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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_free_delegation(struct nfs_delegation *delegation)
  24 {
  25         if (delegation->cred)
  26                 put_rpccred(delegation->cred);
  27         kfree(delegation);
  28 }
  29
  30 static void nfs_free_delegation_callback(struct rcu_head *head)
  31 {
  32         struct nfs_delegation *delegation = container_of(head, struct nfs_delegation, rcu);
  33
  34         nfs_free_delegation(delegation);
  35 }
  36
  37 static int nfs_delegation_claim_locks(struct nfs_open_context *ctx, struct nfs4_state *state)
  38 {
  39         struct inode *inode = state->inode;
  40         struct file_lock *fl;
  41         int status;
  42
  43         for (fl = inode->i_flock; fl != 0; fl = fl->fl_next) {
  44                 if (!(fl->fl_flags & (FL_POSIX|FL_FLOCK)))
  45                         continue;
  46                 if ((struct nfs_open_context *)fl->fl_file->private_data != ctx)
  47                         continue;
  48                 status = nfs4_lock_delegation_recall(state, fl);
  49                 if (status >= 0)
  50                         continue;
  51                 switch (status) {
  52                         default:
  53                                 printk(KERN_ERR "%s: unhandled error %d.\n",
  54                                                 __FUNCTION__, status);
  55                         case -NFS4ERR_EXPIRED:
  56                                 /* kill_proc(fl->fl_pid, SIGLOST, 1); */
  57                         case -NFS4ERR_STALE_CLIENTID:
  58                                 nfs4_schedule_state_recovery(NFS_SERVER(inode)->nfs_client);
  59                                 goto out_err;
  60                 }
  61         }
  62         return 0;
  63 out_err:
  64         return status;
  65 }
  66
  67 static void nfs_delegation_claim_opens(struct inode *inode, const nfs4_stateid *stateid)
  68 {
  69         struct nfs_inode *nfsi = NFS_I(inode);
  70         struct nfs_open_context *ctx;
  71         struct nfs4_state *state;
  72         int err;
  73
  74 again:
  75         spin_lock(&inode->i_lock);
  76         list_for_each_entry(ctx, &nfsi->open_files, list) {
  77                 state = ctx->state;
  78                 if (state == NULL)
  79                         continue;
  80                 if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
  81                         continue;
  82                 if (memcmp(state->stateid.data, stateid->data, sizeof(state->stateid.data)) != 0)
  83                         continue;
  84                 get_nfs_open_context(ctx);
  85                 spin_unlock(&inode->i_lock);
  86                 err = nfs4_open_delegation_recall(ctx, state, stateid);
  87                 if (err >= 0)
  88                         err = nfs_delegation_claim_locks(ctx, state);
  89                 put_nfs_open_context(ctx);
  90                 if (err != 0)
  91                         return;
  92                 goto again;
  93         }
  94         spin_unlock(&inode->i_lock);
  95 }
  96
  97 /*
  98  * Set up a delegation on an inode
  99  */
 100 void nfs_inode_reclaim_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
 101 {
 102         struct nfs_delegation *delegation = NFS_I(inode)->delegation;
 103
 104         if (delegation == NULL)
 105                 return;
 106         memcpy(delegation->stateid.data, res->delegation.data,
 107                         sizeof(delegation->stateid.data));
 108         delegation->type = res->delegation_type;
 109         delegation->maxsize = res->maxsize;
 110         put_rpccred(cred);
 111         delegation->cred = get_rpccred(cred);
 112         delegation->flags &= ~NFS_DELEGATION_NEED_RECLAIM;
 113         NFS_I(inode)->delegation_state = delegation->type;
 114         smp_wmb();
 115 }
 116
 117 /*
 118  * Set up a delegation on an inode
 119  */
 120 int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
 121 {
 122         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 123         struct nfs_inode *nfsi = NFS_I(inode);
 124         struct nfs_delegation *delegation;
 125         int status = 0;
 126
 127         /* Ensure we first revalidate the attributes and page cache! */
 128         if ((nfsi->cache_validity & (NFS_INO_REVAL_PAGECACHE|NFS_INO_INVALID_ATTR)))
 129                 __nfs_revalidate_inode(NFS_SERVER(inode), inode);
 130
 131         delegation = kmalloc(sizeof(*delegation), GFP_KERNEL);
 132         if (delegation == NULL)
 133                 return -ENOMEM;
 134         memcpy(delegation->stateid.data, res->delegation.data,
 135                         sizeof(delegation->stateid.data));
 136         delegation->type = res->delegation_type;
 137         delegation->maxsize = res->maxsize;
 138         delegation->change_attr = nfsi->change_attr;
 139         delegation->cred = get_rpccred(cred);
 140         delegation->inode = inode;
 141
 142         spin_lock(&clp->cl_lock);
 143         if (rcu_dereference(nfsi->delegation) == NULL) {
 144                 list_add_rcu(&delegation->super_list, &clp->cl_delegations);
 145                 nfsi->delegation_state = delegation->type;
 146                 rcu_assign_pointer(nfsi->delegation, delegation);
 147                 delegation = NULL;
 148         } else {
 149                 if (memcmp(&delegation->stateid, &nfsi->delegation->stateid,
 150                                         sizeof(delegation->stateid)) != 0 ||
 151                                 delegation->type != nfsi->delegation->type) {
 152                         printk("%s: server %u.%u.%u.%u, handed out a duplicate delegation!\n",
 153                                         __FUNCTION__, NIPQUAD(clp->cl_addr.sin_addr));
 154                         status = -EIO;
 155                 }
 156         }
 157         spin_unlock(&clp->cl_lock);
 158         kfree(delegation);
 159         return status;
 160 }
 161
 162 static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation)
 163 {
 164         int res = 0;
 165
 166         res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid);
 167         call_rcu(&delegation->rcu, nfs_free_delegation_callback);
 168         return res;
 169 }
 170
 171 /* Sync all data to disk upon delegation return */
 172 static void nfs_msync_inode(struct inode *inode)
 173 {
 174         filemap_fdatawrite(inode->i_mapping);
 175         nfs_wb_all(inode);
 176         filemap_fdatawait(inode->i_mapping);
 177 }
 178
 179 /*
 180  * Basic procedure for returning a delegation to the server
 181  */
 182 static int __nfs_inode_return_delegation(struct inode *inode, struct nfs_delegation *delegation)
 183 {
 184         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 185         struct nfs_inode *nfsi = NFS_I(inode);
 186
 187         nfs_msync_inode(inode);
 188         down_read(&clp->cl_sem);
 189         /* Guard against new delegated open calls */
 190         down_write(&nfsi->rwsem);
 191         nfs_delegation_claim_opens(inode, &delegation->stateid);
 192         up_write(&nfsi->rwsem);
 193         up_read(&clp->cl_sem);
 194         nfs_msync_inode(inode);
 195
 196         return nfs_do_return_delegation(inode, delegation);
 197 }
 198
 199 static struct nfs_delegation *nfs_detach_delegation_locked(struct nfs_inode *nfsi, const nfs4_stateid *stateid)
 200 {
 201         struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
 202
 203         if (delegation == NULL)
 204                 goto nomatch;
 205         if (stateid != NULL && memcmp(delegation->stateid.data, stateid->data,
 206                                 sizeof(delegation->stateid.data)) != 0)
 207                 goto nomatch;
 208         list_del_rcu(&delegation->super_list);
 209         nfsi->delegation_state = 0;
 210         rcu_assign_pointer(nfsi->delegation, NULL);
 211         return delegation;
 212 nomatch:
 213         return NULL;
 214 }
 215
 216 int nfs_inode_return_delegation(struct inode *inode)
 217 {
 218         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 219         struct nfs_inode *nfsi = NFS_I(inode);
 220         struct nfs_delegation *delegation;
 221         int err = 0;
 222
 223         if (rcu_dereference(nfsi->delegation) != NULL) {
 224                 spin_lock(&clp->cl_lock);
 225                 delegation = nfs_detach_delegation_locked(nfsi, NULL);
 226                 spin_unlock(&clp->cl_lock);
 227                 if (delegation != NULL)
 228                         err = __nfs_inode_return_delegation(inode, delegation);
 229         }
 230         return err;
 231 }
 232
 233 /*
 234  * Return all delegations associated to a super block
 235  */
 236 void nfs_return_all_delegations(struct super_block *sb)
 237 {
 238         struct nfs_client *clp = NFS_SB(sb)->nfs_client;
 239         struct nfs_delegation *delegation;
 240         struct inode *inode;
 241
 242         if (clp == NULL)
 243                 return;
 244 restart:
 245         rcu_read_lock();
 246         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 247                 if (delegation->inode->i_sb != sb)
 248                         continue;
 249                 inode = igrab(delegation->inode);
 250                 if (inode == NULL)
 251                         continue;
 252                 spin_lock(&clp->cl_lock);
 253                 delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
 254                 spin_unlock(&clp->cl_lock);
 255                 rcu_read_unlock();
 256                 if (delegation != NULL)
 257                         __nfs_inode_return_delegation(inode, delegation);
 258                 iput(inode);
 259                 goto restart;
 260         }
 261         rcu_read_unlock();
 262 }
 263
 264 static int nfs_do_expire_all_delegations(void *ptr)
 265 {
 266         struct nfs_client *clp = ptr;
 267         struct nfs_delegation *delegation;
 268         struct inode *inode;
 269
 270         allow_signal(SIGKILL);
 271 restart:
 272         if (test_bit(NFS4CLNT_STATE_RECOVER, &clp->cl_state) != 0)
 273                 goto out;
 274         if (test_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state) == 0)
 275                 goto out;
 276         rcu_read_lock();
 277         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 278                 inode = igrab(delegation->inode);
 279                 if (inode == NULL)
 280                         continue;
 281                 spin_lock(&clp->cl_lock);
 282                 delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
 283                 spin_unlock(&clp->cl_lock);
 284                 rcu_read_unlock();
 285                 if (delegation)
 286                         __nfs_inode_return_delegation(inode, delegation);
 287                 iput(inode);
 288                 goto restart;
 289         }
 290         rcu_read_unlock();
 291 out:
 292         nfs_put_client(clp);
 293         module_put_and_exit(0);
 294 }
 295
 296 void nfs_expire_all_delegations(struct nfs_client *clp)
 297 {
 298         struct task_struct *task;
 299
 300         __module_get(THIS_MODULE);
 301         atomic_inc(&clp->cl_count);
 302         task = kthread_run(nfs_do_expire_all_delegations, clp,
 303                         "%u.%u.%u.%u-delegreturn",
 304                         NIPQUAD(clp->cl_addr.sin_addr));
 305         if (!IS_ERR(task))
 306                 return;
 307         nfs_put_client(clp);
 308         module_put(THIS_MODULE);
 309 }
 310
 311 /*
 312  * Return all delegations following an NFS4ERR_CB_PATH_DOWN error.
 313  */
 314 void nfs_handle_cb_pathdown(struct nfs_client *clp)
 315 {
 316         struct nfs_delegation *delegation;
 317         struct inode *inode;
 318
 319         if (clp == NULL)
 320                 return;
 321 restart:
 322         rcu_read_lock();
 323         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 324                 inode = igrab(delegation->inode);
 325                 if (inode == NULL)
 326                         continue;
 327                 spin_lock(&clp->cl_lock);
 328                 delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
 329                 spin_unlock(&clp->cl_lock);
 330                 rcu_read_unlock();
 331                 if (delegation != NULL)
 332                         __nfs_inode_return_delegation(inode, delegation);
 333                 iput(inode);
 334                 goto restart;
 335         }
 336         rcu_read_unlock();
 337 }
 338
 339 struct recall_threadargs {
 340         struct inode *inode;
 341         struct nfs_client *clp;
 342         const nfs4_stateid *stateid;
 343
 344         struct completion started;
 345         int result;
 346 };
 347
 348 static int recall_thread(void *data)
 349 {
 350         struct recall_threadargs *args = (struct recall_threadargs *)data;
 351         struct inode *inode = igrab(args->inode);
 352         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 353         struct nfs_inode *nfsi = NFS_I(inode);
 354         struct nfs_delegation *delegation;
 355
 356         daemonize("nfsv4-delegreturn");
 357
 358         nfs_msync_inode(inode);
 359         down_read(&clp->cl_sem);
 360         down_write(&nfsi->rwsem);
 361         spin_lock(&clp->cl_lock);
 362         delegation = nfs_detach_delegation_locked(nfsi, args->stateid);
 363         if (delegation != NULL)
 364                 args->result = 0;
 365         else
 366                 args->result = -ENOENT;
 367         spin_unlock(&clp->cl_lock);
 368         complete(&args->started);
 369         nfs_delegation_claim_opens(inode, args->stateid);
 370         up_write(&nfsi->rwsem);
 371         up_read(&clp->cl_sem);
 372         nfs_msync_inode(inode);
 373
 374         if (delegation != NULL)
 375                 nfs_do_return_delegation(inode, delegation);
 376         iput(inode);
 377         module_put_and_exit(0);
 378 }
 379
 380 /*
 381  * Asynchronous delegation recall!
 382  */
 383 int nfs_async_inode_return_delegation(struct inode *inode, const nfs4_stateid *stateid)
 384 {
 385         struct recall_threadargs data = {
 386                 .inode = inode,
 387                 .stateid = stateid,
 388         };
 389         int status;
 390
 391         init_completion(&data.started);
 392         __module_get(THIS_MODULE);
 393         status = kernel_thread(recall_thread, &data, CLONE_KERNEL);
 394         if (status < 0)
 395                 goto out_module_put;
 396         wait_for_completion(&data.started);
 397         return data.result;
 398 out_module_put:
 399         module_put(THIS_MODULE);
 400         return status;
 401 }
 402
 403 /*
 404  * Retrieve the inode associated with a delegation
 405  */
 406 struct inode *nfs_delegation_find_inode(struct nfs_client *clp, const struct nfs_fh *fhandle)
 407 {
 408         struct nfs_delegation *delegation;
 409         struct inode *res = NULL;
 410         rcu_read_lock();
 411         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 412                 if (nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
 413                         res = igrab(delegation->inode);
 414                         break;
 415                 }
 416         }
 417         rcu_read_unlock();
 418         return res;
 419 }
 420
 421 /*
 422  * Mark all delegations as needing to be reclaimed
 423  */
 424 void nfs_delegation_mark_reclaim(struct nfs_client *clp)
 425 {
 426         struct nfs_delegation *delegation;
 427         rcu_read_lock();
 428         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list)
 429                 delegation->flags |= NFS_DELEGATION_NEED_RECLAIM;
 430         rcu_read_unlock();
 431 }
 432
 433 /*
 434  * Reap all unclaimed delegations after reboot recovery is done
 435  */
 436 void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
 437 {
 438         struct nfs_delegation *delegation;
 439 restart:
 440         rcu_read_lock();
 441         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 442                 if ((delegation->flags & NFS_DELEGATION_NEED_RECLAIM) == 0)
 443                         continue;
 444                 spin_lock(&clp->cl_lock);
 445                 delegation = nfs_detach_delegation_locked(NFS_I(delegation->inode), NULL);
 446                 spin_unlock(&clp->cl_lock);
 447                 rcu_read_unlock();
 448                 if (delegation != NULL)
 449                         call_rcu(&delegation->rcu, nfs_free_delegation_callback);
 450                 goto restart;
 451         }
 452         rcu_read_unlock();
 453 }
 454
 455 int nfs4_copy_delegation_stateid(nfs4_stateid *dst, struct inode *inode)
 456 {
 457         struct nfs_inode *nfsi = NFS_I(inode);
 458         struct nfs_delegation *delegation;
 459         int ret = 0;
 460
 461         rcu_read_lock();
 462         delegation = rcu_dereference(nfsi->delegation);
 463         if (delegation != NULL) {
 464                 memcpy(dst->data, delegation->stateid.data, sizeof(dst->data));
 465                 ret = 1;
 466         }
 467         rcu_read_unlock();
 468         return ret;
 469 }