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 ((struct nfs_open_context *)fl->fl_file->private_data != 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
 113         if (delegation == NULL)
 114                 return;
 115         memcpy(delegation->stateid.data, res->delegation.data,
 116                         sizeof(delegation->stateid.data));
 117         delegation->type = res->delegation_type;
 118         delegation->maxsize = res->maxsize;
 119         put_rpccred(cred);
 120         delegation->cred = get_rpccred(cred);
 121         delegation->flags &= ~NFS_DELEGATION_NEED_RECLAIM;
 122         NFS_I(inode)->delegation_state = delegation->type;
 123         smp_wmb();
 124 }
 125
 126 /*
 127  * Set up a delegation on an inode
 128  */
 129 int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
 130 {
 131         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 132         struct nfs_inode *nfsi = NFS_I(inode);
 133         struct nfs_delegation *delegation;
 134         int status = 0;
 135
 136         delegation = kmalloc(sizeof(*delegation), GFP_KERNEL);
 137         if (delegation == NULL)
 138                 return -ENOMEM;
 139         memcpy(delegation->stateid.data, res->delegation.data,
 140                         sizeof(delegation->stateid.data));
 141         delegation->type = res->delegation_type;
 142         delegation->maxsize = res->maxsize;
 143         delegation->change_attr = nfsi->change_attr;
 144         delegation->cred = get_rpccred(cred);
 145         delegation->inode = inode;
 146
 147         spin_lock(&clp->cl_lock);
 148         if (rcu_dereference(nfsi->delegation) == NULL) {
 149                 list_add_rcu(&delegation->super_list, &clp->cl_delegations);
 150                 nfsi->delegation_state = delegation->type;
 151                 rcu_assign_pointer(nfsi->delegation, delegation);
 152                 delegation = NULL;
 153         } else {
 154                 if (memcmp(&delegation->stateid, &nfsi->delegation->stateid,
 155                                         sizeof(delegation->stateid)) != 0 ||
 156                                 delegation->type != nfsi->delegation->type) {
 157                         printk("%s: server %u.%u.%u.%u, handed out a duplicate delegation!\n",
 158                                         __FUNCTION__, NIPQUAD(clp->cl_addr.sin_addr));
 159                         status = -EIO;
 160                 }
 161         }
 162
 163         /* Ensure we revalidate the attributes and page cache! */
 164         spin_lock(&inode->i_lock);
 165         nfsi->cache_validity |= NFS_INO_REVAL_FORCED;
 166         spin_unlock(&inode->i_lock);
 167
 168         spin_unlock(&clp->cl_lock);
 169         kfree(delegation);
 170         return status;
 171 }
 172
 173 static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation)
 174 {
 175         int res = 0;
 176
 177         res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid);
 178         nfs_free_delegation(delegation);
 179         return res;
 180 }
 181
 182 /* Sync all data to disk upon delegation return */
 183 static void nfs_msync_inode(struct inode *inode)
 184 {
 185         filemap_fdatawrite(inode->i_mapping);
 186         nfs_wb_all(inode);
 187         filemap_fdatawait(inode->i_mapping);
 188 }
 189
 190 /*
 191  * Basic procedure for returning a delegation to the server
 192  */
 193 static int __nfs_inode_return_delegation(struct inode *inode, struct nfs_delegation *delegation)
 194 {
 195         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 196         struct nfs_inode *nfsi = NFS_I(inode);
 197
 198         nfs_msync_inode(inode);
 199         down_read(&clp->cl_sem);
 200         /* Guard against new delegated open calls */
 201         down_write(&nfsi->rwsem);
 202         nfs_delegation_claim_opens(inode, &delegation->stateid);
 203         up_write(&nfsi->rwsem);
 204         up_read(&clp->cl_sem);
 205         nfs_msync_inode(inode);
 206
 207         return nfs_do_return_delegation(inode, delegation);
 208 }
 209
 210 static struct nfs_delegation *nfs_detach_delegation_locked(struct nfs_inode *nfsi, const nfs4_stateid *stateid)
 211 {
 212         struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
 213
 214         if (delegation == NULL)
 215                 goto nomatch;
 216         if (stateid != NULL && memcmp(delegation->stateid.data, stateid->data,
 217                                 sizeof(delegation->stateid.data)) != 0)
 218                 goto nomatch;
 219         list_del_rcu(&delegation->super_list);
 220         nfsi->delegation_state = 0;
 221         rcu_assign_pointer(nfsi->delegation, NULL);
 222         return delegation;
 223 nomatch:
 224         return NULL;
 225 }
 226
 227 int nfs_inode_return_delegation(struct inode *inode)
 228 {
 229         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 230         struct nfs_inode *nfsi = NFS_I(inode);
 231         struct nfs_delegation *delegation;
 232         int err = 0;
 233
 234         if (rcu_dereference(nfsi->delegation) != NULL) {
 235                 spin_lock(&clp->cl_lock);
 236                 delegation = nfs_detach_delegation_locked(nfsi, NULL);
 237                 spin_unlock(&clp->cl_lock);
 238                 if (delegation != NULL)
 239                         err = __nfs_inode_return_delegation(inode, delegation);
 240         }
 241         return err;
 242 }
 243
 244 /*
 245  * Return all delegations associated to a super block
 246  */
 247 void nfs_return_all_delegations(struct super_block *sb)
 248 {
 249         struct nfs_client *clp = NFS_SB(sb)->nfs_client;
 250         struct nfs_delegation *delegation;
 251         struct inode *inode;
 252
 253         if (clp == NULL)
 254                 return;
 255 restart:
 256         rcu_read_lock();
 257         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 258                 if (delegation->inode->i_sb != sb)
 259                         continue;
 260                 inode = igrab(delegation->inode);
 261                 if (inode == NULL)
 262                         continue;
 263                 spin_lock(&clp->cl_lock);
 264                 delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
 265                 spin_unlock(&clp->cl_lock);
 266                 rcu_read_unlock();
 267                 if (delegation != NULL)
 268                         __nfs_inode_return_delegation(inode, delegation);
 269                 iput(inode);
 270                 goto restart;
 271         }
 272         rcu_read_unlock();
 273 }
 274
 275 static int nfs_do_expire_all_delegations(void *ptr)
 276 {
 277         struct nfs_client *clp = ptr;
 278         struct nfs_delegation *delegation;
 279         struct inode *inode;
 280
 281         allow_signal(SIGKILL);
 282 restart:
 283         if (test_bit(NFS4CLNT_STATE_RECOVER, &clp->cl_state) != 0)
 284                 goto out;
 285         if (test_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state) == 0)
 286                 goto out;
 287         rcu_read_lock();
 288         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 289                 inode = igrab(delegation->inode);
 290                 if (inode == NULL)
 291                         continue;
 292                 spin_lock(&clp->cl_lock);
 293                 delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
 294                 spin_unlock(&clp->cl_lock);
 295                 rcu_read_unlock();
 296                 if (delegation)
 297                         __nfs_inode_return_delegation(inode, delegation);
 298                 iput(inode);
 299                 goto restart;
 300         }
 301         rcu_read_unlock();
 302 out:
 303         nfs_put_client(clp);
 304         module_put_and_exit(0);
 305 }
 306
 307 void nfs_expire_all_delegations(struct nfs_client *clp)
 308 {
 309         struct task_struct *task;
 310
 311         __module_get(THIS_MODULE);
 312         atomic_inc(&clp->cl_count);
 313         task = kthread_run(nfs_do_expire_all_delegations, clp,
 314                         "%u.%u.%u.%u-delegreturn",
 315                         NIPQUAD(clp->cl_addr.sin_addr));
 316         if (!IS_ERR(task))
 317                 return;
 318         nfs_put_client(clp);
 319         module_put(THIS_MODULE);
 320 }
 321
 322 /*
 323  * Return all delegations following an NFS4ERR_CB_PATH_DOWN error.
 324  */
 325 void nfs_handle_cb_pathdown(struct nfs_client *clp)
 326 {
 327         struct nfs_delegation *delegation;
 328         struct inode *inode;
 329
 330         if (clp == NULL)
 331                 return;
 332 restart:
 333         rcu_read_lock();
 334         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 335                 inode = igrab(delegation->inode);
 336                 if (inode == NULL)
 337                         continue;
 338                 spin_lock(&clp->cl_lock);
 339                 delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
 340                 spin_unlock(&clp->cl_lock);
 341                 rcu_read_unlock();
 342                 if (delegation != NULL)
 343                         __nfs_inode_return_delegation(inode, delegation);
 344                 iput(inode);
 345                 goto restart;
 346         }
 347         rcu_read_unlock();
 348 }
 349
 350 struct recall_threadargs {
 351         struct inode *inode;
 352         struct nfs_client *clp;
 353         const nfs4_stateid *stateid;
 354
 355         struct completion started;
 356         int result;
 357 };
 358
 359 static int recall_thread(void *data)
 360 {
 361         struct recall_threadargs *args = (struct recall_threadargs *)data;
 362         struct inode *inode = igrab(args->inode);
 363         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 364         struct nfs_inode *nfsi = NFS_I(inode);
 365         struct nfs_delegation *delegation;
 366
 367         daemonize("nfsv4-delegreturn");
 368
 369         nfs_msync_inode(inode);
 370         down_read(&clp->cl_sem);
 371         down_write(&nfsi->rwsem);
 372         spin_lock(&clp->cl_lock);
 373         delegation = nfs_detach_delegation_locked(nfsi, args->stateid);
 374         if (delegation != NULL)
 375                 args->result = 0;
 376         else
 377                 args->result = -ENOENT;
 378         spin_unlock(&clp->cl_lock);
 379         complete(&args->started);
 380         nfs_delegation_claim_opens(inode, args->stateid);
 381         up_write(&nfsi->rwsem);
 382         up_read(&clp->cl_sem);
 383         nfs_msync_inode(inode);
 384
 385         if (delegation != NULL)
 386                 nfs_do_return_delegation(inode, delegation);
 387         iput(inode);
 388         module_put_and_exit(0);
 389 }
 390
 391 /*
 392  * Asynchronous delegation recall!
 393  */
 394 int nfs_async_inode_return_delegation(struct inode *inode, const nfs4_stateid *stateid)
 395 {
 396         struct recall_threadargs data = {
 397                 .inode = inode,
 398                 .stateid = stateid,
 399         };
 400         int status;
 401
 402         init_completion(&data.started);
 403         __module_get(THIS_MODULE);
 404         status = kernel_thread(recall_thread, &data, CLONE_KERNEL);
 405         if (status < 0)
 406                 goto out_module_put;
 407         wait_for_completion(&data.started);
 408         return data.result;
 409 out_module_put:
 410         module_put(THIS_MODULE);
 411         return status;
 412 }
 413
 414 /*
 415  * Retrieve the inode associated with a delegation
 416  */
 417 struct inode *nfs_delegation_find_inode(struct nfs_client *clp, const struct nfs_fh *fhandle)
 418 {
 419         struct nfs_delegation *delegation;
 420         struct inode *res = NULL;
 421         rcu_read_lock();
 422         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 423                 if (nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
 424                         res = igrab(delegation->inode);
 425                         break;
 426                 }
 427         }
 428         rcu_read_unlock();
 429         return res;
 430 }
 431
 432 /*
 433  * Mark all delegations as needing to be reclaimed
 434  */
 435 void nfs_delegation_mark_reclaim(struct nfs_client *clp)
 436 {
 437         struct nfs_delegation *delegation;
 438         rcu_read_lock();
 439         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list)
 440                 delegation->flags |= NFS_DELEGATION_NEED_RECLAIM;
 441         rcu_read_unlock();
 442 }
 443
 444 /*
 445  * Reap all unclaimed delegations after reboot recovery is done
 446  */
 447 void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
 448 {
 449         struct nfs_delegation *delegation;
 450 restart:
 451         rcu_read_lock();
 452         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 453                 if ((delegation->flags & NFS_DELEGATION_NEED_RECLAIM) == 0)
 454                         continue;
 455                 spin_lock(&clp->cl_lock);
 456                 delegation = nfs_detach_delegation_locked(NFS_I(delegation->inode), NULL);
 457                 spin_unlock(&clp->cl_lock);
 458                 rcu_read_unlock();
 459                 if (delegation != NULL)
 460                         nfs_free_delegation(delegation);
 461                 goto restart;
 462         }
 463         rcu_read_unlock();
 464 }
 465
 466 int nfs4_copy_delegation_stateid(nfs4_stateid *dst, struct inode *inode)
 467 {
 468         struct nfs_inode *nfsi = NFS_I(inode);
 469         struct nfs_delegation *delegation;
 470         int ret = 0;
 471
 472         rcu_read_lock();
 473         delegation = rcu_dereference(nfsi->delegation);
 474         if (delegation != NULL) {
 475                 memcpy(dst->data, delegation->stateid.data, sizeof(dst->data));
 476                 ret = 1;
 477         }
 478         rcu_read_unlock();
 479         return ret;
 480 }