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