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/falloc.h>
  20#include <linux/fcntl.h>
  21#include <linux/namei.h>
  22#include <linux/delay.h>
  23#include <linux/fsnotify.h>
  24#include <linux/posix_acl_xattr.h>
  25#include <linux/xattr.h>
  26#include <linux/jhash.h>
  27#include <linux/ima.h>
  28#include <linux/slab.h>
  29#include <linux/uaccess.h>
  30#include <linux/exportfs.h>
  31#include <linux/writeback.h>
  32#include <linux/security.h>
  33
  34#ifdef CONFIG_NFSD_V3
  35#include "xdr3.h"
  36#endif /* CONFIG_NFSD_V3 */
  37
  38#ifdef CONFIG_NFSD_V4
  39#include "../internal.h"
  40#include "acl.h"
  41#include "idmap.h"
  42#endif /* CONFIG_NFSD_V4 */
  43
  44#include "nfsd.h"
  45#include "vfs.h"
 
  46#include "trace.h"
  47
  48#define NFSDDBG_FACILITY		NFSDDBG_FILEOP
  49
  50
  51/*
  52 * This is a cache of readahead params that help us choose the proper
  53 * readahead strategy. Initially, we set all readahead parameters to 0
  54 * and let the VFS handle things.
  55 * If you increase the number of cached files very much, you'll need to
  56 * add a hash table here.
  57 */
  58struct raparms {
  59	struct raparms		*p_next;
  60	unsigned int		p_count;
  61	ino_t			p_ino;
  62	dev_t			p_dev;
  63	int			p_set;
  64	struct file_ra_state	p_ra;
  65	unsigned int		p_hindex;
  66};
  67
  68struct raparm_hbucket {
  69	struct raparms		*pb_head;
  70	spinlock_t		pb_lock;
  71} ____cacheline_aligned_in_smp;
  72
  73#define RAPARM_HASH_BITS	4
  74#define RAPARM_HASH_SIZE	(1<<RAPARM_HASH_BITS)
  75#define RAPARM_HASH_MASK	(RAPARM_HASH_SIZE-1)
  76static struct raparm_hbucket	raparm_hash[RAPARM_HASH_SIZE];
  77
  78/* 
  79 * Called from nfsd_lookup and encode_dirent. Check if we have crossed 
  80 * a mount point.
  81 * Returns -EAGAIN or -ETIMEDOUT leaving *dpp and *expp unchanged,
  82 *  or nfs_ok having possibly changed *dpp and *expp
  83 */
  84int
  85nfsd_cross_mnt(struct svc_rqst *rqstp, struct dentry **dpp, 
  86		        struct svc_export **expp)
  87{
  88	struct svc_export *exp = *expp, *exp2 = NULL;
  89	struct dentry *dentry = *dpp;
  90	struct path path = {.mnt = mntget(exp->ex_path.mnt),
  91			    .dentry = dget(dentry)};
  92	int err = 0;
  93
  94	err = follow_down(&path);
  95	if (err < 0)
  96		goto out;
 
 
 
 
 
 
  97
  98	exp2 = rqst_exp_get_by_name(rqstp, &path);
  99	if (IS_ERR(exp2)) {
 100		err = PTR_ERR(exp2);
 101		/*
 102		 * We normally allow NFS clients to continue
 103		 * "underneath" a mountpoint that is not exported.
 104		 * The exception is V4ROOT, where no traversal is ever
 105		 * allowed without an explicit export of the new
 106		 * directory.
 107		 */
 108		if (err == -ENOENT && !(exp->ex_flags & NFSEXP_V4ROOT))
 109			err = 0;
 110		path_put(&path);
 111		goto out;
 112	}
 113	if (nfsd_v4client(rqstp) ||
 114		(exp->ex_flags & NFSEXP_CROSSMOUNT) || EX_NOHIDE(exp2)) {
 115		/* successfully crossed mount point */
 116		/*
 117		 * This is subtle: path.dentry is *not* on path.mnt
 118		 * at this point.  The only reason we are safe is that
 119		 * original mnt is pinned down by exp, so we should
 120		 * put path *before* putting exp
 121		 */
 122		*dpp = path.dentry;
 123		path.dentry = dentry;
 124		*expp = exp2;
 125		exp2 = exp;
 126	}
 127	path_put(&path);
 128	exp_put(exp2);
 129out:
 130	return err;
 131}
 132
 133static void follow_to_parent(struct path *path)
 134{
 135	struct dentry *dp;
 136
 137	while (path->dentry == path->mnt->mnt_root && follow_up(path))
 138		;
 139	dp = dget_parent(path->dentry);
 140	dput(path->dentry);
 141	path->dentry = dp;
 142}
 143
 144static int nfsd_lookup_parent(struct svc_rqst *rqstp, struct dentry *dparent, struct svc_export **exp, struct dentry **dentryp)
 145{
 146	struct svc_export *exp2;
 147	struct path path = {.mnt = mntget((*exp)->ex_path.mnt),
 148			    .dentry = dget(dparent)};
 149
 150	follow_to_parent(&path);
 151
 152	exp2 = rqst_exp_parent(rqstp, &path);
 153	if (PTR_ERR(exp2) == -ENOENT) {
 154		*dentryp = dget(dparent);
 155	} else if (IS_ERR(exp2)) {
 156		path_put(&path);
 157		return PTR_ERR(exp2);
 158	} else {
 159		*dentryp = dget(path.dentry);
 160		exp_put(*exp);
 161		*exp = exp2;
 162	}
 163	path_put(&path);
 164	return 0;
 165}
 166
 167/*
 168 * For nfsd purposes, we treat V4ROOT exports as though there was an
 169 * export at *every* directory.
 
 
 
 
 170 */
 171int nfsd_mountpoint(struct dentry *dentry, struct svc_export *exp)
 172{
 173	if (d_mountpoint(dentry))
 
 
 174		return 1;
 175	if (nfsd4_is_junction(dentry))
 176		return 1;
 177	if (!(exp->ex_flags & NFSEXP_V4ROOT))
 178		return 0;
 179	return d_inode(dentry) != NULL;
 
 
 
 
 180}
 181
 182__be32
 183nfsd_lookup_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp,
 184		   const char *name, unsigned int len,
 185		   struct svc_export **exp_ret, struct dentry **dentry_ret)
 186{
 187	struct svc_export	*exp;
 188	struct dentry		*dparent;
 189	struct dentry		*dentry;
 190	int			host_err;
 191
 192	dprintk("nfsd: nfsd_lookup(fh %s, %.*s)\n", SVCFH_fmt(fhp), len,name);
 193
 194	dparent = fhp->fh_dentry;
 195	exp = exp_get(fhp->fh_export);
 196
 197	/* Lookup the name, but don't follow links */
 198	if (isdotent(name, len)) {
 199		if (len==1)
 200			dentry = dget(dparent);
 201		else if (dparent != exp->ex_path.dentry)
 202			dentry = dget_parent(dparent);
 203		else if (!EX_NOHIDE(exp) && !nfsd_v4client(rqstp))
 204			dentry = dget(dparent); /* .. == . just like at / */
 205		else {
 206			/* checking mountpoint crossing is very different when stepping up */
 207			host_err = nfsd_lookup_parent(rqstp, dparent, &exp, &dentry);
 208			if (host_err)
 209				goto out_nfserr;
 210		}
 211	} else {
 212		/*
 213		 * In the nfsd4_open() case, this may be held across
 214		 * subsequent open and delegation acquisition which may
 215		 * need to take the child's i_mutex:
 216		 */
 217		fh_lock_nested(fhp, I_MUTEX_PARENT);
 218		dentry = lookup_one_len(name, dparent, len);
 219		host_err = PTR_ERR(dentry);
 220		if (IS_ERR(dentry))
 221			goto out_nfserr;
 222		if (nfsd_mountpoint(dentry, exp)) {
 223			/*
 224			 * We don't need the i_mutex after all.  It's
 225			 * still possible we could open this (regular
 226			 * files can be mountpoints too), but the
 227			 * i_mutex is just there to prevent renames of
 228			 * something that we might be about to delegate,
 229			 * and a mountpoint won't be renamed:
 230			 */
 231			fh_unlock(fhp);
 232			if ((host_err = nfsd_cross_mnt(rqstp, &dentry, &exp))) {
 233				dput(dentry);
 234				goto out_nfserr;
 235			}
 236		}
 237	}
 238	*dentry_ret = dentry;
 239	*exp_ret = exp;
 240	return 0;
 241
 242out_nfserr:
 243	exp_put(exp);
 244	return nfserrno(host_err);
 245}
 246
 247/*
 248 * Look up one component of a pathname.
 249 * N.B. After this call _both_ fhp and resfh need an fh_put
 250 *
 251 * If the lookup would cross a mountpoint, and the mounted filesystem
 252 * is exported to the client with NFSEXP_NOHIDE, then the lookup is
 253 * accepted as it stands and the mounted directory is
 254 * returned. Otherwise the covered directory is returned.
 255 * NOTE: this mountpoint crossing is not supported properly by all
 256 *   clients and is explicitly disallowed for NFSv3
 257 *      NeilBrown <neilb@cse.unsw.edu.au>
 258 */
 259__be32
 260nfsd_lookup(struct svc_rqst *rqstp, struct svc_fh *fhp, const char *name,
 261				unsigned int len, struct svc_fh *resfh)
 262{
 263	struct svc_export	*exp;
 264	struct dentry		*dentry;
 265	__be32 err;
 266
 267	err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC);
 268	if (err)
 269		return err;
 270	err = nfsd_lookup_dentry(rqstp, fhp, name, len, &exp, &dentry);
 271	if (err)
 272		return err;
 273	err = check_nfsd_access(exp, rqstp);
 274	if (err)
 275		goto out;
 276	/*
 277	 * Note: we compose the file handle now, but as the
 278	 * dentry may be negative, it may need to be updated.
 279	 */
 280	err = fh_compose(resfh, exp, dentry, fhp);
 281	if (!err && d_really_is_negative(dentry))
 282		err = nfserr_noent;
 283out:
 284	dput(dentry);
 285	exp_put(exp);
 286	return err;
 287}
 288
 289/*
 290 * Commit metadata changes to stable storage.
 291 */
 292static int
 293commit_metadata(struct svc_fh *fhp)
 294{
 295	struct inode *inode = d_inode(fhp->fh_dentry);
 296	const struct export_operations *export_ops = inode->i_sb->s_export_op;
 297
 298	if (!EX_ISSYNC(fhp->fh_export))
 299		return 0;
 300
 301	if (export_ops->commit_metadata)
 302		return export_ops->commit_metadata(inode);
 303	return sync_inode_metadata(inode, 1);
 304}
 305
 
 
 
 
 
 
 
 
 
 
 306/*
 307 * Go over the attributes and take care of the small differences between
 308 * NFS semantics and what Linux expects.
 309 */
 310static void
 311nfsd_sanitize_attrs(struct inode *inode, struct iattr *iap)
 312{
 313	/* sanitize the mode change */
 314	if (iap->ia_valid & ATTR_MODE) {
 315		iap->ia_mode &= S_IALLUGO;
 316		iap->ia_mode |= (inode->i_mode & ~S_IALLUGO);
 317	}
 318
 319	/* Revoke setuid/setgid on chown */
 320	if (!S_ISDIR(inode->i_mode) &&
 321	    ((iap->ia_valid & ATTR_UID) || (iap->ia_valid & ATTR_GID))) {
 322		iap->ia_valid |= ATTR_KILL_PRIV;
 323		if (iap->ia_valid & ATTR_MODE) {
 324			/* we're setting mode too, just clear the s*id bits */
 325			iap->ia_mode &= ~S_ISUID;
 326			if (iap->ia_mode & S_IXGRP)
 327				iap->ia_mode &= ~S_ISGID;
 328		} else {
 329			/* set ATTR_KILL_* bits and let VFS handle it */
 330			iap->ia_valid |= (ATTR_KILL_SUID | ATTR_KILL_SGID);
 331		}
 332	}
 333}
 334
 335static __be32
 336nfsd_get_write_access(struct svc_rqst *rqstp, struct svc_fh *fhp,
 337		struct iattr *iap)
 338{
 339	struct inode *inode = d_inode(fhp->fh_dentry);
 340	int host_err;
 341
 342	if (iap->ia_size < inode->i_size) {
 343		__be32 err;
 344
 345		err = nfsd_permission(rqstp, fhp->fh_export, fhp->fh_dentry,
 346				NFSD_MAY_TRUNC | NFSD_MAY_OWNER_OVERRIDE);
 347		if (err)
 348			return err;
 349	}
 350
 351	host_err = get_write_access(inode);
 352	if (host_err)
 353		goto out_nfserrno;
 354
 355	host_err = locks_verify_truncate(inode, NULL, iap->ia_size);
 356	if (host_err)
 357		goto out_put_write_access;
 358	return 0;
 359
 360out_put_write_access:
 361	put_write_access(inode);
 362out_nfserrno:
 363	return nfserrno(host_err);
 364}
 365
 366/*
 367 * Set various file attributes.  After this call fhp needs an fh_put.
 368 */
 369__be32
 370nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
 371	     int check_guard, time_t guardtime)
 372{
 373	struct dentry	*dentry;
 374	struct inode	*inode;
 375	int		accmode = NFSD_MAY_SATTR;
 376	umode_t		ftype = 0;
 377	__be32		err;
 378	int		host_err;
 379	bool		get_write_count;
 380	bool		size_change = (iap->ia_valid & ATTR_SIZE);
 381
 382	if (iap->ia_valid & (ATTR_ATIME | ATTR_MTIME | ATTR_SIZE))
 383		accmode |= NFSD_MAY_WRITE|NFSD_MAY_OWNER_OVERRIDE;
 384	if (iap->ia_valid & ATTR_SIZE)
 385		ftype = S_IFREG;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 386
 387	/* Callers that do fh_verify should do the fh_want_write: */
 388	get_write_count = !fhp->fh_dentry;
 389
 390	/* Get inode */
 391	err = fh_verify(rqstp, fhp, ftype, accmode);
 392	if (err)
 393		return err;
 394	if (get_write_count) {
 395		host_err = fh_want_write(fhp);
 396		if (host_err)
 397			goto out;
 398	}
 399
 400	dentry = fhp->fh_dentry;
 401	inode = d_inode(dentry);
 402
 403	/* Ignore any mode updates on symlinks */
 404	if (S_ISLNK(inode->i_mode))
 405		iap->ia_valid &= ~ATTR_MODE;
 406
 407	if (!iap->ia_valid)
 408		return 0;
 409
 410	nfsd_sanitize_attrs(inode, iap);
 411
 412	if (check_guard && guardtime != inode->i_ctime.tv_sec)
 413		return nfserr_notsync;
 414
 415	/*
 416	 * The size case is special, it changes the file in addition to the
 417	 * attributes, and file systems don't expect it to be mixed with
 418	 * "random" attribute changes.  We thus split out the size change
 419	 * into a separate call to ->setattr, and do the rest as a separate
 420	 * setattr call.
 421	 */
 422	if (size_change) {
 423		err = nfsd_get_write_access(rqstp, fhp, iap);
 424		if (err)
 425			return err;
 426	}
 427
 428	fh_lock(fhp);
 429	if (size_change) {
 430		/*
 431		 * RFC5661, Section 18.30.4:
 432		 *   Changing the size of a file with SETATTR indirectly
 433		 *   changes the time_modify and change attributes.
 434		 *
 435		 * (and similar for the older RFCs)
 436		 */
 437		struct iattr size_attr = {
 438			.ia_valid	= ATTR_SIZE | ATTR_CTIME | ATTR_MTIME,
 439			.ia_size	= iap->ia_size,
 440		};
 441
 442		host_err = notify_change(dentry, &size_attr, NULL);
 443		if (host_err)
 444			goto out_unlock;
 445		iap->ia_valid &= ~ATTR_SIZE;
 446
 447		/*
 448		 * Avoid the additional setattr call below if the only other
 449		 * attribute that the client sends is the mtime, as we update
 450		 * it as part of the size change above.
 451		 */
 452		if ((iap->ia_valid & ~ATTR_MTIME) == 0)
 453			goto out_unlock;
 454	}
 455
 456	iap->ia_valid |= ATTR_CTIME;
 457	host_err = notify_change(dentry, iap, NULL);
 458
 459out_unlock:
 460	fh_unlock(fhp);
 461	if (size_change)
 462		put_write_access(inode);
 463out:
 464	if (!host_err)
 465		host_err = commit_metadata(fhp);
 466	return nfserrno(host_err);
 467}
 468
 469#if defined(CONFIG_NFSD_V4)
 470/*
 471 * NFS junction information is stored in an extended attribute.
 472 */
 473#define NFSD_JUNCTION_XATTR_NAME	XATTR_TRUSTED_PREFIX "junction.nfs"
 474
 475/**
 476 * nfsd4_is_junction - Test if an object could be an NFS junction
 477 *
 478 * @dentry: object to test
 479 *
 480 * Returns 1 if "dentry" appears to contain NFS junction information.
 481 * Otherwise 0 is returned.
 482 */
 483int nfsd4_is_junction(struct dentry *dentry)
 484{
 485	struct inode *inode = d_inode(dentry);
 486
 487	if (inode == NULL)
 488		return 0;
 489	if (inode->i_mode & S_IXUGO)
 490		return 0;
 491	if (!(inode->i_mode & S_ISVTX))
 492		return 0;
 493	if (vfs_getxattr(dentry, NFSD_JUNCTION_XATTR_NAME, NULL, 0) <= 0)
 494		return 0;
 495	return 1;
 496}
 497#ifdef CONFIG_NFSD_V4_SECURITY_LABEL
 498__be32 nfsd4_set_nfs4_label(struct svc_rqst *rqstp, struct svc_fh *fhp,
 499		struct xdr_netobj *label)
 500{
 501	__be32 error;
 502	int host_error;
 503	struct dentry *dentry;
 504
 505	error = fh_verify(rqstp, fhp, 0 /* S_IFREG */, NFSD_MAY_SATTR);
 506	if (error)
 507		return error;
 508
 509	dentry = fhp->fh_dentry;
 510
 511	inode_lock(d_inode(dentry));
 512	host_error = security_inode_setsecctx(dentry, label->data, label->len);
 513	inode_unlock(d_inode(dentry));
 514	return nfserrno(host_error);
 515}
 516#else
 517__be32 nfsd4_set_nfs4_label(struct svc_rqst *rqstp, struct svc_fh *fhp,
 518		struct xdr_netobj *label)
 519{
 520	return nfserr_notsupp;
 521}
 522#endif
 523
 524__be32 nfsd4_clone_file_range(struct file *src, u64 src_pos, struct file *dst,
 525		u64 dst_pos, u64 count)
 526{
 527	return nfserrno(do_clone_file_range(src, src_pos, dst, dst_pos, count));
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 528}
 529
 530ssize_t nfsd_copy_file_range(struct file *src, u64 src_pos, struct file *dst,
 531			     u64 dst_pos, u64 count)
 532{
 533
 534	/*
 535	 * Limit copy to 4MB to prevent indefinitely blocking an nfsd
 536	 * thread and client rpc slot.  The choice of 4MB is somewhat
 537	 * arbitrary.  We might instead base this on r/wsize, or make it
 538	 * tunable, or use a time instead of a byte limit, or implement
 539	 * asynchronous copy.  In theory a client could also recognize a
 540	 * limit like this and pipeline multiple COPY requests.
 541	 */
 542	count = min_t(u64, count, 1 << 22);
 543	return vfs_copy_file_range(src, src_pos, dst, dst_pos, count, 0);
 544}
 545
 546__be32 nfsd4_vfs_fallocate(struct svc_rqst *rqstp, struct svc_fh *fhp,
 547			   struct file *file, loff_t offset, loff_t len,
 548			   int flags)
 549{
 550	int error;
 551
 552	if (!S_ISREG(file_inode(file)->i_mode))
 553		return nfserr_inval;
 554
 555	error = vfs_fallocate(file, flags, offset, len);
 556	if (!error)
 557		error = commit_metadata(fhp);
 558
 559	return nfserrno(error);
 560}
 561#endif /* defined(CONFIG_NFSD_V4) */
 562
 563#ifdef CONFIG_NFSD_V3
 564/*
 565 * Check server access rights to a file system object
 566 */
 567struct accessmap {
 568	u32		access;
 569	int		how;
 570};
 571static struct accessmap	nfs3_regaccess[] = {
 572    {	NFS3_ACCESS_READ,	NFSD_MAY_READ			},
 573    {	NFS3_ACCESS_EXECUTE,	NFSD_MAY_EXEC			},
 574    {	NFS3_ACCESS_MODIFY,	NFSD_MAY_WRITE|NFSD_MAY_TRUNC	},
 575    {	NFS3_ACCESS_EXTEND,	NFSD_MAY_WRITE			},
 576
 
 
 
 
 
 
 577    {	0,			0				}
 578};
 579
 580static struct accessmap	nfs3_diraccess[] = {
 581    {	NFS3_ACCESS_READ,	NFSD_MAY_READ			},
 582    {	NFS3_ACCESS_LOOKUP,	NFSD_MAY_EXEC			},
 583    {	NFS3_ACCESS_MODIFY,	NFSD_MAY_EXEC|NFSD_MAY_WRITE|NFSD_MAY_TRUNC},
 584    {	NFS3_ACCESS_EXTEND,	NFSD_MAY_EXEC|NFSD_MAY_WRITE	},
 585    {	NFS3_ACCESS_DELETE,	NFSD_MAY_REMOVE			},
 586
 
 
 
 
 
 
 587    {	0,			0				}
 588};
 589
 590static struct accessmap	nfs3_anyaccess[] = {
 591	/* Some clients - Solaris 2.6 at least, make an access call
 592	 * to the server to check for access for things like /dev/null
 593	 * (which really, the server doesn't care about).  So
 594	 * We provide simple access checking for them, looking
 595	 * mainly at mode bits, and we make sure to ignore read-only
 596	 * filesystem checks
 597	 */
 598    {	NFS3_ACCESS_READ,	NFSD_MAY_READ			},
 599    {	NFS3_ACCESS_EXECUTE,	NFSD_MAY_EXEC			},
 600    {	NFS3_ACCESS_MODIFY,	NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS	},
 601    {	NFS3_ACCESS_EXTEND,	NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS	},
 602
 603    {	0,			0				}
 604};
 605
 606__be32
 607nfsd_access(struct svc_rqst *rqstp, struct svc_fh *fhp, u32 *access, u32 *supported)
 608{
 609	struct accessmap	*map;
 610	struct svc_export	*export;
 611	struct dentry		*dentry;
 612	u32			query, result = 0, sresult = 0;
 613	__be32			error;
 614
 615	error = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP);
 616	if (error)
 617		goto out;
 618
 619	export = fhp->fh_export;
 620	dentry = fhp->fh_dentry;
 621
 622	if (d_is_reg(dentry))
 623		map = nfs3_regaccess;
 624	else if (d_is_dir(dentry))
 625		map = nfs3_diraccess;
 626	else
 627		map = nfs3_anyaccess;
 628
 629
 630	query = *access;
 631	for  (; map->access; map++) {
 632		if (map->access & query) {
 633			__be32 err2;
 634
 635			sresult |= map->access;
 636
 637			err2 = nfsd_permission(rqstp, export, dentry, map->how);
 638			switch (err2) {
 639			case nfs_ok:
 640				result |= map->access;
 641				break;
 642				
 643			/* the following error codes just mean the access was not allowed,
 644			 * rather than an error occurred */
 645			case nfserr_rofs:
 646			case nfserr_acces:
 647			case nfserr_perm:
 648				/* simply don't "or" in the access bit. */
 649				break;
 650			default:
 651				error = err2;
 652				goto out;
 653			}
 654		}
 655	}
 656	*access = result;
 657	if (supported)
 658		*supported = sresult;
 659
 660 out:
 661	return error;
 662}
 663#endif /* CONFIG_NFSD_V3 */
 664
 665static int nfsd_open_break_lease(struct inode *inode, int access)
 666{
 667	unsigned int mode;
 668
 669	if (access & NFSD_MAY_NOT_BREAK_LEASE)
 670		return 0;
 671	mode = (access & NFSD_MAY_WRITE) ? O_WRONLY : O_RDONLY;
 672	return break_lease(inode, mode | O_NONBLOCK);
 673}
 674
 675/*
 676 * Open an existing file or directory.
 677 * The may_flags argument indicates the type of open (read/write/lock)
 678 * and additional flags.
 679 * N.B. After this call fhp needs an fh_put
 680 */
 681__be32
 682nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type,
 683			int may_flags, struct file **filp)
 684{
 685	struct path	path;
 686	struct inode	*inode;
 687	struct file	*file;
 688	int		flags = O_RDONLY|O_LARGEFILE;
 689	__be32		err;
 690	int		host_err = 0;
 691
 692	validate_process_creds();
 693
 694	/*
 695	 * If we get here, then the client has already done an "open",
 696	 * and (hopefully) checked permission - so allow OWNER_OVERRIDE
 697	 * in case a chmod has now revoked permission.
 698	 *
 699	 * Arguably we should also allow the owner override for
 700	 * directories, but we never have and it doesn't seem to have
 701	 * caused anyone a problem.  If we were to change this, note
 702	 * also that our filldir callbacks would need a variant of
 703	 * lookup_one_len that doesn't check permissions.
 704	 */
 705	if (type == S_IFREG)
 706		may_flags |= NFSD_MAY_OWNER_OVERRIDE;
 707	err = fh_verify(rqstp, fhp, type, may_flags);
 708	if (err)
 709		goto out;
 710
 711	path.mnt = fhp->fh_export->ex_path.mnt;
 712	path.dentry = fhp->fh_dentry;
 713	inode = d_inode(path.dentry);
 714
 715	/* Disallow write access to files with the append-only bit set
 716	 * or any access when mandatory locking enabled
 717	 */
 718	err = nfserr_perm;
 719	if (IS_APPEND(inode) && (may_flags & NFSD_MAY_WRITE))
 720		goto out;
 721	/*
 722	 * We must ignore files (but only files) which might have mandatory
 723	 * locks on them because there is no way to know if the accesser has
 724	 * the lock.
 725	 */
 726	if (S_ISREG((inode)->i_mode) && mandatory_lock(inode))
 727		goto out;
 728
 729	if (!inode->i_fop)
 730		goto out;
 731
 732	host_err = nfsd_open_break_lease(inode, may_flags);
 733	if (host_err) /* NOMEM or WOULDBLOCK */
 734		goto out_nfserr;
 735
 736	if (may_flags & NFSD_MAY_WRITE) {
 737		if (may_flags & NFSD_MAY_READ)
 738			flags = O_RDWR|O_LARGEFILE;
 739		else
 740			flags = O_WRONLY|O_LARGEFILE;
 741	}
 742
 743	file = dentry_open(&path, flags, current_cred());
 744	if (IS_ERR(file)) {
 745		host_err = PTR_ERR(file);
 746		goto out_nfserr;
 747	}
 748
 749	host_err = ima_file_check(file, may_flags, 0);
 750	if (host_err) {
 751		fput(file);
 752		goto out_nfserr;
 753	}
 754
 755	if (may_flags & NFSD_MAY_64BIT_COOKIE)
 756		file->f_mode |= FMODE_64BITHASH;
 757	else
 758		file->f_mode |= FMODE_32BITHASH;
 759
 760	*filp = file;
 761out_nfserr:
 762	err = nfserrno(host_err);
 763out:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 764	validate_process_creds();
 765	return err;
 766}
 767
 768struct raparms *
 769nfsd_init_raparms(struct file *file)
 
 770{
 771	struct inode *inode = file_inode(file);
 772	dev_t dev = inode->i_sb->s_dev;
 773	ino_t ino = inode->i_ino;
 774	struct raparms	*ra, **rap, **frap = NULL;
 775	int depth = 0;
 776	unsigned int hash;
 777	struct raparm_hbucket *rab;
 778
 779	hash = jhash_2words(dev, ino, 0xfeedbeef) & RAPARM_HASH_MASK;
 780	rab = &raparm_hash[hash];
 781
 782	spin_lock(&rab->pb_lock);
 783	for (rap = &rab->pb_head; (ra = *rap); rap = &ra->p_next) {
 784		if (ra->p_ino == ino && ra->p_dev == dev)
 785			goto found;
 786		depth++;
 787		if (ra->p_count == 0)
 788			frap = rap;
 789	}
 790	depth = nfsdstats.ra_size;
 791	if (!frap) {	
 792		spin_unlock(&rab->pb_lock);
 793		return NULL;
 794	}
 795	rap = frap;
 796	ra = *frap;
 797	ra->p_dev = dev;
 798	ra->p_ino = ino;
 799	ra->p_set = 0;
 800	ra->p_hindex = hash;
 801found:
 802	if (rap != &rab->pb_head) {
 803		*rap = ra->p_next;
 804		ra->p_next   = rab->pb_head;
 805		rab->pb_head = ra;
 806	}
 807	ra->p_count++;
 808	nfsdstats.ra_depth[depth*10/nfsdstats.ra_size]++;
 809	spin_unlock(&rab->pb_lock);
 810
 811	if (ra->p_set)
 812		file->f_ra = ra->p_ra;
 813	return ra;
 814}
 815
 816void nfsd_put_raparams(struct file *file, struct raparms *ra)
 817{
 818	struct raparm_hbucket *rab = &raparm_hash[ra->p_hindex];
 819
 820	spin_lock(&rab->pb_lock);
 821	ra->p_ra = file->f_ra;
 822	ra->p_set = 1;
 823	ra->p_count--;
 824	spin_unlock(&rab->pb_lock);
 825}
 826
 827/*
 828 * Grab and keep cached pages associated with a file in the svc_rqst
 829 * so that they can be passed to the network sendmsg/sendpage routines
 830 * directly. They will be released after the sending has completed.
 831 */
 832static int
 833nfsd_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
 834		  struct splice_desc *sd)
 835{
 836	struct svc_rqst *rqstp = sd->u.data;
 837	struct page **pp = rqstp->rq_next_page;
 838	struct page *page = buf->page;
 839	size_t size;
 840
 841	size = sd->len;
 842
 843	if (rqstp->rq_res.page_len == 0) {
 844		get_page(page);
 845		put_page(*rqstp->rq_next_page);
 846		*(rqstp->rq_next_page++) = page;
 847		rqstp->rq_res.page_base = buf->offset;
 848		rqstp->rq_res.page_len = size;
 849	} else if (page != pp[-1]) {
 850		get_page(page);
 851		if (*rqstp->rq_next_page)
 852			put_page(*rqstp->rq_next_page);
 853		*(rqstp->rq_next_page++) = page;
 854		rqstp->rq_res.page_len += size;
 855	} else
 856		rqstp->rq_res.page_len += size;
 857
 858	return size;
 859}
 860
 861static int nfsd_direct_splice_actor(struct pipe_inode_info *pipe,
 862				    struct splice_desc *sd)
 863{
 864	return __splice_from_pipe(pipe, sd, nfsd_splice_actor);
 865}
 866
 867static __be32
 868nfsd_finish_read(struct file *file, unsigned long *count, int host_err)
 
 
 
 
 
 
 
 
 
 
 
 869{
 870	if (host_err >= 0) {
 871		nfsdstats.io_read += host_err;
 
 872		*count = host_err;
 873		fsnotify_access(file);
 
 874		return 0;
 875	} else 
 
 876		return nfserrno(host_err);
 
 877}
 878
 879__be32 nfsd_splice_read(struct svc_rqst *rqstp,
 880		     struct file *file, loff_t offset, unsigned long *count)
 
 881{
 882	struct splice_desc sd = {
 883		.len		= 0,
 884		.total_len	= *count,
 885		.pos		= offset,
 886		.u.data		= rqstp,
 887	};
 888	int host_err;
 889
 
 890	rqstp->rq_next_page = rqstp->rq_respages + 1;
 891	host_err = splice_direct_to_actor(file, &sd, nfsd_direct_splice_actor);
 892	return nfsd_finish_read(file, count, host_err);
 893}
 894
 895__be32 nfsd_readv(struct file *file, loff_t offset, struct kvec *vec, int vlen,
 896		unsigned long *count)
 897{
 898	mm_segment_t oldfs;
 899	int host_err;
 900
 901	oldfs = get_fs();
 902	set_fs(KERNEL_DS);
 903	host_err = vfs_readv(file, (struct iovec __user *)vec, vlen, &offset, 0);
 904	set_fs(oldfs);
 905	return nfsd_finish_read(file, count, host_err);
 906}
 907
 908static __be32
 909nfsd_vfs_read(struct svc_rqst *rqstp, struct file *file,
 910	      loff_t offset, struct kvec *vec, int vlen, unsigned long *count)
 911{
 912	if (file->f_op->splice_read && test_bit(RQ_SPLICE_OK, &rqstp->rq_flags))
 913		return nfsd_splice_read(rqstp, file, offset, count);
 914	else
 915		return nfsd_readv(file, offset, vec, vlen, count);
 916}
 917
 918/*
 919 * Gathered writes: If another process is currently writing to the file,
 920 * there's a high chance this is another nfsd (triggered by a bulk write
 921 * from a client's biod). Rather than syncing the file with each write
 922 * request, we sleep for 10 msec.
 923 *
 924 * I don't know if this roughly approximates C. Juszak's idea of
 925 * gathered writes, but it's a nice and simple solution (IMHO), and it
 926 * seems to work:-)
 927 *
 928 * Note: we do this only in the NFSv2 case, since v3 and higher have a
 929 * better tool (separate unstable writes and commits) for solving this
 930 * problem.
 931 */
 932static int wait_for_concurrent_writes(struct file *file)
 933{
 934	struct inode *inode = file_inode(file);
 935	static ino_t last_ino;
 936	static dev_t last_dev;
 937	int err = 0;
 938
 939	if (atomic_read(&inode->i_writecount) > 1
 940	    || (last_ino == inode->i_ino && last_dev == inode->i_sb->s_dev)) {
 941		dprintk("nfsd: write defer %d\n", task_pid_nr(current));
 942		msleep(10);
 943		dprintk("nfsd: write resume %d\n", task_pid_nr(current));
 944	}
 945
 946	if (inode->i_state & I_DIRTY) {
 947		dprintk("nfsd: write sync %d\n", task_pid_nr(current));
 948		err = vfs_fsync(file, 0);
 949	}
 950	last_ino = inode->i_ino;
 951	last_dev = inode->i_sb->s_dev;
 952	return err;
 953}
 954
 955__be32
 956nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
 957				loff_t offset, struct kvec *vec, int vlen,
 958				unsigned long *cnt, int *stablep)
 
 959{
 
 960	struct svc_export	*exp;
 961	struct inode		*inode;
 962	mm_segment_t		oldfs;
 963	__be32			err = 0;
 964	int			host_err;
 965	int			stable = *stablep;
 966	int			use_wgather;
 967	loff_t			pos = offset;
 968	unsigned int		pflags = current->flags;
 969	int			flags = 0;
 
 
 970
 971	if (test_bit(RQ_LOCAL, &rqstp->rq_flags))
 972		/*
 973		 * We want less throttling in balance_dirty_pages()
 974		 * and shrink_inactive_list() so that nfs to
 
 975		 * localhost doesn't cause nfsd to lock up due to all
 976		 * the client's dirty pages or its congested queue.
 977		 */
 978		current->flags |= PF_LESS_THROTTLE;
 979
 980	inode = file_inode(file);
 981	exp   = fhp->fh_export;
 982
 
 983	use_wgather = (rqstp->rq_vers == 2) && EX_WGATHER(exp);
 984
 985	if (!EX_ISSYNC(exp))
 986		stable = 0;
 987
 988	if (stable && !use_wgather)
 989		flags |= RWF_SYNC;
 990
 991	/* Write the data. */
 992	oldfs = get_fs(); set_fs(KERNEL_DS);
 993	host_err = vfs_writev(file, (struct iovec __user *)vec, vlen, &pos, flags);
 994	set_fs(oldfs);
 995	if (host_err < 0)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 996		goto out_nfserr;
 
 997	*cnt = host_err;
 998	nfsdstats.io_write += host_err;
 999	fsnotify_modify(file);
1000
1001	if (stable && use_wgather)
1002		host_err = wait_for_concurrent_writes(file);
 
 
 
 
1003
1004out_nfserr:
1005	dprintk("nfsd: write complete host_err=%d\n", host_err);
1006	if (host_err >= 0)
1007		err = 0;
1008	else
1009		err = nfserrno(host_err);
 
 
1010	if (test_bit(RQ_LOCAL, &rqstp->rq_flags))
1011		tsk_restore_flags(current, pflags, PF_LESS_THROTTLE);
1012	return err;
1013}
1014
1015/*
1016 * Read data from a file. count must contain the requested read count
1017 * on entry. On return, *count contains the number of bytes actually read.
1018 * N.B. After this call fhp needs an fh_put
1019 */
1020__be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
1021	loff_t offset, struct kvec *vec, int vlen, unsigned long *count)
 
1022{
 
1023	struct file *file;
1024	struct raparms	*ra;
1025	__be32 err;
1026
1027	trace_read_start(rqstp, fhp, offset, vlen);
1028	err = nfsd_open(rqstp, fhp, S_IFREG, NFSD_MAY_READ, &file);
1029	if (err)
1030		return err;
1031
1032	ra = nfsd_init_raparms(file);
1033
1034	trace_read_opened(rqstp, fhp, offset, vlen);
1035	err = nfsd_vfs_read(rqstp, file, offset, vec, vlen, count);
1036	trace_read_io_done(rqstp, fhp, offset, vlen);
1037
1038	if (ra)
1039		nfsd_put_raparams(file, ra);
1040	fput(file);
1041
1042	trace_read_done(rqstp, fhp, offset, vlen);
1043
1044	return err;
1045}
1046
1047/*
1048 * Write data to a file.
1049 * The stable flag requests synchronous writes.
1050 * N.B. After this call fhp needs an fh_put
1051 */
1052__be32
1053nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
1054		loff_t offset, struct kvec *vec, int vlen, unsigned long *cnt,
1055		int *stablep)
1056{
1057	__be32			err = 0;
 
1058
1059	trace_write_start(rqstp, fhp, offset, vlen);
1060
1061	if (file) {
1062		err = nfsd_permission(rqstp, fhp->fh_export, fhp->fh_dentry,
1063				NFSD_MAY_WRITE|NFSD_MAY_OWNER_OVERRIDE);
1064		if (err)
1065			goto out;
1066		trace_write_opened(rqstp, fhp, offset, vlen);
1067		err = nfsd_vfs_write(rqstp, fhp, file, offset, vec, vlen, cnt,
1068				stablep);
1069		trace_write_io_done(rqstp, fhp, offset, vlen);
1070	} else {
1071		err = nfsd_open(rqstp, fhp, S_IFREG, NFSD_MAY_WRITE, &file);
1072		if (err)
1073			goto out;
1074
1075		trace_write_opened(rqstp, fhp, offset, vlen);
1076		if (cnt)
1077			err = nfsd_vfs_write(rqstp, fhp, file, offset, vec, vlen,
1078					     cnt, stablep);
1079		trace_write_io_done(rqstp, fhp, offset, vlen);
1080		fput(file);
1081	}
1082out:
1083	trace_write_done(rqstp, fhp, offset, vlen);
1084	return err;
1085}
1086
1087#ifdef CONFIG_NFSD_V3
1088/*
1089 * Commit all pending writes to stable storage.
1090 *
1091 * Note: we only guarantee that data that lies within the range specified
1092 * by the 'offset' and 'count' parameters will be synced.
1093 *
1094 * Unfortunately we cannot lock the file to make sure we return full WCC
1095 * data to the client, as locking happens lower down in the filesystem.
1096 */
1097__be32
1098nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp,
1099               loff_t offset, unsigned long count)
1100{
1101	struct file	*file;
1102	loff_t		end = LLONG_MAX;
1103	__be32		err = nfserr_inval;
1104
1105	if (offset < 0)
1106		goto out;
1107	if (count != 0) {
1108		end = offset + (loff_t)count - 1;
1109		if (end < offset)
1110			goto out;
1111	}
1112
1113	err = nfsd_open(rqstp, fhp, S_IFREG,
1114			NFSD_MAY_WRITE|NFSD_MAY_NOT_BREAK_LEASE, &file);
1115	if (err)
1116		goto out;
1117	if (EX_ISSYNC(fhp->fh_export)) {
1118		int err2 = vfs_fsync_range(file, offset, end, 0);
1119
1120		if (err2 != -EINVAL)
1121			err = nfserrno(err2);
1122		else
 
 
 
 
 
1123			err = nfserr_notsupp;
1124	}
 
 
 
 
 
 
 
 
 
1125
1126	fput(file);
1127out:
1128	return err;
1129}
1130#endif /* CONFIG_NFSD_V3 */
1131
1132static __be32
1133nfsd_create_setattr(struct svc_rqst *rqstp, struct svc_fh *resfhp,
1134			struct iattr *iap)
1135{
1136	/*
1137	 * Mode has already been set earlier in create:
1138	 */
1139	iap->ia_valid &= ~ATTR_MODE;
1140	/*
1141	 * Setting uid/gid works only for root.  Irix appears to
1142	 * send along the gid on create when it tries to implement
1143	 * setgid directories via NFS:
1144	 */
1145	if (!uid_eq(current_fsuid(), GLOBAL_ROOT_UID))
1146		iap->ia_valid &= ~(ATTR_UID|ATTR_GID);
1147	if (iap->ia_valid)
1148		return nfsd_setattr(rqstp, resfhp, iap, 0, (time_t)0);
1149	/* Callers expect file metadata to be committed here */
1150	return nfserrno(commit_metadata(resfhp));
1151}
1152
1153/* HPUX client sometimes creates a file in mode 000, and sets size to 0.
1154 * setting size to 0 may fail for some specific file systems by the permission
1155 * checking which requires WRITE permission but the mode is 000.
1156 * we ignore the resizing(to 0) on the just new created file, since the size is
1157 * 0 after file created.
1158 *
1159 * call this only after vfs_create() is called.
1160 * */
1161static void
1162nfsd_check_ignore_resizing(struct iattr *iap)
1163{
1164	if ((iap->ia_valid & ATTR_SIZE) && (iap->ia_size == 0))
1165		iap->ia_valid &= ~ATTR_SIZE;
1166}
1167
1168/* The parent directory should already be locked: */
1169__be32
1170nfsd_create_locked(struct svc_rqst *rqstp, struct svc_fh *fhp,
1171		char *fname, int flen, struct iattr *iap,
1172		int type, dev_t rdev, struct svc_fh *resfhp)
1173{
1174	struct dentry	*dentry, *dchild;
1175	struct inode	*dirp;
1176	__be32		err;
1177	__be32		err2;
1178	int		host_err;
1179
1180	dentry = fhp->fh_dentry;
1181	dirp = d_inode(dentry);
1182
1183	dchild = dget(resfhp->fh_dentry);
1184	if (!fhp->fh_locked) {
1185		WARN_ONCE(1, "nfsd_create: parent %pd2 not locked!\n",
1186				dentry);
1187		err = nfserr_io;
1188		goto out;
1189	}
1190
1191	err = nfsd_permission(rqstp, fhp->fh_export, dentry, NFSD_MAY_CREATE);
1192	if (err)
1193		goto out;
1194
1195	if (!(iap->ia_valid & ATTR_MODE))
1196		iap->ia_mode = 0;
1197	iap->ia_mode = (iap->ia_mode & S_IALLUGO) | type;
1198
 
 
 
1199	err = 0;
1200	host_err = 0;
1201	switch (type) {
1202	case S_IFREG:
1203		host_err = vfs_create(dirp, dchild, iap->ia_mode, true);
1204		if (!host_err)
1205			nfsd_check_ignore_resizing(iap);
1206		break;
1207	case S_IFDIR:
1208		host_err = vfs_mkdir(dirp, dchild, iap->ia_mode);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1209		break;
1210	case S_IFCHR:
1211	case S_IFBLK:
1212	case S_IFIFO:
1213	case S_IFSOCK:
1214		host_err = vfs_mknod(dirp, dchild, iap->ia_mode, rdev);
1215		break;
1216	default:
1217		printk(KERN_WARNING "nfsd: bad file type %o in nfsd_create\n",
1218		       type);
1219		host_err = -EINVAL;
1220	}
1221	if (host_err < 0)
1222		goto out_nfserr;
1223
1224	err = nfsd_create_setattr(rqstp, resfhp, iap);
1225
1226	/*
1227	 * nfsd_create_setattr already committed the child.  Transactional
1228	 * filesystems had a chance to commit changes for both parent and
1229	 * child simultaneously making the following commit_metadata a
1230	 * noop.
1231	 */
1232	err2 = nfserrno(commit_metadata(fhp));
1233	if (err2)
1234		err = err2;
1235	/*
1236	 * Update the file handle to get the new inode info.
1237	 */
1238	if (!err)
1239		err = fh_update(resfhp);
1240out:
1241	dput(dchild);
1242	return err;
1243
1244out_nfserr:
1245	err = nfserrno(host_err);
1246	goto out;
1247}
1248
1249/*
1250 * Create a filesystem object (regular, directory, special).
1251 * Note that the parent directory is left locked.
1252 *
1253 * N.B. Every call to nfsd_create needs an fh_put for _both_ fhp and resfhp
1254 */
1255__be32
1256nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
1257		char *fname, int flen, struct iattr *iap,
1258		int type, dev_t rdev, struct svc_fh *resfhp)
1259{
1260	struct dentry	*dentry, *dchild = NULL;
1261	struct inode	*dirp;
1262	__be32		err;
1263	int		host_err;
1264
1265	if (isdotent(fname, flen))
1266		return nfserr_exist;
1267
1268	err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_NOP);
1269	if (err)
1270		return err;
1271
1272	dentry = fhp->fh_dentry;
1273	dirp = d_inode(dentry);
1274
1275	host_err = fh_want_write(fhp);
1276	if (host_err)
1277		return nfserrno(host_err);
1278
1279	fh_lock_nested(fhp, I_MUTEX_PARENT);
1280	dchild = lookup_one_len(fname, dentry, flen);
1281	host_err = PTR_ERR(dchild);
1282	if (IS_ERR(dchild))
1283		return nfserrno(host_err);
1284	err = fh_compose(resfhp, fhp->fh_export, dchild, fhp);
1285	/*
1286	 * We unconditionally drop our ref to dchild as fh_compose will have
1287	 * already grabbed its own ref for it.
1288	 */
1289	dput(dchild);
1290	if (err)
1291		return err;
1292	return nfsd_create_locked(rqstp, fhp, fname, flen, iap, type,
1293					rdev, resfhp);
1294}
1295
1296#ifdef CONFIG_NFSD_V3
1297
1298/*
1299 * NFSv3 and NFSv4 version of nfsd_create
1300 */
1301__be32
1302do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
1303		char *fname, int flen, struct iattr *iap,
1304		struct svc_fh *resfhp, int createmode, u32 *verifier,
1305	        bool *truncp, bool *created)
1306{
1307	struct dentry	*dentry, *dchild = NULL;
1308	struct inode	*dirp;
1309	__be32		err;
1310	int		host_err;
1311	__u32		v_mtime=0, v_atime=0;
1312
1313	err = nfserr_perm;
1314	if (!flen)
1315		goto out;
1316	err = nfserr_exist;
1317	if (isdotent(fname, flen))
1318		goto out;
1319	if (!(iap->ia_valid & ATTR_MODE))
1320		iap->ia_mode = 0;
1321	err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC);
1322	if (err)
1323		goto out;
1324
1325	dentry = fhp->fh_dentry;
1326	dirp = d_inode(dentry);
1327
1328	host_err = fh_want_write(fhp);
1329	if (host_err)
1330		goto out_nfserr;
1331
1332	fh_lock_nested(fhp, I_MUTEX_PARENT);
1333
1334	/*
1335	 * Compose the response file handle.
1336	 */
1337	dchild = lookup_one_len(fname, dentry, flen);
1338	host_err = PTR_ERR(dchild);
1339	if (IS_ERR(dchild))
1340		goto out_nfserr;
1341
1342	/* If file doesn't exist, check for permissions to create one */
1343	if (d_really_is_negative(dchild)) {
1344		err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
1345		if (err)
1346			goto out;
1347	}
1348
1349	err = fh_compose(resfhp, fhp->fh_export, dchild, fhp);
1350	if (err)
1351		goto out;
1352
1353	if (nfsd_create_is_exclusive(createmode)) {
1354		/* solaris7 gets confused (bugid 4218508) if these have
1355		 * the high bit set, so just clear the high bits. If this is
1356		 * ever changed to use different attrs for storing the
1357		 * verifier, then do_open_lookup() will also need to be fixed
1358		 * accordingly.
1359		 */
1360		v_mtime = verifier[0]&0x7fffffff;
1361		v_atime = verifier[1]&0x7fffffff;
1362	}
1363	
1364	if (d_really_is_positive(dchild)) {
1365		err = 0;
1366
1367		switch (createmode) {
1368		case NFS3_CREATE_UNCHECKED:
1369			if (! d_is_reg(dchild))
1370				goto out;
1371			else if (truncp) {
1372				/* in nfsv4, we need to treat this case a little
1373				 * differently.  we don't want to truncate the
1374				 * file now; this would be wrong if the OPEN
1375				 * fails for some other reason.  furthermore,
1376				 * if the size is nonzero, we should ignore it
1377				 * according to spec!
1378				 */
1379				*truncp = (iap->ia_valid & ATTR_SIZE) && !iap->ia_size;
1380			}
1381			else {
1382				iap->ia_valid &= ATTR_SIZE;
1383				goto set_attr;
1384			}
1385			break;
1386		case NFS3_CREATE_EXCLUSIVE:
1387			if (   d_inode(dchild)->i_mtime.tv_sec == v_mtime
1388			    && d_inode(dchild)->i_atime.tv_sec == v_atime
1389			    && d_inode(dchild)->i_size  == 0 ) {
1390				if (created)
1391					*created = 1;
1392				break;
1393			}
 
1394		case NFS4_CREATE_EXCLUSIVE4_1:
1395			if (   d_inode(dchild)->i_mtime.tv_sec == v_mtime
1396			    && d_inode(dchild)->i_atime.tv_sec == v_atime
1397			    && d_inode(dchild)->i_size  == 0 ) {
1398				if (created)
1399					*created = 1;
1400				goto set_attr;
1401			}
1402			 /* fallthru */
1403		case NFS3_CREATE_GUARDED:
1404			err = nfserr_exist;
1405		}
1406		fh_drop_write(fhp);
1407		goto out;
1408	}
1409
 
 
 
1410	host_err = vfs_create(dirp, dchild, iap->ia_mode, true);
1411	if (host_err < 0) {
1412		fh_drop_write(fhp);
1413		goto out_nfserr;
1414	}
1415	if (created)
1416		*created = 1;
1417
1418	nfsd_check_ignore_resizing(iap);
1419
1420	if (nfsd_create_is_exclusive(createmode)) {
1421		/* Cram the verifier into atime/mtime */
1422		iap->ia_valid = ATTR_MTIME|ATTR_ATIME
1423			| ATTR_MTIME_SET|ATTR_ATIME_SET;
1424		/* XXX someone who knows this better please fix it for nsec */ 
1425		iap->ia_mtime.tv_sec = v_mtime;
1426		iap->ia_atime.tv_sec = v_atime;
1427		iap->ia_mtime.tv_nsec = 0;
1428		iap->ia_atime.tv_nsec = 0;
1429	}
1430
1431 set_attr:
1432	err = nfsd_create_setattr(rqstp, resfhp, iap);
1433
1434	/*
1435	 * nfsd_create_setattr already committed the child
1436	 * (and possibly also the parent).
1437	 */
1438	if (!err)
1439		err = nfserrno(commit_metadata(fhp));
1440
1441	/*
1442	 * Update the filehandle to get the new inode info.
1443	 */
1444	if (!err)
1445		err = fh_update(resfhp);
1446
1447 out:
1448	fh_unlock(fhp);
1449	if (dchild && !IS_ERR(dchild))
1450		dput(dchild);
1451	fh_drop_write(fhp);
1452 	return err;
1453 
1454 out_nfserr:
1455	err = nfserrno(host_err);
1456	goto out;
1457}
1458#endif /* CONFIG_NFSD_V3 */
1459
1460/*
1461 * Read a symlink. On entry, *lenp must contain the maximum path length that
1462 * fits into the buffer. On return, it contains the true length.
1463 * N.B. After this call fhp needs an fh_put
1464 */
1465__be32
1466nfsd_readlink(struct svc_rqst *rqstp, struct svc_fh *fhp, char *buf, int *lenp)
1467{
1468	mm_segment_t	oldfs;
1469	__be32		err;
1470	int		host_err;
1471	struct path path;
 
 
1472
1473	err = fh_verify(rqstp, fhp, S_IFLNK, NFSD_MAY_NOP);
1474	if (err)
1475		goto out;
1476
1477	path.mnt = fhp->fh_export->ex_path.mnt;
1478	path.dentry = fhp->fh_dentry;
1479
1480	err = nfserr_inval;
1481	if (!d_is_symlink(path.dentry))
1482		goto out;
1483
1484	touch_atime(&path);
1485	/* N.B. Why does this call need a get_fs()??
1486	 * Remove the set_fs and watch the fireworks:-) --okir
1487	 */
1488
1489	oldfs = get_fs(); set_fs(KERNEL_DS);
1490	host_err = vfs_readlink(path.dentry, (char __user *)buf, *lenp);
1491	set_fs(oldfs);
1492
1493	if (host_err < 0)
1494		goto out_nfserr;
1495	*lenp = host_err;
1496	err = 0;
1497out:
1498	return err;
1499
1500out_nfserr:
1501	err = nfserrno(host_err);
1502	goto out;
 
 
 
 
 
 
 
1503}
1504
1505/*
1506 * Create a symlink and look up its inode
1507 * N.B. After this call _both_ fhp and resfhp need an fh_put
1508 */
1509__be32
1510nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp,
1511				char *fname, int flen,
1512				char *path,
1513				struct svc_fh *resfhp)
1514{
1515	struct dentry	*dentry, *dnew;
1516	__be32		err, cerr;
1517	int		host_err;
1518
1519	err = nfserr_noent;
1520	if (!flen || path[0] == '\0')
1521		goto out;
1522	err = nfserr_exist;
1523	if (isdotent(fname, flen))
1524		goto out;
1525
1526	err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
1527	if (err)
1528		goto out;
1529
1530	host_err = fh_want_write(fhp);
1531	if (host_err)
1532		goto out_nfserr;
1533
1534	fh_lock(fhp);
1535	dentry = fhp->fh_dentry;
1536	dnew = lookup_one_len(fname, dentry, flen);
1537	host_err = PTR_ERR(dnew);
1538	if (IS_ERR(dnew))
1539		goto out_nfserr;
1540
1541	host_err = vfs_symlink(d_inode(dentry), dnew, path);
1542	err = nfserrno(host_err);
1543	if (!err)
1544		err = nfserrno(commit_metadata(fhp));
1545	fh_unlock(fhp);
1546
1547	fh_drop_write(fhp);
1548
1549	cerr = fh_compose(resfhp, fhp->fh_export, dnew, fhp);
1550	dput(dnew);
1551	if (err==0) err = cerr;
1552out:
1553	return err;
1554
1555out_nfserr:
1556	err = nfserrno(host_err);
1557	goto out;
1558}
1559
1560/*
1561 * Create a hardlink
1562 * N.B. After this call _both_ ffhp and tfhp need an fh_put
1563 */
1564__be32
1565nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp,
1566				char *name, int len, struct svc_fh *tfhp)
1567{
1568	struct dentry	*ddir, *dnew, *dold;
1569	struct inode	*dirp;
1570	__be32		err;
1571	int		host_err;
1572
1573	err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_CREATE);
1574	if (err)
1575		goto out;
1576	err = fh_verify(rqstp, tfhp, 0, NFSD_MAY_NOP);
1577	if (err)
1578		goto out;
1579	err = nfserr_isdir;
1580	if (d_is_dir(tfhp->fh_dentry))
1581		goto out;
1582	err = nfserr_perm;
1583	if (!len)
1584		goto out;
1585	err = nfserr_exist;
1586	if (isdotent(name, len))
1587		goto out;
1588
1589	host_err = fh_want_write(tfhp);
1590	if (host_err) {
1591		err = nfserrno(host_err);
1592		goto out;
1593	}
1594
1595	fh_lock_nested(ffhp, I_MUTEX_PARENT);
1596	ddir = ffhp->fh_dentry;
1597	dirp = d_inode(ddir);
1598
1599	dnew = lookup_one_len(name, ddir, len);
1600	host_err = PTR_ERR(dnew);
1601	if (IS_ERR(dnew))
1602		goto out_nfserr;
1603
1604	dold = tfhp->fh_dentry;
1605
1606	err = nfserr_noent;
1607	if (d_really_is_negative(dold))
1608		goto out_dput;
1609	host_err = vfs_link(dold, dirp, dnew, NULL);
1610	if (!host_err) {
1611		err = nfserrno(commit_metadata(ffhp));
1612		if (!err)
1613			err = nfserrno(commit_metadata(tfhp));
1614	} else {
1615		if (host_err == -EXDEV && rqstp->rq_vers == 2)
1616			err = nfserr_acces;
1617		else
1618			err = nfserrno(host_err);
1619	}
1620out_dput:
1621	dput(dnew);
1622out_unlock:
1623	fh_unlock(ffhp);
1624	fh_drop_write(tfhp);
1625out:
1626	return err;
1627
1628out_nfserr:
1629	err = nfserrno(host_err);
1630	goto out_unlock;
1631}
1632
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1633/*
1634 * Rename a file
1635 * N.B. After this call _both_ ffhp and tfhp need an fh_put
1636 */
1637__be32
1638nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
1639			    struct svc_fh *tfhp, char *tname, int tlen)
1640{
1641	struct dentry	*fdentry, *tdentry, *odentry, *ndentry, *trap;
1642	struct inode	*fdir, *tdir;
1643	__be32		err;
1644	int		host_err;
 
1645
1646	err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_REMOVE);
1647	if (err)
1648		goto out;
1649	err = fh_verify(rqstp, tfhp, S_IFDIR, NFSD_MAY_CREATE);
1650	if (err)
1651		goto out;
1652
1653	fdentry = ffhp->fh_dentry;
1654	fdir = d_inode(fdentry);
1655
1656	tdentry = tfhp->fh_dentry;
1657	tdir = d_inode(tdentry);
1658
1659	err = nfserr_perm;
1660	if (!flen || isdotent(fname, flen) || !tlen || isdotent(tname, tlen))
1661		goto out;
1662
 
1663	host_err = fh_want_write(ffhp);
1664	if (host_err) {
1665		err = nfserrno(host_err);
1666		goto out;
1667	}
1668
1669	/* cannot use fh_lock as we need deadlock protective ordering
1670	 * so do it by hand */
1671	trap = lock_rename(tdentry, fdentry);
1672	ffhp->fh_locked = tfhp->fh_locked = true;
1673	fill_pre_wcc(ffhp);
1674	fill_pre_wcc(tfhp);
1675
1676	odentry = lookup_one_len(fname, fdentry, flen);
1677	host_err = PTR_ERR(odentry);
1678	if (IS_ERR(odentry))
1679		goto out_nfserr;
1680
1681	host_err = -ENOENT;
1682	if (d_really_is_negative(odentry))
1683		goto out_dput_old;
1684	host_err = -EINVAL;
1685	if (odentry == trap)
1686		goto out_dput_old;
1687
1688	ndentry = lookup_one_len(tname, tdentry, tlen);
1689	host_err = PTR_ERR(ndentry);
1690	if (IS_ERR(ndentry))
1691		goto out_dput_old;
1692	host_err = -ENOTEMPTY;
1693	if (ndentry == trap)
1694		goto out_dput_new;
1695
1696	host_err = -EXDEV;
1697	if (ffhp->fh_export->ex_path.mnt != tfhp->fh_export->ex_path.mnt)
1698		goto out_dput_new;
1699	if (ffhp->fh_export->ex_path.dentry != tfhp->fh_export->ex_path.dentry)
1700		goto out_dput_new;
1701
1702	host_err = vfs_rename(fdir, odentry, tdir, ndentry, NULL, 0);
1703	if (!host_err) {
1704		host_err = commit_metadata(tfhp);
1705		if (!host_err)
1706			host_err = commit_metadata(ffhp);
 
 
 
 
 
1707	}
1708 out_dput_new:
1709	dput(ndentry);
1710 out_dput_old:
1711	dput(odentry);
1712 out_nfserr:
1713	err = nfserrno(host_err);
1714	/*
1715	 * We cannot rely on fh_unlock on the two filehandles,
1716	 * as that would do the wrong thing if the two directories
1717	 * were the same, so again we do it by hand.
1718	 */
1719	fill_post_wcc(ffhp);
1720	fill_post_wcc(tfhp);
 
 
1721	unlock_rename(tdentry, fdentry);
1722	ffhp->fh_locked = tfhp->fh_locked = false;
1723	fh_drop_write(ffhp);
1724
 
 
 
 
 
 
 
 
 
 
 
 
1725out:
1726	return err;
1727}
1728
1729/*
1730 * Unlink a file or directory
1731 * N.B. After this call fhp needs an fh_put
1732 */
1733__be32
1734nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
1735				char *fname, int flen)
1736{
1737	struct dentry	*dentry, *rdentry;
1738	struct inode	*dirp;
1739	__be32		err;
1740	int		host_err;
1741
1742	err = nfserr_acces;
1743	if (!flen || isdotent(fname, flen))
1744		goto out;
1745	err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_REMOVE);
1746	if (err)
1747		goto out;
1748
1749	host_err = fh_want_write(fhp);
1750	if (host_err)
1751		goto out_nfserr;
1752
1753	fh_lock_nested(fhp, I_MUTEX_PARENT);
1754	dentry = fhp->fh_dentry;
1755	dirp = d_inode(dentry);
1756
1757	rdentry = lookup_one_len(fname, dentry, flen);
1758	host_err = PTR_ERR(rdentry);
1759	if (IS_ERR(rdentry))
1760		goto out_nfserr;
1761
1762	if (d_really_is_negative(rdentry)) {
1763		dput(rdentry);
1764		err = nfserr_noent;
1765		goto out;
1766	}
1767
1768	if (!type)
1769		type = d_inode(rdentry)->i_mode & S_IFMT;
1770
1771	if (type != S_IFDIR)
 
1772		host_err = vfs_unlink(dirp, rdentry, NULL);
1773	else
1774		host_err = vfs_rmdir(dirp, rdentry);
 
 
1775	if (!host_err)
1776		host_err = commit_metadata(fhp);
1777	dput(rdentry);
1778
 
 
1779out_nfserr:
1780	err = nfserrno(host_err);
 
 
 
 
 
 
 
 
 
 
1781out:
1782	return err;
1783}
1784
1785/*
1786 * We do this buffering because we must not call back into the file
1787 * system's ->lookup() method from the filldir callback. That may well
1788 * deadlock a number of file systems.
1789 *
1790 * This is based heavily on the implementation of same in XFS.
1791 */
1792struct buffered_dirent {
1793	u64		ino;
1794	loff_t		offset;
1795	int		namlen;
1796	unsigned int	d_type;
1797	char		name[];
1798};
1799
1800struct readdir_data {
1801	struct dir_context ctx;
1802	char		*dirent;
1803	size_t		used;
1804	int		full;
1805};
1806
1807static int nfsd_buffered_filldir(struct dir_context *ctx, const char *name,
1808				 int namlen, loff_t offset, u64 ino,
1809				 unsigned int d_type)
1810{
1811	struct readdir_data *buf =
1812		container_of(ctx, struct readdir_data, ctx);
1813	struct buffered_dirent *de = (void *)(buf->dirent + buf->used);
1814	unsigned int reclen;
1815
1816	reclen = ALIGN(sizeof(struct buffered_dirent) + namlen, sizeof(u64));
1817	if (buf->used + reclen > PAGE_SIZE) {
1818		buf->full = 1;
1819		return -EINVAL;
1820	}
1821
1822	de->namlen = namlen;
1823	de->offset = offset;
1824	de->ino = ino;
1825	de->d_type = d_type;
1826	memcpy(de->name, name, namlen);
1827	buf->used += reclen;
1828
1829	return 0;
1830}
1831
1832static __be32 nfsd_buffered_readdir(struct file *file, nfsd_filldir_t func,
1833				    struct readdir_cd *cdp, loff_t *offsetp)
1834{
1835	struct buffered_dirent *de;
1836	int host_err;
1837	int size;
1838	loff_t offset;
1839	struct readdir_data buf = {
1840		.ctx.actor = nfsd_buffered_filldir,
1841		.dirent = (void *)__get_free_page(GFP_KERNEL)
1842	};
1843
1844	if (!buf.dirent)
1845		return nfserrno(-ENOMEM);
1846
1847	offset = *offsetp;
1848
1849	while (1) {
1850		unsigned int reclen;
1851
1852		cdp->err = nfserr_eof; /* will be cleared on successful read */
1853		buf.used = 0;
1854		buf.full = 0;
1855
1856		host_err = iterate_dir(file, &buf.ctx);
1857		if (buf.full)
1858			host_err = 0;
1859
1860		if (host_err < 0)
1861			break;
1862
1863		size = buf.used;
1864
1865		if (!size)
1866			break;
1867
1868		de = (struct buffered_dirent *)buf.dirent;
1869		while (size > 0) {
1870			offset = de->offset;
1871
1872			if (func(cdp, de->name, de->namlen, de->offset,
1873				 de->ino, de->d_type))
1874				break;
1875
1876			if (cdp->err != nfs_ok)
1877				break;
1878
1879			reclen = ALIGN(sizeof(*de) + de->namlen,
1880				       sizeof(u64));
1881			size -= reclen;
1882			de = (struct buffered_dirent *)((char *)de + reclen);
1883		}
1884		if (size > 0) /* We bailed out early */
1885			break;
1886
1887		offset = vfs_llseek(file, 0, SEEK_CUR);
1888	}
1889
1890	free_page((unsigned long)(buf.dirent));
1891
1892	if (host_err)
1893		return nfserrno(host_err);
1894
1895	*offsetp = offset;
1896	return cdp->err;
1897}
1898
1899/*
1900 * Read entries from a directory.
1901 * The  NFSv3/4 verifier we ignore for now.
1902 */
1903__be32
1904nfsd_readdir(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t *offsetp, 
1905	     struct readdir_cd *cdp, nfsd_filldir_t func)
1906{
1907	__be32		err;
1908	struct file	*file;
1909	loff_t		offset = *offsetp;
1910	int             may_flags = NFSD_MAY_READ;
1911
1912	/* NFSv2 only supports 32 bit cookies */
1913	if (rqstp->rq_vers > 2)
1914		may_flags |= NFSD_MAY_64BIT_COOKIE;
1915
1916	err = nfsd_open(rqstp, fhp, S_IFDIR, may_flags, &file);
1917	if (err)
1918		goto out;
1919
1920	offset = vfs_llseek(file, offset, SEEK_SET);
1921	if (offset < 0) {
1922		err = nfserrno((int)offset);
1923		goto out_close;
1924	}
1925
1926	err = nfsd_buffered_readdir(file, func, cdp, offsetp);
1927
1928	if (err == nfserr_eof || err == nfserr_toosmall)
1929		err = nfs_ok; /* can still be found in ->err */
1930out_close:
1931	fput(file);
1932out:
1933	return err;
1934}
1935
1936/*
1937 * Get file system stats
1938 * N.B. After this call fhp needs an fh_put
1939 */
1940__be32
1941nfsd_statfs(struct svc_rqst *rqstp, struct svc_fh *fhp, struct kstatfs *stat, int access)
1942{
1943	__be32 err;
1944
1945	err = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP | access);
1946	if (!err) {
1947		struct path path = {
1948			.mnt	= fhp->fh_export->ex_path.mnt,
1949			.dentry	= fhp->fh_dentry,
1950		};
1951		if (vfs_statfs(&path, stat))
1952			err = nfserr_io;
1953	}
1954	return err;
1955}
1956
1957static int exp_rdonly(struct svc_rqst *rqstp, struct svc_export *exp)
1958{
1959	return nfsexp_flags(rqstp, exp) & NFSEXP_READONLY;
1960}
1961
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1962/*
1963 * Check for a user's access permissions to this inode.
1964 */
1965__be32
1966nfsd_permission(struct svc_rqst *rqstp, struct svc_export *exp,
1967					struct dentry *dentry, int acc)
1968{
1969	struct inode	*inode = d_inode(dentry);
1970	int		err;
1971
1972	if ((acc & NFSD_MAY_MASK) == NFSD_MAY_NOP)
1973		return 0;
1974#if 0
1975	dprintk("nfsd: permission 0x%x%s%s%s%s%s%s%s mode 0%o%s%s%s\n",
1976		acc,
1977		(acc & NFSD_MAY_READ)?	" read"  : "",
1978		(acc & NFSD_MAY_WRITE)?	" write" : "",
1979		(acc & NFSD_MAY_EXEC)?	" exec"  : "",
1980		(acc & NFSD_MAY_SATTR)?	" sattr" : "",
1981		(acc & NFSD_MAY_TRUNC)?	" trunc" : "",
1982		(acc & NFSD_MAY_LOCK)?	" lock"  : "",
1983		(acc & NFSD_MAY_OWNER_OVERRIDE)? " owneroverride" : "",
1984		inode->i_mode,
1985		IS_IMMUTABLE(inode)?	" immut" : "",
1986		IS_APPEND(inode)?	" append" : "",
1987		__mnt_is_readonly(exp->ex_path.mnt)?	" ro" : "");
1988	dprintk("      owner %d/%d user %d/%d\n",
1989		inode->i_uid, inode->i_gid, current_fsuid(), current_fsgid());
1990#endif
1991
1992	/* Normally we reject any write/sattr etc access on a read-only file
1993	 * system.  But if it is IRIX doing check on write-access for a 
1994	 * device special file, we ignore rofs.
1995	 */
1996	if (!(acc & NFSD_MAY_LOCAL_ACCESS))
1997		if (acc & (NFSD_MAY_WRITE | NFSD_MAY_SATTR | NFSD_MAY_TRUNC)) {
1998			if (exp_rdonly(rqstp, exp) ||
1999			    __mnt_is_readonly(exp->ex_path.mnt))
2000				return nfserr_rofs;
2001			if (/* (acc & NFSD_MAY_WRITE) && */ IS_IMMUTABLE(inode))
2002				return nfserr_perm;
2003		}
2004	if ((acc & NFSD_MAY_TRUNC) && IS_APPEND(inode))
2005		return nfserr_perm;
2006
2007	if (acc & NFSD_MAY_LOCK) {
2008		/* If we cannot rely on authentication in NLM requests,
2009		 * just allow locks, otherwise require read permission, or
2010		 * ownership
2011		 */
2012		if (exp->ex_flags & NFSEXP_NOAUTHNLM)
2013			return 0;
2014		else
2015			acc = NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE;
2016	}
2017	/*
2018	 * The file owner always gets access permission for accesses that
2019	 * would normally be checked at open time. This is to make
2020	 * file access work even when the client has done a fchmod(fd, 0).
2021	 *
2022	 * However, `cp foo bar' should fail nevertheless when bar is
2023	 * readonly. A sensible way to do this might be to reject all
2024	 * attempts to truncate a read-only file, because a creat() call
2025	 * always implies file truncation.
2026	 * ... but this isn't really fair.  A process may reasonably call
2027	 * ftruncate on an open file descriptor on a file with perm 000.
2028	 * We must trust the client to do permission checking - using "ACCESS"
2029	 * with NFSv3.
2030	 */
2031	if ((acc & NFSD_MAY_OWNER_OVERRIDE) &&
2032	    uid_eq(inode->i_uid, current_fsuid()))
2033		return 0;
2034
2035	/* This assumes  NFSD_MAY_{READ,WRITE,EXEC} == MAY_{READ,WRITE,EXEC} */
2036	err = inode_permission(inode, acc & (MAY_READ|MAY_WRITE|MAY_EXEC));
2037
2038	/* Allow read access to binaries even when mode 111 */
2039	if (err == -EACCES && S_ISREG(inode->i_mode) &&
2040	     (acc == (NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE) ||
2041	      acc == (NFSD_MAY_READ | NFSD_MAY_READ_IF_EXEC)))
2042		err = inode_permission(inode, MAY_EXEC);
2043
2044	return err? nfserrno(err) : 0;
2045}
2046
2047void
2048nfsd_racache_shutdown(void)
2049{
2050	struct raparms *raparm, *last_raparm;
2051	unsigned int i;
2052
2053	dprintk("nfsd: freeing readahead buffers.\n");
2054
2055	for (i = 0; i < RAPARM_HASH_SIZE; i++) {
2056		raparm = raparm_hash[i].pb_head;
2057		while(raparm) {
2058			last_raparm = raparm;
2059			raparm = raparm->p_next;
2060			kfree(last_raparm);
2061		}
2062		raparm_hash[i].pb_head = NULL;
2063	}
2064}
2065/*
2066 * Initialize readahead param cache
2067 */
2068int
2069nfsd_racache_init(int cache_size)
2070{
2071	int	i;
2072	int	j = 0;
2073	int	nperbucket;
2074	struct raparms **raparm = NULL;
2075
2076
2077	if (raparm_hash[0].pb_head)
2078		return 0;
2079	nperbucket = DIV_ROUND_UP(cache_size, RAPARM_HASH_SIZE);
2080	nperbucket = max(2, nperbucket);
2081	cache_size = nperbucket * RAPARM_HASH_SIZE;
2082
2083	dprintk("nfsd: allocating %d readahead buffers.\n", cache_size);
2084
2085	for (i = 0; i < RAPARM_HASH_SIZE; i++) {
2086		spin_lock_init(&raparm_hash[i].pb_lock);
2087
2088		raparm = &raparm_hash[i].pb_head;
2089		for (j = 0; j < nperbucket; j++) {
2090			*raparm = kzalloc(sizeof(struct raparms), GFP_KERNEL);
2091			if (!*raparm)
2092				goto out_nomem;
2093			raparm = &(*raparm)->p_next;
2094		}
2095		*raparm = NULL;
2096	}
2097
2098	nfsdstats.ra_size = cache_size;
2099	return 0;
2100
2101out_nomem:
2102	dprintk("nfsd: kmalloc failed, freeing readahead buffers\n");
2103	nfsd_racache_shutdown();
2104	return -ENOMEM;
2105}