linux/fs/nfsd/vfs.c
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   1/*
   2 * File operations used by nfsd. Some of these have been ripped from
   3 * other parts of the kernel because they weren't exported, others
   4 * are partial duplicates with added or changed functionality.
   5 *
   6 * Note that several functions dget() the dentry upon which they want
   7 * to act, most notably those that create directory entries. Response
   8 * dentry's are dput()'d if necessary in the release callback.
   9 * So if you notice code paths that apparently fail to dput() the
  10 * dentry, don't worry--they have been taken care of.
  11 *
  12 * Copyright (C) 1995-1999 Olaf Kirch <okir@monad.swb.de>
  13 * Zerocpy NFS support (C) 2002 Hirokazu Takahashi <taka@valinux.co.jp>
  14 */
  15
  16#include <linux/fs.h>
  17#include <linux/file.h>
  18#include <linux/splice.h>
  19#include <linux/fcntl.h>
  20#include <linux/namei.h>
  21#include <linux/delay.h>
  22#include <linux/fsnotify.h>
  23#include <linux/posix_acl_xattr.h>
  24#include <linux/xattr.h>
  25#include <linux/jhash.h>
  26#include <linux/ima.h>
  27#include <linux/slab.h>
  28#include <asm/uaccess.h>
  29#include <linux/exportfs.h>
  30#include <linux/writeback.h>
  31
  32#ifdef CONFIG_NFSD_V3
  33#include "xdr3.h"
  34#endif /* CONFIG_NFSD_V3 */
  35
  36#ifdef CONFIG_NFSD_V4
  37#include "acl.h"
  38#include "idmap.h"
  39#endif /* CONFIG_NFSD_V4 */
  40
  41#include "nfsd.h"
  42#include "vfs.h"
  43
  44#define NFSDDBG_FACILITY                NFSDDBG_FILEOP
  45
  46
  47/*
  48 * This is a cache of readahead params that help us choose the proper
  49 * readahead strategy. Initially, we set all readahead parameters to 0
  50 * and let the VFS handle things.
  51 * If you increase the number of cached files very much, you'll need to
  52 * add a hash table here.
  53 */
  54struct raparms {
  55        struct raparms          *p_next;
  56        unsigned int            p_count;
  57        ino_t                   p_ino;
  58        dev_t                   p_dev;
  59        int                     p_set;
  60        struct file_ra_state    p_ra;
  61        unsigned int            p_hindex;
  62};
  63
  64struct raparm_hbucket {
  65        struct raparms          *pb_head;
  66        spinlock_t              pb_lock;
  67} ____cacheline_aligned_in_smp;
  68
  69#define RAPARM_HASH_BITS        4
  70#define RAPARM_HASH_SIZE        (1<<RAPARM_HASH_BITS)
  71#define RAPARM_HASH_MASK        (RAPARM_HASH_SIZE-1)
  72static struct raparm_hbucket    raparm_hash[RAPARM_HASH_SIZE];
  73
  74/* 
  75 * Called from nfsd_lookup and encode_dirent. Check if we have crossed 
  76 * a mount point.
  77 * Returns -EAGAIN or -ETIMEDOUT leaving *dpp and *expp unchanged,
  78 *  or nfs_ok having possibly changed *dpp and *expp
  79 */
  80int
  81nfsd_cross_mnt(struct svc_rqst *rqstp, struct dentry **dpp, 
  82                        struct svc_export **expp)
  83{
  84        struct svc_export *exp = *expp, *exp2 = NULL;
  85        struct dentry *dentry = *dpp;
  86        struct path path = {.mnt = mntget(exp->ex_path.mnt),
  87                            .dentry = dget(dentry)};
  88        int err = 0;
  89
  90        err = follow_down(&path);
  91        if (err < 0)
  92                goto out;
  93
  94        exp2 = rqst_exp_get_by_name(rqstp, &path);
  95        if (IS_ERR(exp2)) {
  96                err = PTR_ERR(exp2);
  97                /*
  98                 * We normally allow NFS clients to continue
  99                 * "underneath" a mountpoint that is not exported.
 100                 * The exception is V4ROOT, where no traversal is ever
 101                 * allowed without an explicit export of the new
 102                 * directory.
 103                 */
 104                if (err == -ENOENT && !(exp->ex_flags & NFSEXP_V4ROOT))
 105                        err = 0;
 106                path_put(&path);
 107                goto out;
 108        }
 109        if (nfsd_v4client(rqstp) ||
 110                (exp->ex_flags & NFSEXP_CROSSMOUNT) || EX_NOHIDE(exp2)) {
 111                /* successfully crossed mount point */
 112                /*
 113                 * This is subtle: path.dentry is *not* on path.mnt
 114                 * at this point.  The only reason we are safe is that
 115                 * original mnt is pinned down by exp, so we should
 116                 * put path *before* putting exp
 117                 */
 118                *dpp = path.dentry;
 119                path.dentry = dentry;
 120                *expp = exp2;
 121                exp2 = exp;
 122        }
 123        path_put(&path);
 124        exp_put(exp2);
 125out:
 126        return err;
 127}
 128
 129static void follow_to_parent(struct path *path)
 130{
 131        struct dentry *dp;
 132
 133        while (path->dentry == path->mnt->mnt_root && follow_up(path))
 134                ;
 135        dp = dget_parent(path->dentry);
 136        dput(path->dentry);
 137        path->dentry = dp;
 138}
 139
 140static int nfsd_lookup_parent(struct svc_rqst *rqstp, struct dentry *dparent, struct svc_export **exp, struct dentry **dentryp)
 141{
 142        struct svc_export *exp2;
 143        struct path path = {.mnt = mntget((*exp)->ex_path.mnt),
 144                            .dentry = dget(dparent)};
 145
 146        follow_to_parent(&path);
 147
 148        exp2 = rqst_exp_parent(rqstp, &path);
 149        if (PTR_ERR(exp2) == -ENOENT) {
 150                *dentryp = dget(dparent);
 151        } else if (IS_ERR(exp2)) {
 152                path_put(&path);
 153                return PTR_ERR(exp2);
 154        } else {
 155                *dentryp = dget(path.dentry);
 156                exp_put(*exp);
 157                *exp = exp2;
 158        }
 159        path_put(&path);
 160        return 0;
 161}
 162
 163/*
 164 * For nfsd purposes, we treat V4ROOT exports as though there was an
 165 * export at *every* directory.
 166 */
 167int nfsd_mountpoint(struct dentry *dentry, struct svc_export *exp)
 168{
 169        if (d_mountpoint(dentry))
 170                return 1;
 171        if (!(exp->ex_flags & NFSEXP_V4ROOT))
 172                return 0;
 173        return dentry->d_inode != NULL;
 174}
 175
 176__be32
 177nfsd_lookup_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp,
 178                   const char *name, unsigned int len,
 179                   struct svc_export **exp_ret, struct dentry **dentry_ret)
 180{
 181        struct svc_export       *exp;
 182        struct dentry           *dparent;
 183        struct dentry           *dentry;
 184        __be32                  err;
 185        int                     host_err;
 186
 187        dprintk("nfsd: nfsd_lookup(fh %s, %.*s)\n", SVCFH_fmt(fhp), len,name);
 188
 189        /* Obtain dentry and export. */
 190        err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC);
 191        if (err)
 192                return err;
 193
 194        dparent = fhp->fh_dentry;
 195        exp  = fhp->fh_export;
 196        exp_get(exp);
 197
 198        /* Lookup the name, but don't follow links */
 199        if (isdotent(name, len)) {
 200                if (len==1)
 201                        dentry = dget(dparent);
 202                else if (dparent != exp->ex_path.dentry)
 203                        dentry = dget_parent(dparent);
 204                else if (!EX_NOHIDE(exp) && !nfsd_v4client(rqstp))
 205                        dentry = dget(dparent); /* .. == . just like at / */
 206                else {
 207                        /* checking mountpoint crossing is very different when stepping up */
 208                        host_err = nfsd_lookup_parent(rqstp, dparent, &exp, &dentry);
 209                        if (host_err)
 210                                goto out_nfserr;
 211                }
 212        } else {
 213                fh_lock(fhp);
 214                dentry = lookup_one_len(name, dparent, len);
 215                host_err = PTR_ERR(dentry);
 216                if (IS_ERR(dentry))
 217                        goto out_nfserr;
 218                /*
 219                 * check if we have crossed a mount point ...
 220                 */
 221                if (nfsd_mountpoint(dentry, exp)) {
 222                        if ((host_err = nfsd_cross_mnt(rqstp, &dentry, &exp))) {
 223                                dput(dentry);
 224                                goto out_nfserr;
 225                        }
 226                }
 227        }
 228        *dentry_ret = dentry;
 229        *exp_ret = exp;
 230        return 0;
 231
 232out_nfserr:
 233        exp_put(exp);
 234        return nfserrno(host_err);
 235}
 236
 237/*
 238 * Look up one component of a pathname.
 239 * N.B. After this call _both_ fhp and resfh need an fh_put
 240 *
 241 * If the lookup would cross a mountpoint, and the mounted filesystem
 242 * is exported to the client with NFSEXP_NOHIDE, then the lookup is
 243 * accepted as it stands and the mounted directory is
 244 * returned. Otherwise the covered directory is returned.
 245 * NOTE: this mountpoint crossing is not supported properly by all
 246 *   clients and is explicitly disallowed for NFSv3
 247 *      NeilBrown <neilb@cse.unsw.edu.au>
 248 */
 249__be32
 250nfsd_lookup(struct svc_rqst *rqstp, struct svc_fh *fhp, const char *name,
 251                                unsigned int len, struct svc_fh *resfh)
 252{
 253        struct svc_export       *exp;
 254        struct dentry           *dentry;
 255        __be32 err;
 256
 257        err = nfsd_lookup_dentry(rqstp, fhp, name, len, &exp, &dentry);
 258        if (err)
 259                return err;
 260        err = check_nfsd_access(exp, rqstp);
 261        if (err)
 262                goto out;
 263        /*
 264         * Note: we compose the file handle now, but as the
 265         * dentry may be negative, it may need to be updated.
 266         */
 267        err = fh_compose(resfh, exp, dentry, fhp);
 268        if (!err && !dentry->d_inode)
 269                err = nfserr_noent;
 270out:
 271        dput(dentry);
 272        exp_put(exp);
 273        return err;
 274}
 275
 276static int nfsd_break_lease(struct inode *inode)
 277{
 278        if (!S_ISREG(inode->i_mode))
 279                return 0;
 280        return break_lease(inode, O_WRONLY | O_NONBLOCK);
 281}
 282
 283/*
 284 * Commit metadata changes to stable storage.
 285 */
 286static int
 287commit_metadata(struct svc_fh *fhp)
 288{
 289        struct inode *inode = fhp->fh_dentry->d_inode;
 290        const struct export_operations *export_ops = inode->i_sb->s_export_op;
 291
 292        if (!EX_ISSYNC(fhp->fh_export))
 293                return 0;
 294
 295        if (export_ops->commit_metadata)
 296                return export_ops->commit_metadata(inode);
 297        return sync_inode_metadata(inode, 1);
 298}
 299
 300/*
 301 * Set various file attributes.
 302 * N.B. After this call fhp needs an fh_put
 303 */
 304__be32
 305nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
 306             int check_guard, time_t guardtime)
 307{
 308        struct dentry   *dentry;
 309        struct inode    *inode;
 310        int             accmode = NFSD_MAY_SATTR;
 311        int             ftype = 0;
 312        __be32          err;
 313        int             host_err;
 314        int             size_change = 0;
 315
 316        if (iap->ia_valid & (ATTR_ATIME | ATTR_MTIME | ATTR_SIZE))
 317                accmode |= NFSD_MAY_WRITE|NFSD_MAY_OWNER_OVERRIDE;
 318        if (iap->ia_valid & ATTR_SIZE)
 319                ftype = S_IFREG;
 320
 321        /* Get inode */
 322        err = fh_verify(rqstp, fhp, ftype, accmode);
 323        if (err)
 324                goto out;
 325
 326        dentry = fhp->fh_dentry;
 327        inode = dentry->d_inode;
 328
 329        /* Ignore any mode updates on symlinks */
 330        if (S_ISLNK(inode->i_mode))
 331                iap->ia_valid &= ~ATTR_MODE;
 332
 333        if (!iap->ia_valid)
 334                goto out;
 335
 336        /*
 337         * NFSv2 does not differentiate between "set-[ac]time-to-now"
 338         * which only requires access, and "set-[ac]time-to-X" which
 339         * requires ownership.
 340         * So if it looks like it might be "set both to the same time which
 341         * is close to now", and if inode_change_ok fails, then we
 342         * convert to "set to now" instead of "set to explicit time"
 343         *
 344         * We only call inode_change_ok as the last test as technically
 345         * it is not an interface that we should be using.  It is only
 346         * valid if the filesystem does not define it's own i_op->setattr.
 347         */
 348#define BOTH_TIME_SET (ATTR_ATIME_SET | ATTR_MTIME_SET)
 349#define MAX_TOUCH_TIME_ERROR (30*60)
 350        if ((iap->ia_valid & BOTH_TIME_SET) == BOTH_TIME_SET &&
 351            iap->ia_mtime.tv_sec == iap->ia_atime.tv_sec) {
 352                /*
 353                 * Looks probable.
 354                 *
 355                 * Now just make sure time is in the right ballpark.
 356                 * Solaris, at least, doesn't seem to care what the time
 357                 * request is.  We require it be within 30 minutes of now.
 358                 */
 359                time_t delta = iap->ia_atime.tv_sec - get_seconds();
 360                if (delta < 0)
 361                        delta = -delta;
 362                if (delta < MAX_TOUCH_TIME_ERROR &&
 363                    inode_change_ok(inode, iap) != 0) {
 364                        /*
 365                         * Turn off ATTR_[AM]TIME_SET but leave ATTR_[AM]TIME.
 366                         * This will cause notify_change to set these times
 367                         * to "now"
 368                         */
 369                        iap->ia_valid &= ~BOTH_TIME_SET;
 370                }
 371        }
 372            
 373        /*
 374         * The size case is special.
 375         * It changes the file as well as the attributes.
 376         */
 377        if (iap->ia_valid & ATTR_SIZE) {
 378                if (iap->ia_size < inode->i_size) {
 379                        err = nfsd_permission(rqstp, fhp->fh_export, dentry,
 380                                        NFSD_MAY_TRUNC|NFSD_MAY_OWNER_OVERRIDE);
 381                        if (err)
 382                                goto out;
 383                }
 384
 385                host_err = get_write_access(inode);
 386                if (host_err)
 387                        goto out_nfserr;
 388
 389                size_change = 1;
 390                host_err = locks_verify_truncate(inode, NULL, iap->ia_size);
 391                if (host_err) {
 392                        put_write_access(inode);
 393                        goto out_nfserr;
 394                }
 395        }
 396
 397        /* sanitize the mode change */
 398        if (iap->ia_valid & ATTR_MODE) {
 399                iap->ia_mode &= S_IALLUGO;
 400                iap->ia_mode |= (inode->i_mode & ~S_IALLUGO);
 401        }
 402
 403        /* Revoke setuid/setgid on chown */
 404        if (!S_ISDIR(inode->i_mode) &&
 405            (((iap->ia_valid & ATTR_UID) && iap->ia_uid != inode->i_uid) ||
 406             ((iap->ia_valid & ATTR_GID) && iap->ia_gid != inode->i_gid))) {
 407                iap->ia_valid |= ATTR_KILL_PRIV;
 408                if (iap->ia_valid & ATTR_MODE) {
 409                        /* we're setting mode too, just clear the s*id bits */
 410                        iap->ia_mode &= ~S_ISUID;
 411                        if (iap->ia_mode & S_IXGRP)
 412                                iap->ia_mode &= ~S_ISGID;
 413                } else {
 414                        /* set ATTR_KILL_* bits and let VFS handle it */
 415                        iap->ia_valid |= (ATTR_KILL_SUID | ATTR_KILL_SGID);
 416                }
 417        }
 418
 419        /* Change the attributes. */
 420
 421        iap->ia_valid |= ATTR_CTIME;
 422
 423        err = nfserr_notsync;
 424        if (!check_guard || guardtime == inode->i_ctime.tv_sec) {
 425                host_err = nfsd_break_lease(inode);
 426                if (host_err)
 427                        goto out_nfserr;
 428                fh_lock(fhp);
 429
 430                host_err = notify_change(dentry, iap);
 431                err = nfserrno(host_err);
 432                fh_unlock(fhp);
 433        }
 434        if (size_change)
 435                put_write_access(inode);
 436        if (!err)
 437                commit_metadata(fhp);
 438out:
 439        return err;
 440
 441out_nfserr:
 442        err = nfserrno(host_err);
 443        goto out;
 444}
 445
 446#if defined(CONFIG_NFSD_V2_ACL) || \
 447    defined(CONFIG_NFSD_V3_ACL) || \
 448    defined(CONFIG_NFSD_V4)
 449static ssize_t nfsd_getxattr(struct dentry *dentry, char *key, void **buf)
 450{
 451        ssize_t buflen;
 452        ssize_t ret;
 453
 454        buflen = vfs_getxattr(dentry, key, NULL, 0);
 455        if (buflen <= 0)
 456                return buflen;
 457
 458        *buf = kmalloc(buflen, GFP_KERNEL);
 459        if (!*buf)
 460                return -ENOMEM;
 461
 462        ret = vfs_getxattr(dentry, key, *buf, buflen);
 463        if (ret < 0)
 464                kfree(*buf);
 465        return ret;
 466}
 467#endif
 468
 469#if defined(CONFIG_NFSD_V4)
 470static int
 471set_nfsv4_acl_one(struct dentry *dentry, struct posix_acl *pacl, char *key)
 472{
 473        int len;
 474        size_t buflen;
 475        char *buf = NULL;
 476        int error = 0;
 477
 478        buflen = posix_acl_xattr_size(pacl->a_count);
 479        buf = kmalloc(buflen, GFP_KERNEL);
 480        error = -ENOMEM;
 481        if (buf == NULL)
 482                goto out;
 483
 484        len = posix_acl_to_xattr(pacl, buf, buflen);
 485        if (len < 0) {
 486                error = len;
 487                goto out;
 488        }
 489
 490        error = vfs_setxattr(dentry, key, buf, len, 0);
 491out:
 492        kfree(buf);
 493        return error;
 494}
 495
 496__be32
 497nfsd4_set_nfs4_acl(struct svc_rqst *rqstp, struct svc_fh *fhp,
 498    struct nfs4_acl *acl)
 499{
 500        __be32 error;
 501        int host_error;
 502        struct dentry *dentry;
 503        struct inode *inode;
 504        struct posix_acl *pacl = NULL, *dpacl = NULL;
 505        unsigned int flags = 0;
 506
 507        /* Get inode */
 508        error = fh_verify(rqstp, fhp, 0 /* S_IFREG */, NFSD_MAY_SATTR);
 509        if (error)
 510                return error;
 511
 512        dentry = fhp->fh_dentry;
 513        inode = dentry->d_inode;
 514        if (S_ISDIR(inode->i_mode))
 515                flags = NFS4_ACL_DIR;
 516
 517        host_error = nfs4_acl_nfsv4_to_posix(acl, &pacl, &dpacl, flags);
 518        if (host_error == -EINVAL) {
 519                return nfserr_attrnotsupp;
 520        } else if (host_error < 0)
 521                goto out_nfserr;
 522
 523        host_error = set_nfsv4_acl_one(dentry, pacl, POSIX_ACL_XATTR_ACCESS);
 524        if (host_error < 0)
 525                goto out_release;
 526
 527        if (S_ISDIR(inode->i_mode))
 528                host_error = set_nfsv4_acl_one(dentry, dpacl, POSIX_ACL_XATTR_DEFAULT);
 529
 530out_release:
 531        posix_acl_release(pacl);
 532        posix_acl_release(dpacl);
 533out_nfserr:
 534        if (host_error == -EOPNOTSUPP)
 535                return nfserr_attrnotsupp;
 536        else
 537                return nfserrno(host_error);
 538}
 539
 540static struct posix_acl *
 541_get_posix_acl(struct dentry *dentry, char *key)
 542{
 543        void *buf = NULL;
 544        struct posix_acl *pacl = NULL;
 545        int buflen;
 546
 547        buflen = nfsd_getxattr(dentry, key, &buf);
 548        if (!buflen)
 549                buflen = -ENODATA;
 550        if (buflen <= 0)
 551                return ERR_PTR(buflen);
 552
 553        pacl = posix_acl_from_xattr(buf, buflen);
 554        kfree(buf);
 555        return pacl;
 556}
 557
 558int
 559nfsd4_get_nfs4_acl(struct svc_rqst *rqstp, struct dentry *dentry, struct nfs4_acl **acl)
 560{
 561        struct inode *inode = dentry->d_inode;
 562        int error = 0;
 563        struct posix_acl *pacl = NULL, *dpacl = NULL;
 564        unsigned int flags = 0;
 565
 566        pacl = _get_posix_acl(dentry, POSIX_ACL_XATTR_ACCESS);
 567        if (IS_ERR(pacl) && PTR_ERR(pacl) == -ENODATA)
 568                pacl = posix_acl_from_mode(inode->i_mode, GFP_KERNEL);
 569        if (IS_ERR(pacl)) {
 570                error = PTR_ERR(pacl);
 571                pacl = NULL;
 572                goto out;
 573        }
 574
 575        if (S_ISDIR(inode->i_mode)) {
 576                dpacl = _get_posix_acl(dentry, POSIX_ACL_XATTR_DEFAULT);
 577                if (IS_ERR(dpacl) && PTR_ERR(dpacl) == -ENODATA)
 578                        dpacl = NULL;
 579                else if (IS_ERR(dpacl)) {
 580                        error = PTR_ERR(dpacl);
 581                        dpacl = NULL;
 582                        goto out;
 583                }
 584                flags = NFS4_ACL_DIR;
 585        }
 586
 587        *acl = nfs4_acl_posix_to_nfsv4(pacl, dpacl, flags);
 588        if (IS_ERR(*acl)) {
 589                error = PTR_ERR(*acl);
 590                *acl = NULL;
 591        }
 592 out:
 593        posix_acl_release(pacl);
 594        posix_acl_release(dpacl);
 595        return error;
 596}
 597
 598#endif /* defined(CONFIG_NFSD_V4) */
 599
 600#ifdef CONFIG_NFSD_V3
 601/*
 602 * Check server access rights to a file system object
 603 */
 604struct accessmap {
 605        u32             access;
 606        int             how;
 607};
 608static struct accessmap nfs3_regaccess[] = {
 609    {   NFS3_ACCESS_READ,       NFSD_MAY_READ                   },
 610    {   NFS3_ACCESS_EXECUTE,    NFSD_MAY_EXEC                   },
 611    {   NFS3_ACCESS_MODIFY,     NFSD_MAY_WRITE|NFSD_MAY_TRUNC   },
 612    {   NFS3_ACCESS_EXTEND,     NFSD_MAY_WRITE                  },
 613
 614    {   0,                      0                               }
 615};
 616
 617static struct accessmap nfs3_diraccess[] = {
 618    {   NFS3_ACCESS_READ,       NFSD_MAY_READ                   },
 619    {   NFS3_ACCESS_LOOKUP,     NFSD_MAY_EXEC                   },
 620    {   NFS3_ACCESS_MODIFY,     NFSD_MAY_EXEC|NFSD_MAY_WRITE|NFSD_MAY_TRUNC},
 621    {   NFS3_ACCESS_EXTEND,     NFSD_MAY_EXEC|NFSD_MAY_WRITE    },
 622    {   NFS3_ACCESS_DELETE,     NFSD_MAY_REMOVE                 },
 623
 624    {   0,                      0                               }
 625};
 626
 627static struct accessmap nfs3_anyaccess[] = {
 628        /* Some clients - Solaris 2.6 at least, make an access call
 629         * to the server to check for access for things like /dev/null
 630         * (which really, the server doesn't care about).  So
 631         * We provide simple access checking for them, looking
 632         * mainly at mode bits, and we make sure to ignore read-only
 633         * filesystem checks
 634         */
 635    {   NFS3_ACCESS_READ,       NFSD_MAY_READ                   },
 636    {   NFS3_ACCESS_EXECUTE,    NFSD_MAY_EXEC                   },
 637    {   NFS3_ACCESS_MODIFY,     NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS    },
 638    {   NFS3_ACCESS_EXTEND,     NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS    },
 639
 640    {   0,                      0                               }
 641};
 642
 643__be32
 644nfsd_access(struct svc_rqst *rqstp, struct svc_fh *fhp, u32 *access, u32 *supported)
 645{
 646        struct accessmap        *map;
 647        struct svc_export       *export;
 648        struct dentry           *dentry;
 649        u32                     query, result = 0, sresult = 0;
 650        __be32                  error;
 651
 652        error = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP);
 653        if (error)
 654                goto out;
 655
 656        export = fhp->fh_export;
 657        dentry = fhp->fh_dentry;
 658
 659        if (S_ISREG(dentry->d_inode->i_mode))
 660                map = nfs3_regaccess;
 661        else if (S_ISDIR(dentry->d_inode->i_mode))
 662                map = nfs3_diraccess;
 663        else
 664                map = nfs3_anyaccess;
 665
 666
 667        query = *access;
 668        for  (; map->access; map++) {
 669                if (map->access & query) {
 670                        __be32 err2;
 671
 672                        sresult |= map->access;
 673
 674                        err2 = nfsd_permission(rqstp, export, dentry, map->how);
 675                        switch (err2) {
 676                        case nfs_ok:
 677                                result |= map->access;
 678                                break;
 679                                
 680                        /* the following error codes just mean the access was not allowed,
 681                         * rather than an error occurred */
 682                        case nfserr_rofs:
 683                        case nfserr_acces:
 684                        case nfserr_perm:
 685                                /* simply don't "or" in the access bit. */
 686                                break;
 687                        default:
 688                                error = err2;
 689                                goto out;
 690                        }
 691                }
 692        }
 693        *access = result;
 694        if (supported)
 695                *supported = sresult;
 696
 697 out:
 698        return error;
 699}
 700#endif /* CONFIG_NFSD_V3 */
 701
 702
 703
 704/*
 705 * Open an existing file or directory.
 706 * The access argument indicates the type of open (read/write/lock)
 707 * N.B. After this call fhp needs an fh_put
 708 */
 709__be32
 710nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
 711                        int access, struct file **filp)
 712{
 713        struct dentry   *dentry;
 714        struct inode    *inode;
 715        int             flags = O_RDONLY|O_LARGEFILE;
 716        __be32          err;
 717        int             host_err = 0;
 718
 719        validate_process_creds();
 720
 721        /*
 722         * If we get here, then the client has already done an "open",
 723         * and (hopefully) checked permission - so allow OWNER_OVERRIDE
 724         * in case a chmod has now revoked permission.
 725         */
 726        err = fh_verify(rqstp, fhp, type, access | NFSD_MAY_OWNER_OVERRIDE);
 727        if (err)
 728                goto out;
 729
 730        dentry = fhp->fh_dentry;
 731        inode = dentry->d_inode;
 732
 733        /* Disallow write access to files with the append-only bit set
 734         * or any access when mandatory locking enabled
 735         */
 736        err = nfserr_perm;
 737        if (IS_APPEND(inode) && (access & NFSD_MAY_WRITE))
 738                goto out;
 739        /*
 740         * We must ignore files (but only files) which might have mandatory
 741         * locks on them because there is no way to know if the accesser has
 742         * the lock.
 743         */
 744        if (S_ISREG((inode)->i_mode) && mandatory_lock(inode))
 745                goto out;
 746
 747        if (!inode->i_fop)
 748                goto out;
 749
 750        /*
 751         * Check to see if there are any leases on this file.
 752         * This may block while leases are broken.
 753         */
 754        if (!(access & NFSD_MAY_NOT_BREAK_LEASE))
 755                host_err = break_lease(inode, O_NONBLOCK | ((access & NFSD_MAY_WRITE) ? O_WRONLY : 0));
 756        if (host_err) /* NOMEM or WOULDBLOCK */
 757                goto out_nfserr;
 758
 759        if (access & NFSD_MAY_WRITE) {
 760                if (access & NFSD_MAY_READ)
 761                        flags = O_RDWR|O_LARGEFILE;
 762                else
 763                        flags = O_WRONLY|O_LARGEFILE;
 764        }
 765        *filp = dentry_open(dget(dentry), mntget(fhp->fh_export->ex_path.mnt),
 766                            flags, current_cred());
 767        if (IS_ERR(*filp))
 768                host_err = PTR_ERR(*filp);
 769        else
 770                host_err = ima_file_check(*filp, access);
 771out_nfserr:
 772        err = nfserrno(host_err);
 773out:
 774        validate_process_creds();
 775        return err;
 776}
 777
 778/*
 779 * Close a file.
 780 */
 781void
 782nfsd_close(struct file *filp)
 783{
 784        fput(filp);
 785}
 786
 787/*
 788 * Obtain the readahead parameters for the file
 789 * specified by (dev, ino).
 790 */
 791
 792static inline struct raparms *
 793nfsd_get_raparms(dev_t dev, ino_t ino)
 794{
 795        struct raparms  *ra, **rap, **frap = NULL;
 796        int depth = 0;
 797        unsigned int hash;
 798        struct raparm_hbucket *rab;
 799
 800        hash = jhash_2words(dev, ino, 0xfeedbeef) & RAPARM_HASH_MASK;
 801        rab = &raparm_hash[hash];
 802
 803        spin_lock(&rab->pb_lock);
 804        for (rap = &rab->pb_head; (ra = *rap); rap = &ra->p_next) {
 805                if (ra->p_ino == ino && ra->p_dev == dev)
 806                        goto found;
 807                depth++;
 808                if (ra->p_count == 0)
 809                        frap = rap;
 810        }
 811        depth = nfsdstats.ra_size;
 812        if (!frap) {    
 813                spin_unlock(&rab->pb_lock);
 814                return NULL;
 815        }
 816        rap = frap;
 817        ra = *frap;
 818        ra->p_dev = dev;
 819        ra->p_ino = ino;
 820        ra->p_set = 0;
 821        ra->p_hindex = hash;
 822found:
 823        if (rap != &rab->pb_head) {
 824                *rap = ra->p_next;
 825                ra->p_next   = rab->pb_head;
 826                rab->pb_head = ra;
 827        }
 828        ra->p_count++;
 829        nfsdstats.ra_depth[depth*10/nfsdstats.ra_size]++;
 830        spin_unlock(&rab->pb_lock);
 831        return ra;
 832}
 833
 834/*
 835 * Grab and keep cached pages associated with a file in the svc_rqst
 836 * so that they can be passed to the network sendmsg/sendpage routines
 837 * directly. They will be released after the sending has completed.
 838 */
 839static int
 840nfsd_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
 841                  struct splice_desc *sd)
 842{
 843        struct svc_rqst *rqstp = sd->u.data;
 844        struct page **pp = rqstp->rq_respages + rqstp->rq_resused;
 845        struct page *page = buf->page;
 846        size_t size;
 847
 848        size = sd->len;
 849
 850        if (rqstp->rq_res.page_len == 0) {
 851                get_page(page);
 852                put_page(*pp);
 853                *pp = page;
 854                rqstp->rq_resused++;
 855                rqstp->rq_res.page_base = buf->offset;
 856                rqstp->rq_res.page_len = size;
 857        } else if (page != pp[-1]) {
 858                get_page(page);
 859                if (*pp)
 860                        put_page(*pp);
 861                *pp = page;
 862                rqstp->rq_resused++;
 863                rqstp->rq_res.page_len += size;
 864        } else
 865                rqstp->rq_res.page_len += size;
 866
 867        return size;
 868}
 869
 870static int nfsd_direct_splice_actor(struct pipe_inode_info *pipe,
 871                                    struct splice_desc *sd)
 872{
 873        return __splice_from_pipe(pipe, sd, nfsd_splice_actor);
 874}
 875
 876static __be32
 877nfsd_vfs_read(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
 878              loff_t offset, struct kvec *vec, int vlen, unsigned long *count)
 879{
 880        struct inode *inode;
 881        mm_segment_t    oldfs;
 882        __be32          err;
 883        int             host_err;
 884
 885        err = nfserr_perm;
 886        inode = file->f_path.dentry->d_inode;
 887
 888        if (file->f_op->splice_read && rqstp->rq_splice_ok) {
 889                struct splice_desc sd = {
 890                        .len            = 0,
 891                        .total_len      = *count,
 892                        .pos            = offset,
 893                        .u.data         = rqstp,
 894                };
 895
 896                rqstp->rq_resused = 1;
 897                host_err = splice_direct_to_actor(file, &sd, nfsd_direct_splice_actor);
 898        } else {
 899                oldfs = get_fs();
 900                set_fs(KERNEL_DS);
 901                host_err = vfs_readv(file, (struct iovec __user *)vec, vlen, &offset);
 902                set_fs(oldfs);
 903        }
 904
 905        if (host_err >= 0) {
 906                nfsdstats.io_read += host_err;
 907                *count = host_err;
 908                err = 0;
 909                fsnotify_access(file);
 910        } else 
 911                err = nfserrno(host_err);
 912        return err;
 913}
 914
 915static void kill_suid(struct dentry *dentry)
 916{
 917        struct iattr    ia;
 918        ia.ia_valid = ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_KILL_PRIV;
 919
 920        mutex_lock(&dentry->d_inode->i_mutex);
 921        notify_change(dentry, &ia);
 922        mutex_unlock(&dentry->d_inode->i_mutex);
 923}
 924
 925/*
 926 * Gathered writes: If another process is currently writing to the file,
 927 * there's a high chance this is another nfsd (triggered by a bulk write
 928 * from a client's biod). Rather than syncing the file with each write
 929 * request, we sleep for 10 msec.
 930 *
 931 * I don't know if this roughly approximates C. Juszak's idea of
 932 * gathered writes, but it's a nice and simple solution (IMHO), and it
 933 * seems to work:-)
 934 *
 935 * Note: we do this only in the NFSv2 case, since v3 and higher have a
 936 * better tool (separate unstable writes and commits) for solving this
 937 * problem.
 938 */
 939static int wait_for_concurrent_writes(struct file *file)
 940{
 941        struct inode *inode = file->f_path.dentry->d_inode;
 942        static ino_t last_ino;
 943        static dev_t last_dev;
 944        int err = 0;
 945
 946        if (atomic_read(&inode->i_writecount) > 1
 947            || (last_ino == inode->i_ino && last_dev == inode->i_sb->s_dev)) {
 948                dprintk("nfsd: write defer %d\n", task_pid_nr(current));
 949                msleep(10);
 950                dprintk("nfsd: write resume %d\n", task_pid_nr(current));
 951        }
 952
 953        if (inode->i_state & I_DIRTY) {
 954                dprintk("nfsd: write sync %d\n", task_pid_nr(current));
 955                err = vfs_fsync(file, 0);
 956        }
 957        last_ino = inode->i_ino;
 958        last_dev = inode->i_sb->s_dev;
 959        return err;
 960}
 961
 962static __be32
 963nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
 964                                loff_t offset, struct kvec *vec, int vlen,
 965                                unsigned long *cnt, int *stablep)
 966{
 967        struct svc_export       *exp;
 968        struct dentry           *dentry;
 969        struct inode            *inode;
 970        mm_segment_t            oldfs;
 971        __be32                  err = 0;
 972        int                     host_err;
 973        int                     stable = *stablep;
 974        int                     use_wgather;
 975
 976        dentry = file->f_path.dentry;
 977        inode = dentry->d_inode;
 978        exp   = fhp->fh_export;
 979
 980        /*
 981         * Request sync writes if
 982         *  -   the sync export option has been set, or
 983         *  -   the client requested O_SYNC behavior (NFSv3 feature).
 984         *  -   The file system doesn't support fsync().
 985         * When NFSv2 gathered writes have been configured for this volume,
 986         * flushing the data to disk is handled separately below.
 987         */
 988        use_wgather = (rqstp->rq_vers == 2) && EX_WGATHER(exp);
 989
 990        if (!file->f_op->fsync) {/* COMMIT3 cannot work */
 991               stable = 2;
 992               *stablep = 2; /* FILE_SYNC */
 993        }
 994
 995        if (!EX_ISSYNC(exp))
 996                stable = 0;
 997        if (stable && !use_wgather) {
 998                spin_lock(&file->f_lock);
 999                file->f_flags |= O_SYNC;
1000                spin_unlock(&file->f_lock);
1001        }
1002
1003        /* Write the data. */
1004        oldfs = get_fs(); set_fs(KERNEL_DS);
1005        host_err = vfs_writev(file, (struct iovec __user *)vec, vlen, &offset);
1006        set_fs(oldfs);
1007        if (host_err < 0)
1008                goto out_nfserr;
1009        *cnt = host_err;
1010        nfsdstats.io_write += host_err;
1011        fsnotify_modify(file);
1012
1013        /* clear setuid/setgid flag after write */
1014        if (inode->i_mode & (S_ISUID | S_ISGID))
1015                kill_suid(dentry);
1016
1017        if (stable && use_wgather)
1018                host_err = wait_for_concurrent_writes(file);
1019
1020out_nfserr:
1021        dprintk("nfsd: write complete host_err=%d\n", host_err);
1022        if (host_err >= 0)
1023                err = 0;
1024        else
1025                err = nfserrno(host_err);
1026        return err;
1027}
1028
1029/*
1030 * Read data from a file. count must contain the requested read count
1031 * on entry. On return, *count contains the number of bytes actually read.
1032 * N.B. After this call fhp needs an fh_put
1033 */
1034__be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
1035        loff_t offset, struct kvec *vec, int vlen, unsigned long *count)
1036{
1037        struct file *file;
1038        struct inode *inode;
1039        struct raparms  *ra;
1040        __be32 err;
1041
1042        err = nfsd_open(rqstp, fhp, S_IFREG, NFSD_MAY_READ, &file);
1043        if (err)
1044                return err;
1045
1046        inode = file->f_path.dentry->d_inode;
1047
1048        /* Get readahead parameters */
1049        ra = nfsd_get_raparms(inode->i_sb->s_dev, inode->i_ino);
1050
1051        if (ra && ra->p_set)
1052                file->f_ra = ra->p_ra;
1053
1054        err = nfsd_vfs_read(rqstp, fhp, file, offset, vec, vlen, count);
1055
1056        /* Write back readahead params */
1057        if (ra) {
1058                struct raparm_hbucket *rab = &raparm_hash[ra->p_hindex];
1059                spin_lock(&rab->pb_lock);
1060                ra->p_ra = file->f_ra;
1061                ra->p_set = 1;
1062                ra->p_count--;
1063                spin_unlock(&rab->pb_lock);
1064        }
1065
1066        nfsd_close(file);
1067        return err;
1068}
1069
1070/* As above, but use the provided file descriptor. */
1071__be32
1072nfsd_read_file(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
1073                loff_t offset, struct kvec *vec, int vlen,
1074                unsigned long *count)
1075{
1076        __be32          err;
1077
1078        if (file) {
1079                err = nfsd_permission(rqstp, fhp->fh_export, fhp->fh_dentry,
1080                                NFSD_MAY_READ|NFSD_MAY_OWNER_OVERRIDE);
1081                if (err)
1082                        goto out;
1083                err = nfsd_vfs_read(rqstp, fhp, file, offset, vec, vlen, count);
1084        } else /* Note file may still be NULL in NFSv4 special stateid case: */
1085                err = nfsd_read(rqstp, fhp, offset, vec, vlen, count);
1086out:
1087        return err;
1088}
1089
1090/*
1091 * Write data to a file.
1092 * The stable flag requests synchronous writes.
1093 * N.B. After this call fhp needs an fh_put
1094 */
1095__be32
1096nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
1097                loff_t offset, struct kvec *vec, int vlen, unsigned long *cnt,
1098                int *stablep)
1099{
1100        __be32                  err = 0;
1101
1102        if (file) {
1103                err = nfsd_permission(rqstp, fhp->fh_export, fhp->fh_dentry,
1104                                NFSD_MAY_WRITE|NFSD_MAY_OWNER_OVERRIDE);
1105                if (err)
1106                        goto out;
1107                err = nfsd_vfs_write(rqstp, fhp, file, offset, vec, vlen, cnt,
1108                                stablep);
1109        } else {
1110                err = nfsd_open(rqstp, fhp, S_IFREG, NFSD_MAY_WRITE, &file);
1111                if (err)
1112                        goto out;
1113
1114                if (cnt)
1115                        err = nfsd_vfs_write(rqstp, fhp, file, offset, vec, vlen,
1116                                             cnt, stablep);
1117                nfsd_close(file);
1118        }
1119out:
1120        return err;
1121}
1122
1123#ifdef CONFIG_NFSD_V3
1124/*
1125 * Commit all pending writes to stable storage.
1126 *
1127 * Note: we only guarantee that data that lies within the range specified
1128 * by the 'offset' and 'count' parameters will be synced.
1129 *
1130 * Unfortunately we cannot lock the file to make sure we return full WCC
1131 * data to the client, as locking happens lower down in the filesystem.
1132 */
1133__be32
1134nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp,
1135               loff_t offset, unsigned long count)
1136{
1137        struct file     *file;
1138        loff_t          end = LLONG_MAX;
1139        __be32          err = nfserr_inval;
1140
1141        if (offset < 0)
1142                goto out;
1143        if (count != 0) {
1144                end = offset + (loff_t)count - 1;
1145                if (end < offset)
1146                        goto out;
1147        }
1148
1149        err = nfsd_open(rqstp, fhp, S_IFREG,
1150                        NFSD_MAY_WRITE|NFSD_MAY_NOT_BREAK_LEASE, &file);
1151        if (err)
1152                goto out;
1153        if (EX_ISSYNC(fhp->fh_export)) {
1154                int err2 = vfs_fsync_range(file, offset, end, 0);
1155
1156                if (err2 != -EINVAL)
1157                        err = nfserrno(err2);
1158                else
1159                        err = nfserr_notsupp;
1160        }
1161
1162        nfsd_close(file);
1163out:
1164        return err;
1165}
1166#endif /* CONFIG_NFSD_V3 */
1167
1168static __be32
1169nfsd_create_setattr(struct svc_rqst *rqstp, struct svc_fh *resfhp,
1170                        struct iattr *iap)
1171{
1172        /*
1173         * Mode has already been set earlier in create:
1174         */
1175        iap->ia_valid &= ~ATTR_MODE;
1176        /*
1177         * Setting uid/gid works only for root.  Irix appears to
1178         * send along the gid on create when it tries to implement
1179         * setgid directories via NFS:
1180         */
1181        if (current_fsuid() != 0)
1182                iap->ia_valid &= ~(ATTR_UID|ATTR_GID);
1183        if (iap->ia_valid)
1184                return nfsd_setattr(rqstp, resfhp, iap, 0, (time_t)0);
1185        return 0;
1186}
1187
1188/* HPUX client sometimes creates a file in mode 000, and sets size to 0.
1189 * setting size to 0 may fail for some specific file systems by the permission
1190 * checking which requires WRITE permission but the mode is 000.
1191 * we ignore the resizing(to 0) on the just new created file, since the size is
1192 * 0 after file created.
1193 *
1194 * call this only after vfs_create() is called.
1195 * */
1196static void
1197nfsd_check_ignore_resizing(struct iattr *iap)
1198{
1199        if ((iap->ia_valid & ATTR_SIZE) && (iap->ia_size == 0))
1200                iap->ia_valid &= ~ATTR_SIZE;
1201}
1202
1203/*
1204 * Create a file (regular, directory, device, fifo); UNIX sockets 
1205 * not yet implemented.
1206 * If the response fh has been verified, the parent directory should
1207 * already be locked. Note that the parent directory is left locked.
1208 *
1209 * N.B. Every call to nfsd_create needs an fh_put for _both_ fhp and resfhp
1210 */
1211__be32
1212nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
1213                char *fname, int flen, struct iattr *iap,
1214                int type, dev_t rdev, struct svc_fh *resfhp)
1215{
1216        struct dentry   *dentry, *dchild = NULL;
1217        struct inode    *dirp;
1218        __be32          err;
1219        __be32          err2;
1220        int             host_err;
1221
1222        err = nfserr_perm;
1223        if (!flen)
1224                goto out;
1225        err = nfserr_exist;
1226        if (isdotent(fname, flen))
1227                goto out;
1228
1229        err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
1230        if (err)
1231                goto out;
1232
1233        dentry = fhp->fh_dentry;
1234        dirp = dentry->d_inode;
1235
1236        err = nfserr_notdir;
1237        if (!dirp->i_op->lookup)
1238                goto out;
1239        /*
1240         * Check whether the response file handle has been verified yet.
1241         * If it has, the parent directory should already be locked.
1242         */
1243        if (!resfhp->fh_dentry) {
1244                /* called from nfsd_proc_mkdir, or possibly nfsd3_proc_create */
1245                fh_lock_nested(fhp, I_MUTEX_PARENT);
1246                dchild = lookup_one_len(fname, dentry, flen);
1247                host_err = PTR_ERR(dchild);
1248                if (IS_ERR(dchild))
1249                        goto out_nfserr;
1250                err = fh_compose(resfhp, fhp->fh_export, dchild, fhp);
1251                if (err)
1252                        goto out;
1253        } else {
1254                /* called from nfsd_proc_create */
1255                dchild = dget(resfhp->fh_dentry);
1256                if (!fhp->fh_locked) {
1257                        /* not actually possible */
1258                        printk(KERN_ERR
1259                                "nfsd_create: parent %s/%s not locked!\n",
1260                                dentry->d_parent->d_name.name,
1261                                dentry->d_name.name);
1262                        err = nfserr_io;
1263                        goto out;
1264                }
1265        }
1266        /*
1267         * Make sure the child dentry is still negative ...
1268         */
1269        err = nfserr_exist;
1270        if (dchild->d_inode) {
1271                dprintk("nfsd_create: dentry %s/%s not negative!\n",
1272                        dentry->d_name.name, dchild->d_name.name);
1273                goto out; 
1274        }
1275
1276        if (!(iap->ia_valid & ATTR_MODE))
1277                iap->ia_mode = 0;
1278        iap->ia_mode = (iap->ia_mode & S_IALLUGO) | type;
1279
1280        err = nfserr_inval;
1281        if (!S_ISREG(type) && !S_ISDIR(type) && !special_file(type)) {
1282                printk(KERN_WARNING "nfsd: bad file type %o in nfsd_create\n",
1283                       type);
1284                goto out;
1285        }
1286
1287        host_err = mnt_want_write(fhp->fh_export->ex_path.mnt);
1288        if (host_err)
1289                goto out_nfserr;
1290
1291        /*
1292         * Get the dir op function pointer.
1293         */
1294        err = 0;
1295        switch (type) {
1296        case S_IFREG:
1297                host_err = vfs_create(dirp, dchild, iap->ia_mode, NULL);
1298                if (!host_err)
1299                        nfsd_check_ignore_resizing(iap);
1300                break;
1301        case S_IFDIR:
1302                host_err = vfs_mkdir(dirp, dchild, iap->ia_mode);
1303                break;
1304        case S_IFCHR:
1305        case S_IFBLK:
1306        case S_IFIFO:
1307        case S_IFSOCK:
1308                host_err = vfs_mknod(dirp, dchild, iap->ia_mode, rdev);
1309                break;
1310        }
1311        if (host_err < 0) {
1312                mnt_drop_write(fhp->fh_export->ex_path.mnt);
1313                goto out_nfserr;
1314        }
1315
1316        err = nfsd_create_setattr(rqstp, resfhp, iap);
1317
1318        /*
1319         * nfsd_setattr already committed the child.  Transactional filesystems
1320         * had a chance to commit changes for both parent and child
1321         * simultaneously making the following commit_metadata a noop.
1322         */
1323        err2 = nfserrno(commit_metadata(fhp));
1324        if (err2)
1325                err = err2;
1326        mnt_drop_write(fhp->fh_export->ex_path.mnt);
1327        /*
1328         * Update the file handle to get the new inode info.
1329         */
1330        if (!err)
1331                err = fh_update(resfhp);
1332out:
1333        if (dchild && !IS_ERR(dchild))
1334                dput(dchild);
1335        return err;
1336
1337out_nfserr:
1338        err = nfserrno(host_err);
1339        goto out;
1340}
1341
1342#ifdef CONFIG_NFSD_V3
1343/*
1344 * NFSv3 version of nfsd_create
1345 */
1346__be32
1347nfsd_create_v3(struct svc_rqst *rqstp, struct svc_fh *fhp,
1348                char *fname, int flen, struct iattr *iap,
1349                struct svc_fh *resfhp, int createmode, u32 *verifier,
1350                int *truncp, int *created)
1351{
1352        struct dentry   *dentry, *dchild = NULL;
1353        struct inode    *dirp;
1354        __be32          err;
1355        int             host_err;
1356        __u32           v_mtime=0, v_atime=0;
1357
1358        err = nfserr_perm;
1359        if (!flen)
1360                goto out;
1361        err = nfserr_exist;
1362        if (isdotent(fname, flen))
1363                goto out;
1364        if (!(iap->ia_valid & ATTR_MODE))
1365                iap->ia_mode = 0;
1366        err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC);
1367        if (err)
1368                goto out;
1369
1370        dentry = fhp->fh_dentry;
1371        dirp = dentry->d_inode;
1372
1373        /* Get all the sanity checks out of the way before
1374         * we lock the parent. */
1375        err = nfserr_notdir;
1376        if (!dirp->i_op->lookup)
1377                goto out;
1378        fh_lock_nested(fhp, I_MUTEX_PARENT);
1379
1380        /*
1381         * Compose the response file handle.
1382         */
1383        dchild = lookup_one_len(fname, dentry, flen);
1384        host_err = PTR_ERR(dchild);
1385        if (IS_ERR(dchild))
1386                goto out_nfserr;
1387
1388        /* If file doesn't exist, check for permissions to create one */
1389        if (!dchild->d_inode) {
1390                err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
1391                if (err)
1392                        goto out;
1393        }
1394
1395        err = fh_compose(resfhp, fhp->fh_export, dchild, fhp);
1396        if (err)
1397                goto out;
1398
1399        if (createmode == NFS3_CREATE_EXCLUSIVE) {
1400                /* solaris7 gets confused (bugid 4218508) if these have
1401                 * the high bit set, so just clear the high bits. If this is
1402                 * ever changed to use different attrs for storing the
1403                 * verifier, then do_open_lookup() will also need to be fixed
1404                 * accordingly.
1405                 */
1406                v_mtime = verifier[0]&0x7fffffff;
1407                v_atime = verifier[1]&0x7fffffff;
1408        }
1409        
1410        host_err = mnt_want_write(fhp->fh_export->ex_path.mnt);
1411        if (host_err)
1412                goto out_nfserr;
1413        if (dchild->d_inode) {
1414                err = 0;
1415
1416                switch (createmode) {
1417                case NFS3_CREATE_UNCHECKED:
1418                        if (! S_ISREG(dchild->d_inode->i_mode))
1419                                err = nfserr_exist;
1420                        else if (truncp) {
1421                                /* in nfsv4, we need to treat this case a little
1422                                 * differently.  we don't want to truncate the
1423                                 * file now; this would be wrong if the OPEN
1424                                 * fails for some other reason.  furthermore,
1425                                 * if the size is nonzero, we should ignore it
1426                                 * according to spec!
1427                                 */
1428                                *truncp = (iap->ia_valid & ATTR_SIZE) && !iap->ia_size;
1429                        }
1430                        else {
1431                                iap->ia_valid &= ATTR_SIZE;
1432                                goto set_attr;
1433                        }
1434                        break;
1435                case NFS3_CREATE_EXCLUSIVE:
1436                        if (   dchild->d_inode->i_mtime.tv_sec == v_mtime
1437                            && dchild->d_inode->i_atime.tv_sec == v_atime
1438                            && dchild->d_inode->i_size  == 0 )
1439                                break;
1440                         /* fallthru */
1441                case NFS3_CREATE_GUARDED:
1442                        err = nfserr_exist;
1443                }
1444                mnt_drop_write(fhp->fh_export->ex_path.mnt);
1445                goto out;
1446        }
1447
1448        host_err = vfs_create(dirp, dchild, iap->ia_mode, NULL);
1449        if (host_err < 0) {
1450                mnt_drop_write(fhp->fh_export->ex_path.mnt);
1451                goto out_nfserr;
1452        }
1453        if (created)
1454                *created = 1;
1455
1456        nfsd_check_ignore_resizing(iap);
1457
1458        if (createmode == NFS3_CREATE_EXCLUSIVE) {
1459                /* Cram the verifier into atime/mtime */
1460                iap->ia_valid = ATTR_MTIME|ATTR_ATIME
1461                        | ATTR_MTIME_SET|ATTR_ATIME_SET;
1462                /* XXX someone who knows this better please fix it for nsec */ 
1463                iap->ia_mtime.tv_sec = v_mtime;
1464                iap->ia_atime.tv_sec = v_atime;
1465                iap->ia_mtime.tv_nsec = 0;
1466                iap->ia_atime.tv_nsec = 0;
1467        }
1468
1469 set_attr:
1470        err = nfsd_create_setattr(rqstp, resfhp, iap);
1471
1472        /*
1473         * nfsd_setattr already committed the child (and possibly also the parent).
1474         */
1475        if (!err)
1476                err = nfserrno(commit_metadata(fhp));
1477
1478        mnt_drop_write(fhp->fh_export->ex_path.mnt);
1479        /*
1480         * Update the filehandle to get the new inode info.
1481         */
1482        if (!err)
1483                err = fh_update(resfhp);
1484
1485 out:
1486        fh_unlock(fhp);
1487        if (dchild && !IS_ERR(dchild))
1488                dput(dchild);
1489        return err;
1490 
1491 out_nfserr:
1492        err = nfserrno(host_err);
1493        goto out;
1494}
1495#endif /* CONFIG_NFSD_V3 */
1496
1497/*
1498 * Read a symlink. On entry, *lenp must contain the maximum path length that
1499 * fits into the buffer. On return, it contains the true length.
1500 * N.B. After this call fhp needs an fh_put
1501 */
1502__be32
1503nfsd_readlink(struct svc_rqst *rqstp, struct svc_fh *fhp, char *buf, int *lenp)
1504{
1505        struct dentry   *dentry;
1506        struct inode    *inode;
1507        mm_segment_t    oldfs;
1508        __be32          err;
1509        int             host_err;
1510
1511        err = fh_verify(rqstp, fhp, S_IFLNK, NFSD_MAY_NOP);
1512        if (err)
1513                goto out;
1514
1515        dentry = fhp->fh_dentry;
1516        inode = dentry->d_inode;
1517
1518        err = nfserr_inval;
1519        if (!inode->i_op->readlink)
1520                goto out;
1521
1522        touch_atime(fhp->fh_export->ex_path.mnt, dentry);
1523        /* N.B. Why does this call need a get_fs()??
1524         * Remove the set_fs and watch the fireworks:-) --okir
1525         */
1526
1527        oldfs = get_fs(); set_fs(KERNEL_DS);
1528        host_err = inode->i_op->readlink(dentry, buf, *lenp);
1529        set_fs(oldfs);
1530
1531        if (host_err < 0)
1532                goto out_nfserr;
1533        *lenp = host_err;
1534        err = 0;
1535out:
1536        return err;
1537
1538out_nfserr:
1539        err = nfserrno(host_err);
1540        goto out;
1541}
1542
1543/*
1544 * Create a symlink and look up its inode
1545 * N.B. After this call _both_ fhp and resfhp need an fh_put
1546 */
1547__be32
1548nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp,
1549                                char *fname, int flen,
1550                                char *path,  int plen,
1551                                struct svc_fh *resfhp,
1552                                struct iattr *iap)
1553{
1554        struct dentry   *dentry, *dnew;
1555        __be32          err, cerr;
1556        int             host_err;
1557
1558        err = nfserr_noent;
1559        if (!flen || !plen)
1560                goto out;
1561        err = nfserr_exist;
1562        if (isdotent(fname, flen))
1563                goto out;
1564
1565        err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
1566        if (err)
1567                goto out;
1568        fh_lock(fhp);
1569        dentry = fhp->fh_dentry;
1570        dnew = lookup_one_len(fname, dentry, flen);
1571        host_err = PTR_ERR(dnew);
1572        if (IS_ERR(dnew))
1573                goto out_nfserr;
1574
1575        host_err = mnt_want_write(fhp->fh_export->ex_path.mnt);
1576        if (host_err)
1577                goto out_nfserr;
1578
1579        if (unlikely(path[plen] != 0)) {
1580                char *path_alloced = kmalloc(plen+1, GFP_KERNEL);
1581                if (path_alloced == NULL)
1582                        host_err = -ENOMEM;
1583                else {
1584                        strncpy(path_alloced, path, plen);
1585                        path_alloced[plen] = 0;
1586                        host_err = vfs_symlink(dentry->d_inode, dnew, path_alloced);
1587                        kfree(path_alloced);
1588                }
1589        } else
1590                host_err = vfs_symlink(dentry->d_inode, dnew, path);
1591        err = nfserrno(host_err);
1592        if (!err)
1593                err = nfserrno(commit_metadata(fhp));
1594        fh_unlock(fhp);
1595
1596        mnt_drop_write(fhp->fh_export->ex_path.mnt);
1597
1598        cerr = fh_compose(resfhp, fhp->fh_export, dnew, fhp);
1599        dput(dnew);
1600        if (err==0) err = cerr;
1601out:
1602        return err;
1603
1604out_nfserr:
1605        err = nfserrno(host_err);
1606        goto out;
1607}
1608
1609/*
1610 * Create a hardlink
1611 * N.B. After this call _both_ ffhp and tfhp need an fh_put
1612 */
1613__be32
1614nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp,
1615                                char *name, int len, struct svc_fh *tfhp)
1616{
1617        struct dentry   *ddir, *dnew, *dold;
1618        struct inode    *dirp;
1619        __be32          err;
1620        int             host_err;
1621
1622        err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_CREATE);
1623        if (err)
1624                goto out;
1625        err = fh_verify(rqstp, tfhp, -S_IFDIR, NFSD_MAY_NOP);
1626        if (err)
1627                goto out;
1628
1629        err = nfserr_perm;
1630        if (!len)
1631                goto out;
1632        err = nfserr_exist;
1633        if (isdotent(name, len))
1634                goto out;
1635
1636        fh_lock_nested(ffhp, I_MUTEX_PARENT);
1637        ddir = ffhp->fh_dentry;
1638        dirp = ddir->d_inode;
1639
1640        dnew = lookup_one_len(name, ddir, len);
1641        host_err = PTR_ERR(dnew);
1642        if (IS_ERR(dnew))
1643                goto out_nfserr;
1644
1645        dold = tfhp->fh_dentry;
1646
1647        host_err = mnt_want_write(tfhp->fh_export->ex_path.mnt);
1648        if (host_err) {
1649                err = nfserrno(host_err);
1650                goto out_dput;
1651        }
1652        err = nfserr_noent;
1653        if (!dold->d_inode)
1654                goto out_drop_write;
1655        host_err = nfsd_break_lease(dold->d_inode);
1656        if (host_err)
1657                goto out_drop_write;
1658        host_err = vfs_link(dold, dirp, dnew);
1659        if (!host_err) {
1660                err = nfserrno(commit_metadata(ffhp));
1661                if (!err)
1662                        err = nfserrno(commit_metadata(tfhp));
1663        } else {
1664                if (host_err == -EXDEV && rqstp->rq_vers == 2)
1665                        err = nfserr_acces;
1666                else
1667                        err = nfserrno(host_err);
1668        }
1669out_drop_write:
1670        mnt_drop_write(tfhp->fh_export->ex_path.mnt);
1671out_dput:
1672        dput(dnew);
1673out_unlock:
1674        fh_unlock(ffhp);
1675out:
1676        return err;
1677
1678out_nfserr:
1679        err = nfserrno(host_err);
1680        goto out_unlock;
1681}
1682
1683/*
1684 * Rename a file
1685 * N.B. After this call _both_ ffhp and tfhp need an fh_put
1686 */
1687__be32
1688nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
1689                            struct svc_fh *tfhp, char *tname, int tlen)
1690{
1691        struct dentry   *fdentry, *tdentry, *odentry, *ndentry, *trap;
1692        struct inode    *fdir, *tdir;
1693        __be32          err;
1694        int             host_err;
1695
1696        err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_REMOVE);
1697        if (err)
1698                goto out;
1699        err = fh_verify(rqstp, tfhp, S_IFDIR, NFSD_MAY_CREATE);
1700        if (err)
1701                goto out;
1702
1703        fdentry = ffhp->fh_dentry;
1704        fdir = fdentry->d_inode;
1705
1706        tdentry = tfhp->fh_dentry;
1707        tdir = tdentry->d_inode;
1708
1709        err = (rqstp->rq_vers == 2) ? nfserr_acces : nfserr_xdev;
1710        if (ffhp->fh_export != tfhp->fh_export)
1711                goto out;
1712
1713        err = nfserr_perm;
1714        if (!flen || isdotent(fname, flen) || !tlen || isdotent(tname, tlen))
1715                goto out;
1716
1717        /* cannot use fh_lock as we need deadlock protective ordering
1718         * so do it by hand */
1719        trap = lock_rename(tdentry, fdentry);
1720        ffhp->fh_locked = tfhp->fh_locked = 1;
1721        fill_pre_wcc(ffhp);
1722        fill_pre_wcc(tfhp);
1723
1724        odentry = lookup_one_len(fname, fdentry, flen);
1725        host_err = PTR_ERR(odentry);
1726        if (IS_ERR(odentry))
1727                goto out_nfserr;
1728
1729        host_err = -ENOENT;
1730        if (!odentry->d_inode)
1731                goto out_dput_old;
1732        host_err = -EINVAL;
1733        if (odentry == trap)
1734                goto out_dput_old;
1735
1736        ndentry = lookup_one_len(tname, tdentry, tlen);
1737        host_err = PTR_ERR(ndentry);
1738        if (IS_ERR(ndentry))
1739                goto out_dput_old;
1740        host_err = -ENOTEMPTY;
1741        if (ndentry == trap)
1742                goto out_dput_new;
1743
1744        host_err = -EXDEV;
1745        if (ffhp->fh_export->ex_path.mnt != tfhp->fh_export->ex_path.mnt)
1746                goto out_dput_new;
1747        host_err = mnt_want_write(ffhp->fh_export->ex_path.mnt);
1748        if (host_err)
1749                goto out_dput_new;
1750
1751        host_err = nfsd_break_lease(odentry->d_inode);
1752        if (host_err)
1753                goto out_drop_write;
1754        if (ndentry->d_inode) {
1755                host_err = nfsd_break_lease(ndentry->d_inode);
1756                if (host_err)
1757                        goto out_drop_write;
1758        }
1759        host_err = vfs_rename(fdir, odentry, tdir, ndentry);
1760        if (!host_err) {
1761                host_err = commit_metadata(tfhp);
1762                if (!host_err)
1763                        host_err = commit_metadata(ffhp);
1764        }
1765out_drop_write:
1766        mnt_drop_write(ffhp->fh_export->ex_path.mnt);
1767 out_dput_new:
1768        dput(ndentry);
1769 out_dput_old:
1770        dput(odentry);
1771 out_nfserr:
1772        err = nfserrno(host_err);
1773
1774        /* we cannot reply on fh_unlock on the two filehandles,
1775         * as that would do the wrong thing if the two directories
1776         * were the same, so again we do it by hand
1777         */
1778        fill_post_wcc(ffhp);
1779        fill_post_wcc(tfhp);
1780        unlock_rename(tdentry, fdentry);
1781        ffhp->fh_locked = tfhp->fh_locked = 0;
1782
1783out:
1784        return err;
1785}
1786
1787/*
1788 * Unlink a file or directory
1789 * N.B. After this call fhp needs an fh_put
1790 */
1791__be32
1792nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
1793                                char *fname, int flen)
1794{
1795        struct dentry   *dentry, *rdentry;
1796        struct inode    *dirp;
1797        __be32          err;
1798        int             host_err;
1799
1800        err = nfserr_acces;
1801        if (!flen || isdotent(fname, flen))
1802                goto out;
1803        err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_REMOVE);
1804        if (err)
1805                goto out;
1806
1807        fh_lock_nested(fhp, I_MUTEX_PARENT);
1808        dentry = fhp->fh_dentry;
1809        dirp = dentry->d_inode;
1810
1811        rdentry = lookup_one_len(fname, dentry, flen);
1812        host_err = PTR_ERR(rdentry);
1813        if (IS_ERR(rdentry))
1814                goto out_nfserr;
1815
1816        if (!rdentry->d_inode) {
1817                dput(rdentry);
1818                err = nfserr_noent;
1819                goto out;
1820        }
1821
1822        if (!type)
1823                type = rdentry->d_inode->i_mode & S_IFMT;
1824
1825        host_err = mnt_want_write(fhp->fh_export->ex_path.mnt);
1826        if (host_err)
1827                goto out_put;
1828
1829        host_err = nfsd_break_lease(rdentry->d_inode);
1830        if (host_err)
1831                goto out_drop_write;
1832        if (type != S_IFDIR)
1833                host_err = vfs_unlink(dirp, rdentry);
1834        else
1835                host_err = vfs_rmdir(dirp, rdentry);
1836        if (!host_err)
1837                host_err = commit_metadata(fhp);
1838out_drop_write:
1839        mnt_drop_write(fhp->fh_export->ex_path.mnt);
1840out_put:
1841        dput(rdentry);
1842
1843out_nfserr:
1844        err = nfserrno(host_err);
1845out:
1846        return err;
1847}
1848
1849/*
1850 * We do this buffering because we must not call back into the file
1851 * system's ->lookup() method from the filldir callback. That may well
1852 * deadlock a number of file systems.
1853 *
1854 * This is based heavily on the implementation of same in XFS.
1855 */
1856struct buffered_dirent {
1857        u64             ino;
1858        loff_t          offset;
1859        int             namlen;
1860        unsigned int    d_type;
1861        char            name[];
1862};
1863
1864struct readdir_data {
1865        char            *dirent;
1866        size_t          used;
1867        int             full;
1868};
1869
1870static int nfsd_buffered_filldir(void *__buf, const char *name, int namlen,
1871                                 loff_t offset, u64 ino, unsigned int d_type)
1872{
1873        struct readdir_data *buf = __buf;
1874        struct buffered_dirent *de = (void *)(buf->dirent + buf->used);
1875        unsigned int reclen;
1876
1877        reclen = ALIGN(sizeof(struct buffered_dirent) + namlen, sizeof(u64));
1878        if (buf->used + reclen > PAGE_SIZE) {
1879                buf->full = 1;
1880                return -EINVAL;
1881        }
1882
1883        de->namlen = namlen;
1884        de->offset = offset;
1885        de->ino = ino;
1886        de->d_type = d_type;
1887        memcpy(de->name, name, namlen);
1888        buf->used += reclen;
1889
1890        return 0;
1891}
1892
1893static __be32 nfsd_buffered_readdir(struct file *file, filldir_t func,
1894                                    struct readdir_cd *cdp, loff_t *offsetp)
1895{
1896        struct readdir_data buf;
1897        struct buffered_dirent *de;
1898        int host_err;
1899        int size;
1900        loff_t offset;
1901
1902        buf.dirent = (void *)__get_free_page(GFP_KERNEL);
1903        if (!buf.dirent)
1904                return nfserrno(-ENOMEM);
1905
1906        offset = *offsetp;
1907
1908        while (1) {
1909                struct inode *dir_inode = file->f_path.dentry->d_inode;
1910                unsigned int reclen;
1911
1912                cdp->err = nfserr_eof; /* will be cleared on successful read */
1913                buf.used = 0;
1914                buf.full = 0;
1915
1916                host_err = vfs_readdir(file, nfsd_buffered_filldir, &buf);
1917                if (buf.full)
1918                        host_err = 0;
1919
1920                if (host_err < 0)
1921                        break;
1922
1923                size = buf.used;
1924
1925                if (!size)
1926                        break;
1927
1928                /*
1929                 * Various filldir functions may end up calling back into
1930                 * lookup_one_len() and the file system's ->lookup() method.
1931                 * These expect i_mutex to be held, as it would within readdir.
1932                 */
1933                host_err = mutex_lock_killable(&dir_inode->i_mutex);
1934                if (host_err)
1935                        break;
1936
1937                de = (struct buffered_dirent *)buf.dirent;
1938                while (size > 0) {
1939                        offset = de->offset;
1940
1941                        if (func(cdp, de->name, de->namlen, de->offset,
1942                                 de->ino, de->d_type))
1943                                break;
1944
1945                        if (cdp->err != nfs_ok)
1946                                break;
1947
1948                        reclen = ALIGN(sizeof(*de) + de->namlen,
1949                                       sizeof(u64));
1950                        size -= reclen;
1951                        de = (struct buffered_dirent *)((char *)de + reclen);
1952                }
1953                mutex_unlock(&dir_inode->i_mutex);
1954                if (size > 0) /* We bailed out early */
1955                        break;
1956
1957                offset = vfs_llseek(file, 0, SEEK_CUR);
1958        }
1959
1960        free_page((unsigned long)(buf.dirent));
1961
1962        if (host_err)
1963                return nfserrno(host_err);
1964
1965        *offsetp = offset;
1966        return cdp->err;
1967}
1968
1969/*
1970 * Read entries from a directory.
1971 * The  NFSv3/4 verifier we ignore for now.
1972 */
1973__be32
1974nfsd_readdir(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t *offsetp, 
1975             struct readdir_cd *cdp, filldir_t func)
1976{
1977        __be32          err;
1978        struct file     *file;
1979        loff_t          offset = *offsetp;
1980
1981        err = nfsd_open(rqstp, fhp, S_IFDIR, NFSD_MAY_READ, &file);
1982        if (err)
1983                goto out;
1984
1985        offset = vfs_llseek(file, offset, 0);
1986        if (offset < 0) {
1987                err = nfserrno((int)offset);
1988                goto out_close;
1989        }
1990
1991        err = nfsd_buffered_readdir(file, func, cdp, offsetp);
1992
1993        if (err == nfserr_eof || err == nfserr_toosmall)
1994                err = nfs_ok; /* can still be found in ->err */
1995out_close:
1996        nfsd_close(file);
1997out:
1998        return err;
1999}
2000
2001/*
2002 * Get file system stats
2003 * N.B. After this call fhp needs an fh_put
2004 */
2005__be32
2006nfsd_statfs(struct svc_rqst *rqstp, struct svc_fh *fhp, struct kstatfs *stat, int access)
2007{
2008        __be32 err;
2009
2010        err = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP | access);
2011        if (!err) {
2012                struct path path = {
2013                        .mnt    = fhp->fh_export->ex_path.mnt,
2014                        .dentry = fhp->fh_dentry,
2015                };
2016                if (vfs_statfs(&path, stat))
2017                        err = nfserr_io;
2018        }
2019        return err;
2020}
2021
2022static int exp_rdonly(struct svc_rqst *rqstp, struct svc_export *exp)
2023{
2024        return nfsexp_flags(rqstp, exp) & NFSEXP_READONLY;
2025}
2026
2027/*
2028 * Check for a user's access permissions to this inode.
2029 */
2030__be32
2031nfsd_permission(struct svc_rqst *rqstp, struct svc_export *exp,
2032                                        struct dentry *dentry, int acc)
2033{
2034        struct inode    *inode = dentry->d_inode;
2035        int             err;
2036
2037        if (acc == NFSD_MAY_NOP)
2038                return 0;
2039#if 0
2040        dprintk("nfsd: permission 0x%x%s%s%s%s%s%s%s mode 0%o%s%s%s\n",
2041                acc,
2042                (acc & NFSD_MAY_READ)?  " read"  : "",
2043                (acc & NFSD_MAY_WRITE)? " write" : "",
2044                (acc & NFSD_MAY_EXEC)?  " exec"  : "",
2045                (acc & NFSD_MAY_SATTR)? " sattr" : "",
2046                (acc & NFSD_MAY_TRUNC)? " trunc" : "",
2047                (acc & NFSD_MAY_LOCK)?  " lock"  : "",
2048                (acc & NFSD_MAY_OWNER_OVERRIDE)? " owneroverride" : "",
2049                inode->i_mode,
2050                IS_IMMUTABLE(inode)?    " immut" : "",
2051                IS_APPEND(inode)?       " append" : "",
2052                __mnt_is_readonly(exp->ex_path.mnt)?    " ro" : "");
2053        dprintk("      owner %d/%d user %d/%d\n",
2054                inode->i_uid, inode->i_gid, current_fsuid(), current_fsgid());
2055#endif
2056
2057        /* Normally we reject any write/sattr etc access on a read-only file
2058         * system.  But if it is IRIX doing check on write-access for a 
2059         * device special file, we ignore rofs.
2060         */
2061        if (!(acc & NFSD_MAY_LOCAL_ACCESS))
2062                if (acc & (NFSD_MAY_WRITE | NFSD_MAY_SATTR | NFSD_MAY_TRUNC)) {
2063                        if (exp_rdonly(rqstp, exp) ||
2064                            __mnt_is_readonly(exp->ex_path.mnt))
2065                                return nfserr_rofs;
2066                        if (/* (acc & NFSD_MAY_WRITE) && */ IS_IMMUTABLE(inode))
2067                                return nfserr_perm;
2068                }
2069        if ((acc & NFSD_MAY_TRUNC) && IS_APPEND(inode))
2070                return nfserr_perm;
2071
2072        if (acc & NFSD_MAY_LOCK) {
2073                /* If we cannot rely on authentication in NLM requests,
2074                 * just allow locks, otherwise require read permission, or
2075                 * ownership
2076                 */
2077                if (exp->ex_flags & NFSEXP_NOAUTHNLM)
2078                        return 0;
2079                else
2080                        acc = NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE;
2081        }
2082        /*
2083         * The file owner always gets access permission for accesses that
2084         * would normally be checked at open time. This is to make
2085         * file access work even when the client has done a fchmod(fd, 0).
2086         *
2087         * However, `cp foo bar' should fail nevertheless when bar is
2088         * readonly. A sensible way to do this might be to reject all
2089         * attempts to truncate a read-only file, because a creat() call
2090         * always implies file truncation.
2091         * ... but this isn't really fair.  A process may reasonably call
2092         * ftruncate on an open file descriptor on a file with perm 000.
2093         * We must trust the client to do permission checking - using "ACCESS"
2094         * with NFSv3.
2095         */
2096        if ((acc & NFSD_MAY_OWNER_OVERRIDE) &&
2097            inode->i_uid == current_fsuid())
2098                return 0;
2099
2100        /* This assumes  NFSD_MAY_{READ,WRITE,EXEC} == MAY_{READ,WRITE,EXEC} */
2101        err = inode_permission(inode, acc & (MAY_READ|MAY_WRITE|MAY_EXEC));
2102
2103        /* Allow read access to binaries even when mode 111 */
2104        if (err == -EACCES && S_ISREG(inode->i_mode) &&
2105            acc == (NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE))
2106                err = inode_permission(inode, MAY_EXEC);
2107
2108        return err? nfserrno(err) : 0;
2109}
2110
2111void
2112nfsd_racache_shutdown(void)
2113{
2114        struct raparms *raparm, *last_raparm;
2115        unsigned int i;
2116
2117        dprintk("nfsd: freeing readahead buffers.\n");
2118
2119        for (i = 0; i < RAPARM_HASH_SIZE; i++) {
2120                raparm = raparm_hash[i].pb_head;
2121                while(raparm) {
2122                        last_raparm = raparm;
2123                        raparm = raparm->p_next;
2124                        kfree(last_raparm);
2125                }
2126                raparm_hash[i].pb_head = NULL;
2127        }
2128}
2129/*
2130 * Initialize readahead param cache
2131 */
2132int
2133nfsd_racache_init(int cache_size)
2134{
2135        int     i;
2136        int     j = 0;
2137        int     nperbucket;
2138        struct raparms **raparm = NULL;
2139
2140
2141        if (raparm_hash[0].pb_head)
2142                return 0;
2143        nperbucket = DIV_ROUND_UP(cache_size, RAPARM_HASH_SIZE);
2144        if (nperbucket < 2)
2145                nperbucket = 2;
2146        cache_size = nperbucket * RAPARM_HASH_SIZE;
2147
2148        dprintk("nfsd: allocating %d readahead buffers.\n", cache_size);
2149
2150        for (i = 0; i < RAPARM_HASH_SIZE; i++) {
2151                spin_lock_init(&raparm_hash[i].pb_lock);
2152
2153                raparm = &raparm_hash[i].pb_head;
2154                for (j = 0; j < nperbucket; j++) {
2155                        *raparm = kzalloc(sizeof(struct raparms), GFP_KERNEL);
2156                        if (!*raparm)
2157                                goto out_nomem;
2158                        raparm = &(*raparm)->p_next;
2159                }
2160                *raparm = NULL;
2161        }
2162
2163        nfsdstats.ra_size = cache_size;
2164        return 0;
2165
2166out_nomem:
2167        dprintk("nfsd: kmalloc failed, freeing readahead buffers\n");
2168        nfsd_racache_shutdown();
2169        return -ENOMEM;
2170}
2171
2172#if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
2173struct posix_acl *
2174nfsd_get_posix_acl(struct svc_fh *fhp, int type)
2175{
2176        struct inode *inode = fhp->fh_dentry->d_inode;
2177        char *name;
2178        void *value = NULL;
2179        ssize_t size;
2180        struct posix_acl *acl;
2181
2182        if (!IS_POSIXACL(inode))
2183                return ERR_PTR(-EOPNOTSUPP);
2184
2185        switch (type) {
2186        case ACL_TYPE_ACCESS:
2187                name = POSIX_ACL_XATTR_ACCESS;
2188                break;
2189        case ACL_TYPE_DEFAULT:
2190                name = POSIX_ACL_XATTR_DEFAULT;
2191                break;
2192        default:
2193                return ERR_PTR(-EOPNOTSUPP);
2194        }
2195
2196        size = nfsd_getxattr(fhp->fh_dentry, name, &value);
2197        if (size < 0)
2198                return ERR_PTR(size);
2199
2200        acl = posix_acl_from_xattr(value, size);
2201        kfree(value);
2202        return acl;
2203}
2204
2205int
2206nfsd_set_posix_acl(struct svc_fh *fhp, int type, struct posix_acl *acl)
2207{
2208        struct inode *inode = fhp->fh_dentry->d_inode;
2209        char *name;
2210        void *value = NULL;
2211        size_t size;
2212        int error;
2213
2214        if (!IS_POSIXACL(inode) ||
2215            !inode->i_op->setxattr || !inode->i_op->removexattr)
2216                return -EOPNOTSUPP;
2217        switch(type) {
2218                case ACL_TYPE_ACCESS:
2219                        name = POSIX_ACL_XATTR_ACCESS;
2220                        break;
2221                case ACL_TYPE_DEFAULT:
2222                        name = POSIX_ACL_XATTR_DEFAULT;
2223                        break;
2224                default:
2225                        return -EOPNOTSUPP;
2226        }
2227
2228        if (acl && acl->a_count) {
2229                size = posix_acl_xattr_size(acl->a_count);
2230                value = kmalloc(size, GFP_KERNEL);
2231                if (!value)
2232                        return -ENOMEM;
2233                error = posix_acl_to_xattr(acl, value, size);
2234                if (error < 0)
2235                        goto getout;
2236                size = error;
2237        } else
2238                size = 0;
2239
2240        error = mnt_want_write(fhp->fh_export->ex_path.mnt);
2241        if (error)
2242                goto getout;
2243        if (size)
2244                error = vfs_setxattr(fhp->fh_dentry, name, value, size, 0);
2245        else {
2246                if (!S_ISDIR(inode->i_mode) && type == ACL_TYPE_DEFAULT)
2247                        error = 0;
2248                else {
2249                        error = vfs_removexattr(fhp->fh_dentry, name);
2250                        if (error == -ENODATA)
2251                                error = 0;
2252                }
2253        }
2254        mnt_drop_write(fhp->fh_export->ex_path.mnt);
2255
2256getout:
2257        kfree(value);
2258        return error;
2259}
2260#endif  /* defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) */
2261