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 != 0; 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                                                 __FUNCTION__, 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 /*
 129  * Set up a delegation on an inode
 130  */
 131 int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
 132 {
 133         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 134         struct nfs_inode *nfsi = NFS_I(inode);
 135         struct nfs_delegation *delegation;
 136         int status = 0;
 137
 138         delegation = kmalloc(sizeof(*delegation), GFP_KERNEL);
 139         if (delegation == NULL)
 140                 return -ENOMEM;
 141         memcpy(delegation->stateid.data, res->delegation.data,
 142                         sizeof(delegation->stateid.data));
 143         delegation->type = res->delegation_type;
 144         delegation->maxsize = res->maxsize;
 145         delegation->change_attr = nfsi->change_attr;
 146         delegation->cred = get_rpccred(cred);
 147         delegation->inode = inode;
 148
 149         spin_lock(&clp->cl_lock);
 150         if (rcu_dereference(nfsi->delegation) == NULL) {
 151                 list_add_rcu(&delegation->super_list, &clp->cl_delegations);
 152                 nfsi->delegation_state = delegation->type;
 153                 rcu_assign_pointer(nfsi->delegation, delegation);
 154                 delegation = NULL;
 155         } else {
 156                 if (memcmp(&delegation->stateid, &nfsi->delegation->stateid,
 157                                         sizeof(delegation->stateid)) != 0 ||
 158                                 delegation->type != nfsi->delegation->type) {
 159                         printk("%s: server %u.%u.%u.%u, handed out a duplicate delegation!\n",
 160                                         __FUNCTION__, NIPQUAD(clp->cl_addr.sin_addr));
 161                         status = -EIO;
 162                 }
 163         }
 164
 165         /* Ensure we revalidate the attributes and page cache! */
 166         spin_lock(&inode->i_lock);
 167         nfsi->cache_validity |= NFS_INO_REVAL_FORCED;
 168         spin_unlock(&inode->i_lock);
 169
 170         spin_unlock(&clp->cl_lock);
 171         if (delegation != NULL)
 172                 nfs_free_delegation(delegation);
 173         return status;
 174 }
 175
 176 static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation)
 177 {
 178         int res = 0;
 179
 180         res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid);
 181         nfs_free_delegation(delegation);
 182         return res;
 183 }
 184
 185 /* Sync all data to disk upon delegation return */
 186 static void nfs_msync_inode(struct inode *inode)
 187 {
 188         filemap_fdatawrite(inode->i_mapping);
 189         nfs_wb_all(inode);
 190         filemap_fdatawait(inode->i_mapping);
 191 }
 192
 193 /*
 194  * Basic procedure for returning a delegation to the server
 195  */
 196 static int __nfs_inode_return_delegation(struct inode *inode, struct nfs_delegation *delegation)
 197 {
 198         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 199         struct nfs_inode *nfsi = NFS_I(inode);
 200
 201         nfs_msync_inode(inode);
 202         down_read(&clp->cl_sem);
 203         /* Guard against new delegated open calls */
 204         down_write(&nfsi->rwsem);
 205         nfs_delegation_claim_opens(inode, &delegation->stateid);
 206         up_write(&nfsi->rwsem);
 207         up_read(&clp->cl_sem);
 208         nfs_msync_inode(inode);
 209
 210         return nfs_do_return_delegation(inode, delegation);
 211 }
 212
 213 static struct nfs_delegation *nfs_detach_delegation_locked(struct nfs_inode *nfsi, const nfs4_stateid *stateid)
 214 {
 215         struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
 216
 217         if (delegation == NULL)
 218                 goto nomatch;
 219         if (stateid != NULL && memcmp(delegation->stateid.data, stateid->data,
 220                                 sizeof(delegation->stateid.data)) != 0)
 221                 goto nomatch;
 222         list_del_rcu(&delegation->super_list);
 223         nfsi->delegation_state = 0;
 224         rcu_assign_pointer(nfsi->delegation, NULL);
 225         return delegation;
 226 nomatch:
 227         return NULL;
 228 }
 229
 230 int nfs_inode_return_delegation(struct inode *inode)
 231 {
 232         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 233         struct nfs_inode *nfsi = NFS_I(inode);
 234         struct nfs_delegation *delegation;
 235         int err = 0;
 236
 237         if (rcu_dereference(nfsi->delegation) != NULL) {
 238                 spin_lock(&clp->cl_lock);
 239                 delegation = nfs_detach_delegation_locked(nfsi, NULL);
 240                 spin_unlock(&clp->cl_lock);
 241                 if (delegation != NULL)
 242                         err = __nfs_inode_return_delegation(inode, delegation);
 243         }
 244         return err;
 245 }
 246
 247 /*
 248  * Return all delegations associated to a super block
 249  */
 250 void nfs_return_all_delegations(struct super_block *sb)
 251 {
 252         struct nfs_client *clp = NFS_SB(sb)->nfs_client;
 253         struct nfs_delegation *delegation;
 254         struct inode *inode;
 255
 256         if (clp == NULL)
 257                 return;
 258 restart:
 259         rcu_read_lock();
 260         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 261                 if (delegation->inode->i_sb != sb)
 262                         continue;
 263                 inode = igrab(delegation->inode);
 264                 if (inode == NULL)
 265                         continue;
 266                 spin_lock(&clp->cl_lock);
 267                 delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
 268                 spin_unlock(&clp->cl_lock);
 269                 rcu_read_unlock();
 270                 if (delegation != NULL)
 271                         __nfs_inode_return_delegation(inode, delegation);
 272                 iput(inode);
 273                 goto restart;
 274         }
 275         rcu_read_unlock();
 276 }
 277
 278 static int nfs_do_expire_all_delegations(void *ptr)
 279 {
 280         struct nfs_client *clp = ptr;
 281         struct nfs_delegation *delegation;
 282         struct inode *inode;
 283
 284         allow_signal(SIGKILL);
 285 restart:
 286         if (test_bit(NFS4CLNT_STATE_RECOVER, &clp->cl_state) != 0)
 287                 goto out;
 288         if (test_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state) == 0)
 289                 goto out;
 290         rcu_read_lock();
 291         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 292                 inode = igrab(delegation->inode);
 293                 if (inode == NULL)
 294                         continue;
 295                 spin_lock(&clp->cl_lock);
 296                 delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
 297                 spin_unlock(&clp->cl_lock);
 298                 rcu_read_unlock();
 299                 if (delegation)
 300                         __nfs_inode_return_delegation(inode, delegation);
 301                 iput(inode);
 302                 goto restart;
 303         }
 304         rcu_read_unlock();
 305 out:
 306         nfs_put_client(clp);
 307         module_put_and_exit(0);
 308 }
 309
 310 void nfs_expire_all_delegations(struct nfs_client *clp)
 311 {
 312         struct task_struct *task;
 313
 314         __module_get(THIS_MODULE);
 315         atomic_inc(&clp->cl_count);
 316         task = kthread_run(nfs_do_expire_all_delegations, clp,
 317                         "%u.%u.%u.%u-delegreturn",
 318                         NIPQUAD(clp->cl_addr.sin_addr));
 319         if (!IS_ERR(task))
 320                 return;
 321         nfs_put_client(clp);
 322         module_put(THIS_MODULE);
 323 }
 324
 325 /*
 326  * Return all delegations following an NFS4ERR_CB_PATH_DOWN error.
 327  */
 328 void nfs_handle_cb_pathdown(struct nfs_client *clp)
 329 {
 330         struct nfs_delegation *delegation;
 331         struct inode *inode;
 332
 333         if (clp == NULL)
 334                 return;
 335 restart:
 336         rcu_read_lock();
 337         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 338                 inode = igrab(delegation->inode);
 339                 if (inode == NULL)
 340                         continue;
 341                 spin_lock(&clp->cl_lock);
 342                 delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
 343                 spin_unlock(&clp->cl_lock);
 344                 rcu_read_unlock();
 345                 if (delegation != NULL)
 346                         __nfs_inode_return_delegation(inode, delegation);
 347                 iput(inode);
 348                 goto restart;
 349         }
 350         rcu_read_unlock();
 351 }
 352
 353 struct recall_threadargs {
 354         struct inode *inode;
 355         struct nfs_client *clp;
 356         const nfs4_stateid *stateid;
 357
 358         struct completion started;
 359         int result;
 360 };
 361
 362 static int recall_thread(void *data)
 363 {
 364         struct recall_threadargs *args = (struct recall_threadargs *)data;
 365         struct inode *inode = igrab(args->inode);
 366         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 367         struct nfs_inode *nfsi = NFS_I(inode);
 368         struct nfs_delegation *delegation;
 369
 370         daemonize("nfsv4-delegreturn");
 371
 372         nfs_msync_inode(inode);
 373         down_read(&clp->cl_sem);
 374         down_write(&nfsi->rwsem);
 375         spin_lock(&clp->cl_lock);
 376         delegation = nfs_detach_delegation_locked(nfsi, args->stateid);
 377         if (delegation != NULL)
 378                 args->result = 0;
 379         else
 380                 args->result = -ENOENT;
 381         spin_unlock(&clp->cl_lock);
 382         complete(&args->started);
 383         nfs_delegation_claim_opens(inode, args->stateid);
 384         up_write(&nfsi->rwsem);
 385         up_read(&clp->cl_sem);
 386         nfs_msync_inode(inode);
 387
 388         if (delegation != NULL)
 389                 nfs_do_return_delegation(inode, delegation);
 390         iput(inode);
 391         module_put_and_exit(0);
 392 }
 393
 394 /*
 395  * Asynchronous delegation recall!
 396  */
 397 int nfs_async_inode_return_delegation(struct inode *inode, const nfs4_stateid *stateid)
 398 {
 399         struct recall_threadargs data = {
 400                 .inode = inode,
 401                 .stateid = stateid,
 402         };
 403         int status;
 404
 405         init_completion(&data.started);
 406         __module_get(THIS_MODULE);
 407         status = kernel_thread(recall_thread, &data, CLONE_KERNEL);
 408         if (status < 0)
 409                 goto out_module_put;
 410         wait_for_completion(&data.started);
 411         return data.result;
 412 out_module_put:
 413         module_put(THIS_MODULE);
 414         return status;
 415 }
 416
 417 /*
 418  * Retrieve the inode associated with a delegation
 419  */
 420 struct inode *nfs_delegation_find_inode(struct nfs_client *clp, const struct nfs_fh *fhandle)
 421 {
 422         struct nfs_delegation *delegation;
 423         struct inode *res = NULL;
 424         rcu_read_lock();
 425         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 426                 if (nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
 427                         res = igrab(delegation->inode);
 428                         break;
 429                 }
 430         }
 431         rcu_read_unlock();
 432         return res;
 433 }
 434
 435 /*
 436  * Mark all delegations as needing to be reclaimed
 437  */
 438 void nfs_delegation_mark_reclaim(struct nfs_client *clp)
 439 {
 440         struct nfs_delegation *delegation;
 441         rcu_read_lock();
 442         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list)
 443                 delegation->flags |= NFS_DELEGATION_NEED_RECLAIM;
 444         rcu_read_unlock();
 445 }
 446
 447 /*
 448  * Reap all unclaimed delegations after reboot recovery is done
 449  */
 450 void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
 451 {
 452         struct nfs_delegation *delegation;
 453 restart:
 454         rcu_read_lock();
 455         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 456                 if ((delegation->flags & NFS_DELEGATION_NEED_RECLAIM) == 0)
 457                         continue;
 458                 spin_lock(&clp->cl_lock);
 459                 delegation = nfs_detach_delegation_locked(NFS_I(delegation->inode), NULL);
 460                 spin_unlock(&clp->cl_lock);
 461                 rcu_read_unlock();
 462                 if (delegation != NULL)
 463                         nfs_free_delegation(delegation);
 464                 goto restart;
 465         }
 466         rcu_read_unlock();
 467 }
 468
 469 int nfs4_copy_delegation_stateid(nfs4_stateid *dst, struct inode *inode)
 470 {
 471         struct nfs_inode *nfsi = NFS_I(inode);
 472         struct nfs_delegation *delegation;
 473         int ret = 0;
 474
 475         rcu_read_lock();
 476         delegation = rcu_dereference(nfsi->delegation);
 477         if (delegation != NULL) {
 478                 memcpy(dst->data, delegation->stateid.data, sizeof(dst->data));
 479                 ret = 1;
 480         }
 481         rcu_read_unlock();
 482         return ret;
 483 }