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