LXR linux/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
  23static void nfs_do_free_delegation(struct nfs_delegation *delegation)
  24{
  25        kfree(delegation);
  26}
  27
  28static 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
  35static 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
  46static 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 != NULL; 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                                                __func__, 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;
  72out_err:
  73        return status;
  74}
  75
  76static 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
  83again:
  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 */
 109void 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
 128static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
 129{
 130        int res = 0;
 131
 132        res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid, issync);
 133        nfs_free_delegation(delegation);
 134        return res;
 135}
 136
 137static struct nfs_delegation *nfs_detach_delegation_locked(struct nfs_inode *nfsi, const nfs4_stateid *stateid)
 138{
 139        struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
 140
 141        if (delegation == NULL)
 142                goto nomatch;
 143        if (stateid != NULL && memcmp(delegation->stateid.data, stateid->data,
 144                                sizeof(delegation->stateid.data)) != 0)
 145                goto nomatch;
 146        list_del_rcu(&delegation->super_list);
 147        nfsi->delegation_state = 0;
 148        rcu_assign_pointer(nfsi->delegation, NULL);
 149        return delegation;
 150nomatch:
 151        return NULL;
 152}
 153
 154/*
 155 * Set up a delegation on an inode
 156 */
 157int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
 158{
 159        struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 160        struct nfs_inode *nfsi = NFS_I(inode);
 161        struct nfs_delegation *delegation;
 162        struct nfs_delegation *freeme = NULL;
 163        int status = 0;
 164
 165        delegation = kmalloc(sizeof(*delegation), GFP_KERNEL);
 166        if (delegation == NULL)
 167                return -ENOMEM;
 168        memcpy(delegation->stateid.data, res->delegation.data,
 169                        sizeof(delegation->stateid.data));
 170        delegation->type = res->delegation_type;
 171        delegation->maxsize = res->maxsize;
 172        delegation->change_attr = nfsi->change_attr;
 173        delegation->cred = get_rpccred(cred);
 174        delegation->inode = inode;
 175
 176        spin_lock(&clp->cl_lock);
 177        if (rcu_dereference(nfsi->delegation) != NULL) {
 178                if (memcmp(&delegation->stateid, &nfsi->delegation->stateid,
 179                                        sizeof(delegation->stateid)) == 0 &&
 180                                delegation->type == nfsi->delegation->type) {
 181                        goto out;
 182                }
 183                /*
 184                 * Deal with broken servers that hand out two
 185                 * delegations for the same file.
 186                 */
 187                dfprintk(FILE, "%s: server %s handed out "
 188                                "a duplicate delegation!\n",
 189                                __func__, clp->cl_hostname);
 190                if (delegation->type <= nfsi->delegation->type) {
 191                        freeme = delegation;
 192                        delegation = NULL;
 193                        goto out;
 194                }
 195                freeme = nfs_detach_delegation_locked(nfsi, NULL);
 196        }
 197        list_add_rcu(&delegation->super_list, &clp->cl_delegations);
 198        nfsi->delegation_state = delegation->type;
 199        rcu_assign_pointer(nfsi->delegation, delegation);
 200        delegation = NULL;
 201
 202        /* Ensure we revalidate the attributes and page cache! */
 203        spin_lock(&inode->i_lock);
 204        nfsi->cache_validity |= NFS_INO_REVAL_FORCED;
 205        spin_unlock(&inode->i_lock);
 206
 207out:
 208        spin_unlock(&clp->cl_lock);
 209        if (delegation != NULL)
 210                nfs_free_delegation(delegation);
 211        if (freeme != NULL)
 212                nfs_do_return_delegation(inode, freeme, 0);
 213        return status;
 214}
 215
 216/* Sync all data to disk upon delegation return */
 217static void nfs_msync_inode(struct inode *inode)
 218{
 219        filemap_fdatawrite(inode->i_mapping);
 220        nfs_wb_all(inode);
 221        filemap_fdatawait(inode->i_mapping);
 222}
 223
 224/*
 225 * Basic procedure for returning a delegation to the server
 226 */
 227static int __nfs_inode_return_delegation(struct inode *inode, struct nfs_delegation *delegation)
 228{
 229        struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 230        struct nfs_inode *nfsi = NFS_I(inode);
 231
 232        nfs_msync_inode(inode);
 233        down_read(&clp->cl_sem);
 234        /* Guard against new delegated open calls */
 235        down_write(&nfsi->rwsem);
 236        nfs_delegation_claim_opens(inode, &delegation->stateid);
 237        up_write(&nfsi->rwsem);
 238        up_read(&clp->cl_sem);
 239        nfs_msync_inode(inode);
 240
 241        return nfs_do_return_delegation(inode, delegation, 1);
 242}
 243
 244/*
 245 * This function returns the delegation without reclaiming opens
 246 * or protecting against delegation reclaims.
 247 * It is therefore really only safe to be called from
 248 * nfs4_clear_inode()
 249 */
 250void nfs_inode_return_delegation_noreclaim(struct inode *inode)
 251{
 252        struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 253        struct nfs_inode *nfsi = NFS_I(inode);
 254        struct nfs_delegation *delegation;
 255
 256        if (rcu_dereference(nfsi->delegation) != NULL) {
 257                spin_lock(&clp->cl_lock);
 258                delegation = nfs_detach_delegation_locked(nfsi, NULL);
 259                spin_unlock(&clp->cl_lock);
 260                if (delegation != NULL)
 261                        nfs_do_return_delegation(inode, delegation, 0);
 262        }
 263}
 264
 265int nfs_inode_return_delegation(struct inode *inode)
 266{
 267        struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 268        struct nfs_inode *nfsi = NFS_I(inode);
 269        struct nfs_delegation *delegation;
 270        int err = 0;
 271
 272        if (rcu_dereference(nfsi->delegation) != NULL) {
 273                spin_lock(&clp->cl_lock);
 274                delegation = nfs_detach_delegation_locked(nfsi, NULL);
 275                spin_unlock(&clp->cl_lock);
 276                if (delegation != NULL)
 277                        err = __nfs_inode_return_delegation(inode, delegation);
 278        }
 279        return err;
 280}
 281
 282/*
 283 * Return all delegations associated to a super block
 284 */
 285void nfs_return_all_delegations(struct super_block *sb)
 286{
 287        struct nfs_client *clp = NFS_SB(sb)->nfs_client;
 288        struct nfs_delegation *delegation;
 289        struct inode *inode;
 290
 291        if (clp == NULL)
 292                return;
 293restart:
 294        rcu_read_lock();
 295        list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 296                if (delegation->inode->i_sb != sb)
 297                        continue;
 298                inode = igrab(delegation->inode);
 299                if (inode == NULL)
 300                        continue;
 301                spin_lock(&clp->cl_lock);
 302                delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
 303                spin_unlock(&clp->cl_lock);
 304                rcu_read_unlock();
 305                if (delegation != NULL)
 306                        __nfs_inode_return_delegation(inode, delegation);
 307                iput(inode);
 308                goto restart;
 309        }
 310        rcu_read_unlock();
 311}
 312
 313static int nfs_do_expire_all_delegations(void *ptr)
 314{
 315        struct nfs_client *clp = ptr;
 316        struct nfs_delegation *delegation;
 317        struct inode *inode;
 318
 319        allow_signal(SIGKILL);
 320restart:
 321        if (test_bit(NFS4CLNT_STATE_RECOVER, &clp->cl_state) != 0)
 322                goto out;
 323        if (test_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state) == 0)
 324                goto out;
 325        rcu_read_lock();
 326        list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 327                inode = igrab(delegation->inode);
 328                if (inode == NULL)
 329                        continue;
 330                spin_lock(&clp->cl_lock);
 331                delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
 332                spin_unlock(&clp->cl_lock);
 333                rcu_read_unlock();
 334                if (delegation)
 335                        __nfs_inode_return_delegation(inode, delegation);
 336                iput(inode);
 337                goto restart;
 338        }
 339        rcu_read_unlock();
 340out:
 341        nfs_put_client(clp);
 342        module_put_and_exit(0);
 343}
 344
 345void nfs_expire_all_delegations(struct nfs_client *clp)
 346{
 347        struct task_struct *task;
 348
 349        __module_get(THIS_MODULE);
 350        atomic_inc(&clp->cl_count);
 351        task = kthread_run(nfs_do_expire_all_delegations, clp,
 352                                "%s-delegreturn",
 353                                rpc_peeraddr2str(clp->cl_rpcclient,
 354                                                        RPC_DISPLAY_ADDR));
 355        if (!IS_ERR(task))
 356                return;
 357        nfs_put_client(clp);
 358        module_put(THIS_MODULE);
 359}
 360
 361/*
 362 * Return all delegations following an NFS4ERR_CB_PATH_DOWN error.
 363 */
 364void nfs_handle_cb_pathdown(struct nfs_client *clp)
 365{
 366        struct nfs_delegation *delegation;
 367        struct inode *inode;
 368
 369        if (clp == NULL)
 370                return;
 371restart:
 372        rcu_read_lock();
 373        list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 374                inode = igrab(delegation->inode);
 375                if (inode == NULL)
 376                        continue;
 377                spin_lock(&clp->cl_lock);
 378                delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
 379                spin_unlock(&clp->cl_lock);
 380                rcu_read_unlock();
 381                if (delegation != NULL)
 382                        __nfs_inode_return_delegation(inode, delegation);
 383                iput(inode);
 384                goto restart;
 385        }
 386        rcu_read_unlock();
 387}
 388
 389struct recall_threadargs {
 390        struct inode *inode;
 391        struct nfs_client *clp;
 392        const nfs4_stateid *stateid;
 393
 394        struct completion started;
 395        int result;
 396};
 397
 398static int recall_thread(void *data)
 399{
 400        struct recall_threadargs *args = (struct recall_threadargs *)data;
 401        struct inode *inode = igrab(args->inode);
 402        struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 403        struct nfs_inode *nfsi = NFS_I(inode);
 404        struct nfs_delegation *delegation;
 405
 406        daemonize("nfsv4-delegreturn");
 407
 408        nfs_msync_inode(inode);
 409        down_read(&clp->cl_sem);
 410        down_write(&nfsi->rwsem);
 411        spin_lock(&clp->cl_lock);
 412        delegation = nfs_detach_delegation_locked(nfsi, args->stateid);
 413        if (delegation != NULL)
 414                args->result = 0;
 415        else
 416                args->result = -ENOENT;
 417        spin_unlock(&clp->cl_lock);
 418        complete(&args->started);
 419        nfs_delegation_claim_opens(inode, args->stateid);
 420        up_write(&nfsi->rwsem);
 421        up_read(&clp->cl_sem);
 422        nfs_msync_inode(inode);
 423
 424        if (delegation != NULL)
 425                nfs_do_return_delegation(inode, delegation, 1);
 426        iput(inode);
 427        module_put_and_exit(0);
 428}
 429
 430/*
 431 * Asynchronous delegation recall!
 432 */
 433int nfs_async_inode_return_delegation(struct inode *inode, const nfs4_stateid *stateid)
 434{
 435        struct recall_threadargs data = {
 436                .inode = inode,
 437                .stateid = stateid,
 438        };
 439        int status;
 440
 441        init_completion(&data.started);
 442        __module_get(THIS_MODULE);
 443        status = kernel_thread(recall_thread, &data, CLONE_KERNEL);
 444        if (status < 0)
 445                goto out_module_put;
 446        wait_for_completion(&data.started);
 447        return data.result;
 448out_module_put:
 449        module_put(THIS_MODULE);
 450        return status;
 451}
 452
 453/*
 454 * Retrieve the inode associated with a delegation
 455 */
 456struct inode *nfs_delegation_find_inode(struct nfs_client *clp, const struct nfs_fh *fhandle)
 457{
 458        struct nfs_delegation *delegation;
 459        struct inode *res = NULL;
 460        rcu_read_lock();
 461        list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 462                if (nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
 463                        res = igrab(delegation->inode);
 464                        break;
 465                }
 466        }
 467        rcu_read_unlock();
 468        return res;
 469}
 470
 471/*
 472 * Mark all delegations as needing to be reclaimed
 473 */
 474void nfs_delegation_mark_reclaim(struct nfs_client *clp)
 475{
 476        struct nfs_delegation *delegation;
 477        rcu_read_lock();
 478        list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list)
 479                delegation->flags |= NFS_DELEGATION_NEED_RECLAIM;
 480        rcu_read_unlock();
 481}
 482
 483/*
 484 * Reap all unclaimed delegations after reboot recovery is done
 485 */
 486void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
 487{
 488        struct nfs_delegation *delegation;
 489restart:
 490        rcu_read_lock();
 491        list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 492                if ((delegation->flags & NFS_DELEGATION_NEED_RECLAIM) == 0)
 493                        continue;
 494                spin_lock(&clp->cl_lock);
 495                delegation = nfs_detach_delegation_locked(NFS_I(delegation->inode), NULL);
 496                spin_unlock(&clp->cl_lock);
 497                rcu_read_unlock();
 498                if (delegation != NULL)
 499                        nfs_free_delegation(delegation);
 500                goto restart;
 501        }
 502        rcu_read_unlock();
 503}
 504
 505int nfs4_copy_delegation_stateid(nfs4_stateid *dst, struct inode *inode)
 506{
 507        struct nfs_inode *nfsi = NFS_I(inode);
 508        struct nfs_delegation *delegation;
 509        int ret = 0;
 510
 511        rcu_read_lock();
 512        delegation = rcu_dereference(nfsi->delegation);
 513        if (delegation != NULL) {
 514                memcpy(dst->data, delegation->stateid.data, sizeof(dst->data));
 515                ret = 1;
 516        }
 517        rcu_read_unlock();
 518        return ret;
 519}
 520