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 <asm/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	int		size_change = 0;
 
 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		goto out;
 394	if (get_write_count) {
 395		host_err = fh_want_write(fhp);
 396		if (host_err)
 397			return nfserrno(host_err);
 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		goto out;
 409
 410	nfsd_sanitize_attrs(inode, iap);
 411
 412	/*
 413	 * The size case is special, it changes the file in addition to the
 414	 * attributes.
 
 
 
 415	 */
 416	if (iap->ia_valid & ATTR_SIZE) {
 417		err = nfsd_get_write_access(rqstp, fhp, iap);
 418		if (err)
 419			goto out;
 420		size_change = 1;
 421
 422		/*
 423		 * RFC5661, Section 18.30.4:
 424		 *   Changing the size of a file with SETATTR indirectly
 425		 *   changes the time_modify and change attributes.
 426		 *
 427		 * (and similar for the older RFCs)
 428		 */
 429		if (iap->ia_size != i_size_read(inode))
 430			iap->ia_valid |= ATTR_MTIME;
 431	}
 432
 433	iap->ia_valid |= ATTR_CTIME;
 
 
 
 434
 435	if (check_guard && guardtime != inode->i_ctime.tv_sec) {
 436		err = nfserr_notsync;
 437		goto out_put_write_access;
 
 
 
 
 438	}
 439
 440	fh_lock(fhp);
 441	host_err = notify_change(dentry, iap, NULL);
 442	fh_unlock(fhp);
 443	err = nfserrno(host_err);
 444
 445out_put_write_access:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 446	if (size_change)
 447		put_write_access(inode);
 448	if (!err)
 449		err = nfserrno(commit_metadata(fhp));
 450out:
 451	return err;
 
 
 452}
 453
 454#if defined(CONFIG_NFSD_V4)
 455/*
 456 * NFS junction information is stored in an extended attribute.
 457 */
 458#define NFSD_JUNCTION_XATTR_NAME	XATTR_TRUSTED_PREFIX "junction.nfs"
 459
 460/**
 461 * nfsd4_is_junction - Test if an object could be an NFS junction
 462 *
 463 * @dentry: object to test
 464 *
 465 * Returns 1 if "dentry" appears to contain NFS junction information.
 466 * Otherwise 0 is returned.
 467 */
 468int nfsd4_is_junction(struct dentry *dentry)
 469{
 470	struct inode *inode = d_inode(dentry);
 471
 472	if (inode == NULL)
 473		return 0;
 474	if (inode->i_mode & S_IXUGO)
 475		return 0;
 476	if (!(inode->i_mode & S_ISVTX))
 477		return 0;
 478	if (vfs_getxattr(dentry, NFSD_JUNCTION_XATTR_NAME, NULL, 0) <= 0)
 
 479		return 0;
 480	return 1;
 481}
 482#ifdef CONFIG_NFSD_V4_SECURITY_LABEL
 483__be32 nfsd4_set_nfs4_label(struct svc_rqst *rqstp, struct svc_fh *fhp,
 484		struct xdr_netobj *label)
 485{
 486	__be32 error;
 487	int host_error;
 488	struct dentry *dentry;
 489
 490	error = fh_verify(rqstp, fhp, 0 /* S_IFREG */, NFSD_MAY_SATTR);
 491	if (error)
 492		return error;
 493
 494	dentry = fhp->fh_dentry;
 495
 496	inode_lock(d_inode(dentry));
 497	host_error = security_inode_setsecctx(dentry, label->data, label->len);
 498	inode_unlock(d_inode(dentry));
 499	return nfserrno(host_error);
 500}
 501#else
 502__be32 nfsd4_set_nfs4_label(struct svc_rqst *rqstp, struct svc_fh *fhp,
 503		struct xdr_netobj *label)
 504{
 505	return nfserr_notsupp;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 506}
 507#endif
 508
 509__be32 nfsd4_clone_file_range(struct file *src, u64 src_pos, struct file *dst,
 510		u64 dst_pos, u64 count)
 511{
 512	return nfserrno(vfs_clone_file_range(src, src_pos, dst, dst_pos,
 513			count));
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 514}
 515
 516__be32 nfsd4_vfs_fallocate(struct svc_rqst *rqstp, struct svc_fh *fhp,
 517			   struct file *file, loff_t offset, loff_t len,
 518			   int flags)
 519{
 520	int error;
 521
 522	if (!S_ISREG(file_inode(file)->i_mode))
 523		return nfserr_inval;
 524
 525	error = vfs_fallocate(file, flags, offset, len);
 526	if (!error)
 527		error = commit_metadata(fhp);
 528
 529	return nfserrno(error);
 530}
 531#endif /* defined(CONFIG_NFSD_V4) */
 532
 533#ifdef CONFIG_NFSD_V3
 534/*
 535 * Check server access rights to a file system object
 536 */
 537struct accessmap {
 538	u32		access;
 539	int		how;
 540};
 541static struct accessmap	nfs3_regaccess[] = {
 542    {	NFS3_ACCESS_READ,	NFSD_MAY_READ			},
 543    {	NFS3_ACCESS_EXECUTE,	NFSD_MAY_EXEC			},
 544    {	NFS3_ACCESS_MODIFY,	NFSD_MAY_WRITE|NFSD_MAY_TRUNC	},
 545    {	NFS3_ACCESS_EXTEND,	NFSD_MAY_WRITE			},
 546
 
 
 
 
 
 
 547    {	0,			0				}
 548};
 549
 550static struct accessmap	nfs3_diraccess[] = {
 551    {	NFS3_ACCESS_READ,	NFSD_MAY_READ			},
 552    {	NFS3_ACCESS_LOOKUP,	NFSD_MAY_EXEC			},
 553    {	NFS3_ACCESS_MODIFY,	NFSD_MAY_EXEC|NFSD_MAY_WRITE|NFSD_MAY_TRUNC},
 554    {	NFS3_ACCESS_EXTEND,	NFSD_MAY_EXEC|NFSD_MAY_WRITE	},
 555    {	NFS3_ACCESS_DELETE,	NFSD_MAY_REMOVE			},
 556
 
 
 
 
 
 
 557    {	0,			0				}
 558};
 559
 560static struct accessmap	nfs3_anyaccess[] = {
 561	/* Some clients - Solaris 2.6 at least, make an access call
 562	 * to the server to check for access for things like /dev/null
 563	 * (which really, the server doesn't care about).  So
 564	 * We provide simple access checking for them, looking
 565	 * mainly at mode bits, and we make sure to ignore read-only
 566	 * filesystem checks
 567	 */
 568    {	NFS3_ACCESS_READ,	NFSD_MAY_READ			},
 569    {	NFS3_ACCESS_EXECUTE,	NFSD_MAY_EXEC			},
 570    {	NFS3_ACCESS_MODIFY,	NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS	},
 571    {	NFS3_ACCESS_EXTEND,	NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS	},
 572
 573    {	0,			0				}
 574};
 575
 576__be32
 577nfsd_access(struct svc_rqst *rqstp, struct svc_fh *fhp, u32 *access, u32 *supported)
 578{
 579	struct accessmap	*map;
 580	struct svc_export	*export;
 581	struct dentry		*dentry;
 582	u32			query, result = 0, sresult = 0;
 583	__be32			error;
 584
 585	error = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP);
 586	if (error)
 587		goto out;
 588
 589	export = fhp->fh_export;
 590	dentry = fhp->fh_dentry;
 591
 592	if (d_is_reg(dentry))
 593		map = nfs3_regaccess;
 594	else if (d_is_dir(dentry))
 595		map = nfs3_diraccess;
 596	else
 597		map = nfs3_anyaccess;
 598
 599
 600	query = *access;
 601	for  (; map->access; map++) {
 602		if (map->access & query) {
 603			__be32 err2;
 604
 605			sresult |= map->access;
 606
 607			err2 = nfsd_permission(rqstp, export, dentry, map->how);
 
 608			switch (err2) {
 609			case nfs_ok:
 610				result |= map->access;
 611				break;
 612				
 613			/* the following error codes just mean the access was not allowed,
 614			 * rather than an error occurred */
 615			case nfserr_rofs:
 616			case nfserr_acces:
 617			case nfserr_perm:
 618				/* simply don't "or" in the access bit. */
 619				break;
 620			default:
 621				error = err2;
 622				goto out;
 623			}
 624		}
 625	}
 626	*access = result;
 627	if (supported)
 628		*supported = sresult;
 629
 630 out:
 631	return error;
 632}
 633#endif /* CONFIG_NFSD_V3 */
 634
 635static int nfsd_open_break_lease(struct inode *inode, int access)
 636{
 637	unsigned int mode;
 638
 639	if (access & NFSD_MAY_NOT_BREAK_LEASE)
 640		return 0;
 641	mode = (access & NFSD_MAY_WRITE) ? O_WRONLY : O_RDONLY;
 642	return break_lease(inode, mode | O_NONBLOCK);
 643}
 644
 645/*
 646 * Open an existing file or directory.
 647 * The may_flags argument indicates the type of open (read/write/lock)
 648 * and additional flags.
 649 * N.B. After this call fhp needs an fh_put
 650 */
 651__be32
 652nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type,
 653			int may_flags, struct file **filp)
 654{
 655	struct path	path;
 656	struct inode	*inode;
 657	struct file	*file;
 658	int		flags = O_RDONLY|O_LARGEFILE;
 659	__be32		err;
 660	int		host_err = 0;
 661
 662	validate_process_creds();
 663
 664	/*
 665	 * If we get here, then the client has already done an "open",
 666	 * and (hopefully) checked permission - so allow OWNER_OVERRIDE
 667	 * in case a chmod has now revoked permission.
 668	 *
 669	 * Arguably we should also allow the owner override for
 670	 * directories, but we never have and it doesn't seem to have
 671	 * caused anyone a problem.  If we were to change this, note
 672	 * also that our filldir callbacks would need a variant of
 673	 * lookup_one_len that doesn't check permissions.
 674	 */
 675	if (type == S_IFREG)
 676		may_flags |= NFSD_MAY_OWNER_OVERRIDE;
 677	err = fh_verify(rqstp, fhp, type, may_flags);
 678	if (err)
 679		goto out;
 680
 681	path.mnt = fhp->fh_export->ex_path.mnt;
 682	path.dentry = fhp->fh_dentry;
 683	inode = d_inode(path.dentry);
 684
 685	/* Disallow write access to files with the append-only bit set
 686	 * or any access when mandatory locking enabled
 687	 */
 688	err = nfserr_perm;
 689	if (IS_APPEND(inode) && (may_flags & NFSD_MAY_WRITE))
 690		goto out;
 691	/*
 692	 * We must ignore files (but only files) which might have mandatory
 693	 * locks on them because there is no way to know if the accesser has
 694	 * the lock.
 695	 */
 696	if (S_ISREG((inode)->i_mode) && mandatory_lock(inode))
 697		goto out;
 698
 699	if (!inode->i_fop)
 700		goto out;
 701
 702	host_err = nfsd_open_break_lease(inode, may_flags);
 703	if (host_err) /* NOMEM or WOULDBLOCK */
 704		goto out_nfserr;
 705
 706	if (may_flags & NFSD_MAY_WRITE) {
 707		if (may_flags & NFSD_MAY_READ)
 708			flags = O_RDWR|O_LARGEFILE;
 709		else
 710			flags = O_WRONLY|O_LARGEFILE;
 711	}
 712
 713	file = dentry_open(&path, flags, current_cred());
 714	if (IS_ERR(file)) {
 715		host_err = PTR_ERR(file);
 716		goto out_nfserr;
 717	}
 718
 719	host_err = ima_file_check(file, may_flags, 0);
 720	if (host_err) {
 721		fput(file);
 722		goto out_nfserr;
 723	}
 724
 725	if (may_flags & NFSD_MAY_64BIT_COOKIE)
 726		file->f_mode |= FMODE_64BITHASH;
 727	else
 728		file->f_mode |= FMODE_32BITHASH;
 729
 730	*filp = file;
 731out_nfserr:
 732	err = nfserrno(host_err);
 733out:
 734	validate_process_creds();
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 735	return err;
 736}
 737
 738struct raparms *
 739nfsd_init_raparms(struct file *file)
 
 
 
 
 
 
 
 
 740{
 741	struct inode *inode = file_inode(file);
 742	dev_t dev = inode->i_sb->s_dev;
 743	ino_t ino = inode->i_ino;
 744	struct raparms	*ra, **rap, **frap = NULL;
 745	int depth = 0;
 746	unsigned int hash;
 747	struct raparm_hbucket *rab;
 748
 749	hash = jhash_2words(dev, ino, 0xfeedbeef) & RAPARM_HASH_MASK;
 750	rab = &raparm_hash[hash];
 751
 752	spin_lock(&rab->pb_lock);
 753	for (rap = &rab->pb_head; (ra = *rap); rap = &ra->p_next) {
 754		if (ra->p_ino == ino && ra->p_dev == dev)
 755			goto found;
 756		depth++;
 757		if (ra->p_count == 0)
 758			frap = rap;
 759	}
 760	depth = nfsdstats.ra_size;
 761	if (!frap) {	
 762		spin_unlock(&rab->pb_lock);
 763		return NULL;
 764	}
 765	rap = frap;
 766	ra = *frap;
 767	ra->p_dev = dev;
 768	ra->p_ino = ino;
 769	ra->p_set = 0;
 770	ra->p_hindex = hash;
 771found:
 772	if (rap != &rab->pb_head) {
 773		*rap = ra->p_next;
 774		ra->p_next   = rab->pb_head;
 775		rab->pb_head = ra;
 776	}
 777	ra->p_count++;
 778	nfsdstats.ra_depth[depth*10/nfsdstats.ra_size]++;
 779	spin_unlock(&rab->pb_lock);
 780
 781	if (ra->p_set)
 782		file->f_ra = ra->p_ra;
 783	return ra;
 784}
 785
 786void nfsd_put_raparams(struct file *file, struct raparms *ra)
 787{
 788	struct raparm_hbucket *rab = &raparm_hash[ra->p_hindex];
 789
 790	spin_lock(&rab->pb_lock);
 791	ra->p_ra = file->f_ra;
 792	ra->p_set = 1;
 793	ra->p_count--;
 794	spin_unlock(&rab->pb_lock);
 795}
 796
 797/*
 798 * Grab and keep cached pages associated with a file in the svc_rqst
 799 * so that they can be passed to the network sendmsg/sendpage routines
 800 * directly. They will be released after the sending has completed.
 
 
 
 801 */
 802static int
 803nfsd_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
 804		  struct splice_desc *sd)
 805{
 806	struct svc_rqst *rqstp = sd->u.data;
 807	struct page **pp = rqstp->rq_next_page;
 808	struct page *page = buf->page;
 809	size_t size;
 810
 811	size = sd->len;
 812
 813	if (rqstp->rq_res.page_len == 0) {
 814		get_page(page);
 815		put_page(*rqstp->rq_next_page);
 816		*(rqstp->rq_next_page++) = page;
 817		rqstp->rq_res.page_base = buf->offset;
 818		rqstp->rq_res.page_len = size;
 819	} else if (page != pp[-1]) {
 820		get_page(page);
 821		if (*rqstp->rq_next_page)
 822			put_page(*rqstp->rq_next_page);
 823		*(rqstp->rq_next_page++) = page;
 824		rqstp->rq_res.page_len += size;
 825	} else
 826		rqstp->rq_res.page_len += size;
 827
 828	return size;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 829}
 830
 831static int nfsd_direct_splice_actor(struct pipe_inode_info *pipe,
 832				    struct splice_desc *sd)
 833{
 834	return __splice_from_pipe(pipe, sd, nfsd_splice_actor);
 835}
 836
 837static __be32
 838nfsd_finish_read(struct file *file, unsigned long *count, int host_err)
 
 
 
 
 
 
 
 
 
 
 
 839{
 840	if (host_err >= 0) {
 841		nfsdstats.io_read += host_err;
 
 
 
 842		*count = host_err;
 843		fsnotify_access(file);
 
 844		return 0;
 845	} else 
 
 846		return nfserrno(host_err);
 
 847}
 848
 849__be32 nfsd_splice_read(struct svc_rqst *rqstp,
 850		     struct file *file, loff_t offset, unsigned long *count)
 
 
 
 
 
 
 
 
 
 
 
 
 
 851{
 852	struct splice_desc sd = {
 853		.len		= 0,
 854		.total_len	= *count,
 855		.pos		= offset,
 856		.u.data		= rqstp,
 857	};
 858	int host_err;
 859
 860	rqstp->rq_next_page = rqstp->rq_respages + 1;
 861	host_err = splice_direct_to_actor(file, &sd, nfsd_direct_splice_actor);
 862	return nfsd_finish_read(file, count, host_err);
 863}
 864
 865__be32 nfsd_readv(struct file *file, loff_t offset, struct kvec *vec, int vlen,
 866		unsigned long *count)
 867{
 868	mm_segment_t oldfs;
 869	int host_err;
 870
 871	oldfs = get_fs();
 872	set_fs(KERNEL_DS);
 873	host_err = vfs_readv(file, (struct iovec __user *)vec, vlen, &offset, 0);
 874	set_fs(oldfs);
 875	return nfsd_finish_read(file, count, host_err);
 876}
 877
 878static __be32
 879nfsd_vfs_read(struct svc_rqst *rqstp, struct file *file,
 880	      loff_t offset, struct kvec *vec, int vlen, unsigned long *count)
 881{
 882	if (file->f_op->splice_read && test_bit(RQ_SPLICE_OK, &rqstp->rq_flags))
 883		return nfsd_splice_read(rqstp, file, offset, count);
 884	else
 885		return nfsd_readv(file, offset, vec, vlen, count);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 886}
 887
 888/*
 889 * Gathered writes: If another process is currently writing to the file,
 890 * there's a high chance this is another nfsd (triggered by a bulk write
 891 * from a client's biod). Rather than syncing the file with each write
 892 * request, we sleep for 10 msec.
 893 *
 894 * I don't know if this roughly approximates C. Juszak's idea of
 895 * gathered writes, but it's a nice and simple solution (IMHO), and it
 896 * seems to work:-)
 897 *
 898 * Note: we do this only in the NFSv2 case, since v3 and higher have a
 899 * better tool (separate unstable writes and commits) for solving this
 900 * problem.
 901 */
 902static int wait_for_concurrent_writes(struct file *file)
 903{
 904	struct inode *inode = file_inode(file);
 905	static ino_t last_ino;
 906	static dev_t last_dev;
 907	int err = 0;
 908
 909	if (atomic_read(&inode->i_writecount) > 1
 910	    || (last_ino == inode->i_ino && last_dev == inode->i_sb->s_dev)) {
 911		dprintk("nfsd: write defer %d\n", task_pid_nr(current));
 912		msleep(10);
 913		dprintk("nfsd: write resume %d\n", task_pid_nr(current));
 914	}
 915
 916	if (inode->i_state & I_DIRTY) {
 917		dprintk("nfsd: write sync %d\n", task_pid_nr(current));
 918		err = vfs_fsync(file, 0);
 919	}
 920	last_ino = inode->i_ino;
 921	last_dev = inode->i_sb->s_dev;
 922	return err;
 923}
 924
 925__be32
 926nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
 927				loff_t offset, struct kvec *vec, int vlen,
 928				unsigned long *cnt, int *stablep)
 
 929{
 
 
 
 930	struct svc_export	*exp;
 931	struct inode		*inode;
 932	mm_segment_t		oldfs;
 933	__be32			err = 0;
 934	int			host_err;
 935	int			stable = *stablep;
 936	int			use_wgather;
 937	loff_t			pos = offset;
 938	loff_t			end = LLONG_MAX;
 939	unsigned int		pflags = current->flags;
 
 
 940
 941	if (test_bit(RQ_LOCAL, &rqstp->rq_flags))
 
 
 
 
 
 
 942		/*
 943		 * We want less throttling in balance_dirty_pages()
 944		 * and shrink_inactive_list() so that nfs to
 
 945		 * localhost doesn't cause nfsd to lock up due to all
 946		 * the client's dirty pages or its congested queue.
 947		 */
 948		current->flags |= PF_LESS_THROTTLE;
 949
 950	inode = file_inode(file);
 951	exp   = fhp->fh_export;
 952
 953	use_wgather = (rqstp->rq_vers == 2) && EX_WGATHER(exp);
 954
 955	if (!EX_ISSYNC(exp))
 956		stable = 0;
 957
 958	/* Write the data. */
 959	oldfs = get_fs(); set_fs(KERNEL_DS);
 960	host_err = vfs_writev(file, (struct iovec __user *)vec, vlen, &pos, 0);
 961	set_fs(oldfs);
 962	if (host_err < 0)
 
 
 
 
 
 963		goto out_nfserr;
 
 964	*cnt = host_err;
 965	nfsdstats.io_write += host_err;
 966	fsnotify_modify(file);
 
 
 
 967
 968	if (stable) {
 969		if (use_wgather) {
 970			host_err = wait_for_concurrent_writes(file);
 971		} else {
 972			if (*cnt)
 973				end = offset + *cnt - 1;
 974			host_err = vfs_fsync_range(file, offset, end, 0);
 975		}
 976	}
 977
 978out_nfserr:
 979	dprintk("nfsd: write complete host_err=%d\n", host_err);
 980	if (host_err >= 0)
 981		err = 0;
 982	else
 983		err = nfserrno(host_err);
 984	if (test_bit(RQ_LOCAL, &rqstp->rq_flags))
 985		tsk_restore_flags(current, pflags, PF_LESS_THROTTLE);
 986	return err;
 
 
 987}
 988
 989/*
 990 * Read data from a file. count must contain the requested read count
 991 * on entry. On return, *count contains the number of bytes actually read.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 992 * N.B. After this call fhp needs an fh_put
 
 
 
 993 */
 994__be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
 995	loff_t offset, struct kvec *vec, int vlen, unsigned long *count)
 996{
 
 997	struct file *file;
 998	struct raparms	*ra;
 999	__be32 err;
1000
1001	trace_read_start(rqstp, fhp, offset, vlen);
1002	err = nfsd_open(rqstp, fhp, S_IFREG, NFSD_MAY_READ, &file);
1003	if (err)
1004		return err;
1005
1006	ra = nfsd_init_raparms(file);
1007
1008	trace_read_opened(rqstp, fhp, offset, vlen);
1009	err = nfsd_vfs_read(rqstp, file, offset, vec, vlen, count);
1010	trace_read_io_done(rqstp, fhp, offset, vlen);
1011
1012	if (ra)
1013		nfsd_put_raparams(file, ra);
1014	fput(file);
1015
1016	trace_read_done(rqstp, fhp, offset, vlen);
1017
 
 
1018	return err;
1019}
1020
1021/*
1022 * Write data to a file.
1023 * The stable flag requests synchronous writes.
1024 * N.B. After this call fhp needs an fh_put
1025 */
1026__be32
1027nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
1028		loff_t offset, struct kvec *vec, int vlen, unsigned long *cnt,
1029		int *stablep)
1030{
1031	__be32			err = 0;
 
1032
1033	trace_write_start(rqstp, fhp, offset, vlen);
1034
1035	if (file) {
1036		err = nfsd_permission(rqstp, fhp->fh_export, fhp->fh_dentry,
1037				NFSD_MAY_WRITE|NFSD_MAY_OWNER_OVERRIDE);
1038		if (err)
1039			goto out;
1040		trace_write_opened(rqstp, fhp, offset, vlen);
1041		err = nfsd_vfs_write(rqstp, fhp, file, offset, vec, vlen, cnt,
1042				stablep);
1043		trace_write_io_done(rqstp, fhp, offset, vlen);
1044	} else {
1045		err = nfsd_open(rqstp, fhp, S_IFREG, NFSD_MAY_WRITE, &file);
1046		if (err)
1047			goto out;
1048
1049		trace_write_opened(rqstp, fhp, offset, vlen);
1050		if (cnt)
1051			err = nfsd_vfs_write(rqstp, fhp, file, offset, vec, vlen,
1052					     cnt, stablep);
1053		trace_write_io_done(rqstp, fhp, offset, vlen);
1054		fput(file);
1055	}
1056out:
1057	trace_write_done(rqstp, fhp, offset, vlen);
1058	return err;
1059}
1060
1061#ifdef CONFIG_NFSD_V3
1062/*
1063 * Commit all pending writes to stable storage.
 
 
 
 
 
1064 *
1065 * Note: we only guarantee that data that lies within the range specified
1066 * by the 'offset' and 'count' parameters will be synced.
 
 
1067 *
1068 * Unfortunately we cannot lock the file to make sure we return full WCC
1069 * data to the client, as locking happens lower down in the filesystem.
 
 
 
1070 */
1071__be32
1072nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp,
1073               loff_t offset, unsigned long count)
1074{
1075	struct file	*file;
1076	loff_t		end = LLONG_MAX;
1077	__be32		err = nfserr_inval;
 
1078
1079	if (offset < 0)
1080		goto out;
1081	if (count != 0) {
1082		end = offset + (loff_t)count - 1;
1083		if (end < offset)
1084			goto out;
 
 
 
 
 
 
 
1085	}
1086
1087	err = nfsd_open(rqstp, fhp, S_IFREG,
1088			NFSD_MAY_WRITE|NFSD_MAY_NOT_BREAK_LEASE, &file);
1089	if (err)
1090		goto out;
1091	if (EX_ISSYNC(fhp->fh_export)) {
1092		int err2 = vfs_fsync_range(file, offset, end, 0);
 
1093
1094		if (err2 != -EINVAL)
 
 
 
 
 
1095			err = nfserrno(err2);
1096		else
 
1097			err = nfserr_notsupp;
1098	}
 
 
 
 
 
 
1099
1100	fput(file);
1101out:
1102	return err;
1103}
1104#endif /* CONFIG_NFSD_V3 */
1105
1106static __be32
1107nfsd_create_setattr(struct svc_rqst *rqstp, struct svc_fh *resfhp,
1108			struct iattr *iap)
 
 
 
 
 
 
 
 
 
1109{
 
 
 
1110	/*
1111	 * Mode has already been set earlier in create:
1112	 */
1113	iap->ia_valid &= ~ATTR_MODE;
 
1114	/*
1115	 * Setting uid/gid works only for root.  Irix appears to
1116	 * send along the gid on create when it tries to implement
1117	 * setgid directories via NFS:
1118	 */
1119	if (!uid_eq(current_fsuid(), GLOBAL_ROOT_UID))
1120		iap->ia_valid &= ~(ATTR_UID|ATTR_GID);
1121	if (iap->ia_valid)
1122		return nfsd_setattr(rqstp, resfhp, iap, 0, (time_t)0);
1123	/* Callers expect file metadata to be committed here */
1124	return nfserrno(commit_metadata(resfhp));
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1125}
1126
1127/* HPUX client sometimes creates a file in mode 000, and sets size to 0.
1128 * setting size to 0 may fail for some specific file systems by the permission
1129 * checking which requires WRITE permission but the mode is 000.
1130 * we ignore the resizing(to 0) on the just new created file, since the size is
1131 * 0 after file created.
1132 *
1133 * call this only after vfs_create() is called.
1134 * */
1135static void
1136nfsd_check_ignore_resizing(struct iattr *iap)
1137{
1138	if ((iap->ia_valid & ATTR_SIZE) && (iap->ia_size == 0))
1139		iap->ia_valid &= ~ATTR_SIZE;
1140}
1141
1142/*
1143 * Create a file (regular, directory, device, fifo); UNIX sockets 
1144 * not yet implemented.
1145 * If the response fh has been verified, the parent directory should
1146 * already be locked. Note that the parent directory is left locked.
1147 *
1148 * N.B. Every call to nfsd_create needs an fh_put for _both_ fhp and resfhp
1149 */
1150__be32
1151nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
1152		char *fname, int flen, struct iattr *iap,
1153		int type, dev_t rdev, struct svc_fh *resfhp)
1154{
1155	struct dentry	*dentry, *dchild = NULL;
1156	struct inode	*dirp;
 
1157	__be32		err;
1158	__be32		err2;
1159	int		host_err;
1160
1161	err = nfserr_perm;
1162	if (!flen)
1163		goto out;
1164	err = nfserr_exist;
1165	if (isdotent(fname, flen))
1166		goto out;
1167
1168	err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
1169	if (err)
1170		goto out;
1171
1172	dentry = fhp->fh_dentry;
1173	dirp = d_inode(dentry);
1174
1175	err = nfserr_notdir;
1176	if (!dirp->i_op->lookup)
 
 
1177		goto out;
1178	/*
1179	 * Check whether the response file handle has been verified yet.
1180	 * If it has, the parent directory should already be locked.
1181	 */
1182	if (!resfhp->fh_dentry) {
1183		host_err = fh_want_write(fhp);
1184		if (host_err)
1185			goto out_nfserr;
1186
1187		/* called from nfsd_proc_mkdir, or possibly nfsd3_proc_create */
1188		fh_lock_nested(fhp, I_MUTEX_PARENT);
1189		dchild = lookup_one_len(fname, dentry, flen);
1190		host_err = PTR_ERR(dchild);
1191		if (IS_ERR(dchild))
1192			goto out_nfserr;
1193		err = fh_compose(resfhp, fhp->fh_export, dchild, fhp);
1194		if (err)
1195			goto out;
1196	} else {
1197		/* called from nfsd_proc_create */
1198		dchild = dget(resfhp->fh_dentry);
1199		if (!fhp->fh_locked) {
1200			/* not actually possible */
1201			printk(KERN_ERR
1202				"nfsd_create: parent %pd2 not locked!\n",
1203				dentry);
1204			err = nfserr_io;
1205			goto out;
1206		}
1207	}
1208	/*
1209	 * Make sure the child dentry is still negative ...
1210	 */
1211	err = nfserr_exist;
1212	if (d_really_is_positive(dchild)) {
1213		dprintk("nfsd_create: dentry %pd/%pd not negative!\n",
1214			dentry, dchild);
1215		goto out; 
1216	}
1217
1218	if (!(iap->ia_valid & ATTR_MODE))
1219		iap->ia_mode = 0;
1220	iap->ia_mode = (iap->ia_mode & S_IALLUGO) | type;
1221
1222	err = nfserr_inval;
1223	if (!S_ISREG(type) && !S_ISDIR(type) && !special_file(type)) {
1224		printk(KERN_WARNING "nfsd: bad file type %o in nfsd_create\n",
1225		       type);
1226		goto out;
1227	}
1228
1229	/*
1230	 * Get the dir op function pointer.
1231	 */
1232	err = 0;
1233	host_err = 0;
1234	switch (type) {
1235	case S_IFREG:
1236		host_err = vfs_create(dirp, dchild, iap->ia_mode, true);
 
1237		if (!host_err)
1238			nfsd_check_ignore_resizing(iap);
1239		break;
1240	case S_IFDIR:
1241		host_err = vfs_mkdir(dirp, dchild, iap->ia_mode);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1242		break;
1243	case S_IFCHR:
1244	case S_IFBLK:
1245	case S_IFIFO:
1246	case S_IFSOCK:
1247		host_err = vfs_mknod(dirp, dchild, iap->ia_mode, rdev);
 
1248		break;
 
 
 
 
1249	}
1250	if (host_err < 0)
1251		goto out_nfserr;
1252
1253	err = nfsd_create_setattr(rqstp, resfhp, iap);
1254
1255	/*
1256	 * nfsd_create_setattr already committed the child.  Transactional
1257	 * filesystems had a chance to commit changes for both parent and
1258	 * child * simultaneously making the following commit_metadata a
1259	 * noop.
1260	 */
1261	err2 = nfserrno(commit_metadata(fhp));
1262	if (err2)
1263		err = err2;
1264	/*
1265	 * Update the file handle to get the new inode info.
1266	 */
1267	if (!err)
1268		err = fh_update(resfhp);
1269out:
1270	if (dchild && !IS_ERR(dchild))
1271		dput(dchild);
1272	return err;
1273
1274out_nfserr:
1275	err = nfserrno(host_err);
1276	goto out;
1277}
1278
1279#ifdef CONFIG_NFSD_V3
1280
1281/*
1282 * NFSv3 and NFSv4 version of nfsd_create
 
 
 
1283 */
1284__be32
1285do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
1286		char *fname, int flen, struct iattr *iap,
1287		struct svc_fh *resfhp, int createmode, u32 *verifier,
1288	        bool *truncp, bool *created)
1289{
1290	struct dentry	*dentry, *dchild = NULL;
1291	struct inode	*dirp;
1292	__be32		err;
1293	int		host_err;
1294	__u32		v_mtime=0, v_atime=0;
1295
1296	err = nfserr_perm;
1297	if (!flen)
1298		goto out;
1299	err = nfserr_exist;
1300	if (isdotent(fname, flen))
1301		goto out;
1302	if (!(iap->ia_valid & ATTR_MODE))
1303		iap->ia_mode = 0;
1304	err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC);
1305	if (err)
1306		goto out;
1307
1308	dentry = fhp->fh_dentry;
1309	dirp = d_inode(dentry);
1310
1311	/* Get all the sanity checks out of the way before
1312	 * we lock the parent. */
1313	err = nfserr_notdir;
1314	if (!dirp->i_op->lookup)
1315		goto out;
1316
1317	host_err = fh_want_write(fhp);
1318	if (host_err)
1319		goto out_nfserr;
1320
1321	fh_lock_nested(fhp, I_MUTEX_PARENT);
1322
1323	/*
1324	 * Compose the response file handle.
1325	 */
1326	dchild = lookup_one_len(fname, dentry, flen);
1327	host_err = PTR_ERR(dchild);
1328	if (IS_ERR(dchild))
1329		goto out_nfserr;
1330
1331	/* If file doesn't exist, check for permissions to create one */
1332	if (d_really_is_negative(dchild)) {
1333		err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
1334		if (err)
1335			goto out;
1336	}
1337
1338	err = fh_compose(resfhp, fhp->fh_export, dchild, fhp);
1339	if (err)
1340		goto out;
1341
1342	if (nfsd_create_is_exclusive(createmode)) {
1343		/* solaris7 gets confused (bugid 4218508) if these have
1344		 * the high bit set, so just clear the high bits. If this is
1345		 * ever changed to use different attrs for storing the
1346		 * verifier, then do_open_lookup() will also need to be fixed
1347		 * accordingly.
1348		 */
1349		v_mtime = verifier[0]&0x7fffffff;
1350		v_atime = verifier[1]&0x7fffffff;
1351	}
1352	
1353	if (d_really_is_positive(dchild)) {
1354		err = 0;
1355
1356		switch (createmode) {
1357		case NFS3_CREATE_UNCHECKED:
1358			if (! d_is_reg(dchild))
1359				goto out;
1360			else if (truncp) {
1361				/* in nfsv4, we need to treat this case a little
1362				 * differently.  we don't want to truncate the
1363				 * file now; this would be wrong if the OPEN
1364				 * fails for some other reason.  furthermore,
1365				 * if the size is nonzero, we should ignore it
1366				 * according to spec!
1367				 */
1368				*truncp = (iap->ia_valid & ATTR_SIZE) && !iap->ia_size;
1369			}
1370			else {
1371				iap->ia_valid &= ATTR_SIZE;
1372				goto set_attr;
1373			}
1374			break;
1375		case NFS3_CREATE_EXCLUSIVE:
1376			if (   d_inode(dchild)->i_mtime.tv_sec == v_mtime
1377			    && d_inode(dchild)->i_atime.tv_sec == v_atime
1378			    && d_inode(dchild)->i_size  == 0 ) {
1379				if (created)
1380					*created = 1;
1381				break;
1382			}
1383		case NFS4_CREATE_EXCLUSIVE4_1:
1384			if (   d_inode(dchild)->i_mtime.tv_sec == v_mtime
1385			    && d_inode(dchild)->i_atime.tv_sec == v_atime
1386			    && d_inode(dchild)->i_size  == 0 ) {
1387				if (created)
1388					*created = 1;
1389				goto set_attr;
1390			}
1391			 /* fallthru */
1392		case NFS3_CREATE_GUARDED:
1393			err = nfserr_exist;
1394		}
1395		fh_drop_write(fhp);
1396		goto out;
1397	}
1398
1399	host_err = vfs_create(dirp, dchild, iap->ia_mode, true);
1400	if (host_err < 0) {
1401		fh_drop_write(fhp);
1402		goto out_nfserr;
1403	}
1404	if (created)
1405		*created = 1;
1406
1407	nfsd_check_ignore_resizing(iap);
1408
1409	if (nfsd_create_is_exclusive(createmode)) {
1410		/* Cram the verifier into atime/mtime */
1411		iap->ia_valid = ATTR_MTIME|ATTR_ATIME
1412			| ATTR_MTIME_SET|ATTR_ATIME_SET;
1413		/* XXX someone who knows this better please fix it for nsec */ 
1414		iap->ia_mtime.tv_sec = v_mtime;
1415		iap->ia_atime.tv_sec = v_atime;
1416		iap->ia_mtime.tv_nsec = 0;
1417		iap->ia_atime.tv_nsec = 0;
1418	}
1419
1420 set_attr:
1421	err = nfsd_create_setattr(rqstp, resfhp, iap);
1422
1423	/*
1424	 * nfsd_create_setattr already committed the child
1425	 * (and possibly also the parent).
1426	 */
1427	if (!err)
1428		err = nfserrno(commit_metadata(fhp));
1429
1430	/*
1431	 * Update the filehandle to get the new inode info.
 
1432	 */
1433	if (!err)
1434		err = fh_update(resfhp);
1435
1436 out:
1437	fh_unlock(fhp);
1438	if (dchild && !IS_ERR(dchild))
1439		dput(dchild);
1440	fh_drop_write(fhp);
1441 	return err;
1442 
1443 out_nfserr:
1444	err = nfserrno(host_err);
1445	goto out;
1446}
1447#endif /* CONFIG_NFSD_V3 */
1448
1449/*
1450 * Read a symlink. On entry, *lenp must contain the maximum path length that
1451 * fits into the buffer. On return, it contains the true length.
1452 * N.B. After this call fhp needs an fh_put
1453 */
1454__be32
1455nfsd_readlink(struct svc_rqst *rqstp, struct svc_fh *fhp, char *buf, int *lenp)
1456{
1457	struct inode	*inode;
1458	mm_segment_t	oldfs;
1459	__be32		err;
1460	int		host_err;
1461	struct path path;
 
 
1462
1463	err = fh_verify(rqstp, fhp, S_IFLNK, NFSD_MAY_NOP);
1464	if (err)
1465		goto out;
1466
1467	path.mnt = fhp->fh_export->ex_path.mnt;
1468	path.dentry = fhp->fh_dentry;
1469	inode = d_inode(path.dentry);
1470
1471	err = nfserr_inval;
1472	if (!inode->i_op->readlink)
1473		goto out;
1474
1475	touch_atime(&path);
1476	/* N.B. Why does this call need a get_fs()??
1477	 * Remove the set_fs and watch the fireworks:-) --okir
1478	 */
1479
1480	oldfs = get_fs(); set_fs(KERNEL_DS);
1481	host_err = inode->i_op->readlink(path.dentry, (char __user *)buf, *lenp);
1482	set_fs(oldfs);
1483
1484	if (host_err < 0)
1485		goto out_nfserr;
1486	*lenp = host_err;
1487	err = 0;
1488out:
1489	return err;
1490
1491out_nfserr:
1492	err = nfserrno(host_err);
1493	goto out;
1494}
1495
1496/*
1497 * Create a symlink and look up its inode
 
 
 
 
 
 
 
 
1498 * N.B. After this call _both_ fhp and resfhp need an fh_put
 
 
1499 */
1500__be32
1501nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp,
1502				char *fname, int flen,
1503				char *path,
1504				struct svc_fh *resfhp)
1505{
1506	struct dentry	*dentry, *dnew;
1507	__be32		err, cerr;
1508	int		host_err;
1509
1510	err = nfserr_noent;
1511	if (!flen || path[0] == '\0')
1512		goto out;
1513	err = nfserr_exist;
1514	if (isdotent(fname, flen))
1515		goto out;
1516
1517	err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
1518	if (err)
1519		goto out;
1520
1521	host_err = fh_want_write(fhp);
1522	if (host_err)
1523		goto out_nfserr;
 
 
1524
1525	fh_lock(fhp);
1526	dentry = fhp->fh_dentry;
 
1527	dnew = lookup_one_len(fname, dentry, flen);
1528	host_err = PTR_ERR(dnew);
1529	if (IS_ERR(dnew))
1530		goto out_nfserr;
1531
1532	host_err = vfs_symlink(d_inode(dentry), dnew, path);
 
 
 
 
1533	err = nfserrno(host_err);
 
 
 
 
 
 
1534	if (!err)
1535		err = nfserrno(commit_metadata(fhp));
1536	fh_unlock(fhp);
1537
1538	fh_drop_write(fhp);
1539
1540	cerr = fh_compose(resfhp, fhp->fh_export, dnew, fhp);
1541	dput(dnew);
1542	if (err==0) err = cerr;
 
 
1543out:
1544	return err;
1545
1546out_nfserr:
1547	err = nfserrno(host_err);
1548	goto out;
1549}
1550
1551/*
1552 * Create a hardlink
1553 * N.B. After this call _both_ ffhp and tfhp need an fh_put
1554 */
1555__be32
1556nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp,
1557				char *name, int len, struct svc_fh *tfhp)
1558{
1559	struct dentry	*ddir, *dnew, *dold;
1560	struct inode	*dirp;
1561	__be32		err;
1562	int		host_err;
1563
1564	err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_CREATE);
1565	if (err)
1566		goto out;
1567	err = fh_verify(rqstp, tfhp, 0, NFSD_MAY_NOP);
1568	if (err)
1569		goto out;
1570	err = nfserr_isdir;
1571	if (d_is_dir(tfhp->fh_dentry))
1572		goto out;
1573	err = nfserr_perm;
1574	if (!len)
1575		goto out;
1576	err = nfserr_exist;
1577	if (isdotent(name, len))
1578		goto out;
1579
1580	host_err = fh_want_write(tfhp);
1581	if (host_err) {
1582		err = nfserrno(host_err);
1583		goto out;
1584	}
1585
1586	fh_lock_nested(ffhp, I_MUTEX_PARENT);
1587	ddir = ffhp->fh_dentry;
1588	dirp = d_inode(ddir);
 
1589
1590	dnew = lookup_one_len(name, ddir, len);
1591	host_err = PTR_ERR(dnew);
1592	if (IS_ERR(dnew))
1593		goto out_nfserr;
 
1594
1595	dold = tfhp->fh_dentry;
1596
1597	err = nfserr_noent;
1598	if (d_really_is_negative(dold))
1599		goto out_dput;
1600	host_err = vfs_link(dold, dirp, dnew, NULL);
 
 
 
 
 
1601	if (!host_err) {
1602		err = nfserrno(commit_metadata(ffhp));
1603		if (!err)
1604			err = nfserrno(commit_metadata(tfhp));
1605	} else {
1606		if (host_err == -EXDEV && rqstp->rq_vers == 2)
1607			err = nfserr_acces;
1608		else
1609			err = nfserrno(host_err);
1610	}
1611out_dput:
1612	dput(dnew);
1613out_unlock:
1614	fh_unlock(ffhp);
1615	fh_drop_write(tfhp);
1616out:
1617	return err;
1618
1619out_nfserr:
1620	err = nfserrno(host_err);
1621	goto out_unlock;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1622}
1623
1624/*
1625 * Rename a file
1626 * N.B. After this call _both_ ffhp and tfhp need an fh_put
1627 */
1628__be32
1629nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
1630			    struct svc_fh *tfhp, char *tname, int tlen)
1631{
1632	struct dentry	*fdentry, *tdentry, *odentry, *ndentry, *trap;
1633	struct inode	*fdir, *tdir;
1634	__be32		err;
1635	int		host_err;
 
1636
1637	err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_REMOVE);
1638	if (err)
1639		goto out;
1640	err = fh_verify(rqstp, tfhp, S_IFDIR, NFSD_MAY_CREATE);
1641	if (err)
1642		goto out;
1643
1644	fdentry = ffhp->fh_dentry;
1645	fdir = d_inode(fdentry);
1646
1647	tdentry = tfhp->fh_dentry;
1648	tdir = d_inode(tdentry);
1649
1650	err = nfserr_perm;
1651	if (!flen || isdotent(fname, flen) || !tlen || isdotent(tname, tlen))
1652		goto out;
1653
 
 
 
 
 
 
 
1654	host_err = fh_want_write(ffhp);
1655	if (host_err) {
1656		err = nfserrno(host_err);
1657		goto out;
1658	}
1659
1660	/* cannot use fh_lock as we need deadlock protective ordering
1661	 * so do it by hand */
1662	trap = lock_rename(tdentry, fdentry);
1663	ffhp->fh_locked = tfhp->fh_locked = true;
1664	fill_pre_wcc(ffhp);
1665	fill_pre_wcc(tfhp);
 
 
 
 
 
 
 
1666
1667	odentry = lookup_one_len(fname, fdentry, flen);
1668	host_err = PTR_ERR(odentry);
1669	if (IS_ERR(odentry))
1670		goto out_nfserr;
1671
1672	host_err = -ENOENT;
1673	if (d_really_is_negative(odentry))
1674		goto out_dput_old;
1675	host_err = -EINVAL;
1676	if (odentry == trap)
1677		goto out_dput_old;
1678
1679	ndentry = lookup_one_len(tname, tdentry, tlen);
1680	host_err = PTR_ERR(ndentry);
1681	if (IS_ERR(ndentry))
1682		goto out_dput_old;
1683	host_err = -ENOTEMPTY;
1684	if (ndentry == trap)
1685		goto out_dput_new;
1686
1687	host_err = -EXDEV;
1688	if (ffhp->fh_export->ex_path.mnt != tfhp->fh_export->ex_path.mnt)
1689		goto out_dput_new;
1690	if (ffhp->fh_export->ex_path.dentry != tfhp->fh_export->ex_path.dentry)
1691		goto out_dput_new;
 
 
 
 
 
 
 
 
 
1692
1693	host_err = vfs_rename(fdir, odentry, tdir, ndentry, NULL, 0);
1694	if (!host_err) {
1695		host_err = commit_metadata(tfhp);
1696		if (!host_err)
1697			host_err = commit_metadata(ffhp);
 
 
 
 
 
 
 
1698	}
1699 out_dput_new:
1700	dput(ndentry);
1701 out_dput_old:
1702	dput(odentry);
1703 out_nfserr:
1704	err = nfserrno(host_err);
1705	/*
1706	 * We cannot rely on fh_unlock on the two filehandles,
1707	 * as that would do the wrong thing if the two directories
1708	 * were the same, so again we do it by hand.
1709	 */
1710	fill_post_wcc(ffhp);
1711	fill_post_wcc(tfhp);
1712	unlock_rename(tdentry, fdentry);
1713	ffhp->fh_locked = tfhp->fh_locked = false;
1714	fh_drop_write(ffhp);
1715
 
 
 
 
 
 
 
 
 
 
 
 
1716out:
1717	return err;
1718}
1719
1720/*
1721 * Unlink a file or directory
1722 * N.B. After this call fhp needs an fh_put
1723 */
1724__be32
1725nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
1726				char *fname, int flen)
1727{
1728	struct dentry	*dentry, *rdentry;
1729	struct inode	*dirp;
 
1730	__be32		err;
1731	int		host_err;
1732
1733	err = nfserr_acces;
1734	if (!flen || isdotent(fname, flen))
1735		goto out;
1736	err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_REMOVE);
1737	if (err)
1738		goto out;
1739
1740	host_err = fh_want_write(fhp);
1741	if (host_err)
1742		goto out_nfserr;
1743
1744	fh_lock_nested(fhp, I_MUTEX_PARENT);
1745	dentry = fhp->fh_dentry;
1746	dirp = d_inode(dentry);
 
1747
1748	rdentry = lookup_one_len(fname, dentry, flen);
1749	host_err = PTR_ERR(rdentry);
1750	if (IS_ERR(rdentry))
1751		goto out_nfserr;
1752
1753	if (d_really_is_negative(rdentry)) {
1754		dput(rdentry);
1755		err = nfserr_noent;
1756		goto out;
1757	}
 
 
 
 
1758
 
1759	if (!type)
1760		type = d_inode(rdentry)->i_mode & S_IFMT;
1761
1762	if (type != S_IFDIR)
1763		host_err = vfs_unlink(dirp, rdentry, NULL);
1764	else
1765		host_err = vfs_rmdir(dirp, rdentry);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1766	if (!host_err)
1767		host_err = commit_metadata(fhp);
1768	dput(rdentry);
 
1769
 
 
1770out_nfserr:
1771	err = nfserrno(host_err);
 
 
 
 
 
 
 
1772out:
1773	return err;
 
 
 
1774}
1775
1776/*
1777 * We do this buffering because we must not call back into the file
1778 * system's ->lookup() method from the filldir callback. That may well
1779 * deadlock a number of file systems.
1780 *
1781 * This is based heavily on the implementation of same in XFS.
1782 */
1783struct buffered_dirent {
1784	u64		ino;
1785	loff_t		offset;
1786	int		namlen;
1787	unsigned int	d_type;
1788	char		name[];
1789};
1790
1791struct readdir_data {
1792	struct dir_context ctx;
1793	char		*dirent;
1794	size_t		used;
1795	int		full;
1796};
1797
1798static int nfsd_buffered_filldir(struct dir_context *ctx, const char *name,
1799				 int namlen, loff_t offset, u64 ino,
1800				 unsigned int d_type)
1801{
1802	struct readdir_data *buf =
1803		container_of(ctx, struct readdir_data, ctx);
1804	struct buffered_dirent *de = (void *)(buf->dirent + buf->used);
1805	unsigned int reclen;
1806
1807	reclen = ALIGN(sizeof(struct buffered_dirent) + namlen, sizeof(u64));
1808	if (buf->used + reclen > PAGE_SIZE) {
1809		buf->full = 1;
1810		return -EINVAL;
1811	}
1812
1813	de->namlen = namlen;
1814	de->offset = offset;
1815	de->ino = ino;
1816	de->d_type = d_type;
1817	memcpy(de->name, name, namlen);
1818	buf->used += reclen;
1819
1820	return 0;
1821}
1822
1823static __be32 nfsd_buffered_readdir(struct file *file, nfsd_filldir_t func,
1824				    struct readdir_cd *cdp, loff_t *offsetp)
 
1825{
1826	struct buffered_dirent *de;
1827	int host_err;
1828	int size;
1829	loff_t offset;
1830	struct readdir_data buf = {
1831		.ctx.actor = nfsd_buffered_filldir,
1832		.dirent = (void *)__get_free_page(GFP_KERNEL)
1833	};
1834
1835	if (!buf.dirent)
1836		return nfserrno(-ENOMEM);
1837
1838	offset = *offsetp;
1839
1840	while (1) {
1841		unsigned int reclen;
1842
1843		cdp->err = nfserr_eof; /* will be cleared on successful read */
1844		buf.used = 0;
1845		buf.full = 0;
1846
1847		host_err = iterate_dir(file, &buf.ctx);
1848		if (buf.full)
1849			host_err = 0;
1850
1851		if (host_err < 0)
1852			break;
1853
1854		size = buf.used;
1855
1856		if (!size)
1857			break;
1858
1859		de = (struct buffered_dirent *)buf.dirent;
1860		while (size > 0) {
1861			offset = de->offset;
1862
1863			if (func(cdp, de->name, de->namlen, de->offset,
1864				 de->ino, de->d_type))
1865				break;
1866
1867			if (cdp->err != nfs_ok)
1868				break;
1869
 
 
1870			reclen = ALIGN(sizeof(*de) + de->namlen,
1871				       sizeof(u64));
1872			size -= reclen;
1873			de = (struct buffered_dirent *)((char *)de + reclen);
1874		}
1875		if (size > 0) /* We bailed out early */
1876			break;
1877
1878		offset = vfs_llseek(file, 0, SEEK_CUR);
1879	}
1880
1881	free_page((unsigned long)(buf.dirent));
1882
1883	if (host_err)
1884		return nfserrno(host_err);
1885
1886	*offsetp = offset;
1887	return cdp->err;
1888}
1889
1890/*
1891 * Read entries from a directory.
1892 * The  NFSv3/4 verifier we ignore for now.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1893 */
1894__be32
1895nfsd_readdir(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t *offsetp, 
1896	     struct readdir_cd *cdp, nfsd_filldir_t func)
1897{
1898	__be32		err;
1899	struct file	*file;
1900	loff_t		offset = *offsetp;
1901	int             may_flags = NFSD_MAY_READ;
1902
1903	/* NFSv2 only supports 32 bit cookies */
1904	if (rqstp->rq_vers > 2)
1905		may_flags |= NFSD_MAY_64BIT_COOKIE;
1906
1907	err = nfsd_open(rqstp, fhp, S_IFDIR, may_flags, &file);
1908	if (err)
1909		goto out;
1910
 
 
 
 
 
1911	offset = vfs_llseek(file, offset, SEEK_SET);
1912	if (offset < 0) {
1913		err = nfserrno((int)offset);
1914		goto out_close;
1915	}
1916
1917	err = nfsd_buffered_readdir(file, func, cdp, offsetp);
1918
1919	if (err == nfserr_eof || err == nfserr_toosmall)
1920		err = nfs_ok; /* can still be found in ->err */
1921out_close:
1922	fput(file);
1923out:
1924	return err;
1925}
1926
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1927/*
1928 * Get file system stats
1929 * N.B. After this call fhp needs an fh_put
1930 */
1931__be32
1932nfsd_statfs(struct svc_rqst *rqstp, struct svc_fh *fhp, struct kstatfs *stat, int access)
1933{
1934	__be32 err;
1935
1936	err = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP | access);
1937	if (!err) {
1938		struct path path = {
1939			.mnt	= fhp->fh_export->ex_path.mnt,
1940			.dentry	= fhp->fh_dentry,
1941		};
1942		if (vfs_statfs(&path, stat))
1943			err = nfserr_io;
1944	}
1945	return err;
1946}
1947
1948static int exp_rdonly(struct svc_rqst *rqstp, struct svc_export *exp)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1949{
1950	return nfsexp_flags(rqstp, exp) & NFSEXP_READONLY;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1951}
 
1952
1953/*
1954 * Check for a user's access permissions to this inode.
1955 */
1956__be32
1957nfsd_permission(struct svc_rqst *rqstp, struct svc_export *exp,
1958					struct dentry *dentry, int acc)
1959{
1960	struct inode	*inode = d_inode(dentry);
1961	int		err;
1962
1963	if ((acc & NFSD_MAY_MASK) == NFSD_MAY_NOP)
1964		return 0;
1965#if 0
1966	dprintk("nfsd: permission 0x%x%s%s%s%s%s%s%s mode 0%o%s%s%s\n",
1967		acc,
1968		(acc & NFSD_MAY_READ)?	" read"  : "",
1969		(acc & NFSD_MAY_WRITE)?	" write" : "",
1970		(acc & NFSD_MAY_EXEC)?	" exec"  : "",
1971		(acc & NFSD_MAY_SATTR)?	" sattr" : "",
1972		(acc & NFSD_MAY_TRUNC)?	" trunc" : "",
1973		(acc & NFSD_MAY_LOCK)?	" lock"  : "",
1974		(acc & NFSD_MAY_OWNER_OVERRIDE)? " owneroverride" : "",
1975		inode->i_mode,
1976		IS_IMMUTABLE(inode)?	" immut" : "",
1977		IS_APPEND(inode)?	" append" : "",
1978		__mnt_is_readonly(exp->ex_path.mnt)?	" ro" : "");
1979	dprintk("      owner %d/%d user %d/%d\n",
1980		inode->i_uid, inode->i_gid, current_fsuid(), current_fsgid());
1981#endif
1982
1983	/* Normally we reject any write/sattr etc access on a read-only file
1984	 * system.  But if it is IRIX doing check on write-access for a 
1985	 * device special file, we ignore rofs.
1986	 */
1987	if (!(acc & NFSD_MAY_LOCAL_ACCESS))
1988		if (acc & (NFSD_MAY_WRITE | NFSD_MAY_SATTR | NFSD_MAY_TRUNC)) {
1989			if (exp_rdonly(rqstp, exp) ||
1990			    __mnt_is_readonly(exp->ex_path.mnt))
1991				return nfserr_rofs;
1992			if (/* (acc & NFSD_MAY_WRITE) && */ IS_IMMUTABLE(inode))
1993				return nfserr_perm;
1994		}
1995	if ((acc & NFSD_MAY_TRUNC) && IS_APPEND(inode))
1996		return nfserr_perm;
1997
1998	if (acc & NFSD_MAY_LOCK) {
1999		/* If we cannot rely on authentication in NLM requests,
2000		 * just allow locks, otherwise require read permission, or
2001		 * ownership
2002		 */
2003		if (exp->ex_flags & NFSEXP_NOAUTHNLM)
2004			return 0;
2005		else
2006			acc = NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE;
2007	}
2008	/*
2009	 * The file owner always gets access permission for accesses that
2010	 * would normally be checked at open time. This is to make
2011	 * file access work even when the client has done a fchmod(fd, 0).
2012	 *
2013	 * However, `cp foo bar' should fail nevertheless when bar is
2014	 * readonly. A sensible way to do this might be to reject all
2015	 * attempts to truncate a read-only file, because a creat() call
2016	 * always implies file truncation.
2017	 * ... but this isn't really fair.  A process may reasonably call
2018	 * ftruncate on an open file descriptor on a file with perm 000.
2019	 * We must trust the client to do permission checking - using "ACCESS"
2020	 * with NFSv3.
2021	 */
2022	if ((acc & NFSD_MAY_OWNER_OVERRIDE) &&
2023	    uid_eq(inode->i_uid, current_fsuid()))
2024		return 0;
2025
2026	/* This assumes  NFSD_MAY_{READ,WRITE,EXEC} == MAY_{READ,WRITE,EXEC} */
2027	err = inode_permission(inode, acc & (MAY_READ|MAY_WRITE|MAY_EXEC));
 
2028
2029	/* Allow read access to binaries even when mode 111 */
2030	if (err == -EACCES && S_ISREG(inode->i_mode) &&
2031	     (acc == (NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE) ||
2032	      acc == (NFSD_MAY_READ | NFSD_MAY_READ_IF_EXEC)))
2033		err = inode_permission(inode, MAY_EXEC);
2034
2035	return err? nfserrno(err) : 0;
2036}
2037
2038void
2039nfsd_racache_shutdown(void)
2040{
2041	struct raparms *raparm, *last_raparm;
2042	unsigned int i;
2043
2044	dprintk("nfsd: freeing readahead buffers.\n");
2045
2046	for (i = 0; i < RAPARM_HASH_SIZE; i++) {
2047		raparm = raparm_hash[i].pb_head;
2048		while(raparm) {
2049			last_raparm = raparm;
2050			raparm = raparm->p_next;
2051			kfree(last_raparm);
2052		}
2053		raparm_hash[i].pb_head = NULL;
2054	}
2055}
2056/*
2057 * Initialize readahead param cache
2058 */
2059int
2060nfsd_racache_init(int cache_size)
2061{
2062	int	i;
2063	int	j = 0;
2064	int	nperbucket;
2065	struct raparms **raparm = NULL;
2066
2067
2068	if (raparm_hash[0].pb_head)
2069		return 0;
2070	nperbucket = DIV_ROUND_UP(cache_size, RAPARM_HASH_SIZE);
2071	nperbucket = max(2, nperbucket);
2072	cache_size = nperbucket * RAPARM_HASH_SIZE;
2073
2074	dprintk("nfsd: allocating %d readahead buffers.\n", cache_size);
2075
2076	for (i = 0; i < RAPARM_HASH_SIZE; i++) {
2077		spin_lock_init(&raparm_hash[i].pb_lock);
2078
2079		raparm = &raparm_hash[i].pb_head;
2080		for (j = 0; j < nperbucket; j++) {
2081			*raparm = kzalloc(sizeof(struct raparms), GFP_KERNEL);
2082			if (!*raparm)
2083				goto out_nomem;
2084			raparm = &(*raparm)->p_next;
2085		}
2086		*raparm = NULL;
2087	}
2088
2089	nfsdstats.ra_size = cache_size;
2090	return 0;
2091
2092out_nomem:
2093	dprintk("nfsd: kmalloc failed, freeing readahead buffers\n");
2094	nfsd_racache_shutdown();
2095	return -ENOMEM;
2096}