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 (nfsd4_is_junction(dentry))
 172		return 1;
 173	if (!(exp->ex_flags & NFSEXP_V4ROOT))
 174		return 0;
 175	return dentry->d_inode != NULL;
 176}
 177
 178__be32
 179nfsd_lookup_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp,
 180		   const char *name, unsigned int len,
 181		   struct svc_export **exp_ret, struct dentry **dentry_ret)
 182{
 183	struct svc_export	*exp;
 184	struct dentry		*dparent;
 185	struct dentry		*dentry;
 186	int			host_err;
 187
 188	dprintk("nfsd: nfsd_lookup(fh %s, %.*s)\n", SVCFH_fmt(fhp), len,name);
 189
 190	dparent = fhp->fh_dentry;
 191	exp  = fhp->fh_export;
 192	exp_get(exp);
 193
 194	/* Lookup the name, but don't follow links */
 195	if (isdotent(name, len)) {
 196		if (len==1)
 197			dentry = dget(dparent);
 198		else if (dparent != exp->ex_path.dentry)
 199			dentry = dget_parent(dparent);
 200		else if (!EX_NOHIDE(exp) && !nfsd_v4client(rqstp))
 201			dentry = dget(dparent); /* .. == . just like at / */
 202		else {
 203			/* checking mountpoint crossing is very different when stepping up */
 204			host_err = nfsd_lookup_parent(rqstp, dparent, &exp, &dentry);
 205			if (host_err)
 206				goto out_nfserr;
 207		}
 208	} else {
 209		fh_lock(fhp);
 210		dentry = lookup_one_len(name, dparent, len);
 211		host_err = PTR_ERR(dentry);
 212		if (IS_ERR(dentry))
 213			goto out_nfserr;
 214		/*
 215		 * check if we have crossed a mount point ...
 216		 */
 217		if (nfsd_mountpoint(dentry, exp)) {
 218			if ((host_err = nfsd_cross_mnt(rqstp, &dentry, &exp))) {
 219				dput(dentry);
 220				goto out_nfserr;
 221			}
 222		}
 223	}
 224	*dentry_ret = dentry;
 225	*exp_ret = exp;
 226	return 0;
 227
 228out_nfserr:
 229	exp_put(exp);
 230	return nfserrno(host_err);
 231}
 232
 233/*
 234 * Look up one component of a pathname.
 235 * N.B. After this call _both_ fhp and resfh need an fh_put
 236 *
 237 * If the lookup would cross a mountpoint, and the mounted filesystem
 238 * is exported to the client with NFSEXP_NOHIDE, then the lookup is
 239 * accepted as it stands and the mounted directory is
 240 * returned. Otherwise the covered directory is returned.
 241 * NOTE: this mountpoint crossing is not supported properly by all
 242 *   clients and is explicitly disallowed for NFSv3
 243 *      NeilBrown <neilb@cse.unsw.edu.au>
 244 */
 245__be32
 246nfsd_lookup(struct svc_rqst *rqstp, struct svc_fh *fhp, const char *name,
 247				unsigned int len, struct svc_fh *resfh)
 248{
 249	struct svc_export	*exp;
 250	struct dentry		*dentry;
 251	__be32 err;
 252
 253	err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC);
 254	if (err)
 255		return err;
 256	err = nfsd_lookup_dentry(rqstp, fhp, name, len, &exp, &dentry);
 257	if (err)
 258		return err;
 259	err = check_nfsd_access(exp, rqstp);
 260	if (err)
 261		goto out;
 262	/*
 263	 * Note: we compose the file handle now, but as the
 264	 * dentry may be negative, it may need to be updated.
 265	 */
 266	err = fh_compose(resfh, exp, dentry, fhp);
 267	if (!err && !dentry->d_inode)
 268		err = nfserr_noent;
 269out:
 270	dput(dentry);
 271	exp_put(exp);
 272	return err;
 273}
 274
 275static int nfsd_break_lease(struct inode *inode)
 276{
 277	if (!S_ISREG(inode->i_mode))
 278		return 0;
 279	return break_lease(inode, O_WRONLY | O_NONBLOCK);
 280}
 281
 282/*
 283 * Commit metadata changes to stable storage.
 284 */
 285static int
 286commit_metadata(struct svc_fh *fhp)
 287{
 288	struct inode *inode = fhp->fh_dentry->d_inode;
 289	const struct export_operations *export_ops = inode->i_sb->s_export_op;
 290
 291	if (!EX_ISSYNC(fhp->fh_export))
 292		return 0;
 293
 294	if (export_ops->commit_metadata)
 295		return export_ops->commit_metadata(inode);
 296	return sync_inode_metadata(inode, 1);
 297}
 298
 299/*
 300 * Set various file attributes.
 301 * N.B. After this call fhp needs an fh_put
 302 */
 303__be32
 304nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
 305	     int check_guard, time_t guardtime)
 306{
 307	struct dentry	*dentry;
 308	struct inode	*inode;
 309	int		accmode = NFSD_MAY_SATTR;
 310	umode_t		ftype = 0;
 311	__be32		err;
 312	int		host_err;
 313	int		size_change = 0;
 314
 315	if (iap->ia_valid & (ATTR_ATIME | ATTR_MTIME | ATTR_SIZE))
 316		accmode |= NFSD_MAY_WRITE|NFSD_MAY_OWNER_OVERRIDE;
 317	if (iap->ia_valid & ATTR_SIZE)
 318		ftype = S_IFREG;
 319
 320	/* Get inode */
 321	err = fh_verify(rqstp, fhp, ftype, accmode);
 322	if (err)
 323		goto out;
 324
 325	dentry = fhp->fh_dentry;
 326	inode = dentry->d_inode;
 327
 328	/* Ignore any mode updates on symlinks */
 329	if (S_ISLNK(inode->i_mode))
 330		iap->ia_valid &= ~ATTR_MODE;
 331
 332	if (!iap->ia_valid)
 333		goto out;
 334
 335	/*
 336	 * NFSv2 does not differentiate between "set-[ac]time-to-now"
 337	 * which only requires access, and "set-[ac]time-to-X" which
 338	 * requires ownership.
 339	 * So if it looks like it might be "set both to the same time which
 340	 * is close to now", and if inode_change_ok fails, then we
 341	 * convert to "set to now" instead of "set to explicit time"
 342	 *
 343	 * We only call inode_change_ok as the last test as technically
 344	 * it is not an interface that we should be using.  It is only
 345	 * valid if the filesystem does not define it's own i_op->setattr.
 346	 */
 347#define BOTH_TIME_SET (ATTR_ATIME_SET | ATTR_MTIME_SET)
 348#define	MAX_TOUCH_TIME_ERROR (30*60)
 349	if ((iap->ia_valid & BOTH_TIME_SET) == BOTH_TIME_SET &&
 350	    iap->ia_mtime.tv_sec == iap->ia_atime.tv_sec) {
 351		/*
 352		 * Looks probable.
 353		 *
 354		 * Now just make sure time is in the right ballpark.
 355		 * Solaris, at least, doesn't seem to care what the time
 356		 * request is.  We require it be within 30 minutes of now.
 357		 */
 358		time_t delta = iap->ia_atime.tv_sec - get_seconds();
 359		if (delta < 0)
 360			delta = -delta;
 361		if (delta < MAX_TOUCH_TIME_ERROR &&
 362		    inode_change_ok(inode, iap) != 0) {
 363			/*
 364			 * Turn off ATTR_[AM]TIME_SET but leave ATTR_[AM]TIME.
 365			 * This will cause notify_change to set these times
 366			 * to "now"
 367			 */
 368			iap->ia_valid &= ~BOTH_TIME_SET;
 369		}
 370	}
 371	    
 372	/*
 373	 * The size case is special.
 374	 * It changes the file as well as the attributes.
 375	 */
 376	if (iap->ia_valid & ATTR_SIZE) {
 377		if (iap->ia_size < inode->i_size) {
 378			err = nfsd_permission(rqstp, fhp->fh_export, dentry,
 379					NFSD_MAY_TRUNC|NFSD_MAY_OWNER_OVERRIDE);
 380			if (err)
 381				goto out;
 382		}
 383
 384		host_err = get_write_access(inode);
 385		if (host_err)
 386			goto out_nfserr;
 387
 388		size_change = 1;
 389		host_err = locks_verify_truncate(inode, NULL, iap->ia_size);
 390		if (host_err) {
 391			put_write_access(inode);
 392			goto out_nfserr;
 393		}
 394	}
 395
 396	/* sanitize the mode change */
 397	if (iap->ia_valid & ATTR_MODE) {
 398		iap->ia_mode &= S_IALLUGO;
 399		iap->ia_mode |= (inode->i_mode & ~S_IALLUGO);
 400	}
 401
 402	/* Revoke setuid/setgid on chown */
 403	if (!S_ISDIR(inode->i_mode) &&
 404	    (((iap->ia_valid & ATTR_UID) && iap->ia_uid != inode->i_uid) ||
 405	     ((iap->ia_valid & ATTR_GID) && iap->ia_gid != inode->i_gid))) {
 406		iap->ia_valid |= ATTR_KILL_PRIV;
 407		if (iap->ia_valid & ATTR_MODE) {
 408			/* we're setting mode too, just clear the s*id bits */
 409			iap->ia_mode &= ~S_ISUID;
 410			if (iap->ia_mode & S_IXGRP)
 411				iap->ia_mode &= ~S_ISGID;
 412		} else {
 413			/* set ATTR_KILL_* bits and let VFS handle it */
 414			iap->ia_valid |= (ATTR_KILL_SUID | ATTR_KILL_SGID);
 415		}
 416	}
 417
 418	/* Change the attributes. */
 419
 420	iap->ia_valid |= ATTR_CTIME;
 421
 422	err = nfserr_notsync;
 423	if (!check_guard || guardtime == inode->i_ctime.tv_sec) {
 424		host_err = nfsd_break_lease(inode);
 425		if (host_err)
 426			goto out_nfserr;
 427		fh_lock(fhp);
 428
 429		host_err = notify_change(dentry, iap);
 430		err = nfserrno(host_err);
 431		fh_unlock(fhp);
 432	}
 433	if (size_change)
 434		put_write_access(inode);
 435	if (!err)
 436		commit_metadata(fhp);
 437out:
 438	return err;
 439
 440out_nfserr:
 441	err = nfserrno(host_err);
 442	goto out;
 443}
 444
 445#if defined(CONFIG_NFSD_V2_ACL) || \
 446    defined(CONFIG_NFSD_V3_ACL) || \
 447    defined(CONFIG_NFSD_V4)
 448static ssize_t nfsd_getxattr(struct dentry *dentry, char *key, void **buf)
 449{
 450	ssize_t buflen;
 451	ssize_t ret;
 452
 453	buflen = vfs_getxattr(dentry, key, NULL, 0);
 454	if (buflen <= 0)
 455		return buflen;
 456
 457	*buf = kmalloc(buflen, GFP_KERNEL);
 458	if (!*buf)
 459		return -ENOMEM;
 460
 461	ret = vfs_getxattr(dentry, key, *buf, buflen);
 462	if (ret < 0)
 463		kfree(*buf);
 464	return ret;
 465}
 466#endif
 467
 468#if defined(CONFIG_NFSD_V4)
 469static int
 470set_nfsv4_acl_one(struct dentry *dentry, struct posix_acl *pacl, char *key)
 471{
 472	int len;
 473	size_t buflen;
 474	char *buf = NULL;
 475	int error = 0;
 476
 477	buflen = posix_acl_xattr_size(pacl->a_count);
 478	buf = kmalloc(buflen, GFP_KERNEL);
 479	error = -ENOMEM;
 480	if (buf == NULL)
 481		goto out;
 482
 483	len = posix_acl_to_xattr(pacl, buf, buflen);
 484	if (len < 0) {
 485		error = len;
 486		goto out;
 487	}
 488
 489	error = vfs_setxattr(dentry, key, buf, len, 0);
 490out:
 491	kfree(buf);
 492	return error;
 493}
 494
 495__be32
 496nfsd4_set_nfs4_acl(struct svc_rqst *rqstp, struct svc_fh *fhp,
 497    struct nfs4_acl *acl)
 498{
 499	__be32 error;
 500	int host_error;
 501	struct dentry *dentry;
 502	struct inode *inode;
 503	struct posix_acl *pacl = NULL, *dpacl = NULL;
 504	unsigned int flags = 0;
 505
 506	/* Get inode */
 507	error = fh_verify(rqstp, fhp, 0, NFSD_MAY_SATTR);
 508	if (error)
 509		return error;
 510
 511	dentry = fhp->fh_dentry;
 512	inode = dentry->d_inode;
 513	if (S_ISDIR(inode->i_mode))
 514		flags = NFS4_ACL_DIR;
 515
 516	host_error = nfs4_acl_nfsv4_to_posix(acl, &pacl, &dpacl, flags);
 517	if (host_error == -EINVAL) {
 518		return nfserr_attrnotsupp;
 519	} else if (host_error < 0)
 520		goto out_nfserr;
 521
 522	host_error = set_nfsv4_acl_one(dentry, pacl, POSIX_ACL_XATTR_ACCESS);
 523	if (host_error < 0)
 524		goto out_release;
 525
 526	if (S_ISDIR(inode->i_mode))
 527		host_error = set_nfsv4_acl_one(dentry, dpacl, POSIX_ACL_XATTR_DEFAULT);
 528
 529out_release:
 530	posix_acl_release(pacl);
 531	posix_acl_release(dpacl);
 532out_nfserr:
 533	if (host_error == -EOPNOTSUPP)
 534		return nfserr_attrnotsupp;
 535	else
 536		return nfserrno(host_error);
 537}
 538
 539static struct posix_acl *
 540_get_posix_acl(struct dentry *dentry, char *key)
 541{
 542	void *buf = NULL;
 543	struct posix_acl *pacl = NULL;
 544	int buflen;
 545
 546	buflen = nfsd_getxattr(dentry, key, &buf);
 547	if (!buflen)
 548		buflen = -ENODATA;
 549	if (buflen <= 0)
 550		return ERR_PTR(buflen);
 551
 552	pacl = posix_acl_from_xattr(buf, buflen);
 553	kfree(buf);
 554	return pacl;
 555}
 556
 557int
 558nfsd4_get_nfs4_acl(struct svc_rqst *rqstp, struct dentry *dentry, struct nfs4_acl **acl)
 559{
 560	struct inode *inode = dentry->d_inode;
 561	int error = 0;
 562	struct posix_acl *pacl = NULL, *dpacl = NULL;
 563	unsigned int flags = 0;
 564
 565	pacl = _get_posix_acl(dentry, POSIX_ACL_XATTR_ACCESS);
 566	if (IS_ERR(pacl) && PTR_ERR(pacl) == -ENODATA)
 567		pacl = posix_acl_from_mode(inode->i_mode, GFP_KERNEL);
 568	if (IS_ERR(pacl)) {
 569		error = PTR_ERR(pacl);
 570		pacl = NULL;
 571		goto out;
 572	}
 573
 574	if (S_ISDIR(inode->i_mode)) {
 575		dpacl = _get_posix_acl(dentry, POSIX_ACL_XATTR_DEFAULT);
 576		if (IS_ERR(dpacl) && PTR_ERR(dpacl) == -ENODATA)
 577			dpacl = NULL;
 578		else if (IS_ERR(dpacl)) {
 579			error = PTR_ERR(dpacl);
 580			dpacl = NULL;
 581			goto out;
 582		}
 583		flags = NFS4_ACL_DIR;
 584	}
 585
 586	*acl = nfs4_acl_posix_to_nfsv4(pacl, dpacl, flags);
 587	if (IS_ERR(*acl)) {
 588		error = PTR_ERR(*acl);
 589		*acl = NULL;
 590	}
 591 out:
 592	posix_acl_release(pacl);
 593	posix_acl_release(dpacl);
 594	return error;
 595}
 596
 597/*
 598 * NFS junction information is stored in an extended attribute.
 599 */
 600#define NFSD_JUNCTION_XATTR_NAME	XATTR_TRUSTED_PREFIX "junction.nfs"
 601
 602/**
 603 * nfsd4_is_junction - Test if an object could be an NFS junction
 604 *
 605 * @dentry: object to test
 606 *
 607 * Returns 1 if "dentry" appears to contain NFS junction information.
 608 * Otherwise 0 is returned.
 609 */
 610int nfsd4_is_junction(struct dentry *dentry)
 611{
 612	struct inode *inode = dentry->d_inode;
 613
 614	if (inode == NULL)
 615		return 0;
 616	if (inode->i_mode & S_IXUGO)
 617		return 0;
 618	if (!(inode->i_mode & S_ISVTX))
 619		return 0;
 620	if (vfs_getxattr(dentry, NFSD_JUNCTION_XATTR_NAME, NULL, 0) <= 0)
 621		return 0;
 622	return 1;
 623}
 624#endif /* defined(CONFIG_NFSD_V4) */
 625
 626#ifdef CONFIG_NFSD_V3
 627/*
 628 * Check server access rights to a file system object
 629 */
 630struct accessmap {
 631	u32		access;
 632	int		how;
 633};
 634static struct accessmap	nfs3_regaccess[] = {
 635    {	NFS3_ACCESS_READ,	NFSD_MAY_READ			},
 636    {	NFS3_ACCESS_EXECUTE,	NFSD_MAY_EXEC			},
 637    {	NFS3_ACCESS_MODIFY,	NFSD_MAY_WRITE|NFSD_MAY_TRUNC	},
 638    {	NFS3_ACCESS_EXTEND,	NFSD_MAY_WRITE			},
 639
 640    {	0,			0				}
 641};
 642
 643static struct accessmap	nfs3_diraccess[] = {
 644    {	NFS3_ACCESS_READ,	NFSD_MAY_READ			},
 645    {	NFS3_ACCESS_LOOKUP,	NFSD_MAY_EXEC			},
 646    {	NFS3_ACCESS_MODIFY,	NFSD_MAY_EXEC|NFSD_MAY_WRITE|NFSD_MAY_TRUNC},
 647    {	NFS3_ACCESS_EXTEND,	NFSD_MAY_EXEC|NFSD_MAY_WRITE	},
 648    {	NFS3_ACCESS_DELETE,	NFSD_MAY_REMOVE			},
 649
 650    {	0,			0				}
 651};
 652
 653static struct accessmap	nfs3_anyaccess[] = {
 654	/* Some clients - Solaris 2.6 at least, make an access call
 655	 * to the server to check for access for things like /dev/null
 656	 * (which really, the server doesn't care about).  So
 657	 * We provide simple access checking for them, looking
 658	 * mainly at mode bits, and we make sure to ignore read-only
 659	 * filesystem checks
 660	 */
 661    {	NFS3_ACCESS_READ,	NFSD_MAY_READ			},
 662    {	NFS3_ACCESS_EXECUTE,	NFSD_MAY_EXEC			},
 663    {	NFS3_ACCESS_MODIFY,	NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS	},
 664    {	NFS3_ACCESS_EXTEND,	NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS	},
 665
 666    {	0,			0				}
 667};
 668
 669__be32
 670nfsd_access(struct svc_rqst *rqstp, struct svc_fh *fhp, u32 *access, u32 *supported)
 671{
 672	struct accessmap	*map;
 673	struct svc_export	*export;
 674	struct dentry		*dentry;
 675	u32			query, result = 0, sresult = 0;
 676	__be32			error;
 677
 678	error = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP);
 679	if (error)
 680		goto out;
 681
 682	export = fhp->fh_export;
 683	dentry = fhp->fh_dentry;
 684
 685	if (S_ISREG(dentry->d_inode->i_mode))
 686		map = nfs3_regaccess;
 687	else if (S_ISDIR(dentry->d_inode->i_mode))
 688		map = nfs3_diraccess;
 689	else
 690		map = nfs3_anyaccess;
 691
 692
 693	query = *access;
 694	for  (; map->access; map++) {
 695		if (map->access & query) {
 696			__be32 err2;
 697
 698			sresult |= map->access;
 699
 700			err2 = nfsd_permission(rqstp, export, dentry, map->how);
 701			switch (err2) {
 702			case nfs_ok:
 703				result |= map->access;
 704				break;
 705				
 706			/* the following error codes just mean the access was not allowed,
 707			 * rather than an error occurred */
 708			case nfserr_rofs:
 709			case nfserr_acces:
 710			case nfserr_perm:
 711				/* simply don't "or" in the access bit. */
 712				break;
 713			default:
 714				error = err2;
 715				goto out;
 716			}
 717		}
 718	}
 719	*access = result;
 720	if (supported)
 721		*supported = sresult;
 722
 723 out:
 724	return error;
 725}
 726#endif /* CONFIG_NFSD_V3 */
 727
 728static int nfsd_open_break_lease(struct inode *inode, int access)
 729{
 730	unsigned int mode;
 731
 732	if (access & NFSD_MAY_NOT_BREAK_LEASE)
 733		return 0;
 734	mode = (access & NFSD_MAY_WRITE) ? O_WRONLY : O_RDONLY;
 735	return break_lease(inode, mode | O_NONBLOCK);
 736}
 737
 738/*
 739 * Open an existing file or directory.
 740 * The may_flags argument indicates the type of open (read/write/lock)
 741 * and additional flags.
 742 * N.B. After this call fhp needs an fh_put
 743 */
 744__be32
 745nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type,
 746			int may_flags, struct file **filp)
 747{
 748	struct dentry	*dentry;
 749	struct inode	*inode;
 750	int		flags = O_RDONLY|O_LARGEFILE;
 751	__be32		err;
 752	int		host_err = 0;
 753
 754	validate_process_creds();
 755
 756	/*
 757	 * If we get here, then the client has already done an "open",
 758	 * and (hopefully) checked permission - so allow OWNER_OVERRIDE
 759	 * in case a chmod has now revoked permission.
 760	 */
 761	err = fh_verify(rqstp, fhp, type, may_flags | NFSD_MAY_OWNER_OVERRIDE);
 762	if (err)
 763		goto out;
 764
 765	dentry = fhp->fh_dentry;
 766	inode = dentry->d_inode;
 767
 768	/* Disallow write access to files with the append-only bit set
 769	 * or any access when mandatory locking enabled
 770	 */
 771	err = nfserr_perm;
 772	if (IS_APPEND(inode) && (may_flags & NFSD_MAY_WRITE))
 773		goto out;
 774	/*
 775	 * We must ignore files (but only files) which might have mandatory
 776	 * locks on them because there is no way to know if the accesser has
 777	 * the lock.
 778	 */
 779	if (S_ISREG((inode)->i_mode) && mandatory_lock(inode))
 780		goto out;
 781
 782	if (!inode->i_fop)
 783		goto out;
 784
 785	host_err = nfsd_open_break_lease(inode, may_flags);
 786	if (host_err) /* NOMEM or WOULDBLOCK */
 787		goto out_nfserr;
 788
 789	if (may_flags & NFSD_MAY_WRITE) {
 790		if (may_flags & NFSD_MAY_READ)
 791			flags = O_RDWR|O_LARGEFILE;
 792		else
 793			flags = O_WRONLY|O_LARGEFILE;
 794	}
 795	*filp = dentry_open(dget(dentry), mntget(fhp->fh_export->ex_path.mnt),
 796			    flags, current_cred());
 797	if (IS_ERR(*filp))
 798		host_err = PTR_ERR(*filp);
 799	else {
 800		host_err = ima_file_check(*filp, may_flags);
 801
 802		if (may_flags & NFSD_MAY_64BIT_COOKIE)
 803			(*filp)->f_mode |= FMODE_64BITHASH;
 804		else
 805			(*filp)->f_mode |= FMODE_32BITHASH;
 806	}
 807
 808out_nfserr:
 809	err = nfserrno(host_err);
 810out:
 811	validate_process_creds();
 812	return err;
 813}
 814
 815/*
 816 * Close a file.
 817 */
 818void
 819nfsd_close(struct file *filp)
 820{
 821	fput(filp);
 822}
 823
 824/*
 825 * Obtain the readahead parameters for the file
 826 * specified by (dev, ino).
 827 */
 828
 829static inline struct raparms *
 830nfsd_get_raparms(dev_t dev, ino_t ino)
 831{
 832	struct raparms	*ra, **rap, **frap = NULL;
 833	int depth = 0;
 834	unsigned int hash;
 835	struct raparm_hbucket *rab;
 836
 837	hash = jhash_2words(dev, ino, 0xfeedbeef) & RAPARM_HASH_MASK;
 838	rab = &raparm_hash[hash];
 839
 840	spin_lock(&rab->pb_lock);
 841	for (rap = &rab->pb_head; (ra = *rap); rap = &ra->p_next) {
 842		if (ra->p_ino == ino && ra->p_dev == dev)
 843			goto found;
 844		depth++;
 845		if (ra->p_count == 0)
 846			frap = rap;
 847	}
 848	depth = nfsdstats.ra_size;
 849	if (!frap) {	
 850		spin_unlock(&rab->pb_lock);
 851		return NULL;
 852	}
 853	rap = frap;
 854	ra = *frap;
 855	ra->p_dev = dev;
 856	ra->p_ino = ino;
 857	ra->p_set = 0;
 858	ra->p_hindex = hash;
 859found:
 860	if (rap != &rab->pb_head) {
 861		*rap = ra->p_next;
 862		ra->p_next   = rab->pb_head;
 863		rab->pb_head = ra;
 864	}
 865	ra->p_count++;
 866	nfsdstats.ra_depth[depth*10/nfsdstats.ra_size]++;
 867	spin_unlock(&rab->pb_lock);
 868	return ra;
 869}
 870
 871/*
 872 * Grab and keep cached pages associated with a file in the svc_rqst
 873 * so that they can be passed to the network sendmsg/sendpage routines
 874 * directly. They will be released after the sending has completed.
 875 */
 876static int
 877nfsd_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
 878		  struct splice_desc *sd)
 879{
 880	struct svc_rqst *rqstp = sd->u.data;
 881	struct page **pp = rqstp->rq_respages + rqstp->rq_resused;
 882	struct page *page = buf->page;
 883	size_t size;
 884
 885	size = sd->len;
 886
 887	if (rqstp->rq_res.page_len == 0) {
 888		get_page(page);
 889		put_page(*pp);
 890		*pp = page;
 891		rqstp->rq_resused++;
 892		rqstp->rq_res.page_base = buf->offset;
 893		rqstp->rq_res.page_len = size;
 894	} else if (page != pp[-1]) {
 895		get_page(page);
 896		if (*pp)
 897			put_page(*pp);
 898		*pp = page;
 899		rqstp->rq_resused++;
 900		rqstp->rq_res.page_len += size;
 901	} else
 902		rqstp->rq_res.page_len += size;
 903
 904	return size;
 905}
 906
 907static int nfsd_direct_splice_actor(struct pipe_inode_info *pipe,
 908				    struct splice_desc *sd)
 909{
 910	return __splice_from_pipe(pipe, sd, nfsd_splice_actor);
 911}
 912
 913static __be32
 914nfsd_vfs_read(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
 915              loff_t offset, struct kvec *vec, int vlen, unsigned long *count)
 916{
 917	mm_segment_t	oldfs;
 918	__be32		err;
 919	int		host_err;
 920
 921	err = nfserr_perm;
 922
 923	if (file->f_op->splice_read && rqstp->rq_splice_ok) {
 924		struct splice_desc sd = {
 925			.len		= 0,
 926			.total_len	= *count,
 927			.pos		= offset,
 928			.u.data		= rqstp,
 929		};
 930
 931		rqstp->rq_resused = 1;
 932		host_err = splice_direct_to_actor(file, &sd, nfsd_direct_splice_actor);
 933	} else {
 934		oldfs = get_fs();
 935		set_fs(KERNEL_DS);
 936		host_err = vfs_readv(file, (struct iovec __user *)vec, vlen, &offset);
 937		set_fs(oldfs);
 938	}
 939
 940	if (host_err >= 0) {
 941		nfsdstats.io_read += host_err;
 942		*count = host_err;
 943		err = 0;
 944		fsnotify_access(file);
 945	} else 
 946		err = nfserrno(host_err);
 947	return err;
 948}
 949
 950static void kill_suid(struct dentry *dentry)
 951{
 952	struct iattr	ia;
 953	ia.ia_valid = ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_KILL_PRIV;
 954
 955	mutex_lock(&dentry->d_inode->i_mutex);
 956	notify_change(dentry, &ia);
 957	mutex_unlock(&dentry->d_inode->i_mutex);
 958}
 959
 960/*
 961 * Gathered writes: If another process is currently writing to the file,
 962 * there's a high chance this is another nfsd (triggered by a bulk write
 963 * from a client's biod). Rather than syncing the file with each write
 964 * request, we sleep for 10 msec.
 965 *
 966 * I don't know if this roughly approximates C. Juszak's idea of
 967 * gathered writes, but it's a nice and simple solution (IMHO), and it
 968 * seems to work:-)
 969 *
 970 * Note: we do this only in the NFSv2 case, since v3 and higher have a
 971 * better tool (separate unstable writes and commits) for solving this
 972 * problem.
 973 */
 974static int wait_for_concurrent_writes(struct file *file)
 975{
 976	struct inode *inode = file->f_path.dentry->d_inode;
 977	static ino_t last_ino;
 978	static dev_t last_dev;
 979	int err = 0;
 980
 981	if (atomic_read(&inode->i_writecount) > 1
 982	    || (last_ino == inode->i_ino && last_dev == inode->i_sb->s_dev)) {
 983		dprintk("nfsd: write defer %d\n", task_pid_nr(current));
 984		msleep(10);
 985		dprintk("nfsd: write resume %d\n", task_pid_nr(current));
 986	}
 987
 988	if (inode->i_state & I_DIRTY) {
 989		dprintk("nfsd: write sync %d\n", task_pid_nr(current));
 990		err = vfs_fsync(file, 0);
 991	}
 992	last_ino = inode->i_ino;
 993	last_dev = inode->i_sb->s_dev;
 994	return err;
 995}
 996
 997static __be32
 998nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
 999				loff_t offset, struct kvec *vec, int vlen,
1000				unsigned long *cnt, int *stablep)
1001{
1002	struct svc_export	*exp;
1003	struct dentry		*dentry;
1004	struct inode		*inode;
1005	mm_segment_t		oldfs;
1006	__be32			err = 0;
1007	int			host_err;
1008	int			stable = *stablep;
1009	int			use_wgather;
1010
1011	dentry = file->f_path.dentry;
1012	inode = dentry->d_inode;
1013	exp   = fhp->fh_export;
1014
1015	/*
1016	 * Request sync writes if
1017	 *  -	the sync export option has been set, or
1018	 *  -	the client requested O_SYNC behavior (NFSv3 feature).
1019	 *  -   The file system doesn't support fsync().
1020	 * When NFSv2 gathered writes have been configured for this volume,
1021	 * flushing the data to disk is handled separately below.
1022	 */
1023	use_wgather = (rqstp->rq_vers == 2) && EX_WGATHER(exp);
1024
1025	if (!file->f_op->fsync) {/* COMMIT3 cannot work */
1026	       stable = 2;
1027	       *stablep = 2; /* FILE_SYNC */
1028	}
1029
1030	if (!EX_ISSYNC(exp))
1031		stable = 0;
1032	if (stable && !use_wgather) {
1033		spin_lock(&file->f_lock);
1034		file->f_flags |= O_SYNC;
1035		spin_unlock(&file->f_lock);
1036	}
1037
1038	/* Write the data. */
1039	oldfs = get_fs(); set_fs(KERNEL_DS);
1040	host_err = vfs_writev(file, (struct iovec __user *)vec, vlen, &offset);
1041	set_fs(oldfs);
1042	if (host_err < 0)
1043		goto out_nfserr;
1044	*cnt = host_err;
1045	nfsdstats.io_write += host_err;
1046	fsnotify_modify(file);
1047
1048	/* clear setuid/setgid flag after write */
1049	if (inode->i_mode & (S_ISUID | S_ISGID))
1050		kill_suid(dentry);
1051
1052	if (stable && use_wgather)
1053		host_err = wait_for_concurrent_writes(file);
1054
1055out_nfserr:
1056	dprintk("nfsd: write complete host_err=%d\n", host_err);
1057	if (host_err >= 0)
1058		err = 0;
1059	else
1060		err = nfserrno(host_err);
1061	return err;
1062}
1063
1064/*
1065 * Read data from a file. count must contain the requested read count
1066 * on entry. On return, *count contains the number of bytes actually read.
1067 * N.B. After this call fhp needs an fh_put
1068 */
1069__be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
1070	loff_t offset, struct kvec *vec, int vlen, unsigned long *count)
1071{
1072	struct file *file;
1073	struct inode *inode;
1074	struct raparms	*ra;
1075	__be32 err;
1076
1077	err = nfsd_open(rqstp, fhp, S_IFREG, NFSD_MAY_READ, &file);
1078	if (err)
1079		return err;
1080
1081	inode = file->f_path.dentry->d_inode;
1082
1083	/* Get readahead parameters */
1084	ra = nfsd_get_raparms(inode->i_sb->s_dev, inode->i_ino);
1085
1086	if (ra && ra->p_set)
1087		file->f_ra = ra->p_ra;
1088
1089	err = nfsd_vfs_read(rqstp, fhp, file, offset, vec, vlen, count);
1090
1091	/* Write back readahead params */
1092	if (ra) {
1093		struct raparm_hbucket *rab = &raparm_hash[ra->p_hindex];
1094		spin_lock(&rab->pb_lock);
1095		ra->p_ra = file->f_ra;
1096		ra->p_set = 1;
1097		ra->p_count--;
1098		spin_unlock(&rab->pb_lock);
1099	}
1100
1101	nfsd_close(file);
1102	return err;
1103}
1104
1105/* As above, but use the provided file descriptor. */
1106__be32
1107nfsd_read_file(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
1108		loff_t offset, struct kvec *vec, int vlen,
1109		unsigned long *count)
1110{
1111	__be32		err;
1112
1113	if (file) {
1114		err = nfsd_permission(rqstp, fhp->fh_export, fhp->fh_dentry,
1115				NFSD_MAY_READ|NFSD_MAY_OWNER_OVERRIDE);
1116		if (err)
1117			goto out;
1118		err = nfsd_vfs_read(rqstp, fhp, file, offset, vec, vlen, count);
1119	} else /* Note file may still be NULL in NFSv4 special stateid case: */
1120		err = nfsd_read(rqstp, fhp, offset, vec, vlen, count);
1121out:
1122	return err;
1123}
1124
1125/*
1126 * Write data to a file.
1127 * The stable flag requests synchronous writes.
1128 * N.B. After this call fhp needs an fh_put
1129 */
1130__be32
1131nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
1132		loff_t offset, struct kvec *vec, int vlen, unsigned long *cnt,
1133		int *stablep)
1134{
1135	__be32			err = 0;
1136
1137	if (file) {
1138		err = nfsd_permission(rqstp, fhp->fh_export, fhp->fh_dentry,
1139				NFSD_MAY_WRITE|NFSD_MAY_OWNER_OVERRIDE);
1140		if (err)
1141			goto out;
1142		err = nfsd_vfs_write(rqstp, fhp, file, offset, vec, vlen, cnt,
1143				stablep);
1144	} else {
1145		err = nfsd_open(rqstp, fhp, S_IFREG, NFSD_MAY_WRITE, &file);
1146		if (err)
1147			goto out;
1148
1149		if (cnt)
1150			err = nfsd_vfs_write(rqstp, fhp, file, offset, vec, vlen,
1151					     cnt, stablep);
1152		nfsd_close(file);
1153	}
1154out:
1155	return err;
1156}
1157
1158#ifdef CONFIG_NFSD_V3
1159/*
1160 * Commit all pending writes to stable storage.
1161 *
1162 * Note: we only guarantee that data that lies within the range specified
1163 * by the 'offset' and 'count' parameters will be synced.
1164 *
1165 * Unfortunately we cannot lock the file to make sure we return full WCC
1166 * data to the client, as locking happens lower down in the filesystem.
1167 */
1168__be32
1169nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp,
1170               loff_t offset, unsigned long count)
1171{
1172	struct file	*file;
1173	loff_t		end = LLONG_MAX;
1174	__be32		err = nfserr_inval;
1175
1176	if (offset < 0)
1177		goto out;
1178	if (count != 0) {
1179		end = offset + (loff_t)count - 1;
1180		if (end < offset)
1181			goto out;
1182	}
1183
1184	err = nfsd_open(rqstp, fhp, S_IFREG,
1185			NFSD_MAY_WRITE|NFSD_MAY_NOT_BREAK_LEASE, &file);
1186	if (err)
1187		goto out;
1188	if (EX_ISSYNC(fhp->fh_export)) {
1189		int err2 = vfs_fsync_range(file, offset, end, 0);
1190
1191		if (err2 != -EINVAL)
1192			err = nfserrno(err2);
1193		else
1194			err = nfserr_notsupp;
1195	}
1196
1197	nfsd_close(file);
1198out:
1199	return err;
1200}
1201#endif /* CONFIG_NFSD_V3 */
1202
1203static __be32
1204nfsd_create_setattr(struct svc_rqst *rqstp, struct svc_fh *resfhp,
1205			struct iattr *iap)
1206{
1207	/*
1208	 * Mode has already been set earlier in create:
1209	 */
1210	iap->ia_valid &= ~ATTR_MODE;
1211	/*
1212	 * Setting uid/gid works only for root.  Irix appears to
1213	 * send along the gid on create when it tries to implement
1214	 * setgid directories via NFS:
1215	 */
1216	if (current_fsuid() != 0)
1217		iap->ia_valid &= ~(ATTR_UID|ATTR_GID);
1218	if (iap->ia_valid)
1219		return nfsd_setattr(rqstp, resfhp, iap, 0, (time_t)0);
1220	return 0;
1221}
1222
1223/* HPUX client sometimes creates a file in mode 000, and sets size to 0.
1224 * setting size to 0 may fail for some specific file systems by the permission
1225 * checking which requires WRITE permission but the mode is 000.
1226 * we ignore the resizing(to 0) on the just new created file, since the size is
1227 * 0 after file created.
1228 *
1229 * call this only after vfs_create() is called.
1230 * */
1231static void
1232nfsd_check_ignore_resizing(struct iattr *iap)
1233{
1234	if ((iap->ia_valid & ATTR_SIZE) && (iap->ia_size == 0))
1235		iap->ia_valid &= ~ATTR_SIZE;
1236}
1237
1238/*
1239 * Create a file (regular, directory, device, fifo); UNIX sockets 
1240 * not yet implemented.
1241 * If the response fh has been verified, the parent directory should
1242 * already be locked. Note that the parent directory is left locked.
1243 *
1244 * N.B. Every call to nfsd_create needs an fh_put for _both_ fhp and resfhp
1245 */
1246__be32
1247nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
1248		char *fname, int flen, struct iattr *iap,
1249		int type, dev_t rdev, struct svc_fh *resfhp)
1250{
1251	struct dentry	*dentry, *dchild = NULL;
1252	struct inode	*dirp;
1253	__be32		err;
1254	__be32		err2;
1255	int		host_err;
1256
1257	err = nfserr_perm;
1258	if (!flen)
1259		goto out;
1260	err = nfserr_exist;
1261	if (isdotent(fname, flen))
1262		goto out;
1263
1264	err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
1265	if (err)
1266		goto out;
1267
1268	dentry = fhp->fh_dentry;
1269	dirp = dentry->d_inode;
1270
1271	err = nfserr_notdir;
1272	if (!dirp->i_op->lookup)
1273		goto out;
1274	/*
1275	 * Check whether the response file handle has been verified yet.
1276	 * If it has, the parent directory should already be locked.
1277	 */
1278	if (!resfhp->fh_dentry) {
1279		/* called from nfsd_proc_mkdir, or possibly nfsd3_proc_create */
1280		fh_lock_nested(fhp, I_MUTEX_PARENT);
1281		dchild = lookup_one_len(fname, dentry, flen);
1282		host_err = PTR_ERR(dchild);
1283		if (IS_ERR(dchild))
1284			goto out_nfserr;
1285		err = fh_compose(resfhp, fhp->fh_export, dchild, fhp);
1286		if (err)
1287			goto out;
1288	} else {
1289		/* called from nfsd_proc_create */
1290		dchild = dget(resfhp->fh_dentry);
1291		if (!fhp->fh_locked) {
1292			/* not actually possible */
1293			printk(KERN_ERR
1294				"nfsd_create: parent %s/%s not locked!\n",
1295				dentry->d_parent->d_name.name,
1296				dentry->d_name.name);
1297			err = nfserr_io;
1298			goto out;
1299		}
1300	}
1301	/*
1302	 * Make sure the child dentry is still negative ...
1303	 */
1304	err = nfserr_exist;
1305	if (dchild->d_inode) {
1306		dprintk("nfsd_create: dentry %s/%s not negative!\n",
1307			dentry->d_name.name, dchild->d_name.name);
1308		goto out; 
1309	}
1310
1311	if (!(iap->ia_valid & ATTR_MODE))
1312		iap->ia_mode = 0;
1313	iap->ia_mode = (iap->ia_mode & S_IALLUGO) | type;
1314
1315	err = nfserr_inval;
1316	if (!S_ISREG(type) && !S_ISDIR(type) && !special_file(type)) {
1317		printk(KERN_WARNING "nfsd: bad file type %o in nfsd_create\n",
1318		       type);
1319		goto out;
1320	}
1321
1322	host_err = fh_want_write(fhp);
1323	if (host_err)
1324		goto out_nfserr;
1325
1326	/*
1327	 * Get the dir op function pointer.
1328	 */
1329	err = 0;
1330	switch (type) {
1331	case S_IFREG:
1332		host_err = vfs_create(dirp, dchild, iap->ia_mode, NULL);
1333		if (!host_err)
1334			nfsd_check_ignore_resizing(iap);
1335		break;
1336	case S_IFDIR:
1337		host_err = vfs_mkdir(dirp, dchild, iap->ia_mode);
1338		break;
1339	case S_IFCHR:
1340	case S_IFBLK:
1341	case S_IFIFO:
1342	case S_IFSOCK:
1343		host_err = vfs_mknod(dirp, dchild, iap->ia_mode, rdev);
1344		break;
1345	}
1346	if (host_err < 0) {
1347		fh_drop_write(fhp);
1348		goto out_nfserr;
1349	}
1350
1351	err = nfsd_create_setattr(rqstp, resfhp, iap);
1352
1353	/*
1354	 * nfsd_setattr already committed the child.  Transactional filesystems
1355	 * had a chance to commit changes for both parent and child
1356	 * simultaneously making the following commit_metadata a noop.
1357	 */
1358	err2 = nfserrno(commit_metadata(fhp));
1359	if (err2)
1360		err = err2;
1361	fh_drop_write(fhp);
1362	/*
1363	 * Update the file handle to get the new inode info.
1364	 */
1365	if (!err)
1366		err = fh_update(resfhp);
1367out:
1368	if (dchild && !IS_ERR(dchild))
1369		dput(dchild);
1370	return err;
1371
1372out_nfserr:
1373	err = nfserrno(host_err);
1374	goto out;
1375}
1376
1377#ifdef CONFIG_NFSD_V3
1378
1379static inline int nfsd_create_is_exclusive(int createmode)
1380{
1381	return createmode == NFS3_CREATE_EXCLUSIVE
1382	       || createmode == NFS4_CREATE_EXCLUSIVE4_1;
1383}
1384
1385/*
1386 * NFSv3 and NFSv4 version of nfsd_create
1387 */
1388__be32
1389do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
1390		char *fname, int flen, struct iattr *iap,
1391		struct svc_fh *resfhp, int createmode, u32 *verifier,
1392	        bool *truncp, bool *created)
1393{
1394	struct dentry	*dentry, *dchild = NULL;
1395	struct inode	*dirp;
1396	__be32		err;
1397	int		host_err;
1398	__u32		v_mtime=0, v_atime=0;
1399
1400	err = nfserr_perm;
1401	if (!flen)
1402		goto out;
1403	err = nfserr_exist;
1404	if (isdotent(fname, flen))
1405		goto out;
1406	if (!(iap->ia_valid & ATTR_MODE))
1407		iap->ia_mode = 0;
1408	err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC);
1409	if (err)
1410		goto out;
1411
1412	dentry = fhp->fh_dentry;
1413	dirp = dentry->d_inode;
1414
1415	/* Get all the sanity checks out of the way before
1416	 * we lock the parent. */
1417	err = nfserr_notdir;
1418	if (!dirp->i_op->lookup)
1419		goto out;
1420	fh_lock_nested(fhp, I_MUTEX_PARENT);
1421
1422	/*
1423	 * Compose the response file handle.
1424	 */
1425	dchild = lookup_one_len(fname, dentry, flen);
1426	host_err = PTR_ERR(dchild);
1427	if (IS_ERR(dchild))
1428		goto out_nfserr;
1429
1430	/* If file doesn't exist, check for permissions to create one */
1431	if (!dchild->d_inode) {
1432		err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
1433		if (err)
1434			goto out;
1435	}
1436
1437	err = fh_compose(resfhp, fhp->fh_export, dchild, fhp);
1438	if (err)
1439		goto out;
1440
1441	if (nfsd_create_is_exclusive(createmode)) {
1442		/* solaris7 gets confused (bugid 4218508) if these have
1443		 * the high bit set, so just clear the high bits. If this is
1444		 * ever changed to use different attrs for storing the
1445		 * verifier, then do_open_lookup() will also need to be fixed
1446		 * accordingly.
1447		 */
1448		v_mtime = verifier[0]&0x7fffffff;
1449		v_atime = verifier[1]&0x7fffffff;
1450	}
1451	
1452	host_err = fh_want_write(fhp);
1453	if (host_err)
1454		goto out_nfserr;
1455	if (dchild->d_inode) {
1456		err = 0;
1457
1458		switch (createmode) {
1459		case NFS3_CREATE_UNCHECKED:
1460			if (! S_ISREG(dchild->d_inode->i_mode))
1461				goto out;
1462			else if (truncp) {
1463				/* in nfsv4, we need to treat this case a little
1464				 * differently.  we don't want to truncate the
1465				 * file now; this would be wrong if the OPEN
1466				 * fails for some other reason.  furthermore,
1467				 * if the size is nonzero, we should ignore it
1468				 * according to spec!
1469				 */
1470				*truncp = (iap->ia_valid & ATTR_SIZE) && !iap->ia_size;
1471			}
1472			else {
1473				iap->ia_valid &= ATTR_SIZE;
1474				goto set_attr;
1475			}
1476			break;
1477		case NFS3_CREATE_EXCLUSIVE:
1478			if (   dchild->d_inode->i_mtime.tv_sec == v_mtime
1479			    && dchild->d_inode->i_atime.tv_sec == v_atime
1480			    && dchild->d_inode->i_size  == 0 )
1481				break;
1482		case NFS4_CREATE_EXCLUSIVE4_1:
1483			if (   dchild->d_inode->i_mtime.tv_sec == v_mtime
1484			    && dchild->d_inode->i_atime.tv_sec == v_atime
1485			    && dchild->d_inode->i_size  == 0 )
1486				goto set_attr;
1487			 /* fallthru */
1488		case NFS3_CREATE_GUARDED:
1489			err = nfserr_exist;
1490		}
1491		fh_drop_write(fhp);
1492		goto out;
1493	}
1494
1495	host_err = vfs_create(dirp, dchild, iap->ia_mode, NULL);
1496	if (host_err < 0) {
1497		fh_drop_write(fhp);
1498		goto out_nfserr;
1499	}
1500	if (created)
1501		*created = 1;
1502
1503	nfsd_check_ignore_resizing(iap);
1504
1505	if (nfsd_create_is_exclusive(createmode)) {
1506		/* Cram the verifier into atime/mtime */
1507		iap->ia_valid = ATTR_MTIME|ATTR_ATIME
1508			| ATTR_MTIME_SET|ATTR_ATIME_SET;
1509		/* XXX someone who knows this better please fix it for nsec */ 
1510		iap->ia_mtime.tv_sec = v_mtime;
1511		iap->ia_atime.tv_sec = v_atime;
1512		iap->ia_mtime.tv_nsec = 0;
1513		iap->ia_atime.tv_nsec = 0;
1514	}
1515
1516 set_attr:
1517	err = nfsd_create_setattr(rqstp, resfhp, iap);
1518
1519	/*
1520	 * nfsd_setattr already committed the child (and possibly also the parent).
1521	 */
1522	if (!err)
1523		err = nfserrno(commit_metadata(fhp));
1524
1525	fh_drop_write(fhp);
1526	/*
1527	 * Update the filehandle to get the new inode info.
1528	 */
1529	if (!err)
1530		err = fh_update(resfhp);
1531
1532 out:
1533	fh_unlock(fhp);
1534	if (dchild && !IS_ERR(dchild))
1535		dput(dchild);
1536 	return err;
1537 
1538 out_nfserr:
1539	err = nfserrno(host_err);
1540	goto out;
1541}
1542#endif /* CONFIG_NFSD_V3 */
1543
1544/*
1545 * Read a symlink. On entry, *lenp must contain the maximum path length that
1546 * fits into the buffer. On return, it contains the true length.
1547 * N.B. After this call fhp needs an fh_put
1548 */
1549__be32
1550nfsd_readlink(struct svc_rqst *rqstp, struct svc_fh *fhp, char *buf, int *lenp)
1551{
 
1552	struct inode	*inode;
1553	mm_segment_t	oldfs;
1554	__be32		err;
1555	int		host_err;
1556	struct path path;
1557
1558	err = fh_verify(rqstp, fhp, S_IFLNK, NFSD_MAY_NOP);
1559	if (err)
1560		goto out;
1561
1562	path.mnt = fhp->fh_export->ex_path.mnt;
1563	path.dentry = fhp->fh_dentry;
1564	inode = path.dentry->d_inode;
1565
1566	err = nfserr_inval;
1567	if (!inode->i_op->readlink)
1568		goto out;
1569
1570	touch_atime(&path);
1571	/* N.B. Why does this call need a get_fs()??
1572	 * Remove the set_fs and watch the fireworks:-) --okir
1573	 */
1574
1575	oldfs = get_fs(); set_fs(KERNEL_DS);
1576	host_err = inode->i_op->readlink(path.dentry, buf, *lenp);
1577	set_fs(oldfs);
1578
1579	if (host_err < 0)
1580		goto out_nfserr;
1581	*lenp = host_err;
1582	err = 0;
1583out:
1584	return err;
1585
1586out_nfserr:
1587	err = nfserrno(host_err);
1588	goto out;
1589}
1590
1591/*
1592 * Create a symlink and look up its inode
1593 * N.B. After this call _both_ fhp and resfhp need an fh_put
1594 */
1595__be32
1596nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp,
1597				char *fname, int flen,
1598				char *path,  int plen,
1599				struct svc_fh *resfhp,
1600				struct iattr *iap)
1601{
1602	struct dentry	*dentry, *dnew;
1603	__be32		err, cerr;
1604	int		host_err;
1605
1606	err = nfserr_noent;
1607	if (!flen || !plen)
1608		goto out;
1609	err = nfserr_exist;
1610	if (isdotent(fname, flen))
1611		goto out;
1612
1613	err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
1614	if (err)
1615		goto out;
1616	fh_lock(fhp);
1617	dentry = fhp->fh_dentry;
1618	dnew = lookup_one_len(fname, dentry, flen);
1619	host_err = PTR_ERR(dnew);
1620	if (IS_ERR(dnew))
1621		goto out_nfserr;
1622
1623	host_err = fh_want_write(fhp);
1624	if (host_err)
1625		goto out_nfserr;
1626
1627	if (unlikely(path[plen] != 0)) {
1628		char *path_alloced = kmalloc(plen+1, GFP_KERNEL);
1629		if (path_alloced == NULL)
1630			host_err = -ENOMEM;
1631		else {
1632			strncpy(path_alloced, path, plen);
1633			path_alloced[plen] = 0;
1634			host_err = vfs_symlink(dentry->d_inode, dnew, path_alloced);
1635			kfree(path_alloced);
1636		}
1637	} else
1638		host_err = vfs_symlink(dentry->d_inode, dnew, path);
1639	err = nfserrno(host_err);
1640	if (!err)
1641		err = nfserrno(commit_metadata(fhp));
1642	fh_unlock(fhp);
1643
1644	fh_drop_write(fhp);
1645
1646	cerr = fh_compose(resfhp, fhp->fh_export, dnew, fhp);
1647	dput(dnew);
1648	if (err==0) err = cerr;
1649out:
1650	return err;
1651
1652out_nfserr:
1653	err = nfserrno(host_err);
1654	goto out;
1655}
1656
1657/*
1658 * Create a hardlink
1659 * N.B. After this call _both_ ffhp and tfhp need an fh_put
1660 */
1661__be32
1662nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp,
1663				char *name, int len, struct svc_fh *tfhp)
1664{
1665	struct dentry	*ddir, *dnew, *dold;
1666	struct inode	*dirp;
1667	__be32		err;
1668	int		host_err;
1669
1670	err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_CREATE);
1671	if (err)
1672		goto out;
1673	err = fh_verify(rqstp, tfhp, 0, NFSD_MAY_NOP);
1674	if (err)
1675		goto out;
1676	err = nfserr_isdir;
1677	if (S_ISDIR(tfhp->fh_dentry->d_inode->i_mode))
1678		goto out;
1679	err = nfserr_perm;
1680	if (!len)
1681		goto out;
1682	err = nfserr_exist;
1683	if (isdotent(name, len))
1684		goto out;
1685
1686	fh_lock_nested(ffhp, I_MUTEX_PARENT);
1687	ddir = ffhp->fh_dentry;
1688	dirp = ddir->d_inode;
1689
1690	dnew = lookup_one_len(name, ddir, len);
1691	host_err = PTR_ERR(dnew);
1692	if (IS_ERR(dnew))
1693		goto out_nfserr;
1694
1695	dold = tfhp->fh_dentry;
1696
1697	host_err = fh_want_write(tfhp);
1698	if (host_err) {
1699		err = nfserrno(host_err);
1700		goto out_dput;
1701	}
1702	err = nfserr_noent;
1703	if (!dold->d_inode)
1704		goto out_drop_write;
1705	host_err = nfsd_break_lease(dold->d_inode);
1706	if (host_err) {
1707		err = nfserrno(host_err);
1708		goto out_drop_write;
1709	}
1710	host_err = vfs_link(dold, dirp, dnew);
1711	if (!host_err) {
1712		err = nfserrno(commit_metadata(ffhp));
1713		if (!err)
1714			err = nfserrno(commit_metadata(tfhp));
1715	} else {
1716		if (host_err == -EXDEV && rqstp->rq_vers == 2)
1717			err = nfserr_acces;
1718		else
1719			err = nfserrno(host_err);
1720	}
1721out_drop_write:
1722	fh_drop_write(tfhp);
1723out_dput:
1724	dput(dnew);
1725out_unlock:
1726	fh_unlock(ffhp);
1727out:
1728	return err;
1729
1730out_nfserr:
1731	err = nfserrno(host_err);
1732	goto out_unlock;
1733}
1734
1735/*
1736 * Rename a file
1737 * N.B. After this call _both_ ffhp and tfhp need an fh_put
1738 */
1739__be32
1740nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
1741			    struct svc_fh *tfhp, char *tname, int tlen)
1742{
1743	struct dentry	*fdentry, *tdentry, *odentry, *ndentry, *trap;
1744	struct inode	*fdir, *tdir;
1745	__be32		err;
1746	int		host_err;
1747
1748	err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_REMOVE);
1749	if (err)
1750		goto out;
1751	err = fh_verify(rqstp, tfhp, S_IFDIR, NFSD_MAY_CREATE);
1752	if (err)
1753		goto out;
1754
1755	fdentry = ffhp->fh_dentry;
1756	fdir = fdentry->d_inode;
1757
1758	tdentry = tfhp->fh_dentry;
1759	tdir = tdentry->d_inode;
1760
1761	err = (rqstp->rq_vers == 2) ? nfserr_acces : nfserr_xdev;
1762	if (ffhp->fh_export != tfhp->fh_export)
1763		goto out;
1764
1765	err = nfserr_perm;
1766	if (!flen || isdotent(fname, flen) || !tlen || isdotent(tname, tlen))
1767		goto out;
1768
1769	/* cannot use fh_lock as we need deadlock protective ordering
1770	 * so do it by hand */
1771	trap = lock_rename(tdentry, fdentry);
1772	ffhp->fh_locked = tfhp->fh_locked = 1;
1773	fill_pre_wcc(ffhp);
1774	fill_pre_wcc(tfhp);
1775
1776	odentry = lookup_one_len(fname, fdentry, flen);
1777	host_err = PTR_ERR(odentry);
1778	if (IS_ERR(odentry))
1779		goto out_nfserr;
1780
1781	host_err = -ENOENT;
1782	if (!odentry->d_inode)
1783		goto out_dput_old;
1784	host_err = -EINVAL;
1785	if (odentry == trap)
1786		goto out_dput_old;
1787
1788	ndentry = lookup_one_len(tname, tdentry, tlen);
1789	host_err = PTR_ERR(ndentry);
1790	if (IS_ERR(ndentry))
1791		goto out_dput_old;
1792	host_err = -ENOTEMPTY;
1793	if (ndentry == trap)
1794		goto out_dput_new;
1795
1796	host_err = -EXDEV;
1797	if (ffhp->fh_export->ex_path.mnt != tfhp->fh_export->ex_path.mnt)
1798		goto out_dput_new;
1799	host_err = fh_want_write(ffhp);
1800	if (host_err)
1801		goto out_dput_new;
1802
1803	host_err = nfsd_break_lease(odentry->d_inode);
1804	if (host_err)
1805		goto out_drop_write;
1806	if (ndentry->d_inode) {
1807		host_err = nfsd_break_lease(ndentry->d_inode);
1808		if (host_err)
1809			goto out_drop_write;
1810	}
1811	host_err = vfs_rename(fdir, odentry, tdir, ndentry);
1812	if (!host_err) {
1813		host_err = commit_metadata(tfhp);
1814		if (!host_err)
1815			host_err = commit_metadata(ffhp);
1816	}
1817out_drop_write:
1818	fh_drop_write(ffhp);
1819 out_dput_new:
1820	dput(ndentry);
1821 out_dput_old:
1822	dput(odentry);
1823 out_nfserr:
1824	err = nfserrno(host_err);
1825
1826	/* we cannot reply on fh_unlock on the two filehandles,
1827	 * as that would do the wrong thing if the two directories
1828	 * were the same, so again we do it by hand
1829	 */
1830	fill_post_wcc(ffhp);
1831	fill_post_wcc(tfhp);
1832	unlock_rename(tdentry, fdentry);
1833	ffhp->fh_locked = tfhp->fh_locked = 0;
1834
1835out:
1836	return err;
1837}
1838
1839/*
1840 * Unlink a file or directory
1841 * N.B. After this call fhp needs an fh_put
1842 */
1843__be32
1844nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
1845				char *fname, int flen)
1846{
1847	struct dentry	*dentry, *rdentry;
1848	struct inode	*dirp;
1849	__be32		err;
1850	int		host_err;
1851
1852	err = nfserr_acces;
1853	if (!flen || isdotent(fname, flen))
1854		goto out;
1855	err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_REMOVE);
1856	if (err)
1857		goto out;
1858
1859	fh_lock_nested(fhp, I_MUTEX_PARENT);
1860	dentry = fhp->fh_dentry;
1861	dirp = dentry->d_inode;
1862
1863	rdentry = lookup_one_len(fname, dentry, flen);
1864	host_err = PTR_ERR(rdentry);
1865	if (IS_ERR(rdentry))
1866		goto out_nfserr;
1867
1868	if (!rdentry->d_inode) {
1869		dput(rdentry);
1870		err = nfserr_noent;
1871		goto out;
1872	}
1873
1874	if (!type)
1875		type = rdentry->d_inode->i_mode & S_IFMT;
1876
1877	host_err = fh_want_write(fhp);
1878	if (host_err)
1879		goto out_put;
1880
1881	host_err = nfsd_break_lease(rdentry->d_inode);
1882	if (host_err)
1883		goto out_drop_write;
1884	if (type != S_IFDIR)
1885		host_err = vfs_unlink(dirp, rdentry);
1886	else
1887		host_err = vfs_rmdir(dirp, rdentry);
1888	if (!host_err)
1889		host_err = commit_metadata(fhp);
1890out_drop_write:
1891	fh_drop_write(fhp);
1892out_put:
1893	dput(rdentry);
1894
1895out_nfserr:
1896	err = nfserrno(host_err);
1897out:
1898	return err;
1899}
1900
1901/*
1902 * We do this buffering because we must not call back into the file
1903 * system's ->lookup() method from the filldir callback. That may well
1904 * deadlock a number of file systems.
1905 *
1906 * This is based heavily on the implementation of same in XFS.
1907 */
1908struct buffered_dirent {
1909	u64		ino;
1910	loff_t		offset;
1911	int		namlen;
1912	unsigned int	d_type;
1913	char		name[];
1914};
1915
1916struct readdir_data {
1917	char		*dirent;
1918	size_t		used;
1919	int		full;
1920};
1921
1922static int nfsd_buffered_filldir(void *__buf, const char *name, int namlen,
1923				 loff_t offset, u64 ino, unsigned int d_type)
1924{
1925	struct readdir_data *buf = __buf;
1926	struct buffered_dirent *de = (void *)(buf->dirent + buf->used);
1927	unsigned int reclen;
1928
1929	reclen = ALIGN(sizeof(struct buffered_dirent) + namlen, sizeof(u64));
1930	if (buf->used + reclen > PAGE_SIZE) {
1931		buf->full = 1;
1932		return -EINVAL;
1933	}
1934
1935	de->namlen = namlen;
1936	de->offset = offset;
1937	de->ino = ino;
1938	de->d_type = d_type;
1939	memcpy(de->name, name, namlen);
1940	buf->used += reclen;
1941
1942	return 0;
1943}
1944
1945static __be32 nfsd_buffered_readdir(struct file *file, filldir_t func,
1946				    struct readdir_cd *cdp, loff_t *offsetp)
1947{
1948	struct readdir_data buf;
1949	struct buffered_dirent *de;
1950	int host_err;
1951	int size;
1952	loff_t offset;
1953
1954	buf.dirent = (void *)__get_free_page(GFP_KERNEL);
1955	if (!buf.dirent)
1956		return nfserrno(-ENOMEM);
1957
1958	offset = *offsetp;
1959
1960	while (1) {
1961		struct inode *dir_inode = file->f_path.dentry->d_inode;
1962		unsigned int reclen;
1963
1964		cdp->err = nfserr_eof; /* will be cleared on successful read */
1965		buf.used = 0;
1966		buf.full = 0;
1967
1968		host_err = vfs_readdir(file, nfsd_buffered_filldir, &buf);
1969		if (buf.full)
1970			host_err = 0;
1971
1972		if (host_err < 0)
1973			break;
1974
1975		size = buf.used;
1976
1977		if (!size)
1978			break;
1979
1980		/*
1981		 * Various filldir functions may end up calling back into
1982		 * lookup_one_len() and the file system's ->lookup() method.
1983		 * These expect i_mutex to be held, as it would within readdir.
1984		 */
1985		host_err = mutex_lock_killable(&dir_inode->i_mutex);
1986		if (host_err)
1987			break;
1988
1989		de = (struct buffered_dirent *)buf.dirent;
1990		while (size > 0) {
1991			offset = de->offset;
1992
1993			if (func(cdp, de->name, de->namlen, de->offset,
1994				 de->ino, de->d_type))
1995				break;
1996
1997			if (cdp->err != nfs_ok)
1998				break;
1999
2000			reclen = ALIGN(sizeof(*de) + de->namlen,
2001				       sizeof(u64));
2002			size -= reclen;
2003			de = (struct buffered_dirent *)((char *)de + reclen);
2004		}
2005		mutex_unlock(&dir_inode->i_mutex);
2006		if (size > 0) /* We bailed out early */
2007			break;
2008
2009		offset = vfs_llseek(file, 0, SEEK_CUR);
2010	}
2011
2012	free_page((unsigned long)(buf.dirent));
2013
2014	if (host_err)
2015		return nfserrno(host_err);
2016
2017	*offsetp = offset;
2018	return cdp->err;
2019}
2020
2021/*
2022 * Read entries from a directory.
2023 * The  NFSv3/4 verifier we ignore for now.
2024 */
2025__be32
2026nfsd_readdir(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t *offsetp, 
2027	     struct readdir_cd *cdp, filldir_t func)
2028{
2029	__be32		err;
2030	struct file	*file;
2031	loff_t		offset = *offsetp;
2032	int             may_flags = NFSD_MAY_READ;
2033
2034	/* NFSv2 only supports 32 bit cookies */
2035	if (rqstp->rq_vers > 2)
2036		may_flags |= NFSD_MAY_64BIT_COOKIE;
2037
2038	err = nfsd_open(rqstp, fhp, S_IFDIR, may_flags, &file);
2039	if (err)
2040		goto out;
2041
2042	offset = vfs_llseek(file, offset, SEEK_SET);
2043	if (offset < 0) {
2044		err = nfserrno((int)offset);
2045		goto out_close;
2046	}
2047
2048	err = nfsd_buffered_readdir(file, func, cdp, offsetp);
2049
2050	if (err == nfserr_eof || err == nfserr_toosmall)
2051		err = nfs_ok; /* can still be found in ->err */
2052out_close:
2053	nfsd_close(file);
2054out:
2055	return err;
2056}
2057
2058/*
2059 * Get file system stats
2060 * N.B. After this call fhp needs an fh_put
2061 */
2062__be32
2063nfsd_statfs(struct svc_rqst *rqstp, struct svc_fh *fhp, struct kstatfs *stat, int access)
2064{
2065	__be32 err;
2066
2067	err = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP | access);
2068	if (!err) {
2069		struct path path = {
2070			.mnt	= fhp->fh_export->ex_path.mnt,
2071			.dentry	= fhp->fh_dentry,
2072		};
2073		if (vfs_statfs(&path, stat))
2074			err = nfserr_io;
2075	}
2076	return err;
2077}
2078
2079static int exp_rdonly(struct svc_rqst *rqstp, struct svc_export *exp)
2080{
2081	return nfsexp_flags(rqstp, exp) & NFSEXP_READONLY;
2082}
2083
2084/*
2085 * Check for a user's access permissions to this inode.
2086 */
2087__be32
2088nfsd_permission(struct svc_rqst *rqstp, struct svc_export *exp,
2089					struct dentry *dentry, int acc)
2090{
2091	struct inode	*inode = dentry->d_inode;
2092	int		err;
2093
2094	if ((acc & NFSD_MAY_MASK) == NFSD_MAY_NOP)
2095		return 0;
2096#if 0
2097	dprintk("nfsd: permission 0x%x%s%s%s%s%s%s%s mode 0%o%s%s%s\n",
2098		acc,
2099		(acc & NFSD_MAY_READ)?	" read"  : "",
2100		(acc & NFSD_MAY_WRITE)?	" write" : "",
2101		(acc & NFSD_MAY_EXEC)?	" exec"  : "",
2102		(acc & NFSD_MAY_SATTR)?	" sattr" : "",
2103		(acc & NFSD_MAY_TRUNC)?	" trunc" : "",
2104		(acc & NFSD_MAY_LOCK)?	" lock"  : "",
2105		(acc & NFSD_MAY_OWNER_OVERRIDE)? " owneroverride" : "",
2106		inode->i_mode,
2107		IS_IMMUTABLE(inode)?	" immut" : "",
2108		IS_APPEND(inode)?	" append" : "",
2109		__mnt_is_readonly(exp->ex_path.mnt)?	" ro" : "");
2110	dprintk("      owner %d/%d user %d/%d\n",
2111		inode->i_uid, inode->i_gid, current_fsuid(), current_fsgid());
2112#endif
2113
2114	/* Normally we reject any write/sattr etc access on a read-only file
2115	 * system.  But if it is IRIX doing check on write-access for a 
2116	 * device special file, we ignore rofs.
2117	 */
2118	if (!(acc & NFSD_MAY_LOCAL_ACCESS))
2119		if (acc & (NFSD_MAY_WRITE | NFSD_MAY_SATTR | NFSD_MAY_TRUNC)) {
2120			if (exp_rdonly(rqstp, exp) ||
2121			    __mnt_is_readonly(exp->ex_path.mnt))
2122				return nfserr_rofs;
2123			if (/* (acc & NFSD_MAY_WRITE) && */ IS_IMMUTABLE(inode))
2124				return nfserr_perm;
2125		}
2126	if ((acc & NFSD_MAY_TRUNC) && IS_APPEND(inode))
2127		return nfserr_perm;
2128
2129	if (acc & NFSD_MAY_LOCK) {
2130		/* If we cannot rely on authentication in NLM requests,
2131		 * just allow locks, otherwise require read permission, or
2132		 * ownership
2133		 */
2134		if (exp->ex_flags & NFSEXP_NOAUTHNLM)
2135			return 0;
2136		else
2137			acc = NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE;
2138	}
2139	/*
2140	 * The file owner always gets access permission for accesses that
2141	 * would normally be checked at open time. This is to make
2142	 * file access work even when the client has done a fchmod(fd, 0).
2143	 *
2144	 * However, `cp foo bar' should fail nevertheless when bar is
2145	 * readonly. A sensible way to do this might be to reject all
2146	 * attempts to truncate a read-only file, because a creat() call
2147	 * always implies file truncation.
2148	 * ... but this isn't really fair.  A process may reasonably call
2149	 * ftruncate on an open file descriptor on a file with perm 000.
2150	 * We must trust the client to do permission checking - using "ACCESS"
2151	 * with NFSv3.
2152	 */
2153	if ((acc & NFSD_MAY_OWNER_OVERRIDE) &&
2154	    inode->i_uid == current_fsuid())
2155		return 0;
2156
2157	/* This assumes  NFSD_MAY_{READ,WRITE,EXEC} == MAY_{READ,WRITE,EXEC} */
2158	err = inode_permission(inode, acc & (MAY_READ|MAY_WRITE|MAY_EXEC));
2159
2160	/* Allow read access to binaries even when mode 111 */
2161	if (err == -EACCES && S_ISREG(inode->i_mode) &&
2162	     (acc == (NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE) ||
2163	      acc == (NFSD_MAY_READ | NFSD_MAY_READ_IF_EXEC)))
2164		err = inode_permission(inode, MAY_EXEC);
2165
2166	return err? nfserrno(err) : 0;
2167}
2168
2169void
2170nfsd_racache_shutdown(void)
2171{
2172	struct raparms *raparm, *last_raparm;
2173	unsigned int i;
2174
2175	dprintk("nfsd: freeing readahead buffers.\n");
2176
2177	for (i = 0; i < RAPARM_HASH_SIZE; i++) {
2178		raparm = raparm_hash[i].pb_head;
2179		while(raparm) {
2180			last_raparm = raparm;
2181			raparm = raparm->p_next;
2182			kfree(last_raparm);
2183		}
2184		raparm_hash[i].pb_head = NULL;
2185	}
2186}
2187/*
2188 * Initialize readahead param cache
2189 */
2190int
2191nfsd_racache_init(int cache_size)
2192{
2193	int	i;
2194	int	j = 0;
2195	int	nperbucket;
2196	struct raparms **raparm = NULL;
2197
2198
2199	if (raparm_hash[0].pb_head)
2200		return 0;
2201	nperbucket = DIV_ROUND_UP(cache_size, RAPARM_HASH_SIZE);
2202	if (nperbucket < 2)
2203		nperbucket = 2;
2204	cache_size = nperbucket * RAPARM_HASH_SIZE;
2205
2206	dprintk("nfsd: allocating %d readahead buffers.\n", cache_size);
2207
2208	for (i = 0; i < RAPARM_HASH_SIZE; i++) {
2209		spin_lock_init(&raparm_hash[i].pb_lock);
2210
2211		raparm = &raparm_hash[i].pb_head;
2212		for (j = 0; j < nperbucket; j++) {
2213			*raparm = kzalloc(sizeof(struct raparms), GFP_KERNEL);
2214			if (!*raparm)
2215				goto out_nomem;
2216			raparm = &(*raparm)->p_next;
2217		}
2218		*raparm = NULL;
2219	}
2220
2221	nfsdstats.ra_size = cache_size;
2222	return 0;
2223
2224out_nomem:
2225	dprintk("nfsd: kmalloc failed, freeing readahead buffers\n");
2226	nfsd_racache_shutdown();
2227	return -ENOMEM;
2228}
2229
2230#if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
2231struct posix_acl *
2232nfsd_get_posix_acl(struct svc_fh *fhp, int type)
2233{
2234	struct inode *inode = fhp->fh_dentry->d_inode;
2235	char *name;
2236	void *value = NULL;
2237	ssize_t size;
2238	struct posix_acl *acl;
2239
2240	if (!IS_POSIXACL(inode))
2241		return ERR_PTR(-EOPNOTSUPP);
2242
2243	switch (type) {
2244	case ACL_TYPE_ACCESS:
2245		name = POSIX_ACL_XATTR_ACCESS;
2246		break;
2247	case ACL_TYPE_DEFAULT:
2248		name = POSIX_ACL_XATTR_DEFAULT;
2249		break;
2250	default:
2251		return ERR_PTR(-EOPNOTSUPP);
2252	}
2253
2254	size = nfsd_getxattr(fhp->fh_dentry, name, &value);
2255	if (size < 0)
2256		return ERR_PTR(size);
2257
2258	acl = posix_acl_from_xattr(value, size);
2259	kfree(value);
2260	return acl;
2261}
2262
2263int
2264nfsd_set_posix_acl(struct svc_fh *fhp, int type, struct posix_acl *acl)
2265{
2266	struct inode *inode = fhp->fh_dentry->d_inode;
2267	char *name;
2268	void *value = NULL;
2269	size_t size;
2270	int error;
2271
2272	if (!IS_POSIXACL(inode) ||
2273	    !inode->i_op->setxattr || !inode->i_op->removexattr)
2274		return -EOPNOTSUPP;
2275	switch(type) {
2276		case ACL_TYPE_ACCESS:
2277			name = POSIX_ACL_XATTR_ACCESS;
2278			break;
2279		case ACL_TYPE_DEFAULT:
2280			name = POSIX_ACL_XATTR_DEFAULT;
2281			break;
2282		default:
2283			return -EOPNOTSUPP;
2284	}
2285
2286	if (acl && acl->a_count) {
2287		size = posix_acl_xattr_size(acl->a_count);
2288		value = kmalloc(size, GFP_KERNEL);
2289		if (!value)
2290			return -ENOMEM;
2291		error = posix_acl_to_xattr(acl, value, size);
2292		if (error < 0)
2293			goto getout;
2294		size = error;
2295	} else
2296		size = 0;
2297
2298	error = fh_want_write(fhp);
2299	if (error)
2300		goto getout;
2301	if (size)
2302		error = vfs_setxattr(fhp->fh_dentry, name, value, size, 0);
2303	else {
2304		if (!S_ISDIR(inode->i_mode) && type == ACL_TYPE_DEFAULT)
2305			error = 0;
2306		else {
2307			error = vfs_removexattr(fhp->fh_dentry, name);
2308			if (error == -ENODATA)
2309				error = 0;
2310		}
2311	}
2312	fh_drop_write(fhp);
2313
2314getout:
2315	kfree(value);
2316	return error;
2317}
2318#endif  /* defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) */