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