1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * File operations used by nfsd. Some of these have been ripped from
   4 * other parts of the kernel because they weren't exported, others
   5 * are partial duplicates with added or changed functionality.
   6 *
   7 * Note that several functions dget() the dentry upon which they want
   8 * to act, most notably those that create directory entries. Response
   9 * dentry's are dput()'d if necessary in the release callback.
  10 * So if you notice code paths that apparently fail to dput() the
  11 * dentry, don't worry--they have been taken care of.
  12 *
  13 * Copyright (C) 1995-1999 Olaf Kirch <okir@monad.swb.de>
  14 * Zerocpy NFS support (C) 2002 Hirokazu Takahashi <taka@valinux.co.jp>
  15 */
  16
  17#include <linux/fs.h>
  18#include <linux/file.h>
  19#include <linux/splice.h>
  20#include <linux/falloc.h>
  21#include <linux/fcntl.h>
  22#include <linux/namei.h>
  23#include <linux/delay.h>
  24#include <linux/fsnotify.h>
  25#include <linux/posix_acl_xattr.h>
  26#include <linux/xattr.h>
  27#include <linux/jhash.h>
  28#include <linux/pagemap.h>
  29#include <linux/slab.h>
  30#include <linux/uaccess.h>
  31#include <linux/exportfs.h>
  32#include <linux/writeback.h>
  33#include <linux/security.h>
  34
  35#include "xdr3.h"
  36
  37#ifdef CONFIG_NFSD_V4
  38#include "../internal.h"
  39#include "acl.h"
  40#include "idmap.h"
  41#include "xdr4.h"
  42#endif /* CONFIG_NFSD_V4 */
  43
  44#include "nfsd.h"
  45#include "vfs.h"
  46#include "filecache.h"
  47#include "trace.h"
  48
  49#define NFSDDBG_FACILITY		NFSDDBG_FILEOP
  50
  51/**
  52 * nfserrno - Map Linux errnos to NFS errnos
  53 * @errno: POSIX(-ish) error code to be mapped
  54 *
  55 * Returns the appropriate (net-endian) nfserr_* (or nfs_ok if errno is 0). If
  56 * it's an error we don't expect, log it once and return nfserr_io.
  57 */
  58__be32
  59nfserrno (int errno)
  60{
  61	static struct {
  62		__be32	nfserr;
  63		int	syserr;
  64	} nfs_errtbl[] = {
  65		{ nfs_ok, 0 },
  66		{ nfserr_perm, -EPERM },
  67		{ nfserr_noent, -ENOENT },
  68		{ nfserr_io, -EIO },
  69		{ nfserr_nxio, -ENXIO },
  70		{ nfserr_fbig, -E2BIG },
  71		{ nfserr_stale, -EBADF },
  72		{ nfserr_acces, -EACCES },
  73		{ nfserr_exist, -EEXIST },
  74		{ nfserr_xdev, -EXDEV },
  75		{ nfserr_mlink, -EMLINK },
  76		{ nfserr_nodev, -ENODEV },
  77		{ nfserr_notdir, -ENOTDIR },
  78		{ nfserr_isdir, -EISDIR },
  79		{ nfserr_inval, -EINVAL },
  80		{ nfserr_fbig, -EFBIG },
  81		{ nfserr_nospc, -ENOSPC },
  82		{ nfserr_rofs, -EROFS },
  83		{ nfserr_mlink, -EMLINK },
  84		{ nfserr_nametoolong, -ENAMETOOLONG },
  85		{ nfserr_notempty, -ENOTEMPTY },
  86		{ nfserr_dquot, -EDQUOT },
  87		{ nfserr_stale, -ESTALE },
  88		{ nfserr_jukebox, -ETIMEDOUT },
  89		{ nfserr_jukebox, -ERESTARTSYS },
  90		{ nfserr_jukebox, -EAGAIN },
  91		{ nfserr_jukebox, -EWOULDBLOCK },
  92		{ nfserr_jukebox, -ENOMEM },
  93		{ nfserr_io, -ETXTBSY },
  94		{ nfserr_notsupp, -EOPNOTSUPP },
  95		{ nfserr_toosmall, -ETOOSMALL },
  96		{ nfserr_serverfault, -ESERVERFAULT },
  97		{ nfserr_serverfault, -ENFILE },
  98		{ nfserr_io, -EREMOTEIO },
  99		{ nfserr_stale, -EOPENSTALE },
 100		{ nfserr_io, -EUCLEAN },
 101		{ nfserr_perm, -ENOKEY },
 102		{ nfserr_no_grace, -ENOGRACE},
 
 103	};
 104	int	i;
 105
 106	for (i = 0; i < ARRAY_SIZE(nfs_errtbl); i++) {
 107		if (nfs_errtbl[i].syserr == errno)
 108			return nfs_errtbl[i].nfserr;
 109	}
 110	WARN_ONCE(1, "nfsd: non-standard errno: %d\n", errno);
 111	return nfserr_io;
 112}
 113
 114/* 
 115 * Called from nfsd_lookup and encode_dirent. Check if we have crossed 
 116 * a mount point.
 117 * Returns -EAGAIN or -ETIMEDOUT leaving *dpp and *expp unchanged,
 118 *  or nfs_ok having possibly changed *dpp and *expp
 119 */
 120int
 121nfsd_cross_mnt(struct svc_rqst *rqstp, struct dentry **dpp, 
 122		        struct svc_export **expp)
 123{
 124	struct svc_export *exp = *expp, *exp2 = NULL;
 125	struct dentry *dentry = *dpp;
 126	struct path path = {.mnt = mntget(exp->ex_path.mnt),
 127			    .dentry = dget(dentry)};
 128	unsigned int follow_flags = 0;
 129	int err = 0;
 130
 131	if (exp->ex_flags & NFSEXP_CROSSMOUNT)
 132		follow_flags = LOOKUP_AUTOMOUNT;
 133
 134	err = follow_down(&path, follow_flags);
 135	if (err < 0)
 136		goto out;
 137	if (path.mnt == exp->ex_path.mnt && path.dentry == dentry &&
 138	    nfsd_mountpoint(dentry, exp) == 2) {
 139		/* This is only a mountpoint in some other namespace */
 140		path_put(&path);
 141		goto out;
 142	}
 143
 144	exp2 = rqst_exp_get_by_name(rqstp, &path);
 145	if (IS_ERR(exp2)) {
 146		err = PTR_ERR(exp2);
 147		/*
 148		 * We normally allow NFS clients to continue
 149		 * "underneath" a mountpoint that is not exported.
 150		 * The exception is V4ROOT, where no traversal is ever
 151		 * allowed without an explicit export of the new
 152		 * directory.
 153		 */
 154		if (err == -ENOENT && !(exp->ex_flags & NFSEXP_V4ROOT))
 155			err = 0;
 156		path_put(&path);
 157		goto out;
 158	}
 159	if (nfsd_v4client(rqstp) ||
 160		(exp->ex_flags & NFSEXP_CROSSMOUNT) || EX_NOHIDE(exp2)) {
 161		/* successfully crossed mount point */
 162		/*
 163		 * This is subtle: path.dentry is *not* on path.mnt
 164		 * at this point.  The only reason we are safe is that
 165		 * original mnt is pinned down by exp, so we should
 166		 * put path *before* putting exp
 167		 */
 168		*dpp = path.dentry;
 169		path.dentry = dentry;
 170		*expp = exp2;
 171		exp2 = exp;
 172	}
 173	path_put(&path);
 174	exp_put(exp2);
 175out:
 176	return err;
 177}
 178
 179static void follow_to_parent(struct path *path)
 180{
 181	struct dentry *dp;
 182
 183	while (path->dentry == path->mnt->mnt_root && follow_up(path))
 184		;
 185	dp = dget_parent(path->dentry);
 186	dput(path->dentry);
 187	path->dentry = dp;
 188}
 189
 190static int nfsd_lookup_parent(struct svc_rqst *rqstp, struct dentry *dparent, struct svc_export **exp, struct dentry **dentryp)
 191{
 192	struct svc_export *exp2;
 193	struct path path = {.mnt = mntget((*exp)->ex_path.mnt),
 194			    .dentry = dget(dparent)};
 195
 196	follow_to_parent(&path);
 197
 198	exp2 = rqst_exp_parent(rqstp, &path);
 199	if (PTR_ERR(exp2) == -ENOENT) {
 200		*dentryp = dget(dparent);
 201	} else if (IS_ERR(exp2)) {
 202		path_put(&path);
 203		return PTR_ERR(exp2);
 204	} else {
 205		*dentryp = dget(path.dentry);
 206		exp_put(*exp);
 207		*exp = exp2;
 208	}
 209	path_put(&path);
 210	return 0;
 211}
 212
 213/*
 214 * For nfsd purposes, we treat V4ROOT exports as though there was an
 215 * export at *every* directory.
 216 * We return:
 217 * '1' if this dentry *must* be an export point,
 218 * '2' if it might be, if there is really a mount here, and
 219 * '0' if there is no chance of an export point here.
 220 */
 221int nfsd_mountpoint(struct dentry *dentry, struct svc_export *exp)
 222{
 223	if (!d_inode(dentry))
 224		return 0;
 225	if (exp->ex_flags & NFSEXP_V4ROOT)
 226		return 1;
 227	if (nfsd4_is_junction(dentry))
 228		return 1;
 229	if (d_managed(dentry))
 230		/*
 231		 * Might only be a mountpoint in a different namespace,
 232		 * but we need to check.
 233		 */
 234		return 2;
 235	return 0;
 236}
 237
 238__be32
 239nfsd_lookup_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp,
 240		   const char *name, unsigned int len,
 241		   struct svc_export **exp_ret, struct dentry **dentry_ret)
 242{
 243	struct svc_export	*exp;
 244	struct dentry		*dparent;
 245	struct dentry		*dentry;
 246	int			host_err;
 247
 248	dprintk("nfsd: nfsd_lookup(fh %s, %.*s)\n", SVCFH_fmt(fhp), len,name);
 249
 250	dparent = fhp->fh_dentry;
 251	exp = exp_get(fhp->fh_export);
 252
 253	/* Lookup the name, but don't follow links */
 254	if (isdotent(name, len)) {
 255		if (len==1)
 256			dentry = dget(dparent);
 257		else if (dparent != exp->ex_path.dentry)
 258			dentry = dget_parent(dparent);
 259		else if (!EX_NOHIDE(exp) && !nfsd_v4client(rqstp))
 260			dentry = dget(dparent); /* .. == . just like at / */
 261		else {
 262			/* checking mountpoint crossing is very different when stepping up */
 263			host_err = nfsd_lookup_parent(rqstp, dparent, &exp, &dentry);
 264			if (host_err)
 265				goto out_nfserr;
 266		}
 267	} else {
 268		dentry = lookup_one_len_unlocked(name, dparent, len);
 269		host_err = PTR_ERR(dentry);
 270		if (IS_ERR(dentry))
 271			goto out_nfserr;
 272		if (nfsd_mountpoint(dentry, exp)) {
 273			host_err = nfsd_cross_mnt(rqstp, &dentry, &exp);
 274			if (host_err) {
 275				dput(dentry);
 276				goto out_nfserr;
 277			}
 278		}
 279	}
 280	*dentry_ret = dentry;
 281	*exp_ret = exp;
 282	return 0;
 283
 284out_nfserr:
 285	exp_put(exp);
 286	return nfserrno(host_err);
 287}
 288
 289/**
 290 * nfsd_lookup - look up a single path component for nfsd
 291 *
 292 * @rqstp:   the request context
 293 * @fhp:     the file handle of the directory
 294 * @name:    the component name, or %NULL to look up parent
 295 * @len:     length of name to examine
 296 * @resfh:   pointer to pre-initialised filehandle to hold result.
 297 *
 298 * Look up one component of a pathname.
 299 * N.B. After this call _both_ fhp and resfh need an fh_put
 300 *
 301 * If the lookup would cross a mountpoint, and the mounted filesystem
 302 * is exported to the client with NFSEXP_NOHIDE, then the lookup is
 303 * accepted as it stands and the mounted directory is
 304 * returned. Otherwise the covered directory is returned.
 305 * NOTE: this mountpoint crossing is not supported properly by all
 306 *   clients and is explicitly disallowed for NFSv3
 307 *
 308 */
 309__be32
 310nfsd_lookup(struct svc_rqst *rqstp, struct svc_fh *fhp, const char *name,
 311	    unsigned int len, struct svc_fh *resfh)
 312{
 313	struct svc_export	*exp;
 314	struct dentry		*dentry;
 315	__be32 err;
 316
 317	err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC);
 318	if (err)
 319		return err;
 320	err = nfsd_lookup_dentry(rqstp, fhp, name, len, &exp, &dentry);
 321	if (err)
 322		return err;
 323	err = check_nfsd_access(exp, rqstp);
 324	if (err)
 325		goto out;
 326	/*
 327	 * Note: we compose the file handle now, but as the
 328	 * dentry may be negative, it may need to be updated.
 329	 */
 330	err = fh_compose(resfh, exp, dentry, fhp);
 331	if (!err && d_really_is_negative(dentry))
 332		err = nfserr_noent;
 333out:
 334	dput(dentry);
 335	exp_put(exp);
 336	return err;
 337}
 338
 339static void
 340commit_reset_write_verifier(struct nfsd_net *nn, struct svc_rqst *rqstp,
 341			    int err)
 342{
 343	switch (err) {
 344	case -EAGAIN:
 345	case -ESTALE:
 346		/*
 347		 * Neither of these are the result of a problem with
 348		 * durable storage, so avoid a write verifier reset.
 349		 */
 350		break;
 351	default:
 352		nfsd_reset_write_verifier(nn);
 353		trace_nfsd_writeverf_reset(nn, rqstp, err);
 354	}
 355}
 356
 357/*
 358 * Commit metadata changes to stable storage.
 359 */
 360static int
 361commit_inode_metadata(struct inode *inode)
 362{
 363	const struct export_operations *export_ops = inode->i_sb->s_export_op;
 364
 365	if (export_ops->commit_metadata)
 366		return export_ops->commit_metadata(inode);
 367	return sync_inode_metadata(inode, 1);
 368}
 369
 370static int
 371commit_metadata(struct svc_fh *fhp)
 372{
 373	struct inode *inode = d_inode(fhp->fh_dentry);
 374
 375	if (!EX_ISSYNC(fhp->fh_export))
 376		return 0;
 377	return commit_inode_metadata(inode);
 378}
 379
 380/*
 381 * Go over the attributes and take care of the small differences between
 382 * NFS semantics and what Linux expects.
 383 */
 384static void
 385nfsd_sanitize_attrs(struct inode *inode, struct iattr *iap)
 386{
 387	/* Ignore mode updates on symlinks */
 388	if (S_ISLNK(inode->i_mode))
 389		iap->ia_valid &= ~ATTR_MODE;
 390
 391	/* sanitize the mode change */
 392	if (iap->ia_valid & ATTR_MODE) {
 393		iap->ia_mode &= S_IALLUGO;
 394		iap->ia_mode |= (inode->i_mode & ~S_IALLUGO);
 395	}
 396
 397	/* Revoke setuid/setgid on chown */
 398	if (!S_ISDIR(inode->i_mode) &&
 399	    ((iap->ia_valid & ATTR_UID) || (iap->ia_valid & ATTR_GID))) {
 400		iap->ia_valid |= ATTR_KILL_PRIV;
 401		if (iap->ia_valid & ATTR_MODE) {
 402			/* we're setting mode too, just clear the s*id bits */
 403			iap->ia_mode &= ~S_ISUID;
 404			if (iap->ia_mode & S_IXGRP)
 405				iap->ia_mode &= ~S_ISGID;
 406		} else {
 407			/* set ATTR_KILL_* bits and let VFS handle it */
 408			iap->ia_valid |= ATTR_KILL_SUID;
 409			iap->ia_valid |=
 410				setattr_should_drop_sgid(&nop_mnt_idmap, inode);
 411		}
 412	}
 413}
 414
 415static __be32
 416nfsd_get_write_access(struct svc_rqst *rqstp, struct svc_fh *fhp,
 417		struct iattr *iap)
 418{
 419	struct inode *inode = d_inode(fhp->fh_dentry);
 420
 421	if (iap->ia_size < inode->i_size) {
 422		__be32 err;
 423
 424		err = nfsd_permission(rqstp, fhp->fh_export, fhp->fh_dentry,
 425				NFSD_MAY_TRUNC | NFSD_MAY_OWNER_OVERRIDE);
 
 426		if (err)
 427			return err;
 428	}
 429	return nfserrno(get_write_access(inode));
 430}
 431
 432static int __nfsd_setattr(struct dentry *dentry, struct iattr *iap)
 433{
 434	int host_err;
 435
 436	if (iap->ia_valid & ATTR_SIZE) {
 437		/*
 438		 * RFC5661, Section 18.30.4:
 439		 *   Changing the size of a file with SETATTR indirectly
 440		 *   changes the time_modify and change attributes.
 441		 *
 442		 * (and similar for the older RFCs)
 443		 */
 444		struct iattr size_attr = {
 445			.ia_valid	= ATTR_SIZE | ATTR_CTIME | ATTR_MTIME,
 446			.ia_size	= iap->ia_size,
 447		};
 448
 449		if (iap->ia_size < 0)
 450			return -EFBIG;
 451
 452		host_err = notify_change(&nop_mnt_idmap, dentry, &size_attr, NULL);
 453		if (host_err)
 454			return host_err;
 455		iap->ia_valid &= ~ATTR_SIZE;
 456
 457		/*
 458		 * Avoid the additional setattr call below if the only other
 459		 * attribute that the client sends is the mtime, as we update
 460		 * it as part of the size change above.
 461		 */
 462		if ((iap->ia_valid & ~ATTR_MTIME) == 0)
 463			return 0;
 464	}
 465
 466	if (!iap->ia_valid)
 467		return 0;
 468
 469	iap->ia_valid |= ATTR_CTIME;
 470	return notify_change(&nop_mnt_idmap, dentry, iap, NULL);
 471}
 472
 473/**
 474 * nfsd_setattr - Set various file attributes.
 475 * @rqstp: controlling RPC transaction
 476 * @fhp: filehandle of target
 477 * @attr: attributes to set
 478 * @guardtime: do not act if ctime.tv_sec does not match this timestamp
 479 *
 480 * This call may adjust the contents of @attr (in particular, this
 481 * call may change the bits in the na_iattr.ia_valid field).
 482 *
 483 * Returns nfs_ok on success, otherwise an NFS status code is
 484 * returned. Caller must release @fhp by calling fh_put in either
 485 * case.
 486 */
 487__be32
 488nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp,
 489	     struct nfsd_attrs *attr, const struct timespec64 *guardtime)
 490{
 491	struct dentry	*dentry;
 492	struct inode	*inode;
 493	struct iattr	*iap = attr->na_iattr;
 494	int		accmode = NFSD_MAY_SATTR;
 495	umode_t		ftype = 0;
 496	__be32		err;
 497	int		host_err = 0;
 498	bool		get_write_count;
 499	bool		size_change = (iap->ia_valid & ATTR_SIZE);
 500	int		retries;
 501
 502	if (iap->ia_valid & ATTR_SIZE) {
 503		accmode |= NFSD_MAY_WRITE|NFSD_MAY_OWNER_OVERRIDE;
 504		ftype = S_IFREG;
 505	}
 506
 507	/*
 508	 * If utimes(2) and friends are called with times not NULL, we should
 509	 * not set NFSD_MAY_WRITE bit. Otherwise fh_verify->nfsd_permission
 510	 * will return EACCES, when the caller's effective UID does not match
 511	 * the owner of the file, and the caller is not privileged. In this
 512	 * situation, we should return EPERM(notify_change will return this).
 513	 */
 514	if (iap->ia_valid & (ATTR_ATIME | ATTR_MTIME)) {
 515		accmode |= NFSD_MAY_OWNER_OVERRIDE;
 516		if (!(iap->ia_valid & (ATTR_ATIME_SET | ATTR_MTIME_SET)))
 517			accmode |= NFSD_MAY_WRITE;
 518	}
 519
 520	/* Callers that do fh_verify should do the fh_want_write: */
 521	get_write_count = !fhp->fh_dentry;
 522
 523	/* Get inode */
 524	err = fh_verify(rqstp, fhp, ftype, accmode);
 525	if (err)
 526		return err;
 527	if (get_write_count) {
 528		host_err = fh_want_write(fhp);
 529		if (host_err)
 530			goto out;
 531	}
 532
 533	dentry = fhp->fh_dentry;
 534	inode = d_inode(dentry);
 535
 536	nfsd_sanitize_attrs(inode, iap);
 537
 538	/*
 539	 * The size case is special, it changes the file in addition to the
 540	 * attributes, and file systems don't expect it to be mixed with
 541	 * "random" attribute changes.  We thus split out the size change
 542	 * into a separate call to ->setattr, and do the rest as a separate
 543	 * setattr call.
 544	 */
 545	if (size_change) {
 546		err = nfsd_get_write_access(rqstp, fhp, iap);
 547		if (err)
 548			return err;
 549	}
 550
 551	inode_lock(inode);
 552	err = fh_fill_pre_attrs(fhp);
 553	if (err)
 554		goto out_unlock;
 555
 556	if (guardtime) {
 557		struct timespec64 ctime = inode_get_ctime(inode);
 558		if ((u32)guardtime->tv_sec != (u32)ctime.tv_sec ||
 559		    guardtime->tv_nsec != ctime.tv_nsec) {
 560			err = nfserr_notsync;
 561			goto out_fill_attrs;
 562		}
 563	}
 564
 565	for (retries = 1;;) {
 566		struct iattr attrs;
 567
 568		/*
 569		 * notify_change() can alter its iattr argument, making
 570		 * @iap unsuitable for submission multiple times. Make a
 571		 * copy for every loop iteration.
 572		 */
 573		attrs = *iap;
 574		host_err = __nfsd_setattr(dentry, &attrs);
 575		if (host_err != -EAGAIN || !retries--)
 576			break;
 577		if (!nfsd_wait_for_delegreturn(rqstp, inode))
 578			break;
 579	}
 580	if (attr->na_seclabel && attr->na_seclabel->len)
 581		attr->na_labelerr = security_inode_setsecctx(dentry,
 582			attr->na_seclabel->data, attr->na_seclabel->len);
 583	if (IS_ENABLED(CONFIG_FS_POSIX_ACL) && attr->na_pacl)
 584		attr->na_aclerr = set_posix_acl(&nop_mnt_idmap,
 585						dentry, ACL_TYPE_ACCESS,
 586						attr->na_pacl);
 587	if (IS_ENABLED(CONFIG_FS_POSIX_ACL) &&
 588	    !attr->na_aclerr && attr->na_dpacl && S_ISDIR(inode->i_mode))
 589		attr->na_aclerr = set_posix_acl(&nop_mnt_idmap,
 590						dentry, ACL_TYPE_DEFAULT,
 591						attr->na_dpacl);
 592out_fill_attrs:
 593	/*
 594	 * RFC 1813 Section 3.3.2 does not mandate that an NFS server
 595	 * returns wcc_data for SETATTR. Some client implementations
 596	 * depend on receiving wcc_data, however, to sort out partial
 597	 * updates (eg., the client requested that size and mode be
 598	 * modified, but the server changed only the file mode).
 599	 */
 600	fh_fill_post_attrs(fhp);
 601out_unlock:
 602	inode_unlock(inode);
 603	if (size_change)
 604		put_write_access(inode);
 605out:
 606	if (!host_err)
 607		host_err = commit_metadata(fhp);
 608	return err != 0 ? err : nfserrno(host_err);
 609}
 610
 611#if defined(CONFIG_NFSD_V4)
 612/*
 613 * NFS junction information is stored in an extended attribute.
 614 */
 615#define NFSD_JUNCTION_XATTR_NAME	XATTR_TRUSTED_PREFIX "junction.nfs"
 616
 617/**
 618 * nfsd4_is_junction - Test if an object could be an NFS junction
 619 *
 620 * @dentry: object to test
 621 *
 622 * Returns 1 if "dentry" appears to contain NFS junction information.
 623 * Otherwise 0 is returned.
 624 */
 625int nfsd4_is_junction(struct dentry *dentry)
 626{
 627	struct inode *inode = d_inode(dentry);
 628
 629	if (inode == NULL)
 630		return 0;
 631	if (inode->i_mode & S_IXUGO)
 632		return 0;
 633	if (!(inode->i_mode & S_ISVTX))
 634		return 0;
 635	if (vfs_getxattr(&nop_mnt_idmap, dentry, NFSD_JUNCTION_XATTR_NAME,
 636			 NULL, 0) <= 0)
 637		return 0;
 638	return 1;
 639}
 640
 641static struct nfsd4_compound_state *nfsd4_get_cstate(struct svc_rqst *rqstp)
 642{
 643	return &((struct nfsd4_compoundres *)rqstp->rq_resp)->cstate;
 644}
 645
 646__be32 nfsd4_clone_file_range(struct svc_rqst *rqstp,
 647		struct nfsd_file *nf_src, u64 src_pos,
 648		struct nfsd_file *nf_dst, u64 dst_pos,
 649		u64 count, bool sync)
 650{
 651	struct file *src = nf_src->nf_file;
 652	struct file *dst = nf_dst->nf_file;
 653	errseq_t since;
 654	loff_t cloned;
 655	__be32 ret = 0;
 656
 657	since = READ_ONCE(dst->f_wb_err);
 658	cloned = vfs_clone_file_range(src, src_pos, dst, dst_pos, count, 0);
 659	if (cloned < 0) {
 660		ret = nfserrno(cloned);
 661		goto out_err;
 662	}
 663	if (count && cloned != count) {
 664		ret = nfserrno(-EINVAL);
 665		goto out_err;
 666	}
 667	if (sync) {
 668		loff_t dst_end = count ? dst_pos + count - 1 : LLONG_MAX;
 669		int status = vfs_fsync_range(dst, dst_pos, dst_end, 0);
 670
 671		if (!status)
 672			status = filemap_check_wb_err(dst->f_mapping, since);
 673		if (!status)
 674			status = commit_inode_metadata(file_inode(src));
 675		if (status < 0) {
 676			struct nfsd_net *nn = net_generic(nf_dst->nf_net,
 677							  nfsd_net_id);
 678
 679			trace_nfsd_clone_file_range_err(rqstp,
 680					&nfsd4_get_cstate(rqstp)->save_fh,
 681					src_pos,
 682					&nfsd4_get_cstate(rqstp)->current_fh,
 683					dst_pos,
 684					count, status);
 685			commit_reset_write_verifier(nn, rqstp, status);
 686			ret = nfserrno(status);
 687		}
 688	}
 689out_err:
 690	return ret;
 691}
 692
 693ssize_t nfsd_copy_file_range(struct file *src, u64 src_pos, struct file *dst,
 694			     u64 dst_pos, u64 count)
 695{
 696	ssize_t ret;
 697
 698	/*
 699	 * Limit copy to 4MB to prevent indefinitely blocking an nfsd
 700	 * thread and client rpc slot.  The choice of 4MB is somewhat
 701	 * arbitrary.  We might instead base this on r/wsize, or make it
 702	 * tunable, or use a time instead of a byte limit, or implement
 703	 * asynchronous copy.  In theory a client could also recognize a
 704	 * limit like this and pipeline multiple COPY requests.
 705	 */
 706	count = min_t(u64, count, 1 << 22);
 707	ret = vfs_copy_file_range(src, src_pos, dst, dst_pos, count, 0);
 708
 709	if (ret == -EOPNOTSUPP || ret == -EXDEV)
 710		ret = vfs_copy_file_range(src, src_pos, dst, dst_pos, count,
 711					  COPY_FILE_SPLICE);
 712	return ret;
 713}
 714
 715__be32 nfsd4_vfs_fallocate(struct svc_rqst *rqstp, struct svc_fh *fhp,
 716			   struct file *file, loff_t offset, loff_t len,
 717			   int flags)
 718{
 719	int error;
 720
 721	if (!S_ISREG(file_inode(file)->i_mode))
 722		return nfserr_inval;
 723
 724	error = vfs_fallocate(file, flags, offset, len);
 725	if (!error)
 726		error = commit_metadata(fhp);
 727
 728	return nfserrno(error);
 729}
 730#endif /* defined(CONFIG_NFSD_V4) */
 731
 732/*
 733 * Check server access rights to a file system object
 734 */
 735struct accessmap {
 736	u32		access;
 737	int		how;
 738};
 739static struct accessmap	nfs3_regaccess[] = {
 740    {	NFS3_ACCESS_READ,	NFSD_MAY_READ			},
 741    {	NFS3_ACCESS_EXECUTE,	NFSD_MAY_EXEC			},
 742    {	NFS3_ACCESS_MODIFY,	NFSD_MAY_WRITE|NFSD_MAY_TRUNC	},
 743    {	NFS3_ACCESS_EXTEND,	NFSD_MAY_WRITE			},
 744
 745#ifdef CONFIG_NFSD_V4
 746    {	NFS4_ACCESS_XAREAD,	NFSD_MAY_READ			},
 747    {	NFS4_ACCESS_XAWRITE,	NFSD_MAY_WRITE			},
 748    {	NFS4_ACCESS_XALIST,	NFSD_MAY_READ			},
 749#endif
 750
 751    {	0,			0				}
 752};
 753
 754static struct accessmap	nfs3_diraccess[] = {
 755    {	NFS3_ACCESS_READ,	NFSD_MAY_READ			},
 756    {	NFS3_ACCESS_LOOKUP,	NFSD_MAY_EXEC			},
 757    {	NFS3_ACCESS_MODIFY,	NFSD_MAY_EXEC|NFSD_MAY_WRITE|NFSD_MAY_TRUNC},
 758    {	NFS3_ACCESS_EXTEND,	NFSD_MAY_EXEC|NFSD_MAY_WRITE	},
 759    {	NFS3_ACCESS_DELETE,	NFSD_MAY_REMOVE			},
 760
 761#ifdef CONFIG_NFSD_V4
 762    {	NFS4_ACCESS_XAREAD,	NFSD_MAY_READ			},
 763    {	NFS4_ACCESS_XAWRITE,	NFSD_MAY_WRITE			},
 764    {	NFS4_ACCESS_XALIST,	NFSD_MAY_READ			},
 765#endif
 766
 767    {	0,			0				}
 768};
 769
 770static struct accessmap	nfs3_anyaccess[] = {
 771	/* Some clients - Solaris 2.6 at least, make an access call
 772	 * to the server to check for access for things like /dev/null
 773	 * (which really, the server doesn't care about).  So
 774	 * We provide simple access checking for them, looking
 775	 * mainly at mode bits, and we make sure to ignore read-only
 776	 * filesystem checks
 777	 */
 778    {	NFS3_ACCESS_READ,	NFSD_MAY_READ			},
 779    {	NFS3_ACCESS_EXECUTE,	NFSD_MAY_EXEC			},
 780    {	NFS3_ACCESS_MODIFY,	NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS	},
 781    {	NFS3_ACCESS_EXTEND,	NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS	},
 782
 783    {	0,			0				}
 784};
 785
 786__be32
 787nfsd_access(struct svc_rqst *rqstp, struct svc_fh *fhp, u32 *access, u32 *supported)
 788{
 789	struct accessmap	*map;
 790	struct svc_export	*export;
 791	struct dentry		*dentry;
 792	u32			query, result = 0, sresult = 0;
 793	__be32			error;
 794
 795	error = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP);
 796	if (error)
 797		goto out;
 798
 799	export = fhp->fh_export;
 800	dentry = fhp->fh_dentry;
 801
 802	if (d_is_reg(dentry))
 803		map = nfs3_regaccess;
 804	else if (d_is_dir(dentry))
 805		map = nfs3_diraccess;
 806	else
 807		map = nfs3_anyaccess;
 808
 809
 810	query = *access;
 811	for  (; map->access; map++) {
 812		if (map->access & query) {
 813			__be32 err2;
 814
 815			sresult |= map->access;
 816
 817			err2 = nfsd_permission(rqstp, export, dentry, map->how);
 
 818			switch (err2) {
 819			case nfs_ok:
 820				result |= map->access;
 821				break;
 822				
 823			/* the following error codes just mean the access was not allowed,
 824			 * rather than an error occurred */
 825			case nfserr_rofs:
 826			case nfserr_acces:
 827			case nfserr_perm:
 828				/* simply don't "or" in the access bit. */
 829				break;
 830			default:
 831				error = err2;
 832				goto out;
 833			}
 834		}
 835	}
 836	*access = result;
 837	if (supported)
 838		*supported = sresult;
 839
 840 out:
 841	return error;
 842}
 843
 844int nfsd_open_break_lease(struct inode *inode, int access)
 845{
 846	unsigned int mode;
 847
 848	if (access & NFSD_MAY_NOT_BREAK_LEASE)
 849		return 0;
 850	mode = (access & NFSD_MAY_WRITE) ? O_WRONLY : O_RDONLY;
 851	return break_lease(inode, mode | O_NONBLOCK);
 852}
 853
 854/*
 855 * Open an existing file or directory.
 856 * The may_flags argument indicates the type of open (read/write/lock)
 857 * and additional flags.
 858 * N.B. After this call fhp needs an fh_put
 859 */
 860static int
 861__nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type,
 862			int may_flags, struct file **filp)
 863{
 864	struct path	path;
 865	struct inode	*inode;
 866	struct file	*file;
 867	int		flags = O_RDONLY|O_LARGEFILE;
 868	int		host_err = -EPERM;
 869
 870	path.mnt = fhp->fh_export->ex_path.mnt;
 871	path.dentry = fhp->fh_dentry;
 872	inode = d_inode(path.dentry);
 873
 874	if (IS_APPEND(inode) && (may_flags & NFSD_MAY_WRITE))
 875		goto out;
 876
 877	if (!inode->i_fop)
 878		goto out;
 879
 880	host_err = nfsd_open_break_lease(inode, may_flags);
 881	if (host_err) /* NOMEM or WOULDBLOCK */
 882		goto out;
 883
 884	if (may_flags & NFSD_MAY_WRITE) {
 885		if (may_flags & NFSD_MAY_READ)
 886			flags = O_RDWR|O_LARGEFILE;
 887		else
 888			flags = O_WRONLY|O_LARGEFILE;
 889	}
 890
 891	file = dentry_open(&path, flags, current_cred());
 892	if (IS_ERR(file)) {
 893		host_err = PTR_ERR(file);
 894		goto out;
 895	}
 896
 897	host_err = security_file_post_open(file, may_flags);
 898	if (host_err) {
 899		fput(file);
 900		goto out;
 901	}
 902
 903	if (may_flags & NFSD_MAY_64BIT_COOKIE)
 904		file->f_mode |= FMODE_64BITHASH;
 905	else
 906		file->f_mode |= FMODE_32BITHASH;
 907
 908	*filp = file;
 909out:
 910	return host_err;
 911}
 912
 913__be32
 914nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type,
 915		int may_flags, struct file **filp)
 916{
 917	__be32 err;
 918	int host_err;
 919	bool retried = false;
 920
 921	/*
 922	 * If we get here, then the client has already done an "open",
 923	 * and (hopefully) checked permission - so allow OWNER_OVERRIDE
 924	 * in case a chmod has now revoked permission.
 925	 *
 926	 * Arguably we should also allow the owner override for
 927	 * directories, but we never have and it doesn't seem to have
 928	 * caused anyone a problem.  If we were to change this, note
 929	 * also that our filldir callbacks would need a variant of
 930	 * lookup_one_len that doesn't check permissions.
 931	 */
 932	if (type == S_IFREG)
 933		may_flags |= NFSD_MAY_OWNER_OVERRIDE;
 934retry:
 935	err = fh_verify(rqstp, fhp, type, may_flags);
 936	if (!err) {
 937		host_err = __nfsd_open(rqstp, fhp, type, may_flags, filp);
 938		if (host_err == -EOPENSTALE && !retried) {
 939			retried = true;
 940			fh_put(fhp);
 941			goto retry;
 942		}
 943		err = nfserrno(host_err);
 944	}
 945	return err;
 946}
 947
 948/**
 949 * nfsd_open_verified - Open a regular file for the filecache
 950 * @rqstp: RPC request
 951 * @fhp: NFS filehandle of the file to open
 952 * @may_flags: internal permission flags
 953 * @filp: OUT: open "struct file *"
 954 *
 955 * Returns zero on success, or a negative errno value.
 956 */
 957int
 958nfsd_open_verified(struct svc_rqst *rqstp, struct svc_fh *fhp, int may_flags,
 959		   struct file **filp)
 960{
 961	return __nfsd_open(rqstp, fhp, S_IFREG, may_flags, filp);
 962}
 963
 964/*
 965 * Grab and keep cached pages associated with a file in the svc_rqst
 966 * so that they can be passed to the network sendmsg routines
 967 * directly. They will be released after the sending has completed.
 968 *
 969 * Return values: Number of bytes consumed, or -EIO if there are no
 970 * remaining pages in rqstp->rq_pages.
 971 */
 972static int
 973nfsd_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
 974		  struct splice_desc *sd)
 975{
 976	struct svc_rqst *rqstp = sd->u.data;
 977	struct page *page = buf->page;	// may be a compound one
 978	unsigned offset = buf->offset;
 979	struct page *last_page;
 980
 981	last_page = page + (offset + sd->len - 1) / PAGE_SIZE;
 982	for (page += offset / PAGE_SIZE; page <= last_page; page++) {
 983		/*
 984		 * Skip page replacement when extending the contents of the
 985		 * current page.  But note that we may get two zero_pages in a
 986		 * row from shmem.
 987		 */
 988		if (page == *(rqstp->rq_next_page - 1) &&
 989		    offset_in_page(rqstp->rq_res.page_base +
 990				   rqstp->rq_res.page_len))
 991			continue;
 992		if (unlikely(!svc_rqst_replace_page(rqstp, page)))
 993			return -EIO;
 994	}
 995	if (rqstp->rq_res.page_len == 0)	// first call
 996		rqstp->rq_res.page_base = offset % PAGE_SIZE;
 997	rqstp->rq_res.page_len += sd->len;
 998	return sd->len;
 999}
1000
1001static int nfsd_direct_splice_actor(struct pipe_inode_info *pipe,
1002				    struct splice_desc *sd)
1003{
1004	return __splice_from_pipe(pipe, sd, nfsd_splice_actor);
1005}
1006
1007static u32 nfsd_eof_on_read(struct file *file, loff_t offset, ssize_t len,
1008		size_t expected)
1009{
1010	if (expected != 0 && len == 0)
1011		return 1;
1012	if (offset+len >= i_size_read(file_inode(file)))
1013		return 1;
1014	return 0;
1015}
1016
1017static __be32 nfsd_finish_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
1018			       struct file *file, loff_t offset,
1019			       unsigned long *count, u32 *eof, ssize_t host_err)
1020{
1021	if (host_err >= 0) {
1022		struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
1023
1024		nfsd_stats_io_read_add(nn, fhp->fh_export, host_err);
1025		*eof = nfsd_eof_on_read(file, offset, host_err, *count);
1026		*count = host_err;
1027		fsnotify_access(file);
1028		trace_nfsd_read_io_done(rqstp, fhp, offset, *count);
1029		return 0;
1030	} else {
1031		trace_nfsd_read_err(rqstp, fhp, offset, host_err);
1032		return nfserrno(host_err);
1033	}
1034}
1035
1036/**
1037 * nfsd_splice_read - Perform a VFS read using a splice pipe
1038 * @rqstp: RPC transaction context
1039 * @fhp: file handle of file to be read
1040 * @file: opened struct file of file to be read
1041 * @offset: starting byte offset
1042 * @count: IN: requested number of bytes; OUT: number of bytes read
1043 * @eof: OUT: set non-zero if operation reached the end of the file
1044 *
1045 * Returns nfs_ok on success, otherwise an nfserr stat value is
1046 * returned.
1047 */
1048__be32 nfsd_splice_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
1049			struct file *file, loff_t offset, unsigned long *count,
1050			u32 *eof)
1051{
1052	struct splice_desc sd = {
1053		.len		= 0,
1054		.total_len	= *count,
1055		.pos		= offset,
1056		.u.data		= rqstp,
1057	};
1058	ssize_t host_err;
1059
1060	trace_nfsd_read_splice(rqstp, fhp, offset, *count);
1061	host_err = rw_verify_area(READ, file, &offset, *count);
1062	if (!host_err)
1063		host_err = splice_direct_to_actor(file, &sd,
1064						  nfsd_direct_splice_actor);
1065	return nfsd_finish_read(rqstp, fhp, file, offset, count, eof, host_err);
1066}
1067
1068/**
1069 * nfsd_iter_read - Perform a VFS read using an iterator
1070 * @rqstp: RPC transaction context
1071 * @fhp: file handle of file to be read
1072 * @file: opened struct file of file to be read
1073 * @offset: starting byte offset
1074 * @count: IN: requested number of bytes; OUT: number of bytes read
1075 * @base: offset in first page of read buffer
1076 * @eof: OUT: set non-zero if operation reached the end of the file
1077 *
1078 * Some filesystems or situations cannot use nfsd_splice_read. This
1079 * function is the slightly less-performant fallback for those cases.
1080 *
1081 * Returns nfs_ok on success, otherwise an nfserr stat value is
1082 * returned.
1083 */
1084__be32 nfsd_iter_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
1085		      struct file *file, loff_t offset, unsigned long *count,
1086		      unsigned int base, u32 *eof)
1087{
1088	unsigned long v, total;
1089	struct iov_iter iter;
1090	loff_t ppos = offset;
1091	struct page *page;
1092	ssize_t host_err;
1093
1094	v = 0;
1095	total = *count;
1096	while (total) {
1097		page = *(rqstp->rq_next_page++);
1098		rqstp->rq_vec[v].iov_base = page_address(page) + base;
1099		rqstp->rq_vec[v].iov_len = min_t(size_t, total, PAGE_SIZE - base);
1100		total -= rqstp->rq_vec[v].iov_len;
1101		++v;
1102		base = 0;
1103	}
1104	WARN_ON_ONCE(v > ARRAY_SIZE(rqstp->rq_vec));
1105
1106	trace_nfsd_read_vector(rqstp, fhp, offset, *count);
1107	iov_iter_kvec(&iter, ITER_DEST, rqstp->rq_vec, v, *count);
1108	host_err = vfs_iter_read(file, &iter, &ppos, 0);
1109	return nfsd_finish_read(rqstp, fhp, file, offset, count, eof, host_err);
1110}
1111
1112/*
1113 * Gathered writes: If another process is currently writing to the file,
1114 * there's a high chance this is another nfsd (triggered by a bulk write
1115 * from a client's biod). Rather than syncing the file with each write
1116 * request, we sleep for 10 msec.
1117 *
1118 * I don't know if this roughly approximates C. Juszak's idea of
1119 * gathered writes, but it's a nice and simple solution (IMHO), and it
1120 * seems to work:-)
1121 *
1122 * Note: we do this only in the NFSv2 case, since v3 and higher have a
1123 * better tool (separate unstable writes and commits) for solving this
1124 * problem.
1125 */
1126static int wait_for_concurrent_writes(struct file *file)
1127{
1128	struct inode *inode = file_inode(file);
1129	static ino_t last_ino;
1130	static dev_t last_dev;
1131	int err = 0;
1132
1133	if (atomic_read(&inode->i_writecount) > 1
1134	    || (last_ino == inode->i_ino && last_dev == inode->i_sb->s_dev)) {
1135		dprintk("nfsd: write defer %d\n", task_pid_nr(current));
1136		msleep(10);
1137		dprintk("nfsd: write resume %d\n", task_pid_nr(current));
1138	}
1139
1140	if (inode->i_state & I_DIRTY) {
1141		dprintk("nfsd: write sync %d\n", task_pid_nr(current));
1142		err = vfs_fsync(file, 0);
1143	}
1144	last_ino = inode->i_ino;
1145	last_dev = inode->i_sb->s_dev;
1146	return err;
1147}
1148
1149__be32
1150nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf,
1151				loff_t offset, struct kvec *vec, int vlen,
1152				unsigned long *cnt, int stable,
1153				__be32 *verf)
1154{
1155	struct nfsd_net		*nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
1156	struct file		*file = nf->nf_file;
1157	struct super_block	*sb = file_inode(file)->i_sb;
1158	struct svc_export	*exp;
1159	struct iov_iter		iter;
1160	errseq_t		since;
1161	__be32			nfserr;
1162	int			host_err;
1163	int			use_wgather;
1164	loff_t			pos = offset;
1165	unsigned long		exp_op_flags = 0;
1166	unsigned int		pflags = current->flags;
1167	rwf_t			flags = 0;
1168	bool			restore_flags = false;
1169
1170	trace_nfsd_write_opened(rqstp, fhp, offset, *cnt);
1171
1172	if (sb->s_export_op)
1173		exp_op_flags = sb->s_export_op->flags;
1174
1175	if (test_bit(RQ_LOCAL, &rqstp->rq_flags) &&
1176	    !(exp_op_flags & EXPORT_OP_REMOTE_FS)) {
1177		/*
1178		 * We want throttling in balance_dirty_pages()
1179		 * and shrink_inactive_list() to only consider
1180		 * the backingdev we are writing to, so that nfs to
1181		 * localhost doesn't cause nfsd to lock up due to all
1182		 * the client's dirty pages or its congested queue.
1183		 */
1184		current->flags |= PF_LOCAL_THROTTLE;
1185		restore_flags = true;
1186	}
1187
1188	exp = fhp->fh_export;
1189	use_wgather = (rqstp->rq_vers == 2) && EX_WGATHER(exp);
1190
1191	if (!EX_ISSYNC(exp))
1192		stable = NFS_UNSTABLE;
1193
1194	if (stable && !use_wgather)
1195		flags |= RWF_SYNC;
1196
1197	iov_iter_kvec(&iter, ITER_SOURCE, vec, vlen, *cnt);
1198	since = READ_ONCE(file->f_wb_err);
1199	if (verf)
1200		nfsd_copy_write_verifier(verf, nn);
1201	host_err = vfs_iter_write(file, &iter, &pos, flags);
1202	if (host_err < 0) {
1203		commit_reset_write_verifier(nn, rqstp, host_err);
1204		goto out_nfserr;
1205	}
1206	*cnt = host_err;
1207	nfsd_stats_io_write_add(nn, exp, *cnt);
1208	fsnotify_modify(file);
1209	host_err = filemap_check_wb_err(file->f_mapping, since);
1210	if (host_err < 0)
1211		goto out_nfserr;
1212
1213	if (stable && use_wgather) {
1214		host_err = wait_for_concurrent_writes(file);
1215		if (host_err < 0)
1216			commit_reset_write_verifier(nn, rqstp, host_err);
1217	}
1218
1219out_nfserr:
1220	if (host_err >= 0) {
1221		trace_nfsd_write_io_done(rqstp, fhp, offset, *cnt);
1222		nfserr = nfs_ok;
1223	} else {
1224		trace_nfsd_write_err(rqstp, fhp, offset, host_err);
1225		nfserr = nfserrno(host_err);
1226	}
1227	if (restore_flags)
1228		current_restore_flags(pflags, PF_LOCAL_THROTTLE);
1229	return nfserr;
1230}
1231
1232/**
1233 * nfsd_read_splice_ok - check if spliced reading is supported
1234 * @rqstp: RPC transaction context
1235 *
1236 * Return values:
1237 *   %true: nfsd_splice_read() may be used
1238 *   %false: nfsd_splice_read() must not be used
1239 *
1240 * NFS READ normally uses splice to send data in-place. However the
1241 * data in cache can change after the reply's MIC is computed but
1242 * before the RPC reply is sent. To prevent the client from
1243 * rejecting the server-computed MIC in this somewhat rare case, do
1244 * not use splice with the GSS integrity and privacy services.
1245 */
1246bool nfsd_read_splice_ok(struct svc_rqst *rqstp)
1247{
1248	switch (svc_auth_flavor(rqstp)) {
1249	case RPC_AUTH_GSS_KRB5I:
1250	case RPC_AUTH_GSS_KRB5P:
1251		return false;
1252	}
1253	return true;
1254}
1255
1256/**
1257 * nfsd_read - Read data from a file
1258 * @rqstp: RPC transaction context
1259 * @fhp: file handle of file to be read
1260 * @offset: starting byte offset
1261 * @count: IN: requested number of bytes; OUT: number of bytes read
1262 * @eof: OUT: set non-zero if operation reached the end of the file
1263 *
1264 * The caller must verify that there is enough space in @rqstp.rq_res
1265 * to perform this operation.
1266 *
1267 * N.B. After this call fhp needs an fh_put
1268 *
1269 * Returns nfs_ok on success, otherwise an nfserr stat value is
1270 * returned.
1271 */
1272__be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
1273		 loff_t offset, unsigned long *count, u32 *eof)
1274{
1275	struct nfsd_file	*nf;
1276	struct file *file;
1277	__be32 err;
1278
1279	trace_nfsd_read_start(rqstp, fhp, offset, *count);
1280	err = nfsd_file_acquire_gc(rqstp, fhp, NFSD_MAY_READ, &nf);
1281	if (err)
1282		return err;
1283
1284	file = nf->nf_file;
1285	if (file->f_op->splice_read && nfsd_read_splice_ok(rqstp))
1286		err = nfsd_splice_read(rqstp, fhp, file, offset, count, eof);
1287	else
1288		err = nfsd_iter_read(rqstp, fhp, file, offset, count, 0, eof);
1289
1290	nfsd_file_put(nf);
1291	trace_nfsd_read_done(rqstp, fhp, offset, *count);
1292	return err;
1293}
1294
1295/*
1296 * Write data to a file.
1297 * The stable flag requests synchronous writes.
1298 * N.B. After this call fhp needs an fh_put
1299 */
1300__be32
1301nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t offset,
1302	   struct kvec *vec, int vlen, unsigned long *cnt, int stable,
1303	   __be32 *verf)
1304{
1305	struct nfsd_file *nf;
1306	__be32 err;
1307
1308	trace_nfsd_write_start(rqstp, fhp, offset, *cnt);
1309
1310	err = nfsd_file_acquire_gc(rqstp, fhp, NFSD_MAY_WRITE, &nf);
1311	if (err)
1312		goto out;
1313
1314	err = nfsd_vfs_write(rqstp, fhp, nf, offset, vec,
1315			vlen, cnt, stable, verf);
1316	nfsd_file_put(nf);
1317out:
1318	trace_nfsd_write_done(rqstp, fhp, offset, *cnt);
1319	return err;
1320}
1321
1322/**
1323 * nfsd_commit - Commit pending writes to stable storage
1324 * @rqstp: RPC request being processed
1325 * @fhp: NFS filehandle
1326 * @nf: target file
1327 * @offset: raw offset from beginning of file
1328 * @count: raw count of bytes to sync
1329 * @verf: filled in with the server's current write verifier
1330 *
1331 * Note: we guarantee that data that lies within the range specified
1332 * by the 'offset' and 'count' parameters will be synced. The server
1333 * is permitted to sync data that lies outside this range at the
1334 * same time.
1335 *
1336 * Unfortunately we cannot lock the file to make sure we return full WCC
1337 * data to the client, as locking happens lower down in the filesystem.
1338 *
1339 * Return values:
1340 *   An nfsstat value in network byte order.
1341 */
1342__be32
1343nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf,
1344	    u64 offset, u32 count, __be32 *verf)
1345{
1346	__be32			err = nfs_ok;
1347	u64			maxbytes;
1348	loff_t			start, end;
1349	struct nfsd_net		*nn;
1350
1351	/*
1352	 * Convert the client-provided (offset, count) range to a
1353	 * (start, end) range. If the client-provided range falls
1354	 * outside the maximum file size of the underlying FS,
1355	 * clamp the sync range appropriately.
1356	 */
1357	start = 0;
1358	end = LLONG_MAX;
1359	maxbytes = (u64)fhp->fh_dentry->d_sb->s_maxbytes;
1360	if (offset < maxbytes) {
1361		start = offset;
1362		if (count && (offset + count - 1 < maxbytes))
1363			end = offset + count - 1;
1364	}
1365
1366	nn = net_generic(nf->nf_net, nfsd_net_id);
1367	if (EX_ISSYNC(fhp->fh_export)) {
1368		errseq_t since = READ_ONCE(nf->nf_file->f_wb_err);
1369		int err2;
1370
1371		err2 = vfs_fsync_range(nf->nf_file, start, end, 0);
1372		switch (err2) {
1373		case 0:
1374			nfsd_copy_write_verifier(verf, nn);
1375			err2 = filemap_check_wb_err(nf->nf_file->f_mapping,
1376						    since);
1377			err = nfserrno(err2);
1378			break;
1379		case -EINVAL:
1380			err = nfserr_notsupp;
1381			break;
1382		default:
1383			commit_reset_write_verifier(nn, rqstp, err2);
1384			err = nfserrno(err2);
1385		}
1386	} else
1387		nfsd_copy_write_verifier(verf, nn);
1388
1389	return err;
1390}
1391
1392/**
1393 * nfsd_create_setattr - Set a created file's attributes
1394 * @rqstp: RPC transaction being executed
1395 * @fhp: NFS filehandle of parent directory
1396 * @resfhp: NFS filehandle of new object
1397 * @attrs: requested attributes of new object
1398 *
1399 * Returns nfs_ok on success, or an nfsstat in network byte order.
1400 */
1401__be32
1402nfsd_create_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp,
1403		    struct svc_fh *resfhp, struct nfsd_attrs *attrs)
1404{
1405	struct iattr *iap = attrs->na_iattr;
1406	__be32 status;
1407
1408	/*
1409	 * Mode has already been set by file creation.
1410	 */
1411	iap->ia_valid &= ~ATTR_MODE;
1412
1413	/*
1414	 * Setting uid/gid works only for root.  Irix appears to
1415	 * send along the gid on create when it tries to implement
1416	 * setgid directories via NFS:
1417	 */
1418	if (!uid_eq(current_fsuid(), GLOBAL_ROOT_UID))
1419		iap->ia_valid &= ~(ATTR_UID|ATTR_GID);
1420
1421	/*
1422	 * Callers expect new file metadata to be committed even
1423	 * if the attributes have not changed.
1424	 */
1425	if (iap->ia_valid)
1426		status = nfsd_setattr(rqstp, resfhp, attrs, NULL);
1427	else
1428		status = nfserrno(commit_metadata(resfhp));
1429
1430	/*
1431	 * Transactional filesystems had a chance to commit changes
1432	 * for both parent and child simultaneously making the
1433	 * following commit_metadata a noop in many cases.
1434	 */
1435	if (!status)
1436		status = nfserrno(commit_metadata(fhp));
1437
1438	/*
1439	 * Update the new filehandle to pick up the new attributes.
1440	 */
1441	if (!status)
1442		status = fh_update(resfhp);
1443
1444	return status;
1445}
1446
1447/* HPUX client sometimes creates a file in mode 000, and sets size to 0.
1448 * setting size to 0 may fail for some specific file systems by the permission
1449 * checking which requires WRITE permission but the mode is 000.
1450 * we ignore the resizing(to 0) on the just new created file, since the size is
1451 * 0 after file created.
1452 *
1453 * call this only after vfs_create() is called.
1454 * */
1455static void
1456nfsd_check_ignore_resizing(struct iattr *iap)
1457{
1458	if ((iap->ia_valid & ATTR_SIZE) && (iap->ia_size == 0))
1459		iap->ia_valid &= ~ATTR_SIZE;
1460}
1461
1462/* The parent directory should already be locked: */
1463__be32
1464nfsd_create_locked(struct svc_rqst *rqstp, struct svc_fh *fhp,
1465		   struct nfsd_attrs *attrs,
1466		   int type, dev_t rdev, struct svc_fh *resfhp)
1467{
1468	struct dentry	*dentry, *dchild;
1469	struct inode	*dirp;
1470	struct iattr	*iap = attrs->na_iattr;
1471	__be32		err;
1472	int		host_err;
1473
1474	dentry = fhp->fh_dentry;
1475	dirp = d_inode(dentry);
1476
1477	dchild = dget(resfhp->fh_dentry);
1478	err = nfsd_permission(rqstp, fhp->fh_export, dentry, NFSD_MAY_CREATE);
 
1479	if (err)
1480		goto out;
1481
1482	if (!(iap->ia_valid & ATTR_MODE))
1483		iap->ia_mode = 0;
1484	iap->ia_mode = (iap->ia_mode & S_IALLUGO) | type;
1485
1486	if (!IS_POSIXACL(dirp))
1487		iap->ia_mode &= ~current_umask();
1488
1489	err = 0;
1490	switch (type) {
1491	case S_IFREG:
1492		host_err = vfs_create(&nop_mnt_idmap, dirp, dchild,
1493				      iap->ia_mode, true);
1494		if (!host_err)
1495			nfsd_check_ignore_resizing(iap);
1496		break;
1497	case S_IFDIR:
1498		host_err = vfs_mkdir(&nop_mnt_idmap, dirp, dchild, iap->ia_mode);
1499		if (!host_err && unlikely(d_unhashed(dchild))) {
1500			struct dentry *d;
1501			d = lookup_one_len(dchild->d_name.name,
1502					   dchild->d_parent,
1503					   dchild->d_name.len);
1504			if (IS_ERR(d)) {
1505				host_err = PTR_ERR(d);
1506				break;
1507			}
1508			if (unlikely(d_is_negative(d))) {
1509				dput(d);
1510				err = nfserr_serverfault;
1511				goto out;
1512			}
1513			dput(resfhp->fh_dentry);
1514			resfhp->fh_dentry = dget(d);
1515			err = fh_update(resfhp);
1516			dput(dchild);
1517			dchild = d;
1518			if (err)
1519				goto out;
1520		}
1521		break;
1522	case S_IFCHR:
1523	case S_IFBLK:
1524	case S_IFIFO:
1525	case S_IFSOCK:
1526		host_err = vfs_mknod(&nop_mnt_idmap, dirp, dchild,
1527				     iap->ia_mode, rdev);
1528		break;
1529	default:
1530		printk(KERN_WARNING "nfsd: bad file type %o in nfsd_create\n",
1531		       type);
1532		host_err = -EINVAL;
1533	}
1534	if (host_err < 0)
1535		goto out_nfserr;
1536
1537	err = nfsd_create_setattr(rqstp, fhp, resfhp, attrs);
1538
1539out:
1540	dput(dchild);
1541	return err;
1542
1543out_nfserr:
1544	err = nfserrno(host_err);
1545	goto out;
1546}
1547
1548/*
1549 * Create a filesystem object (regular, directory, special).
1550 * Note that the parent directory is left locked.
1551 *
1552 * N.B. Every call to nfsd_create needs an fh_put for _both_ fhp and resfhp
1553 */
1554__be32
1555nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
1556	    char *fname, int flen, struct nfsd_attrs *attrs,
1557	    int type, dev_t rdev, struct svc_fh *resfhp)
1558{
1559	struct dentry	*dentry, *dchild = NULL;
1560	__be32		err;
1561	int		host_err;
1562
1563	if (isdotent(fname, flen))
1564		return nfserr_exist;
1565
1566	err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_NOP);
1567	if (err)
1568		return err;
1569
1570	dentry = fhp->fh_dentry;
1571
1572	host_err = fh_want_write(fhp);
1573	if (host_err)
1574		return nfserrno(host_err);
1575
1576	inode_lock_nested(dentry->d_inode, I_MUTEX_PARENT);
1577	dchild = lookup_one_len(fname, dentry, flen);
1578	host_err = PTR_ERR(dchild);
1579	if (IS_ERR(dchild)) {
1580		err = nfserrno(host_err);
1581		goto out_unlock;
1582	}
1583	err = fh_compose(resfhp, fhp->fh_export, dchild, fhp);
1584	/*
1585	 * We unconditionally drop our ref to dchild as fh_compose will have
1586	 * already grabbed its own ref for it.
1587	 */
1588	dput(dchild);
1589	if (err)
1590		goto out_unlock;
1591	err = fh_fill_pre_attrs(fhp);
1592	if (err != nfs_ok)
1593		goto out_unlock;
1594	err = nfsd_create_locked(rqstp, fhp, attrs, type, rdev, resfhp);
1595	fh_fill_post_attrs(fhp);
1596out_unlock:
1597	inode_unlock(dentry->d_inode);
1598	return err;
1599}
1600
1601/*
1602 * Read a symlink. On entry, *lenp must contain the maximum path length that
1603 * fits into the buffer. On return, it contains the true length.
1604 * N.B. After this call fhp needs an fh_put
1605 */
1606__be32
1607nfsd_readlink(struct svc_rqst *rqstp, struct svc_fh *fhp, char *buf, int *lenp)
1608{
1609	__be32		err;
1610	const char *link;
1611	struct path path;
1612	DEFINE_DELAYED_CALL(done);
1613	int len;
1614
1615	err = fh_verify(rqstp, fhp, S_IFLNK, NFSD_MAY_NOP);
1616	if (unlikely(err))
1617		return err;
1618
1619	path.mnt = fhp->fh_export->ex_path.mnt;
1620	path.dentry = fhp->fh_dentry;
1621
1622	if (unlikely(!d_is_symlink(path.dentry)))
1623		return nfserr_inval;
1624
1625	touch_atime(&path);
1626
1627	link = vfs_get_link(path.dentry, &done);
1628	if (IS_ERR(link))
1629		return nfserrno(PTR_ERR(link));
1630
1631	len = strlen(link);
1632	if (len < *lenp)
1633		*lenp = len;
1634	memcpy(buf, link, *lenp);
1635	do_delayed_call(&done);
1636	return 0;
1637}
1638
1639/**
1640 * nfsd_symlink - Create a symlink and look up its inode
1641 * @rqstp: RPC transaction being executed
1642 * @fhp: NFS filehandle of parent directory
1643 * @fname: filename of the new symlink
1644 * @flen: length of @fname
1645 * @path: content of the new symlink (NUL-terminated)
1646 * @attrs: requested attributes of new object
1647 * @resfhp: NFS filehandle of new object
1648 *
1649 * N.B. After this call _both_ fhp and resfhp need an fh_put
1650 *
1651 * Returns nfs_ok on success, or an nfsstat in network byte order.
1652 */
1653__be32
1654nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp,
1655	     char *fname, int flen,
1656	     char *path, struct nfsd_attrs *attrs,
1657	     struct svc_fh *resfhp)
1658{
1659	struct dentry	*dentry, *dnew;
1660	__be32		err, cerr;
1661	int		host_err;
1662
1663	err = nfserr_noent;
1664	if (!flen || path[0] == '\0')
1665		goto out;
1666	err = nfserr_exist;
1667	if (isdotent(fname, flen))
1668		goto out;
1669
1670	err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
1671	if (err)
1672		goto out;
1673
1674	host_err = fh_want_write(fhp);
1675	if (host_err) {
1676		err = nfserrno(host_err);
1677		goto out;
1678	}
1679
1680	dentry = fhp->fh_dentry;
1681	inode_lock_nested(dentry->d_inode, I_MUTEX_PARENT);
1682	dnew = lookup_one_len(fname, dentry, flen);
1683	if (IS_ERR(dnew)) {
1684		err = nfserrno(PTR_ERR(dnew));
1685		inode_unlock(dentry->d_inode);
1686		goto out_drop_write;
1687	}
1688	err = fh_fill_pre_attrs(fhp);
1689	if (err != nfs_ok)
1690		goto out_unlock;
1691	host_err = vfs_symlink(&nop_mnt_idmap, d_inode(dentry), dnew, path);
1692	err = nfserrno(host_err);
1693	cerr = fh_compose(resfhp, fhp->fh_export, dnew, fhp);
1694	if (!err)
1695		nfsd_create_setattr(rqstp, fhp, resfhp, attrs);
1696	fh_fill_post_attrs(fhp);
1697out_unlock:
1698	inode_unlock(dentry->d_inode);
1699	if (!err)
1700		err = nfserrno(commit_metadata(fhp));
1701	dput(dnew);
1702	if (err==0) err = cerr;
1703out_drop_write:
1704	fh_drop_write(fhp);
1705out:
1706	return err;
1707}
1708
1709/*
1710 * Create a hardlink
1711 * N.B. After this call _both_ ffhp and tfhp need an fh_put
1712 */
1713__be32
1714nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp,
1715				char *name, int len, struct svc_fh *tfhp)
1716{
1717	struct dentry	*ddir, *dnew, *dold;
1718	struct inode	*dirp;
1719	__be32		err;
1720	int		host_err;
1721
1722	err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_CREATE);
1723	if (err)
1724		goto out;
1725	err = fh_verify(rqstp, tfhp, 0, NFSD_MAY_NOP);
1726	if (err)
1727		goto out;
1728	err = nfserr_isdir;
1729	if (d_is_dir(tfhp->fh_dentry))
1730		goto out;
1731	err = nfserr_perm;
1732	if (!len)
1733		goto out;
1734	err = nfserr_exist;
1735	if (isdotent(name, len))
1736		goto out;
1737
1738	host_err = fh_want_write(tfhp);
1739	if (host_err) {
1740		err = nfserrno(host_err);
1741		goto out;
1742	}
1743
1744	ddir = ffhp->fh_dentry;
1745	dirp = d_inode(ddir);
1746	inode_lock_nested(dirp, I_MUTEX_PARENT);
1747
1748	dnew = lookup_one_len(name, ddir, len);
1749	if (IS_ERR(dnew)) {
1750		err = nfserrno(PTR_ERR(dnew));
1751		goto out_unlock;
1752	}
1753
1754	dold = tfhp->fh_dentry;
1755
1756	err = nfserr_noent;
1757	if (d_really_is_negative(dold))
1758		goto out_dput;
1759	err = fh_fill_pre_attrs(ffhp);
1760	if (err != nfs_ok)
1761		goto out_dput;
1762	host_err = vfs_link(dold, &nop_mnt_idmap, dirp, dnew, NULL);
1763	fh_fill_post_attrs(ffhp);
1764	inode_unlock(dirp);
1765	if (!host_err) {
1766		err = nfserrno(commit_metadata(ffhp));
1767		if (!err)
1768			err = nfserrno(commit_metadata(tfhp));
1769	} else {
1770		if (host_err == -EXDEV && rqstp->rq_vers == 2)
1771			err = nfserr_acces;
1772		else
1773			err = nfserrno(host_err);
1774	}
1775	dput(dnew);
1776out_drop_write:
1777	fh_drop_write(tfhp);
1778out:
1779	return err;
1780
1781out_dput:
1782	dput(dnew);
1783out_unlock:
1784	inode_unlock(dirp);
1785	goto out_drop_write;
1786}
1787
1788static void
1789nfsd_close_cached_files(struct dentry *dentry)
1790{
1791	struct inode *inode = d_inode(dentry);
1792
1793	if (inode && S_ISREG(inode->i_mode))
1794		nfsd_file_close_inode_sync(inode);
1795}
1796
1797static bool
1798nfsd_has_cached_files(struct dentry *dentry)
1799{
1800	bool		ret = false;
1801	struct inode *inode = d_inode(dentry);
1802
1803	if (inode && S_ISREG(inode->i_mode))
1804		ret = nfsd_file_is_cached(inode);
1805	return ret;
1806}
1807
1808/*
1809 * Rename a file
1810 * N.B. After this call _both_ ffhp and tfhp need an fh_put
1811 */
1812__be32
1813nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
1814			    struct svc_fh *tfhp, char *tname, int tlen)
1815{
1816	struct dentry	*fdentry, *tdentry, *odentry, *ndentry, *trap;
1817	struct inode	*fdir, *tdir;
1818	__be32		err;
1819	int		host_err;
1820	bool		close_cached = false;
1821
1822	err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_REMOVE);
1823	if (err)
1824		goto out;
1825	err = fh_verify(rqstp, tfhp, S_IFDIR, NFSD_MAY_CREATE);
1826	if (err)
1827		goto out;
1828
1829	fdentry = ffhp->fh_dentry;
1830	fdir = d_inode(fdentry);
1831
1832	tdentry = tfhp->fh_dentry;
1833	tdir = d_inode(tdentry);
1834
1835	err = nfserr_perm;
1836	if (!flen || isdotent(fname, flen) || !tlen || isdotent(tname, tlen))
1837		goto out;
1838
1839	err = (rqstp->rq_vers == 2) ? nfserr_acces : nfserr_xdev;
1840	if (ffhp->fh_export->ex_path.mnt != tfhp->fh_export->ex_path.mnt)
1841		goto out;
1842	if (ffhp->fh_export->ex_path.dentry != tfhp->fh_export->ex_path.dentry)
1843		goto out;
1844
1845retry:
1846	host_err = fh_want_write(ffhp);
1847	if (host_err) {
1848		err = nfserrno(host_err);
1849		goto out;
1850	}
1851
1852	trap = lock_rename(tdentry, fdentry);
1853	if (IS_ERR(trap)) {
1854		err = (rqstp->rq_vers == 2) ? nfserr_acces : nfserr_xdev;
1855		goto out_want_write;
1856	}
1857	err = fh_fill_pre_attrs(ffhp);
1858	if (err != nfs_ok)
1859		goto out_unlock;
1860	err = fh_fill_pre_attrs(tfhp);
1861	if (err != nfs_ok)
1862		goto out_unlock;
1863
1864	odentry = lookup_one_len(fname, fdentry, flen);
1865	host_err = PTR_ERR(odentry);
1866	if (IS_ERR(odentry))
1867		goto out_nfserr;
1868
1869	host_err = -ENOENT;
1870	if (d_really_is_negative(odentry))
1871		goto out_dput_old;
1872	host_err = -EINVAL;
1873	if (odentry == trap)
1874		goto out_dput_old;
1875
1876	ndentry = lookup_one_len(tname, tdentry, tlen);
1877	host_err = PTR_ERR(ndentry);
1878	if (IS_ERR(ndentry))
1879		goto out_dput_old;
1880	host_err = -ENOTEMPTY;
1881	if (ndentry == trap)
1882		goto out_dput_new;
1883
1884	if ((ndentry->d_sb->s_export_op->flags & EXPORT_OP_CLOSE_BEFORE_UNLINK) &&
1885	    nfsd_has_cached_files(ndentry)) {
1886		close_cached = true;
1887		goto out_dput_old;
1888	} else {
1889		struct renamedata rd = {
1890			.old_mnt_idmap	= &nop_mnt_idmap,
1891			.old_dir	= fdir,
1892			.old_dentry	= odentry,
1893			.new_mnt_idmap	= &nop_mnt_idmap,
1894			.new_dir	= tdir,
1895			.new_dentry	= ndentry,
1896		};
1897		int retries;
1898
1899		for (retries = 1;;) {
1900			host_err = vfs_rename(&rd);
1901			if (host_err != -EAGAIN || !retries--)
1902				break;
1903			if (!nfsd_wait_for_delegreturn(rqstp, d_inode(odentry)))
1904				break;
1905		}
1906		if (!host_err) {
1907			host_err = commit_metadata(tfhp);
1908			if (!host_err)
1909				host_err = commit_metadata(ffhp);
1910		}
1911	}
1912 out_dput_new:
1913	dput(ndentry);
1914 out_dput_old:
1915	dput(odentry);
1916 out_nfserr:
1917	err = nfserrno(host_err);
1918
1919	if (!close_cached) {
1920		fh_fill_post_attrs(ffhp);
1921		fh_fill_post_attrs(tfhp);
1922	}
1923out_unlock:
1924	unlock_rename(tdentry, fdentry);
1925out_want_write:
1926	fh_drop_write(ffhp);
1927
1928	/*
1929	 * If the target dentry has cached open files, then we need to
1930	 * try to close them prior to doing the rename.  Final fput
1931	 * shouldn't be done with locks held however, so we delay it
1932	 * until this point and then reattempt the whole shebang.
1933	 */
1934	if (close_cached) {
1935		close_cached = false;
1936		nfsd_close_cached_files(ndentry);
1937		dput(ndentry);
1938		goto retry;
1939	}
1940out:
1941	return err;
1942}
1943
1944/*
1945 * Unlink a file or directory
1946 * N.B. After this call fhp needs an fh_put
1947 */
1948__be32
1949nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
1950				char *fname, int flen)
1951{
1952	struct dentry	*dentry, *rdentry;
1953	struct inode	*dirp;
1954	struct inode	*rinode;
1955	__be32		err;
1956	int		host_err;
1957
1958	err = nfserr_acces;
1959	if (!flen || isdotent(fname, flen))
1960		goto out;
1961	err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_REMOVE);
1962	if (err)
1963		goto out;
1964
1965	host_err = fh_want_write(fhp);
1966	if (host_err)
1967		goto out_nfserr;
1968
1969	dentry = fhp->fh_dentry;
1970	dirp = d_inode(dentry);
1971	inode_lock_nested(dirp, I_MUTEX_PARENT);
1972
1973	rdentry = lookup_one_len(fname, dentry, flen);
1974	host_err = PTR_ERR(rdentry);
1975	if (IS_ERR(rdentry))
1976		goto out_unlock;
1977
1978	if (d_really_is_negative(rdentry)) {
1979		dput(rdentry);
1980		host_err = -ENOENT;
1981		goto out_unlock;
1982	}
1983	rinode = d_inode(rdentry);
1984	err = fh_fill_pre_attrs(fhp);
1985	if (err != nfs_ok)
1986		goto out_unlock;
1987
1988	ihold(rinode);
1989	if (!type)
1990		type = d_inode(rdentry)->i_mode & S_IFMT;
1991
1992	if (type != S_IFDIR) {
1993		int retries;
1994
1995		if (rdentry->d_sb->s_export_op->flags & EXPORT_OP_CLOSE_BEFORE_UNLINK)
1996			nfsd_close_cached_files(rdentry);
1997
1998		for (retries = 1;;) {
1999			host_err = vfs_unlink(&nop_mnt_idmap, dirp, rdentry, NULL);
2000			if (host_err != -EAGAIN || !retries--)
2001				break;
2002			if (!nfsd_wait_for_delegreturn(rqstp, rinode))
2003				break;
2004		}
2005	} else {
2006		host_err = vfs_rmdir(&nop_mnt_idmap, dirp, rdentry);
2007	}
2008	fh_fill_post_attrs(fhp);
2009
2010	inode_unlock(dirp);
2011	if (!host_err)
2012		host_err = commit_metadata(fhp);
2013	dput(rdentry);
2014	iput(rinode);    /* truncate the inode here */
2015
2016out_drop_write:
2017	fh_drop_write(fhp);
2018out_nfserr:
2019	if (host_err == -EBUSY) {
2020		/* name is mounted-on. There is no perfect
2021		 * error status.
2022		 */
2023		if (nfsd_v4client(rqstp))
2024			err = nfserr_file_open;
2025		else
2026			err = nfserr_acces;
2027	} else {
2028		err = nfserrno(host_err);
2029	}
2030out:
2031	return err;
2032out_unlock:
2033	inode_unlock(dirp);
2034	goto out_drop_write;
2035}
2036
2037/*
2038 * We do this buffering because we must not call back into the file
2039 * system's ->lookup() method from the filldir callback. That may well
2040 * deadlock a number of file systems.
2041 *
2042 * This is based heavily on the implementation of same in XFS.
2043 */
2044struct buffered_dirent {
2045	u64		ino;
2046	loff_t		offset;
2047	int		namlen;
2048	unsigned int	d_type;
2049	char		name[];
2050};
2051
2052struct readdir_data {
2053	struct dir_context ctx;
2054	char		*dirent;
2055	size_t		used;
2056	int		full;
2057};
2058
2059static bool nfsd_buffered_filldir(struct dir_context *ctx, const char *name,
2060				 int namlen, loff_t offset, u64 ino,
2061				 unsigned int d_type)
2062{
2063	struct readdir_data *buf =
2064		container_of(ctx, struct readdir_data, ctx);
2065	struct buffered_dirent *de = (void *)(buf->dirent + buf->used);
2066	unsigned int reclen;
2067
2068	reclen = ALIGN(sizeof(struct buffered_dirent) + namlen, sizeof(u64));
2069	if (buf->used + reclen > PAGE_SIZE) {
2070		buf->full = 1;
2071		return false;
2072	}
2073
2074	de->namlen = namlen;
2075	de->offset = offset;
2076	de->ino = ino;
2077	de->d_type = d_type;
2078	memcpy(de->name, name, namlen);
2079	buf->used += reclen;
2080
2081	return true;
2082}
2083
2084static __be32 nfsd_buffered_readdir(struct file *file, struct svc_fh *fhp,
2085				    nfsd_filldir_t func, struct readdir_cd *cdp,
2086				    loff_t *offsetp)
2087{
2088	struct buffered_dirent *de;
2089	int host_err;
2090	int size;
2091	loff_t offset;
2092	struct readdir_data buf = {
2093		.ctx.actor = nfsd_buffered_filldir,
2094		.dirent = (void *)__get_free_page(GFP_KERNEL)
2095	};
2096
2097	if (!buf.dirent)
2098		return nfserrno(-ENOMEM);
2099
2100	offset = *offsetp;
2101
2102	while (1) {
2103		unsigned int reclen;
2104
2105		cdp->err = nfserr_eof; /* will be cleared on successful read */
2106		buf.used = 0;
2107		buf.full = 0;
2108
2109		host_err = iterate_dir(file, &buf.ctx);
2110		if (buf.full)
2111			host_err = 0;
2112
2113		if (host_err < 0)
2114			break;
2115
2116		size = buf.used;
2117
2118		if (!size)
2119			break;
2120
2121		de = (struct buffered_dirent *)buf.dirent;
2122		while (size > 0) {
2123			offset = de->offset;
2124
2125			if (func(cdp, de->name, de->namlen, de->offset,
2126				 de->ino, de->d_type))
2127				break;
2128
2129			if (cdp->err != nfs_ok)
2130				break;
2131
2132			trace_nfsd_dirent(fhp, de->ino, de->name, de->namlen);
2133
2134			reclen = ALIGN(sizeof(*de) + de->namlen,
2135				       sizeof(u64));
2136			size -= reclen;
2137			de = (struct buffered_dirent *)((char *)de + reclen);
2138		}
2139		if (size > 0) /* We bailed out early */
2140			break;
2141
2142		offset = vfs_llseek(file, 0, SEEK_CUR);
2143	}
2144
2145	free_page((unsigned long)(buf.dirent));
2146
2147	if (host_err)
2148		return nfserrno(host_err);
2149
2150	*offsetp = offset;
2151	return cdp->err;
2152}
2153
2154/**
2155 * nfsd_readdir - Read entries from a directory
2156 * @rqstp: RPC transaction context
2157 * @fhp: NFS file handle of directory to be read
2158 * @offsetp: OUT: seek offset of final entry that was read
2159 * @cdp: OUT: an eof error value
2160 * @func: entry filler actor
2161 *
2162 * This implementation ignores the NFSv3/4 verifier cookie.
2163 *
2164 * NB: normal system calls hold file->f_pos_lock when calling
2165 * ->iterate_shared and ->llseek, but nfsd_readdir() does not.
2166 * Because the struct file acquired here is not visible to other
2167 * threads, it's internal state does not need mutex protection.
2168 *
2169 * Returns nfs_ok on success, otherwise an nfsstat code is
2170 * returned.
2171 */
2172__be32
2173nfsd_readdir(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t *offsetp, 
2174	     struct readdir_cd *cdp, nfsd_filldir_t func)
2175{
2176	__be32		err;
2177	struct file	*file;
2178	loff_t		offset = *offsetp;
2179	int             may_flags = NFSD_MAY_READ;
2180
2181	/* NFSv2 only supports 32 bit cookies */
2182	if (rqstp->rq_vers > 2)
2183		may_flags |= NFSD_MAY_64BIT_COOKIE;
2184
2185	err = nfsd_open(rqstp, fhp, S_IFDIR, may_flags, &file);
2186	if (err)
2187		goto out;
2188
 
 
 
 
 
2189	offset = vfs_llseek(file, offset, SEEK_SET);
2190	if (offset < 0) {
2191		err = nfserrno((int)offset);
2192		goto out_close;
2193	}
2194
2195	err = nfsd_buffered_readdir(file, fhp, func, cdp, offsetp);
2196
2197	if (err == nfserr_eof || err == nfserr_toosmall)
2198		err = nfs_ok; /* can still be found in ->err */
2199out_close:
2200	nfsd_filp_close(file);
2201out:
2202	return err;
2203}
2204
2205/**
2206 * nfsd_filp_close: close a file synchronously
2207 * @fp: the file to close
2208 *
2209 * nfsd_filp_close() is similar in behaviour to filp_close().
2210 * The difference is that if this is the final close on the
2211 * file, the that finalisation happens immediately, rather then
2212 * being handed over to a work_queue, as it the case for
2213 * filp_close().
2214 * When a user-space process closes a file (even when using
2215 * filp_close() the finalisation happens before returning to
2216 * userspace, so it is effectively synchronous.  When a kernel thread
2217 * uses file_close(), on the other hand, the handling is completely
2218 * asynchronous.  This means that any cost imposed by that finalisation
2219 * is not imposed on the nfsd thread, and nfsd could potentually
2220 * close files more quickly than the work queue finalises the close,
2221 * which would lead to unbounded growth in the queue.
2222 *
2223 * In some contexts is it not safe to synchronously wait for
2224 * close finalisation (see comment for __fput_sync()), but nfsd
2225 * does not match those contexts.  In partcilarly it does not, at the
2226 * time that this function is called, hold and locks and no finalisation
2227 * of any file, socket, or device driver would have any cause to wait
2228 * for nfsd to make progress.
2229 */
2230void nfsd_filp_close(struct file *fp)
2231{
2232	get_file(fp);
2233	filp_close(fp, NULL);
2234	__fput_sync(fp);
2235}
2236
2237/*
2238 * Get file system stats
2239 * N.B. After this call fhp needs an fh_put
2240 */
2241__be32
2242nfsd_statfs(struct svc_rqst *rqstp, struct svc_fh *fhp, struct kstatfs *stat, int access)
2243{
2244	__be32 err;
2245
2246	err = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP | access);
2247	if (!err) {
2248		struct path path = {
2249			.mnt	= fhp->fh_export->ex_path.mnt,
2250			.dentry	= fhp->fh_dentry,
2251		};
2252		if (vfs_statfs(&path, stat))
2253			err = nfserr_io;
2254	}
2255	return err;
2256}
2257
2258static int exp_rdonly(struct svc_rqst *rqstp, struct svc_export *exp)
2259{
2260	return nfsexp_flags(rqstp, exp) & NFSEXP_READONLY;
2261}
2262
2263#ifdef CONFIG_NFSD_V4
2264/*
2265 * Helper function to translate error numbers. In the case of xattr operations,
2266 * some error codes need to be translated outside of the standard translations.
2267 *
2268 * ENODATA needs to be translated to nfserr_noxattr.
2269 * E2BIG to nfserr_xattr2big.
2270 *
2271 * Additionally, vfs_listxattr can return -ERANGE. This means that the
2272 * file has too many extended attributes to retrieve inside an
2273 * XATTR_LIST_MAX sized buffer. This is a bug in the xattr implementation:
2274 * filesystems will allow the adding of extended attributes until they hit
2275 * their own internal limit. This limit may be larger than XATTR_LIST_MAX.
2276 * So, at that point, the attributes are present and valid, but can't
2277 * be retrieved using listxattr, since the upper level xattr code enforces
2278 * the XATTR_LIST_MAX limit.
2279 *
2280 * This bug means that we need to deal with listxattr returning -ERANGE. The
2281 * best mapping is to return TOOSMALL.
2282 */
2283static __be32
2284nfsd_xattr_errno(int err)
2285{
2286	switch (err) {
2287	case -ENODATA:
2288		return nfserr_noxattr;
2289	case -E2BIG:
2290		return nfserr_xattr2big;
2291	case -ERANGE:
2292		return nfserr_toosmall;
2293	}
2294	return nfserrno(err);
2295}
2296
2297/*
2298 * Retrieve the specified user extended attribute. To avoid always
2299 * having to allocate the maximum size (since we are not getting
2300 * a maximum size from the RPC), do a probe + alloc. Hold a reader
2301 * lock on i_rwsem to prevent the extended attribute from changing
2302 * size while we're doing this.
2303 */
2304__be32
2305nfsd_getxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name,
2306	      void **bufp, int *lenp)
2307{
2308	ssize_t len;
2309	__be32 err;
2310	char *buf;
2311	struct inode *inode;
2312	struct dentry *dentry;
2313
2314	err = fh_verify(rqstp, fhp, 0, NFSD_MAY_READ);
2315	if (err)
2316		return err;
2317
2318	err = nfs_ok;
2319	dentry = fhp->fh_dentry;
2320	inode = d_inode(dentry);
2321
2322	inode_lock_shared(inode);
2323
2324	len = vfs_getxattr(&nop_mnt_idmap, dentry, name, NULL, 0);
2325
2326	/*
2327	 * Zero-length attribute, just return.
2328	 */
2329	if (len == 0) {
2330		*bufp = NULL;
2331		*lenp = 0;
2332		goto out;
2333	}
2334
2335	if (len < 0) {
2336		err = nfsd_xattr_errno(len);
2337		goto out;
2338	}
2339
2340	if (len > *lenp) {
2341		err = nfserr_toosmall;
2342		goto out;
2343	}
2344
2345	buf = kvmalloc(len, GFP_KERNEL);
2346	if (buf == NULL) {
2347		err = nfserr_jukebox;
2348		goto out;
2349	}
2350
2351	len = vfs_getxattr(&nop_mnt_idmap, dentry, name, buf, len);
2352	if (len <= 0) {
2353		kvfree(buf);
2354		buf = NULL;
2355		err = nfsd_xattr_errno(len);
2356	}
2357
2358	*lenp = len;
2359	*bufp = buf;
2360
2361out:
2362	inode_unlock_shared(inode);
2363
2364	return err;
2365}
2366
2367/*
2368 * Retrieve the xattr names. Since we can't know how many are
2369 * user extended attributes, we must get all attributes here,
2370 * and have the XDR encode filter out the "user." ones.
2371 *
2372 * While this could always just allocate an XATTR_LIST_MAX
2373 * buffer, that's a waste, so do a probe + allocate. To
2374 * avoid any changes between the probe and allocate, wrap
2375 * this in inode_lock.
2376 */
2377__be32
2378nfsd_listxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char **bufp,
2379	       int *lenp)
2380{
2381	ssize_t len;
2382	__be32 err;
2383	char *buf;
2384	struct inode *inode;
2385	struct dentry *dentry;
2386
2387	err = fh_verify(rqstp, fhp, 0, NFSD_MAY_READ);
2388	if (err)
2389		return err;
2390
2391	dentry = fhp->fh_dentry;
2392	inode = d_inode(dentry);
2393	*lenp = 0;
2394
2395	inode_lock_shared(inode);
2396
2397	len = vfs_listxattr(dentry, NULL, 0);
2398	if (len <= 0) {
2399		err = nfsd_xattr_errno(len);
2400		goto out;
2401	}
2402
2403	if (len > XATTR_LIST_MAX) {
2404		err = nfserr_xattr2big;
2405		goto out;
2406	}
2407
2408	buf = kvmalloc(len, GFP_KERNEL);
2409	if (buf == NULL) {
2410		err = nfserr_jukebox;
2411		goto out;
2412	}
2413
2414	len = vfs_listxattr(dentry, buf, len);
2415	if (len <= 0) {
2416		kvfree(buf);
2417		err = nfsd_xattr_errno(len);
2418		goto out;
2419	}
2420
2421	*lenp = len;
2422	*bufp = buf;
2423
2424	err = nfs_ok;
2425out:
2426	inode_unlock_shared(inode);
2427
2428	return err;
2429}
2430
2431/**
2432 * nfsd_removexattr - Remove an extended attribute
2433 * @rqstp: RPC transaction being executed
2434 * @fhp: NFS filehandle of object with xattr to remove
2435 * @name: name of xattr to remove (NUL-terminate)
2436 *
2437 * Pass in a NULL pointer for delegated_inode, and let the client deal
2438 * with NFS4ERR_DELAY (same as with e.g. setattr and remove).
2439 *
2440 * Returns nfs_ok on success, or an nfsstat in network byte order.
2441 */
2442__be32
2443nfsd_removexattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name)
2444{
2445	__be32 err;
2446	int ret;
2447
2448	err = fh_verify(rqstp, fhp, 0, NFSD_MAY_WRITE);
2449	if (err)
2450		return err;
2451
2452	ret = fh_want_write(fhp);
2453	if (ret)
2454		return nfserrno(ret);
2455
2456	inode_lock(fhp->fh_dentry->d_inode);
2457	err = fh_fill_pre_attrs(fhp);
2458	if (err != nfs_ok)
2459		goto out_unlock;
2460	ret = __vfs_removexattr_locked(&nop_mnt_idmap, fhp->fh_dentry,
2461				       name, NULL);
2462	err = nfsd_xattr_errno(ret);
2463	fh_fill_post_attrs(fhp);
2464out_unlock:
2465	inode_unlock(fhp->fh_dentry->d_inode);
2466	fh_drop_write(fhp);
2467
2468	return err;
2469}
2470
2471__be32
2472nfsd_setxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name,
2473	      void *buf, u32 len, u32 flags)
2474{
2475	__be32 err;
2476	int ret;
2477
2478	err = fh_verify(rqstp, fhp, 0, NFSD_MAY_WRITE);
2479	if (err)
2480		return err;
2481
2482	ret = fh_want_write(fhp);
2483	if (ret)
2484		return nfserrno(ret);
2485	inode_lock(fhp->fh_dentry->d_inode);
2486	err = fh_fill_pre_attrs(fhp);
2487	if (err != nfs_ok)
2488		goto out_unlock;
2489	ret = __vfs_setxattr_locked(&nop_mnt_idmap, fhp->fh_dentry,
2490				    name, buf, len, flags, NULL);
2491	fh_fill_post_attrs(fhp);
2492	err = nfsd_xattr_errno(ret);
2493out_unlock:
2494	inode_unlock(fhp->fh_dentry->d_inode);
2495	fh_drop_write(fhp);
2496	return err;
2497}
2498#endif
2499
2500/*
2501 * Check for a user's access permissions to this inode.
2502 */
2503__be32
2504nfsd_permission(struct svc_rqst *rqstp, struct svc_export *exp,
2505					struct dentry *dentry, int acc)
2506{
2507	struct inode	*inode = d_inode(dentry);
2508	int		err;
2509
2510	if ((acc & NFSD_MAY_MASK) == NFSD_MAY_NOP)
2511		return 0;
2512#if 0
2513	dprintk("nfsd: permission 0x%x%s%s%s%s%s%s%s mode 0%o%s%s%s\n",
2514		acc,
2515		(acc & NFSD_MAY_READ)?	" read"  : "",
2516		(acc & NFSD_MAY_WRITE)?	" write" : "",
2517		(acc & NFSD_MAY_EXEC)?	" exec"  : "",
2518		(acc & NFSD_MAY_SATTR)?	" sattr" : "",
2519		(acc & NFSD_MAY_TRUNC)?	" trunc" : "",
2520		(acc & NFSD_MAY_LOCK)?	" lock"  : "",
2521		(acc & NFSD_MAY_OWNER_OVERRIDE)? " owneroverride" : "",
2522		inode->i_mode,
2523		IS_IMMUTABLE(inode)?	" immut" : "",
2524		IS_APPEND(inode)?	" append" : "",
2525		__mnt_is_readonly(exp->ex_path.mnt)?	" ro" : "");
2526	dprintk("      owner %d/%d user %d/%d\n",
2527		inode->i_uid, inode->i_gid, current_fsuid(), current_fsgid());
2528#endif
2529
2530	/* Normally we reject any write/sattr etc access on a read-only file
2531	 * system.  But if it is IRIX doing check on write-access for a 
2532	 * device special file, we ignore rofs.
2533	 */
2534	if (!(acc & NFSD_MAY_LOCAL_ACCESS))
2535		if (acc & (NFSD_MAY_WRITE | NFSD_MAY_SATTR | NFSD_MAY_TRUNC)) {
2536			if (exp_rdonly(rqstp, exp) ||
2537			    __mnt_is_readonly(exp->ex_path.mnt))
2538				return nfserr_rofs;
2539			if (/* (acc & NFSD_MAY_WRITE) && */ IS_IMMUTABLE(inode))
2540				return nfserr_perm;
2541		}
2542	if ((acc & NFSD_MAY_TRUNC) && IS_APPEND(inode))
2543		return nfserr_perm;
2544
2545	if (acc & NFSD_MAY_LOCK) {
2546		/* If we cannot rely on authentication in NLM requests,
2547		 * just allow locks, otherwise require read permission, or
2548		 * ownership
2549		 */
2550		if (exp->ex_flags & NFSEXP_NOAUTHNLM)
2551			return 0;
2552		else
2553			acc = NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE;
2554	}
2555	/*
2556	 * The file owner always gets access permission for accesses that
2557	 * would normally be checked at open time. This is to make
2558	 * file access work even when the client has done a fchmod(fd, 0).
2559	 *
2560	 * However, `cp foo bar' should fail nevertheless when bar is
2561	 * readonly. A sensible way to do this might be to reject all
2562	 * attempts to truncate a read-only file, because a creat() call
2563	 * always implies file truncation.
2564	 * ... but this isn't really fair.  A process may reasonably call
2565	 * ftruncate on an open file descriptor on a file with perm 000.
2566	 * We must trust the client to do permission checking - using "ACCESS"
2567	 * with NFSv3.
2568	 */
2569	if ((acc & NFSD_MAY_OWNER_OVERRIDE) &&
2570	    uid_eq(inode->i_uid, current_fsuid()))
2571		return 0;
2572
2573	/* This assumes  NFSD_MAY_{READ,WRITE,EXEC} == MAY_{READ,WRITE,EXEC} */
2574	err = inode_permission(&nop_mnt_idmap, inode,
2575			       acc & (MAY_READ | MAY_WRITE | MAY_EXEC));
2576
2577	/* Allow read access to binaries even when mode 111 */
2578	if (err == -EACCES && S_ISREG(inode->i_mode) &&
2579	     (acc == (NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE) ||
2580	      acc == (NFSD_MAY_READ | NFSD_MAY_READ_IF_EXEC)))
2581		err = inode_permission(&nop_mnt_idmap, inode, MAY_EXEC);
2582
2583	return err? nfserrno(err) : 0;
2584}