 240         down_write(&nfsi->rwsem);
 241         nfs_delegation_claim_opens(inode, &delegation->stateid);
 242         up_write(&nfsi->rwsem);
 243         up_read(&clp->cl_sem);
 244         nfs_msync_inode(inode);
 245
 246         return nfs_do_return_delegation(inode, delegation, 1);
 247 }
 248
 249 /*
 250  * This function returns the delegation without reclaiming opens
 251  * or protecting against delegation reclaims.
 252  * It is therefore really only safe to be called from
 253  * nfs4_clear_inode()
 254  */
 255 void nfs_inode_return_delegation_noreclaim(struct inode *inode)
 256 {
 257         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 258         struct nfs_inode *nfsi = NFS_I(inode);
 259         struct nfs_delegation *delegation;
 260
 261         if (rcu_dereference(nfsi->delegation) != NULL) {
 262                 spin_lock(&clp->cl_lock);
 263                 delegation = nfs_detach_delegation_locked(nfsi, NULL);
 264                 spin_unlock(&clp->cl_lock);
 265                 if (delegation != NULL)
 266                         nfs_do_return_delegation(inode, delegation, 0);
 267         }
 268 }
 269
 270 int nfs_inode_return_delegation(struct inode *inode)
 271 {
 272         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 273         struct nfs_inode *nfsi = NFS_I(inode);
 274         struct nfs_delegation *delegation;
 275         int err = 0;
 276
 277         if (rcu_dereference(nfsi->delegation) != NULL) {
 278                 spin_lock(&clp->cl_lock);
 279                 delegation = nfs_detach_delegation_locked(nfsi, NULL);
 280                 spin_unlock(&clp->cl_lock);
 281                 if (delegation != NULL)
 282                         err = __nfs_inode_return_delegation(inode, delegation);
 283         }
 284         return err;
 285 }
 286
 287 /*
 288  * Return all delegations associated to a super block
 289  */
 290 void nfs_return_all_delegations(struct super_block *sb)
 291 {
 292         struct nfs_client *clp = NFS_SB(sb)->nfs_client;
 293         struct nfs_delegation *delegation;
 294         struct inode *inode;
 295
 296         if (clp == NULL)
 297                 return;
 298 restart:
 299         rcu_read_lock();
 300         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 301                 if (delegation->inode->i_sb != sb)
 302                         continue;
 303                 inode = igrab(delegation->inode);
 304                 if (inode == NULL)
 305                         continue;
 306                 spin_lock(&clp->cl_lock);
 307                 delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
 308                 spin_unlock(&clp->cl_lock);
 309                 rcu_read_unlock();
 310                 if (delegation != NULL)
 311                         __nfs_inode_return_delegation(inode, delegation);
 312                 iput(inode);
 313                 goto restart;
 314         }
 315         rcu_read_unlock();
 316 }
 317
 318 static int nfs_do_expire_all_delegations(void *ptr)
 319 {
 320         struct nfs_client *clp = ptr;
 321         struct nfs_delegation *delegation;
 322         struct inode *inode;
 323
 324         allow_signal(SIGKILL);
 325 restart:
 326         if (test_bit(NFS4CLNT_STATE_RECOVER, &clp->cl_state) != 0)
 327                 goto out;
 328         if (test_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state) == 0)
 329                 goto out;
 330         rcu_read_lock();
 331         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 332                 inode = igrab(delegation->inode);
 333                 if (inode == NULL)
 334                         continue;
 335                 spin_lock(&clp->cl_lock);
 336                 delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
 337                 spin_unlock(&clp->cl_lock);
 338                 rcu_read_unlock();
 339                 if (delegation)
 340                         __nfs_inode_return_delegation(inode, delegation);
 341                 iput(inode);
 342                 goto restart;
 343         }
 344         rcu_read_unlock();
 345 out:
 346         nfs_put_client(clp);
 347         module_put_and_exit(0);
 348 }
 349
 350 void nfs_expire_all_delegations(struct nfs_client *clp)
 351 {
 352         struct task_struct *task;
 353
 354         __module_get(THIS_MODULE);
 355         atomic_inc(&clp->cl_count);
 356         task = kthread_run(nfs_do_expire_all_delegations, clp,
 357                                 "%s-delegreturn",
 358                                 rpc_peeraddr2str(clp->cl_rpcclient,
 359                                                         RPC_DISPLAY_ADDR));
 360         if (!IS_ERR(task))
 361                 return;
 362         nfs_put_client(clp);
 363         module_put(THIS_MODULE);
 364 }
 365
 366 /*
 367  * Return all delegations following an NFS4ERR_CB_PATH_DOWN error.
 368  */
 369 void nfs_handle_cb_pathdown(struct nfs_client *clp)
 370 {
 371         struct nfs_delegation *delegation;
 372         struct inode *inode;
 373
 374         if (clp == NULL)
 375                 return;
 376 restart:
 377         rcu_read_lock();
 378         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 379                 inode = igrab(delegation->inode);
 380                 if (inode == NULL)
 381                         continue;
 382                 spin_lock(&clp->cl_lock);
 383                 delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
 384                 spin_unlock(&clp->cl_lock);
 385                 rcu_read_unlock();
 386                 if (delegation != NULL)
 387                         __nfs_inode_return_delegation(inode, delegation);
 388                 iput(inode);
 389                 goto restart;
 390         }
 391         rcu_read_unlock();
 392 }
 393
 394 struct recall_threadargs {
 395         struct inode *inode;
 396         struct nfs_client *clp;
 397         const nfs4_stateid *stateid;
 398
 399         struct completion started;
 400         int result;
 401 };
 402
 403 static int recall_thread(void *data)
 404 {
 405         struct recall_threadargs *args = (struct recall_threadargs *)data;
 406         struct inode *inode = igrab(args->inode);
 407         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 408         struct nfs_inode *nfsi = NFS_I(inode);
 409         struct nfs_delegation *delegation;
 410
 411         daemonize("nfsv4-delegreturn");
 412
 413         nfs_msync_inode(inode);
 414         down_read(&clp->cl_sem);
 415         down_write(&nfsi->rwsem);
 416         spin_lock(&clp->cl_lock);
 417         delegation = nfs_detach_delegation_locked(nfsi, args->stateid);
 418         if (delegation != NULL)
 419                 args->result = 0;
 420         else
 421                 args->result = -ENOENT;
 422         spin_unlock(&clp->cl_lock);
 423         complete(&args->started);
 424         nfs_delegation_claim_opens(inode, args->stateid);
 425         up_write(&nfsi->rwsem);
 426         up_read(&clp->cl_sem);
 427         nfs_msync_inode(inode);
 428
 429         if (delegation != NULL)
 430                 nfs_do_return_delegation(inode, delegation, 1);
 431         iput(inode);
 432         module_put_and_exit(0);
 433 }
 434
 435 /*
 436  * Asynchronous delegation recall!
 437  */
 438 int nfs_async_inode_return_delegation(struct inode *inode, const nfs4_stateid *stateid)
 439 {
 440         struct recall_threadargs data = {
 441                 .inode = inode,
 442                 .stateid = stateid,
 443         };
 444         int status;
 445
 446         init_completion(&data.started);
 447         __module_get(THIS_MODULE);
 448         status = kernel_thread(recall_thread, &data, CLONE_KERNEL);
 449         if (status < 0)
 450                 goto out_module_put;
 451         wait_for_completion(&data.started);
 452         return data.result;
 453 out_module_put:
 454         module_put(THIS_MODULE);
 455         return status;
 456 }
 457
 458 /*
 459  * Retrieve the inode associated with a delegation
 460  */
 461 struct inode *nfs_delegation_find_inode(struct nfs_client *clp, const struct nfs_fh *fhandle)
 462 {
 463         struct nfs_delegation *delegation;
 464         struct inode *res = NULL;
 465         rcu_read_lock();
 466         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 467                 if (nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
 468                         res = igrab(delegation->inode);
 469                         break;
 470                 }
 471         }
 472         rcu_read_unlock();
 473         return res;
 474 }
 475
 476 /*
 477  * Mark all delegations as needing to be reclaimed
 478  */
 479 void nfs_delegation_mark_reclaim(struct nfs_client *clp)
 480 {
 481         struct nfs_delegation *delegation;
 482         rcu_read_lock();
 483         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list)
 484                 delegation->flags |= NFS_DELEGATION_NEED_RECLAIM;
 485         rcu_read_unlock();
 486 }
 487
 488 /*
 489  * Reap all unclaimed delegations after reboot recovery is done
 490  */
 491 void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
 492 {
 493         struct nfs_delegation *delegation;
 494 restart:
 495         rcu_read_lock();
 496         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 497                 if ((delegation->flags & NFS_DELEGATION_NEED_RECLAIM) == 0)
 498                         continue;
 499                 spin_lock(&clp->cl_lock);
 500                 delegation = nfs_detach_delegation_locked(NFS_I(delegation->inode), NULL);
 501                 spin_unlock(&clp->cl_lock);
 502                 rcu_read_unlock();
 503                 if (delegation != NULL)
 504                         nfs_free_delegation(delegation);
 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 }