linux/fs/nfsd/nfs4recover.c
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   1/*
   2*  Copyright (c) 2004 The Regents of the University of Michigan.
   3*  Copyright (c) 2012 Jeff Layton <jlayton@redhat.com>
   4*  All rights reserved.
   5*
   6*  Andy Adamson <andros@citi.umich.edu>
   7*
   8*  Redistribution and use in source and binary forms, with or without
   9*  modification, are permitted provided that the following conditions
  10*  are met:
  11*
  12*  1. Redistributions of source code must retain the above copyright
  13*     notice, this list of conditions and the following disclaimer.
  14*  2. Redistributions in binary form must reproduce the above copyright
  15*     notice, this list of conditions and the following disclaimer in the
  16*     documentation and/or other materials provided with the distribution.
  17*  3. Neither the name of the University nor the names of its
  18*     contributors may be used to endorse or promote products derived
  19*     from this software without specific prior written permission.
  20*
  21*  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
  22*  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  23*  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  24*  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25*  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  26*  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  27*  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
  28*  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  29*  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  30*  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  31*  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  32*
  33*/
  34
  35#include <linux/file.h>
  36#include <linux/slab.h>
  37#include <linux/namei.h>
  38#include <linux/crypto.h>
  39#include <linux/sched.h>
  40#include <linux/fs.h>
  41#include <linux/module.h>
  42#include <net/net_namespace.h>
  43#include <linux/sunrpc/rpc_pipe_fs.h>
  44#include <linux/sunrpc/clnt.h>
  45#include <linux/nfsd/cld.h>
  46
  47#include "nfsd.h"
  48#include "state.h"
  49#include "vfs.h"
  50#include "netns.h"
  51
  52#define NFSDDBG_FACILITY                NFSDDBG_PROC
  53
  54/* Declarations */
  55struct nfsd4_client_tracking_ops {
  56        int (*init)(struct net *);
  57        void (*exit)(struct net *);
  58        void (*create)(struct nfs4_client *);
  59        void (*remove)(struct nfs4_client *);
  60        int (*check)(struct nfs4_client *);
  61        void (*grace_done)(struct nfsd_net *, time_t);
  62};
  63
  64/* Globals */
  65static char user_recovery_dirname[PATH_MAX] = "/var/lib/nfs/v4recovery";
  66
  67static int
  68nfs4_save_creds(const struct cred **original_creds)
  69{
  70        struct cred *new;
  71
  72        new = prepare_creds();
  73        if (!new)
  74                return -ENOMEM;
  75
  76        new->fsuid = GLOBAL_ROOT_UID;
  77        new->fsgid = GLOBAL_ROOT_GID;
  78        *original_creds = override_creds(new);
  79        put_cred(new);
  80        return 0;
  81}
  82
  83static void
  84nfs4_reset_creds(const struct cred *original)
  85{
  86        revert_creds(original);
  87}
  88
  89static void
  90md5_to_hex(char *out, char *md5)
  91{
  92        int i;
  93
  94        for (i=0; i<16; i++) {
  95                unsigned char c = md5[i];
  96
  97                *out++ = '0' + ((c&0xf0)>>4) + (c>=0xa0)*('a'-'9'-1);
  98                *out++ = '0' + (c&0x0f) + ((c&0x0f)>=0x0a)*('a'-'9'-1);
  99        }
 100        *out = '\0';
 101}
 102
 103static int
 104nfs4_make_rec_clidname(char *dname, const struct xdr_netobj *clname)
 105{
 106        struct xdr_netobj cksum;
 107        struct hash_desc desc;
 108        struct scatterlist sg;
 109        int status;
 110
 111        dprintk("NFSD: nfs4_make_rec_clidname for %.*s\n",
 112                        clname->len, clname->data);
 113        desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 114        desc.tfm = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
 115        if (IS_ERR(desc.tfm)) {
 116                status = PTR_ERR(desc.tfm);
 117                goto out_no_tfm;
 118        }
 119
 120        cksum.len = crypto_hash_digestsize(desc.tfm);
 121        cksum.data = kmalloc(cksum.len, GFP_KERNEL);
 122        if (cksum.data == NULL) {
 123                status = -ENOMEM;
 124                goto out;
 125        }
 126
 127        sg_init_one(&sg, clname->data, clname->len);
 128
 129        status = crypto_hash_digest(&desc, &sg, sg.length, cksum.data);
 130        if (status)
 131                goto out;
 132
 133        md5_to_hex(dname, cksum.data);
 134
 135        status = 0;
 136out:
 137        kfree(cksum.data);
 138        crypto_free_hash(desc.tfm);
 139out_no_tfm:
 140        return status;
 141}
 142
 143/*
 144 * If we had an error generating the recdir name for the legacy tracker
 145 * then warn the admin. If the error doesn't appear to be transient,
 146 * then disable recovery tracking.
 147 */
 148static void
 149legacy_recdir_name_error(struct nfs4_client *clp, int error)
 150{
 151        printk(KERN_ERR "NFSD: unable to generate recoverydir "
 152                        "name (%d).\n", error);
 153
 154        /*
 155         * if the algorithm just doesn't exist, then disable the recovery
 156         * tracker altogether. The crypto libs will generally return this if
 157         * FIPS is enabled as well.
 158         */
 159        if (error == -ENOENT) {
 160                printk(KERN_ERR "NFSD: disabling legacy clientid tracking. "
 161                        "Reboot recovery will not function correctly!\n");
 162                nfsd4_client_tracking_exit(clp->net);
 163        }
 164}
 165
 166static void
 167nfsd4_create_clid_dir(struct nfs4_client *clp)
 168{
 169        const struct cred *original_cred;
 170        char dname[HEXDIR_LEN];
 171        struct dentry *dir, *dentry;
 172        struct nfs4_client_reclaim *crp;
 173        int status;
 174        struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
 175
 176        dprintk("NFSD: nfsd4_create_clid_dir for \"%s\"\n", dname);
 177
 178        if (test_and_set_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags))
 179                return;
 180        if (!nn->rec_file)
 181                return;
 182
 183        status = nfs4_make_rec_clidname(dname, &clp->cl_name);
 184        if (status)
 185                return legacy_recdir_name_error(clp, status);
 186
 187        status = nfs4_save_creds(&original_cred);
 188        if (status < 0)
 189                return;
 190
 191        status = mnt_want_write_file(nn->rec_file);
 192        if (status)
 193                return;
 194
 195        dir = nn->rec_file->f_path.dentry;
 196        /* lock the parent */
 197        mutex_lock(&dir->d_inode->i_mutex);
 198
 199        dentry = lookup_one_len(dname, dir, HEXDIR_LEN-1);
 200        if (IS_ERR(dentry)) {
 201                status = PTR_ERR(dentry);
 202                goto out_unlock;
 203        }
 204        if (dentry->d_inode)
 205                /*
 206                 * In the 4.1 case, where we're called from
 207                 * reclaim_complete(), records from the previous reboot
 208                 * may still be left, so this is OK.
 209                 *
 210                 * In the 4.0 case, we should never get here; but we may
 211                 * as well be forgiving and just succeed silently.
 212                 */
 213                goto out_put;
 214        status = vfs_mkdir(dir->d_inode, dentry, S_IRWXU);
 215out_put:
 216        dput(dentry);
 217out_unlock:
 218        mutex_unlock(&dir->d_inode->i_mutex);
 219        if (status == 0) {
 220                if (nn->in_grace) {
 221                        crp = nfs4_client_to_reclaim(dname, nn);
 222                        if (crp)
 223                                crp->cr_clp = clp;
 224                }
 225                vfs_fsync(nn->rec_file, 0);
 226        } else {
 227                printk(KERN_ERR "NFSD: failed to write recovery record"
 228                                " (err %d); please check that %s exists"
 229                                " and is writeable", status,
 230                                user_recovery_dirname);
 231        }
 232        mnt_drop_write_file(nn->rec_file);
 233        nfs4_reset_creds(original_cred);
 234}
 235
 236typedef int (recdir_func)(struct dentry *, struct dentry *, struct nfsd_net *);
 237
 238struct name_list {
 239        char name[HEXDIR_LEN];
 240        struct list_head list;
 241};
 242
 243struct nfs4_dir_ctx {
 244        struct dir_context ctx;
 245        struct list_head names;
 246};
 247
 248static int
 249nfsd4_build_namelist(void *arg, const char *name, int namlen,
 250                loff_t offset, u64 ino, unsigned int d_type)
 251{
 252        struct nfs4_dir_ctx *ctx = arg;
 253        struct name_list *entry;
 254
 255        if (namlen != HEXDIR_LEN - 1)
 256                return 0;
 257        entry = kmalloc(sizeof(struct name_list), GFP_KERNEL);
 258        if (entry == NULL)
 259                return -ENOMEM;
 260        memcpy(entry->name, name, HEXDIR_LEN - 1);
 261        entry->name[HEXDIR_LEN - 1] = '\0';
 262        list_add(&entry->list, &ctx->names);
 263        return 0;
 264}
 265
 266static int
 267nfsd4_list_rec_dir(recdir_func *f, struct nfsd_net *nn)
 268{
 269        const struct cred *original_cred;
 270        struct dentry *dir = nn->rec_file->f_path.dentry;
 271        struct nfs4_dir_ctx ctx = {
 272                .ctx.actor = nfsd4_build_namelist,
 273                .names = LIST_HEAD_INIT(ctx.names)
 274        };
 275        int status;
 276
 277        status = nfs4_save_creds(&original_cred);
 278        if (status < 0)
 279                return status;
 280
 281        status = vfs_llseek(nn->rec_file, 0, SEEK_SET);
 282        if (status < 0) {
 283                nfs4_reset_creds(original_cred);
 284                return status;
 285        }
 286
 287        status = iterate_dir(nn->rec_file, &ctx.ctx);
 288        mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
 289        while (!list_empty(&ctx.names)) {
 290                struct name_list *entry;
 291                entry = list_entry(ctx.names.next, struct name_list, list);
 292                if (!status) {
 293                        struct dentry *dentry;
 294                        dentry = lookup_one_len(entry->name, dir, HEXDIR_LEN-1);
 295                        if (IS_ERR(dentry)) {
 296                                status = PTR_ERR(dentry);
 297                                break;
 298                        }
 299                        status = f(dir, dentry, nn);
 300                        dput(dentry);
 301                }
 302                list_del(&entry->list);
 303                kfree(entry);
 304        }
 305        mutex_unlock(&dir->d_inode->i_mutex);
 306        nfs4_reset_creds(original_cred);
 307        return status;
 308}
 309
 310static int
 311nfsd4_unlink_clid_dir(char *name, int namlen, struct nfsd_net *nn)
 312{
 313        struct dentry *dir, *dentry;
 314        int status;
 315
 316        dprintk("NFSD: nfsd4_unlink_clid_dir. name %.*s\n", namlen, name);
 317
 318        dir = nn->rec_file->f_path.dentry;
 319        mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
 320        dentry = lookup_one_len(name, dir, namlen);
 321        if (IS_ERR(dentry)) {
 322                status = PTR_ERR(dentry);
 323                goto out_unlock;
 324        }
 325        status = -ENOENT;
 326        if (!dentry->d_inode)
 327                goto out;
 328        status = vfs_rmdir(dir->d_inode, dentry);
 329out:
 330        dput(dentry);
 331out_unlock:
 332        mutex_unlock(&dir->d_inode->i_mutex);
 333        return status;
 334}
 335
 336static void
 337nfsd4_remove_clid_dir(struct nfs4_client *clp)
 338{
 339        const struct cred *original_cred;
 340        struct nfs4_client_reclaim *crp;
 341        char dname[HEXDIR_LEN];
 342        int status;
 343        struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
 344
 345        if (!nn->rec_file || !test_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags))
 346                return;
 347
 348        status = nfs4_make_rec_clidname(dname, &clp->cl_name);
 349        if (status)
 350                return legacy_recdir_name_error(clp, status);
 351
 352        status = mnt_want_write_file(nn->rec_file);
 353        if (status)
 354                goto out;
 355        clear_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags);
 356
 357        status = nfs4_save_creds(&original_cred);
 358        if (status < 0)
 359                goto out_drop_write;
 360
 361        status = nfsd4_unlink_clid_dir(dname, HEXDIR_LEN-1, nn);
 362        nfs4_reset_creds(original_cred);
 363        if (status == 0) {
 364                vfs_fsync(nn->rec_file, 0);
 365                if (nn->in_grace) {
 366                        /* remove reclaim record */
 367                        crp = nfsd4_find_reclaim_client(dname, nn);
 368                        if (crp)
 369                                nfs4_remove_reclaim_record(crp, nn);
 370                }
 371        }
 372out_drop_write:
 373        mnt_drop_write_file(nn->rec_file);
 374out:
 375        if (status)
 376                printk("NFSD: Failed to remove expired client state directory"
 377                                " %.*s\n", HEXDIR_LEN, dname);
 378}
 379
 380static int
 381purge_old(struct dentry *parent, struct dentry *child, struct nfsd_net *nn)
 382{
 383        int status;
 384
 385        if (nfs4_has_reclaimed_state(child->d_name.name, nn))
 386                return 0;
 387
 388        status = vfs_rmdir(parent->d_inode, child);
 389        if (status)
 390                printk("failed to remove client recovery directory %s\n",
 391                                child->d_name.name);
 392        /* Keep trying, success or failure: */
 393        return 0;
 394}
 395
 396static void
 397nfsd4_recdir_purge_old(struct nfsd_net *nn, time_t boot_time)
 398{
 399        int status;
 400
 401        nn->in_grace = false;
 402        if (!nn->rec_file)
 403                return;
 404        status = mnt_want_write_file(nn->rec_file);
 405        if (status)
 406                goto out;
 407        status = nfsd4_list_rec_dir(purge_old, nn);
 408        if (status == 0)
 409                vfs_fsync(nn->rec_file, 0);
 410        mnt_drop_write_file(nn->rec_file);
 411out:
 412        nfs4_release_reclaim(nn);
 413        if (status)
 414                printk("nfsd4: failed to purge old clients from recovery"
 415                        " directory %s\n", nn->rec_file->f_path.dentry->d_name.name);
 416}
 417
 418static int
 419load_recdir(struct dentry *parent, struct dentry *child, struct nfsd_net *nn)
 420{
 421        if (child->d_name.len != HEXDIR_LEN - 1) {
 422                printk("nfsd4: illegal name %s in recovery directory\n",
 423                                child->d_name.name);
 424                /* Keep trying; maybe the others are OK: */
 425                return 0;
 426        }
 427        nfs4_client_to_reclaim(child->d_name.name, nn);
 428        return 0;
 429}
 430
 431static int
 432nfsd4_recdir_load(struct net *net) {
 433        int status;
 434        struct nfsd_net *nn =  net_generic(net, nfsd_net_id);
 435
 436        if (!nn->rec_file)
 437                return 0;
 438
 439        status = nfsd4_list_rec_dir(load_recdir, nn);
 440        if (status)
 441                printk("nfsd4: failed loading clients from recovery"
 442                        " directory %s\n", nn->rec_file->f_path.dentry->d_name.name);
 443        return status;
 444}
 445
 446/*
 447 * Hold reference to the recovery directory.
 448 */
 449
 450static int
 451nfsd4_init_recdir(struct net *net)
 452{
 453        struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 454        const struct cred *original_cred;
 455        int status;
 456
 457        printk("NFSD: Using %s as the NFSv4 state recovery directory\n",
 458                        user_recovery_dirname);
 459
 460        BUG_ON(nn->rec_file);
 461
 462        status = nfs4_save_creds(&original_cred);
 463        if (status < 0) {
 464                printk("NFSD: Unable to change credentials to find recovery"
 465                       " directory: error %d\n",
 466                       status);
 467                return status;
 468        }
 469
 470        nn->rec_file = filp_open(user_recovery_dirname, O_RDONLY | O_DIRECTORY, 0);
 471        if (IS_ERR(nn->rec_file)) {
 472                printk("NFSD: unable to find recovery directory %s\n",
 473                                user_recovery_dirname);
 474                status = PTR_ERR(nn->rec_file);
 475                nn->rec_file = NULL;
 476        }
 477
 478        nfs4_reset_creds(original_cred);
 479        if (!status)
 480                nn->in_grace = true;
 481        return status;
 482}
 483
 484
 485static int
 486nfs4_legacy_state_init(struct net *net)
 487{
 488        struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 489        int i;
 490
 491        nn->reclaim_str_hashtbl = kmalloc(sizeof(struct list_head) *
 492                                          CLIENT_HASH_SIZE, GFP_KERNEL);
 493        if (!nn->reclaim_str_hashtbl)
 494                return -ENOMEM;
 495
 496        for (i = 0; i < CLIENT_HASH_SIZE; i++)
 497                INIT_LIST_HEAD(&nn->reclaim_str_hashtbl[i]);
 498        nn->reclaim_str_hashtbl_size = 0;
 499
 500        return 0;
 501}
 502
 503static void
 504nfs4_legacy_state_shutdown(struct net *net)
 505{
 506        struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 507
 508        kfree(nn->reclaim_str_hashtbl);
 509}
 510
 511static int
 512nfsd4_load_reboot_recovery_data(struct net *net)
 513{
 514        int status;
 515
 516        status = nfsd4_init_recdir(net);
 517        if (!status)
 518                status = nfsd4_recdir_load(net);
 519        if (status)
 520                printk(KERN_ERR "NFSD: Failure reading reboot recovery data\n");
 521        return status;
 522}
 523
 524static int
 525nfsd4_legacy_tracking_init(struct net *net)
 526{
 527        int status;
 528
 529        /* XXX: The legacy code won't work in a container */
 530        if (net != &init_net) {
 531                WARN(1, KERN_ERR "NFSD: attempt to initialize legacy client "
 532                        "tracking in a container!\n");
 533                return -EINVAL;
 534        }
 535
 536        status = nfs4_legacy_state_init(net);
 537        if (status)
 538                return status;
 539
 540        status = nfsd4_load_reboot_recovery_data(net);
 541        if (status)
 542                goto err;
 543        return 0;
 544
 545err:
 546        nfs4_legacy_state_shutdown(net);
 547        return status;
 548}
 549
 550static void
 551nfsd4_shutdown_recdir(struct nfsd_net *nn)
 552{
 553        if (!nn->rec_file)
 554                return;
 555        fput(nn->rec_file);
 556        nn->rec_file = NULL;
 557}
 558
 559static void
 560nfsd4_legacy_tracking_exit(struct net *net)
 561{
 562        struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 563
 564        nfs4_release_reclaim(nn);
 565        nfsd4_shutdown_recdir(nn);
 566        nfs4_legacy_state_shutdown(net);
 567}
 568
 569/*
 570 * Change the NFSv4 recovery directory to recdir.
 571 */
 572int
 573nfs4_reset_recoverydir(char *recdir)
 574{
 575        int status;
 576        struct path path;
 577
 578        status = kern_path(recdir, LOOKUP_FOLLOW, &path);
 579        if (status)
 580                return status;
 581        status = -ENOTDIR;
 582        if (S_ISDIR(path.dentry->d_inode->i_mode)) {
 583                strcpy(user_recovery_dirname, recdir);
 584                status = 0;
 585        }
 586        path_put(&path);
 587        return status;
 588}
 589
 590char *
 591nfs4_recoverydir(void)
 592{
 593        return user_recovery_dirname;
 594}
 595
 596static int
 597nfsd4_check_legacy_client(struct nfs4_client *clp)
 598{
 599        int status;
 600        char dname[HEXDIR_LEN];
 601        struct nfs4_client_reclaim *crp;
 602        struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
 603
 604        /* did we already find that this client is stable? */
 605        if (test_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags))
 606                return 0;
 607
 608        status = nfs4_make_rec_clidname(dname, &clp->cl_name);
 609        if (status) {
 610                legacy_recdir_name_error(clp, status);
 611                return status;
 612        }
 613
 614        /* look for it in the reclaim hashtable otherwise */
 615        crp = nfsd4_find_reclaim_client(dname, nn);
 616        if (crp) {
 617                set_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags);
 618                crp->cr_clp = clp;
 619                return 0;
 620        }
 621
 622        return -ENOENT;
 623}
 624
 625static struct nfsd4_client_tracking_ops nfsd4_legacy_tracking_ops = {
 626        .init           = nfsd4_legacy_tracking_init,
 627        .exit           = nfsd4_legacy_tracking_exit,
 628        .create         = nfsd4_create_clid_dir,
 629        .remove         = nfsd4_remove_clid_dir,
 630        .check          = nfsd4_check_legacy_client,
 631        .grace_done     = nfsd4_recdir_purge_old,
 632};
 633
 634/* Globals */
 635#define NFSD_PIPE_DIR           "nfsd"
 636#define NFSD_CLD_PIPE           "cld"
 637
 638/* per-net-ns structure for holding cld upcall info */
 639struct cld_net {
 640        struct rpc_pipe         *cn_pipe;
 641        spinlock_t               cn_lock;
 642        struct list_head         cn_list;
 643        unsigned int             cn_xid;
 644};
 645
 646struct cld_upcall {
 647        struct list_head         cu_list;
 648        struct cld_net          *cu_net;
 649        struct task_struct      *cu_task;
 650        struct cld_msg           cu_msg;
 651};
 652
 653static int
 654__cld_pipe_upcall(struct rpc_pipe *pipe, struct cld_msg *cmsg)
 655{
 656        int ret;
 657        struct rpc_pipe_msg msg;
 658
 659        memset(&msg, 0, sizeof(msg));
 660        msg.data = cmsg;
 661        msg.len = sizeof(*cmsg);
 662
 663        /*
 664         * Set task state before we queue the upcall. That prevents
 665         * wake_up_process in the downcall from racing with schedule.
 666         */
 667        set_current_state(TASK_UNINTERRUPTIBLE);
 668        ret = rpc_queue_upcall(pipe, &msg);
 669        if (ret < 0) {
 670                set_current_state(TASK_RUNNING);
 671                goto out;
 672        }
 673
 674        schedule();
 675        set_current_state(TASK_RUNNING);
 676
 677        if (msg.errno < 0)
 678                ret = msg.errno;
 679out:
 680        return ret;
 681}
 682
 683static int
 684cld_pipe_upcall(struct rpc_pipe *pipe, struct cld_msg *cmsg)
 685{
 686        int ret;
 687
 688        /*
 689         * -EAGAIN occurs when pipe is closed and reopened while there are
 690         *  upcalls queued.
 691         */
 692        do {
 693                ret = __cld_pipe_upcall(pipe, cmsg);
 694        } while (ret == -EAGAIN);
 695
 696        return ret;
 697}
 698
 699static ssize_t
 700cld_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
 701{
 702        struct cld_upcall *tmp, *cup;
 703        struct cld_msg __user *cmsg = (struct cld_msg __user *)src;
 704        uint32_t xid;
 705        struct nfsd_net *nn = net_generic(filp->f_dentry->d_sb->s_fs_info,
 706                                                nfsd_net_id);
 707        struct cld_net *cn = nn->cld_net;
 708
 709        if (mlen != sizeof(*cmsg)) {
 710                dprintk("%s: got %zu bytes, expected %zu\n", __func__, mlen,
 711                        sizeof(*cmsg));
 712                return -EINVAL;
 713        }
 714
 715        /* copy just the xid so we can try to find that */
 716        if (copy_from_user(&xid, &cmsg->cm_xid, sizeof(xid)) != 0) {
 717                dprintk("%s: error when copying xid from userspace", __func__);
 718                return -EFAULT;
 719        }
 720
 721        /* walk the list and find corresponding xid */
 722        cup = NULL;
 723        spin_lock(&cn->cn_lock);
 724        list_for_each_entry(tmp, &cn->cn_list, cu_list) {
 725                if (get_unaligned(&tmp->cu_msg.cm_xid) == xid) {
 726                        cup = tmp;
 727                        list_del_init(&cup->cu_list);
 728                        break;
 729                }
 730        }
 731        spin_unlock(&cn->cn_lock);
 732
 733        /* couldn't find upcall? */
 734        if (!cup) {
 735                dprintk("%s: couldn't find upcall -- xid=%u\n", __func__, xid);
 736                return -EINVAL;
 737        }
 738
 739        if (copy_from_user(&cup->cu_msg, src, mlen) != 0)
 740                return -EFAULT;
 741
 742        wake_up_process(cup->cu_task);
 743        return mlen;
 744}
 745
 746static void
 747cld_pipe_destroy_msg(struct rpc_pipe_msg *msg)
 748{
 749        struct cld_msg *cmsg = msg->data;
 750        struct cld_upcall *cup = container_of(cmsg, struct cld_upcall,
 751                                                 cu_msg);
 752
 753        /* errno >= 0 means we got a downcall */
 754        if (msg->errno >= 0)
 755                return;
 756
 757        wake_up_process(cup->cu_task);
 758}
 759
 760static const struct rpc_pipe_ops cld_upcall_ops = {
 761        .upcall         = rpc_pipe_generic_upcall,
 762        .downcall       = cld_pipe_downcall,
 763        .destroy_msg    = cld_pipe_destroy_msg,
 764};
 765
 766static struct dentry *
 767nfsd4_cld_register_sb(struct super_block *sb, struct rpc_pipe *pipe)
 768{
 769        struct dentry *dir, *dentry;
 770
 771        dir = rpc_d_lookup_sb(sb, NFSD_PIPE_DIR);
 772        if (dir == NULL)
 773                return ERR_PTR(-ENOENT);
 774        dentry = rpc_mkpipe_dentry(dir, NFSD_CLD_PIPE, NULL, pipe);
 775        dput(dir);
 776        return dentry;
 777}
 778
 779static void
 780nfsd4_cld_unregister_sb(struct rpc_pipe *pipe)
 781{
 782        if (pipe->dentry)
 783                rpc_unlink(pipe->dentry);
 784}
 785
 786static struct dentry *
 787nfsd4_cld_register_net(struct net *net, struct rpc_pipe *pipe)
 788{
 789        struct super_block *sb;
 790        struct dentry *dentry;
 791
 792        sb = rpc_get_sb_net(net);
 793        if (!sb)
 794                return NULL;
 795        dentry = nfsd4_cld_register_sb(sb, pipe);
 796        rpc_put_sb_net(net);
 797        return dentry;
 798}
 799
 800static void
 801nfsd4_cld_unregister_net(struct net *net, struct rpc_pipe *pipe)
 802{
 803        struct super_block *sb;
 804
 805        sb = rpc_get_sb_net(net);
 806        if (sb) {
 807                nfsd4_cld_unregister_sb(pipe);
 808                rpc_put_sb_net(net);
 809        }
 810}
 811
 812/* Initialize rpc_pipefs pipe for communication with client tracking daemon */
 813static int
 814nfsd4_init_cld_pipe(struct net *net)
 815{
 816        int ret;
 817        struct dentry *dentry;
 818        struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 819        struct cld_net *cn;
 820
 821        if (nn->cld_net)
 822                return 0;
 823
 824        cn = kzalloc(sizeof(*cn), GFP_KERNEL);
 825        if (!cn) {
 826                ret = -ENOMEM;
 827                goto err;
 828        }
 829
 830        cn->cn_pipe = rpc_mkpipe_data(&cld_upcall_ops, RPC_PIPE_WAIT_FOR_OPEN);
 831        if (IS_ERR(cn->cn_pipe)) {
 832                ret = PTR_ERR(cn->cn_pipe);
 833                goto err;
 834        }
 835        spin_lock_init(&cn->cn_lock);
 836        INIT_LIST_HEAD(&cn->cn_list);
 837
 838        dentry = nfsd4_cld_register_net(net, cn->cn_pipe);
 839        if (IS_ERR(dentry)) {
 840                ret = PTR_ERR(dentry);
 841                goto err_destroy_data;
 842        }
 843
 844        cn->cn_pipe->dentry = dentry;
 845        nn->cld_net = cn;
 846        return 0;
 847
 848err_destroy_data:
 849        rpc_destroy_pipe_data(cn->cn_pipe);
 850err:
 851        kfree(cn);
 852        printk(KERN_ERR "NFSD: unable to create nfsdcld upcall pipe (%d)\n",
 853                        ret);
 854        return ret;
 855}
 856
 857static void
 858nfsd4_remove_cld_pipe(struct net *net)
 859{
 860        struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 861        struct cld_net *cn = nn->cld_net;
 862
 863        nfsd4_cld_unregister_net(net, cn->cn_pipe);
 864        rpc_destroy_pipe_data(cn->cn_pipe);
 865        kfree(nn->cld_net);
 866        nn->cld_net = NULL;
 867}
 868
 869static struct cld_upcall *
 870alloc_cld_upcall(struct cld_net *cn)
 871{
 872        struct cld_upcall *new, *tmp;
 873
 874        new = kzalloc(sizeof(*new), GFP_KERNEL);
 875        if (!new)
 876                return new;
 877
 878        /* FIXME: hard cap on number in flight? */
 879restart_search:
 880        spin_lock(&cn->cn_lock);
 881        list_for_each_entry(tmp, &cn->cn_list, cu_list) {
 882                if (tmp->cu_msg.cm_xid == cn->cn_xid) {
 883                        cn->cn_xid++;
 884                        spin_unlock(&cn->cn_lock);
 885                        goto restart_search;
 886                }
 887        }
 888        new->cu_task = current;
 889        new->cu_msg.cm_vers = CLD_UPCALL_VERSION;
 890        put_unaligned(cn->cn_xid++, &new->cu_msg.cm_xid);
 891        new->cu_net = cn;
 892        list_add(&new->cu_list, &cn->cn_list);
 893        spin_unlock(&cn->cn_lock);
 894
 895        dprintk("%s: allocated xid %u\n", __func__, new->cu_msg.cm_xid);
 896
 897        return new;
 898}
 899
 900static void
 901free_cld_upcall(struct cld_upcall *victim)
 902{
 903        struct cld_net *cn = victim->cu_net;
 904
 905        spin_lock(&cn->cn_lock);
 906        list_del(&victim->cu_list);
 907        spin_unlock(&cn->cn_lock);
 908        kfree(victim);
 909}
 910
 911/* Ask daemon to create a new record */
 912static void
 913nfsd4_cld_create(struct nfs4_client *clp)
 914{
 915        int ret;
 916        struct cld_upcall *cup;
 917        struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
 918        struct cld_net *cn = nn->cld_net;
 919
 920        /* Don't upcall if it's already stored */
 921        if (test_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags))
 922                return;
 923
 924        cup = alloc_cld_upcall(cn);
 925        if (!cup) {
 926                ret = -ENOMEM;
 927                goto out_err;
 928        }
 929
 930        cup->cu_msg.cm_cmd = Cld_Create;
 931        cup->cu_msg.cm_u.cm_name.cn_len = clp->cl_name.len;
 932        memcpy(cup->cu_msg.cm_u.cm_name.cn_id, clp->cl_name.data,
 933                        clp->cl_name.len);
 934
 935        ret = cld_pipe_upcall(cn->cn_pipe, &cup->cu_msg);
 936        if (!ret) {
 937                ret = cup->cu_msg.cm_status;
 938                set_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags);
 939        }
 940
 941        free_cld_upcall(cup);
 942out_err:
 943        if (ret)
 944                printk(KERN_ERR "NFSD: Unable to create client "
 945                                "record on stable storage: %d\n", ret);
 946}
 947
 948/* Ask daemon to create a new record */
 949static void
 950nfsd4_cld_remove(struct nfs4_client *clp)
 951{
 952        int ret;
 953        struct cld_upcall *cup;
 954        struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
 955        struct cld_net *cn = nn->cld_net;
 956
 957        /* Don't upcall if it's already removed */
 958        if (!test_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags))
 959                return;
 960
 961        cup = alloc_cld_upcall(cn);
 962        if (!cup) {
 963                ret = -ENOMEM;
 964                goto out_err;
 965        }
 966
 967        cup->cu_msg.cm_cmd = Cld_Remove;
 968        cup->cu_msg.cm_u.cm_name.cn_len = clp->cl_name.len;
 969        memcpy(cup->cu_msg.cm_u.cm_name.cn_id, clp->cl_name.data,
 970                        clp->cl_name.len);
 971
 972        ret = cld_pipe_upcall(cn->cn_pipe, &cup->cu_msg);
 973        if (!ret) {
 974                ret = cup->cu_msg.cm_status;
 975                clear_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags);
 976        }
 977
 978        free_cld_upcall(cup);
 979out_err:
 980        if (ret)
 981                printk(KERN_ERR "NFSD: Unable to remove client "
 982                                "record from stable storage: %d\n", ret);
 983}
 984
 985/* Check for presence of a record, and update its timestamp */
 986static int
 987nfsd4_cld_check(struct nfs4_client *clp)
 988{
 989        int ret;
 990        struct cld_upcall *cup;
 991        struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
 992        struct cld_net *cn = nn->cld_net;
 993
 994        /* Don't upcall if one was already stored during this grace pd */
 995        if (test_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags))
 996                return 0;
 997
 998        cup = alloc_cld_upcall(cn);
 999        if (!cup) {
1000                printk(KERN_ERR "NFSD: Unable to check client record on "
1001                                "stable storage: %d\n", -ENOMEM);
1002                return -ENOMEM;
1003        }
1004
1005        cup->cu_msg.cm_cmd = Cld_Check;
1006        cup->cu_msg.cm_u.cm_name.cn_len = clp->cl_name.len;
1007        memcpy(cup->cu_msg.cm_u.cm_name.cn_id, clp->cl_name.data,
1008                        clp->cl_name.len);
1009
1010        ret = cld_pipe_upcall(cn->cn_pipe, &cup->cu_msg);
1011        if (!ret) {
1012                ret = cup->cu_msg.cm_status;
1013                set_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags);
1014        }
1015
1016        free_cld_upcall(cup);
1017        return ret;
1018}
1019
1020static void
1021nfsd4_cld_grace_done(struct nfsd_net *nn, time_t boot_time)
1022{
1023        int ret;
1024        struct cld_upcall *cup;
1025        struct cld_net *cn = nn->cld_net;
1026
1027        cup = alloc_cld_upcall(cn);
1028        if (!cup) {
1029                ret = -ENOMEM;
1030                goto out_err;
1031        }
1032
1033        cup->cu_msg.cm_cmd = Cld_GraceDone;
1034        cup->cu_msg.cm_u.cm_gracetime = (int64_t)boot_time;
1035        ret = cld_pipe_upcall(cn->cn_pipe, &cup->cu_msg);
1036        if (!ret)
1037                ret = cup->cu_msg.cm_status;
1038
1039        free_cld_upcall(cup);
1040out_err:
1041        if (ret)
1042                printk(KERN_ERR "NFSD: Unable to end grace period: %d\n", ret);
1043}
1044
1045static struct nfsd4_client_tracking_ops nfsd4_cld_tracking_ops = {
1046        .init           = nfsd4_init_cld_pipe,
1047        .exit           = nfsd4_remove_cld_pipe,
1048        .create         = nfsd4_cld_create,
1049        .remove         = nfsd4_cld_remove,
1050        .check          = nfsd4_cld_check,
1051        .grace_done     = nfsd4_cld_grace_done,
1052};
1053
1054/* upcall via usermodehelper */
1055static char cltrack_prog[PATH_MAX] = "/sbin/nfsdcltrack";
1056module_param_string(cltrack_prog, cltrack_prog, sizeof(cltrack_prog),
1057                        S_IRUGO|S_IWUSR);
1058MODULE_PARM_DESC(cltrack_prog, "Path to the nfsdcltrack upcall program");
1059
1060static bool cltrack_legacy_disable;
1061module_param(cltrack_legacy_disable, bool, S_IRUGO|S_IWUSR);
1062MODULE_PARM_DESC(cltrack_legacy_disable,
1063                "Disable legacy recoverydir conversion. Default: false");
1064
1065#define LEGACY_TOPDIR_ENV_PREFIX "NFSDCLTRACK_LEGACY_TOPDIR="
1066#define LEGACY_RECDIR_ENV_PREFIX "NFSDCLTRACK_LEGACY_RECDIR="
1067
1068static char *
1069nfsd4_cltrack_legacy_topdir(void)
1070{
1071        int copied;
1072        size_t len;
1073        char *result;
1074
1075        if (cltrack_legacy_disable)
1076                return NULL;
1077
1078        len = strlen(LEGACY_TOPDIR_ENV_PREFIX) +
1079                strlen(nfs4_recoverydir()) + 1;
1080
1081        result = kmalloc(len, GFP_KERNEL);
1082        if (!result)
1083                return result;
1084
1085        copied = snprintf(result, len, LEGACY_TOPDIR_ENV_PREFIX "%s",
1086                                nfs4_recoverydir());
1087        if (copied >= len) {
1088                /* just return nothing if output was truncated */
1089                kfree(result);
1090                return NULL;
1091        }
1092
1093        return result;
1094}
1095
1096static char *
1097nfsd4_cltrack_legacy_recdir(const struct xdr_netobj *name)
1098{
1099        int copied;
1100        size_t len;
1101        char *result;
1102
1103        if (cltrack_legacy_disable)
1104                return NULL;
1105
1106        /* +1 is for '/' between "topdir" and "recdir" */
1107        len = strlen(LEGACY_RECDIR_ENV_PREFIX) +
1108                strlen(nfs4_recoverydir()) + 1 + HEXDIR_LEN;
1109
1110        result = kmalloc(len, GFP_KERNEL);
1111        if (!result)
1112                return result;
1113
1114        copied = snprintf(result, len, LEGACY_RECDIR_ENV_PREFIX "%s/",
1115                                nfs4_recoverydir());
1116        if (copied > (len - HEXDIR_LEN)) {
1117                /* just return nothing if output will be truncated */
1118                kfree(result);
1119                return NULL;
1120        }
1121
1122        copied = nfs4_make_rec_clidname(result + copied, name);
1123        if (copied) {
1124                kfree(result);
1125                return NULL;
1126        }
1127
1128        return result;
1129}
1130
1131static int
1132nfsd4_umh_cltrack_upcall(char *cmd, char *arg, char *legacy)
1133{
1134        char *envp[2];
1135        char *argv[4];
1136        int ret;
1137
1138        if (unlikely(!cltrack_prog[0])) {
1139                dprintk("%s: cltrack_prog is disabled\n", __func__);
1140                return -EACCES;
1141        }
1142
1143        dprintk("%s: cmd: %s\n", __func__, cmd);
1144        dprintk("%s: arg: %s\n", __func__, arg ? arg : "(null)");
1145        dprintk("%s: legacy: %s\n", __func__, legacy ? legacy : "(null)");
1146
1147        envp[0] = legacy;
1148        envp[1] = NULL;
1149
1150        argv[0] = (char *)cltrack_prog;
1151        argv[1] = cmd;
1152        argv[2] = arg;
1153        argv[3] = NULL;
1154
1155        ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_PROC);
1156        /*
1157         * Disable the upcall mechanism if we're getting an ENOENT or EACCES
1158         * error. The admin can re-enable it on the fly by using sysfs
1159         * once the problem has been fixed.
1160         */
1161        if (ret == -ENOENT || ret == -EACCES) {
1162                dprintk("NFSD: %s was not found or isn't executable (%d). "
1163                        "Setting cltrack_prog to blank string!",
1164                        cltrack_prog, ret);
1165                cltrack_prog[0] = '\0';
1166        }
1167        dprintk("%s: %s return value: %d\n", __func__, cltrack_prog, ret);
1168
1169        return ret;
1170}
1171
1172static char *
1173bin_to_hex_dup(const unsigned char *src, int srclen)
1174{
1175        int i;
1176        char *buf, *hex;
1177
1178        /* +1 for terminating NULL */
1179        buf = kmalloc((srclen * 2) + 1, GFP_KERNEL);
1180        if (!buf)
1181                return buf;
1182
1183        hex = buf;
1184        for (i = 0; i < srclen; i++) {
1185                sprintf(hex, "%2.2x", *src++);
1186                hex += 2;
1187        }
1188        return buf;
1189}
1190
1191static int
1192nfsd4_umh_cltrack_init(struct net __attribute__((unused)) *net)
1193{
1194        /* XXX: The usermode helper s not working in container yet. */
1195        if (net != &init_net) {
1196                WARN(1, KERN_ERR "NFSD: attempt to initialize umh client "
1197                        "tracking in a container!\n");
1198                return -EINVAL;
1199        }
1200        return nfsd4_umh_cltrack_upcall("init", NULL, NULL);
1201}
1202
1203static void
1204nfsd4_umh_cltrack_create(struct nfs4_client *clp)
1205{
1206        char *hexid;
1207
1208        hexid = bin_to_hex_dup(clp->cl_name.data, clp->cl_name.len);
1209        if (!hexid) {
1210                dprintk("%s: can't allocate memory for upcall!\n", __func__);
1211                return;
1212        }
1213        nfsd4_umh_cltrack_upcall("create", hexid, NULL);
1214        kfree(hexid);
1215}
1216
1217static void
1218nfsd4_umh_cltrack_remove(struct nfs4_client *clp)
1219{
1220        char *hexid;
1221
1222        hexid = bin_to_hex_dup(clp->cl_name.data, clp->cl_name.len);
1223        if (!hexid) {
1224                dprintk("%s: can't allocate memory for upcall!\n", __func__);
1225                return;
1226        }
1227        nfsd4_umh_cltrack_upcall("remove", hexid, NULL);
1228        kfree(hexid);
1229}
1230
1231static int
1232nfsd4_umh_cltrack_check(struct nfs4_client *clp)
1233{
1234        int ret;
1235        char *hexid, *legacy;
1236
1237        hexid = bin_to_hex_dup(clp->cl_name.data, clp->cl_name.len);
1238        if (!hexid) {
1239                dprintk("%s: can't allocate memory for upcall!\n", __func__);
1240                return -ENOMEM;
1241        }
1242        legacy = nfsd4_cltrack_legacy_recdir(&clp->cl_name);
1243        ret = nfsd4_umh_cltrack_upcall("check", hexid, legacy);
1244        kfree(legacy);
1245        kfree(hexid);
1246        return ret;
1247}
1248
1249static void
1250nfsd4_umh_cltrack_grace_done(struct nfsd_net __attribute__((unused)) *nn,
1251                                time_t boot_time)
1252{
1253        char *legacy;
1254        char timestr[22]; /* FIXME: better way to determine max size? */
1255
1256        sprintf(timestr, "%ld", boot_time);
1257        legacy = nfsd4_cltrack_legacy_topdir();
1258        nfsd4_umh_cltrack_upcall("gracedone", timestr, legacy);
1259        kfree(legacy);
1260}
1261
1262static struct nfsd4_client_tracking_ops nfsd4_umh_tracking_ops = {
1263        .init           = nfsd4_umh_cltrack_init,
1264        .exit           = NULL,
1265        .create         = nfsd4_umh_cltrack_create,
1266        .remove         = nfsd4_umh_cltrack_remove,
1267        .check          = nfsd4_umh_cltrack_check,
1268        .grace_done     = nfsd4_umh_cltrack_grace_done,
1269};
1270
1271int
1272nfsd4_client_tracking_init(struct net *net)
1273{
1274        int status;
1275        struct path path;
1276        struct nfsd_net *nn = net_generic(net, nfsd_net_id);
1277
1278        /* just run the init if it the method is already decided */
1279        if (nn->client_tracking_ops)
1280                goto do_init;
1281
1282        /*
1283         * First, try a UMH upcall. It should succeed or fail quickly, so
1284         * there's little harm in trying that first.
1285         */
1286        nn->client_tracking_ops = &nfsd4_umh_tracking_ops;
1287        status = nn->client_tracking_ops->init(net);
1288        if (!status)
1289                return status;
1290
1291        /*
1292         * See if the recoverydir exists and is a directory. If it is,
1293         * then use the legacy ops.
1294         */
1295        nn->client_tracking_ops = &nfsd4_legacy_tracking_ops;
1296        status = kern_path(nfs4_recoverydir(), LOOKUP_FOLLOW, &path);
1297        if (!status) {
1298                status = S_ISDIR(path.dentry->d_inode->i_mode);
1299                path_put(&path);
1300                if (status)
1301                        goto do_init;
1302        }
1303
1304        /* Finally, try to use nfsdcld */
1305        nn->client_tracking_ops = &nfsd4_cld_tracking_ops;
1306        printk(KERN_WARNING "NFSD: the nfsdcld client tracking upcall will be "
1307                        "removed in 3.10. Please transition to using "
1308                        "nfsdcltrack.\n");
1309do_init:
1310        status = nn->client_tracking_ops->init(net);
1311        if (status) {
1312                printk(KERN_WARNING "NFSD: Unable to initialize client "
1313                                    "recovery tracking! (%d)\n", status);
1314                nn->client_tracking_ops = NULL;
1315        }
1316        return status;
1317}
1318
1319void
1320nfsd4_client_tracking_exit(struct net *net)
1321{
1322        struct nfsd_net *nn = net_generic(net, nfsd_net_id);
1323
1324        if (nn->client_tracking_ops) {
1325                if (nn->client_tracking_ops->exit)
1326                        nn->client_tracking_ops->exit(net);
1327                nn->client_tracking_ops = NULL;
1328        }
1329}
1330
1331void
1332nfsd4_client_record_create(struct nfs4_client *clp)
1333{
1334        struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
1335
1336        if (nn->client_tracking_ops)
1337                nn->client_tracking_ops->create(clp);
1338}
1339
1340void
1341nfsd4_client_record_remove(struct nfs4_client *clp)
1342{
1343        struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
1344
1345        if (nn->client_tracking_ops)
1346                nn->client_tracking_ops->remove(clp);
1347}
1348
1349int
1350nfsd4_client_record_check(struct nfs4_client *clp)
1351{
1352        struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
1353
1354        if (nn->client_tracking_ops)
1355                return nn->client_tracking_ops->check(clp);
1356
1357        return -EOPNOTSUPP;
1358}
1359
1360void
1361nfsd4_record_grace_done(struct nfsd_net *nn, time_t boot_time)
1362{
1363        if (nn->client_tracking_ops)
1364                nn->client_tracking_ops->grace_done(nn, boot_time);
1365}
1366
1367static int
1368rpc_pipefs_event(struct notifier_block *nb, unsigned long event, void *ptr)
1369{
1370        struct super_block *sb = ptr;
1371        struct net *net = sb->s_fs_info;
1372        struct nfsd_net *nn = net_generic(net, nfsd_net_id);
1373        struct cld_net *cn = nn->cld_net;
1374        struct dentry *dentry;
1375        int ret = 0;
1376
1377        if (!try_module_get(THIS_MODULE))
1378                return 0;
1379
1380        if (!cn) {
1381                module_put(THIS_MODULE);
1382                return 0;
1383        }
1384
1385        switch (event) {
1386        case RPC_PIPEFS_MOUNT:
1387                dentry = nfsd4_cld_register_sb(sb, cn->cn_pipe);
1388                if (IS_ERR(dentry)) {
1389                        ret = PTR_ERR(dentry);
1390                        break;
1391                }
1392                cn->cn_pipe->dentry = dentry;
1393                break;
1394        case RPC_PIPEFS_UMOUNT:
1395                if (cn->cn_pipe->dentry)
1396                        nfsd4_cld_unregister_sb(cn->cn_pipe);
1397                break;
1398        default:
1399                ret = -ENOTSUPP;
1400                break;
1401        }
1402        module_put(THIS_MODULE);
1403        return ret;
1404}
1405
1406static struct notifier_block nfsd4_cld_block = {
1407        .notifier_call = rpc_pipefs_event,
1408};
1409
1410int
1411register_cld_notifier(void)
1412{
1413        return rpc_pipefs_notifier_register(&nfsd4_cld_block);
1414}
1415
1416void
1417unregister_cld_notifier(void)
1418{
1419        rpc_pipefs_notifier_unregister(&nfsd4_cld_block);
1420}
1421
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