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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(KERN_WARNING "%s: server %s handed out "
 160                                         "a duplicate delegation!\n",
 161                                         __FUNCTION__, clp->cl_hostname);
 162                         status = -EIO;
 163                 }
 164         }
 165
 166         /* Ensure we revalidate the attributes and page cache! */
 167         spin_lock(&inode->i_lock);
 168         nfsi->cache_validity |= NFS_INO_REVAL_FORCED;
 169         spin_unlock(&inode->i_lock);
 170
 171         spin_unlock(&clp->cl_lock);
 172         if (delegation != NULL)
 173                 nfs_free_delegation(delegation);
 174         return status;
 175 }
 176
 177 static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation)
 178 {
 179         int res = 0;
 180
 181         res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid);
 182         nfs_free_delegation(delegation);
 183         return res;
 184 }
 185
 186 /* Sync all data to disk upon delegation return */
 187 static void nfs_msync_inode(struct inode *inode)
 188 {
 189         filemap_fdatawrite(inode->i_mapping);
 190         nfs_wb_all(inode);
 191         filemap_fdatawait(inode->i_mapping);
 192 }
 193
 194 /*
 195  * Basic procedure for returning a delegation to the server
 196  */
 197 static int __nfs_inode_return_delegation(struct inode *inode, struct nfs_delegation *delegation)
 198 {
 199         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 200         struct nfs_inode *nfsi = NFS_I(inode);
 201
 202         nfs_msync_inode(inode);
 203         down_read(&clp->cl_sem);
 204         /* Guard against new delegated open calls */
 205         down_write(&nfsi->rwsem);
 206         nfs_delegation_claim_opens(inode, &delegation->stateid);
 207         up_write(&nfsi->rwsem);
 208         up_read(&clp->cl_sem);
 209         nfs_msync_inode(inode);
 210
 211         return nfs_do_return_delegation(inode, delegation);
 212 }
 213
 214 static struct nfs_delegation *nfs_detach_delegation_locked(struct nfs_inode *nfsi, const nfs4_stateid *stateid)
 215 {
 216         struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
 217
 218         if (delegation == NULL)
 219                 goto nomatch;
 220         if (stateid != NULL && memcmp(delegation->stateid.data, stateid->data,
 221                                 sizeof(delegation->stateid.data)) != 0)
 222                 goto nomatch;
 223         list_del_rcu(&delegation->super_list);
 224         nfsi->delegation_state = 0;
 225         rcu_assign_pointer(nfsi->delegation, NULL);
 226         return delegation;
 227 nomatch:
 228         return NULL;
 229 }
 230
 231 int nfs_inode_return_delegation(struct inode *inode)
 232 {
 233         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 234         struct nfs_inode *nfsi = NFS_I(inode);
 235         struct nfs_delegation *delegation;
 236         int err = 0;
 237
 238         if (rcu_dereference(nfsi->delegation) != NULL) {
 239                 spin_lock(&clp->cl_lock);
 240                 delegation = nfs_detach_delegation_locked(nfsi, NULL);
 241                 spin_unlock(&clp->cl_lock);
 242                 if (delegation != NULL)
 243                         err = __nfs_inode_return_delegation(inode, delegation);
 244         }
 245         return err;
 246 }
 247
 248 /*
 249  * Return all delegations associated to a super block
 250  */
 251 void nfs_return_all_delegations(struct super_block *sb)
 252 {
 253         struct nfs_client *clp = NFS_SB(sb)->nfs_client;
 254         struct nfs_delegation *delegation;
 255         struct inode *inode;
 256
 257         if (clp == NULL)
 258                 return;
 259 restart:
 260         rcu_read_lock();
 261         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 262                 if (delegation->inode->i_sb != sb)
 263                         continue;
 264                 inode = igrab(delegation->inode);
 265                 if (inode == NULL)
 266                         continue;
 267                 spin_lock(&clp->cl_lock);
 268                 delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
 269                 spin_unlock(&clp->cl_lock);
 270                 rcu_read_unlock();
 271                 if (delegation != NULL)
 272                         __nfs_inode_return_delegation(inode, delegation);
 273                 iput(inode);
 274                 goto restart;
 275         }
 276         rcu_read_unlock();
 277 }
 278
 279 static int nfs_do_expire_all_delegations(void *ptr)
 280 {
 281         struct nfs_client *clp = ptr;
 282         struct nfs_delegation *delegation;
 283         struct inode *inode;
 284
 285         allow_signal(SIGKILL);
 286 restart:
 287         if (test_bit(NFS4CLNT_STATE_RECOVER, &clp->cl_state) != 0)
 288                 goto out;
 289         if (test_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state) == 0)
 290                 goto out;
 291         rcu_read_lock();
 292         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 293                 inode = igrab(delegation->inode);
 294                 if (inode == NULL)
 295                         continue;
 296                 spin_lock(&clp->cl_lock);
 297                 delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
 298                 spin_unlock(&clp->cl_lock);
 299                 rcu_read_unlock();
 300                 if (delegation)
 301                         __nfs_inode_return_delegation(inode, delegation);
 302                 iput(inode);
 303                 goto restart;
 304         }
 305         rcu_read_unlock();
 306 out:
 307         nfs_put_client(clp);
 308         module_put_and_exit(0);
 309 }
 310
 311 void nfs_expire_all_delegations(struct nfs_client *clp)
 312 {
 313         struct task_struct *task;
 314
 315         __module_get(THIS_MODULE);
 316         atomic_inc(&clp->cl_count);
 317         task = kthread_run(nfs_do_expire_all_delegations, clp,
 318                                 "%s-delegreturn",
 319                                 rpc_peeraddr2str(clp->cl_rpcclient,
 320                                                         RPC_DISPLAY_ADDR));
 321         if (!IS_ERR(task))
 322                 return;
 323         nfs_put_client(clp);
 324         module_put(THIS_MODULE);
 325 }
 326
 327 /*
 328  * Return all delegations following an NFS4ERR_CB_PATH_DOWN error.
 329  */
 330 void nfs_handle_cb_pathdown(struct nfs_client *clp)
 331 {
 332         struct nfs_delegation *delegation;
 333         struct inode *inode;
 334
 335         if (clp == NULL)
 336                 return;
 337 restart:
 338         rcu_read_lock();
 339         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 340                 inode = igrab(delegation->inode);
 341                 if (inode == NULL)
 342                         continue;
 343                 spin_lock(&clp->cl_lock);
 344                 delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
 345                 spin_unlock(&clp->cl_lock);
 346                 rcu_read_unlock();
 347                 if (delegation != NULL)
 348                         __nfs_inode_return_delegation(inode, delegation);
 349                 iput(inode);
 350                 goto restart;
 351         }
 352         rcu_read_unlock();
 353 }
 354
 355 struct recall_threadargs {
 356         struct inode *inode;
 357         struct nfs_client *clp;
 358         const nfs4_stateid *stateid;
 359
 360         struct completion started;
 361         int result;
 362 };
 363
 364 static int recall_thread(void *data)
 365 {
 366         struct recall_threadargs *args = (struct recall_threadargs *)data;
 367         struct inode *inode = igrab(args->inode);
 368         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 369         struct nfs_inode *nfsi = NFS_I(inode);
 370         struct nfs_delegation *delegation;
 371
 372         daemonize("nfsv4-delegreturn");
 373
 374         nfs_msync_inode(inode);
 375         down_read(&clp->cl_sem);
 376         down_write(&nfsi->rwsem);
 377         spin_lock(&clp->cl_lock);
 378         delegation = nfs_detach_delegation_locked(nfsi, args->stateid);
 379         if (delegation != NULL)
 380                 args->result = 0;
 381         else
 382                 args->result = -ENOENT;
 383         spin_unlock(&clp->cl_lock);
 384         complete(&args->started);
 385         nfs_delegation_claim_opens(inode, args->stateid);
 386         up_write(&nfsi->rwsem);
 387         up_read(&clp->cl_sem);
 388         nfs_msync_inode(inode);
 389
 390         if (delegation != NULL)
 391                 nfs_do_return_delegation(inode, delegation);
 392         iput(inode);
 393         module_put_and_exit(0);
 394 }
 395
 396 /*
 397  * Asynchronous delegation recall!
 398  */
 399 int nfs_async_inode_return_delegation(struct inode *inode, const nfs4_stateid *stateid)
 400 {
 401         struct recall_threadargs data = {
 402                 .inode = inode,
 403                 .stateid = stateid,
 404         };
 405         int status;
 406
 407         init_completion(&data.started);
 408         __module_get(THIS_MODULE);
 409         status = kernel_thread(recall_thread, &data, CLONE_KERNEL);
 410         if (status < 0)
 411                 goto out_module_put;
 412         wait_for_completion(&data.started);
 413         return data.result;
 414 out_module_put:
 415         module_put(THIS_MODULE);
 416         return status;
 417 }
 418
 419 /*
 420  * Retrieve the inode associated with a delegation
 421  */
 422 struct inode *nfs_delegation_find_inode(struct nfs_client *clp, const struct nfs_fh *fhandle)
 423 {
 424         struct nfs_delegation *delegation;
 425         struct inode *res = NULL;
 426         rcu_read_lock();
 427         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 428                 if (nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
 429                         res = igrab(delegation->inode);
 430                         break;
 431                 }
 432         }
 433         rcu_read_unlock();
 434         return res;
 435 }
 436
 437 /*
 438  * Mark all delegations as needing to be reclaimed
 439  */
 440 void nfs_delegation_mark_reclaim(struct nfs_client *clp)
 441 {
 442         struct nfs_delegation *delegation;
 443         rcu_read_lock();
 444         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list)
 445                 delegation->flags |= NFS_DELEGATION_NEED_RECLAIM;
 446         rcu_read_unlock();
 447 }
 448
 449 /*
 450  * Reap all unclaimed delegations after reboot recovery is done
 451  */
 452 void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
 453 {
 454         struct nfs_delegation *delegation;
 455 restart:
 456         rcu_read_lock();
 457         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 458                 if ((delegation->flags & NFS_DELEGATION_NEED_RECLAIM) == 0)
 459                         continue;
 460                 spin_lock(&clp->cl_lock);
 461                 delegation = nfs_detach_delegation_locked(NFS_I(delegation->inode), NULL);
 462                 spin_unlock(&clp->cl_lock);
 463                 rcu_read_unlock();
 464                 if (delegation != NULL)
 465                         nfs_free_delegation(delegation);
 466                 goto restart;
 467         }
 468         rcu_read_unlock();
 469 }
 470
 471 int nfs4_copy_delegation_stateid(nfs4_stateid *dst, struct inode *inode)
 472 {
 473         struct nfs_inode *nfsi = NFS_I(inode);
 474         struct nfs_delegation *delegation;
 475         int ret = 0;
 476
 477         rcu_read_lock();
 478         delegation = rcu_dereference(nfsi->delegation);
 479         if (delegation != NULL) {
 480                 memcpy(dst->data, delegation->stateid.data, sizeof(dst->data));
 481                 ret = 1;
 482         }
 483         rcu_read_unlock();
 484         return ret;
 485 }