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vfs.c
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linux-6.19.14/fs/nfsd/vfs.c
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#include <linux/sunrpc/xdr.h> 35 36#include "xdr3.h" 37 38#ifdef CONFIG_NFSD_V4 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 51bool nfsd_disable_splice_read __read_mostly; 52u64 nfsd_io_cache_read __read_mostly = NFSD_IO_BUFFERED; 53u64 nfsd_io_cache_write __read_mostly = NFSD_IO_BUFFERED; 54 55/** 56 * nfserrno - Map Linux errnos to NFS errnos 57 * @errno: POSIX(-ish) error code to be mapped 58 * 59 * Returns the appropriate (net-endian) nfserr_* (or nfs_ok if errno is 0). If 60 * it's an error we don't expect, log it once and return nfserr_io. 61 */ 62__be32 63nfserrno (int errno) 64{ 65 static struct { 66 __be32 nfserr; 67 int syserr; 68 } nfs_errtbl[] = { 69 { nfs_ok, 0 }, 70 { nfserr_perm, -EPERM }, 71 { nfserr_noent, -ENOENT }, 72 { nfserr_io, -EIO }, 73 { nfserr_nxio, -ENXIO }, 74 { nfserr_fbig, -E2BIG }, 75 { nfserr_stale, -EBADF }, 76 { nfserr_acces, -EACCES }, 77 { nfserr_exist, -EEXIST }, 78 { nfserr_xdev, -EXDEV }, 79 { nfserr_nodev, -ENODEV }, 80 { nfserr_notdir, -ENOTDIR }, 81 { nfserr_isdir, -EISDIR }, 82 { nfserr_inval, -EINVAL }, 83 { nfserr_fbig, -EFBIG }, 84 { nfserr_nospc, -ENOSPC }, 85 { nfserr_rofs, -EROFS }, 86 { nfserr_mlink, -EMLINK }, 87 { nfserr_nametoolong, -ENAMETOOLONG }, 88 { nfserr_notempty, -ENOTEMPTY }, 89 { nfserr_dquot, -EDQUOT }, 90 { nfserr_stale, -ESTALE }, 91 { nfserr_jukebox, -ETIMEDOUT }, 92 { nfserr_jukebox, -ERESTARTSYS }, 93 { nfserr_jukebox, -EAGAIN }, 94 { nfserr_jukebox, -EWOULDBLOCK }, 95 { nfserr_jukebox, -ENOMEM }, 96 { nfserr_io, -ETXTBSY }, 97 { nfserr_notsupp, -EOPNOTSUPP }, 98 { nfserr_toosmall, -ETOOSMALL }, 99 { nfserr_serverfault, -ESERVERFAULT }, 100 { nfserr_serverfault, -ENFILE }, 101 { nfserr_io, -EREMOTEIO }, 102 { nfserr_stale, -EOPENSTALE }, 103 { nfserr_io, -EUCLEAN }, 104 { nfserr_perm, -ENOKEY }, 105 { nfserr_no_grace, -ENOGRACE}, 106 { nfserr_io, -EBADMSG }, 107 }; 108 int i; 109 110 for (i = 0; i < ARRAY_SIZE(nfs_errtbl); i++) { 111 if (nfs_errtbl[i].syserr == errno) 112 return nfs_errtbl[i].nfserr; 113 } 114 WARN_ONCE(1, "nfsd: non-standard errno: %d\n", errno); 115 return nfserr_io; 116} 117 118/* 119 * Called from nfsd_lookup and encode_dirent. Check if we have crossed 120 * a mount point. 121 * Returns -EAGAIN or -ETIMEDOUT leaving *dpp and *expp unchanged, 122 * or nfs_ok having possibly changed *dpp and *expp 123 */ 124int 125nfsd_cross_mnt(struct svc_rqst *rqstp, struct dentry **dpp, 126 struct svc_export **expp) 127{ 128 struct svc_export *exp = *expp, *exp2 = NULL; 129 struct dentry *dentry = *dpp; 130 struct path path = {.mnt = mntget(exp->ex_path.mnt), 131 .dentry = dget(dentry)}; 132 unsigned int follow_flags = 0; 133 int err = 0; 134 135 if (exp->ex_flags & NFSEXP_CROSSMOUNT) 136 follow_flags = LOOKUP_AUTOMOUNT; 137 138 err = follow_down(&path, follow_flags); 139 if (err < 0) 140 goto out; 141 if (path.mnt == exp->ex_path.mnt && path.dentry == dentry && 142 nfsd_mountpoint(dentry, exp) == 2) { 143 /* This is only a mountpoint in some other namespace */ 144 path_put(&path); 145 goto out; 146 } 147 148 exp2 = rqst_exp_get_by_name(rqstp, &path); 149 if (IS_ERR(exp2)) { 150 err = PTR_ERR(exp2); 151 /* 152 * We normally allow NFS clients to continue 153 * "underneath" a mountpoint that is not exported. 154 * The exception is V4ROOT, where no traversal is ever 155 * allowed without an explicit export of the new 156 * directory. 157 */ 158 if (err == -ENOENT && !(exp->ex_flags & NFSEXP_V4ROOT)) 159 err = 0; 160 path_put(&path); 161 goto out; 162 } 163 if (nfsd_v4client(rqstp) || 164 (exp->ex_flags & NFSEXP_CROSSMOUNT) || EX_NOHIDE(exp2)) { 165 /* successfully crossed mount point */ 166 /* 167 * This is subtle: path.dentry is *not* on path.mnt 168 * at this point. The only reason we are safe is that 169 * original mnt is pinned down by exp, so we should 170 * put path *before* putting exp 171 */ 172 *dpp = path.dentry; 173 path.dentry = dentry; 174 *expp = exp2; 175 exp2 = exp; 176 } 177 path_put(&path); 178 exp_put(exp2); 179out: 180 return err; 181} 182 183static void follow_to_parent(struct path *path) 184{ 185 struct dentry *dp; 186 187 while (path->dentry == path->mnt->mnt_root && follow_up(path)) 188 ; 189 dp = dget_parent(path->dentry); 190 dput(path->dentry); 191 path->dentry = dp; 192} 193 194static int nfsd_lookup_parent(struct svc_rqst *rqstp, struct dentry *dparent, struct svc_export **exp, struct dentry **dentryp) 195{ 196 struct svc_export *exp2; 197 struct path path = {.mnt = mntget((*exp)->ex_path.mnt), 198 .dentry = dget(dparent)}; 199 200 follow_to_parent(&path); 201 202 exp2 = rqst_exp_parent(rqstp, &path); 203 if (PTR_ERR(exp2) == -ENOENT) { 204 *dentryp = dget(dparent); 205 } else if (IS_ERR(exp2)) { 206 path_put(&path); 207 return PTR_ERR(exp2); 208 } else { 209 *dentryp = dget(path.dentry); 210 exp_put(*exp); 211 *exp = exp2; 212 } 213 path_put(&path); 214 return 0; 215} 216 217/* 218 * For nfsd purposes, we treat V4ROOT exports as though there was an 219 * export at *every* directory. 220 * We return: 221 * '1' if this dentry *must* be an export point, 222 * '2' if it might be, if there is really a mount here, and 223 * '0' if there is no chance of an export point here. 224 */ 225int nfsd_mountpoint(struct dentry *dentry, struct svc_export *exp) 226{ 227 if (!d_inode(dentry)) 228 return 0; 229 if (exp->ex_flags & NFSEXP_V4ROOT) 230 return 1; 231 if (nfsd4_is_junction(dentry)) 232 return 1; 233 if (d_managed(dentry)) 234 /* 235 * Might only be a mountpoint in a different namespace, 236 * but we need to check. 237 */ 238 return 2; 239 return 0; 240} 241 242__be32 243nfsd_lookup_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp, 244 const char *name, unsigned int len, 245 struct svc_export **exp_ret, struct dentry **dentry_ret) 246{ 247 struct svc_export *exp; 248 struct dentry *dparent; 249 struct dentry *dentry; 250 int host_err; 251 252 trace_nfsd_vfs_lookup(rqstp, fhp, name, len); 253 254 dparent = fhp->fh_dentry; 255 exp = exp_get(fhp->fh_export); 256 257 /* Lookup the name, but don't follow links */ 258 if (isdotent(name, len)) { 259 if (len==1) 260 dentry = dget(dparent); 261 else if (dparent != exp->ex_path.dentry) 262 dentry = dget_parent(dparent); 263 else if (!EX_NOHIDE(exp) && !nfsd_v4client(rqstp)) 264 dentry = dget(dparent); /* .. == . just like at / */ 265 else { 266 /* checking mountpoint crossing is very different when stepping up */ 267 host_err = nfsd_lookup_parent(rqstp, dparent, &exp, &dentry); 268 if (host_err) 269 goto out_nfserr; 270 } 271 } else { 272 dentry = lookup_one_unlocked(&nop_mnt_idmap, 273 &QSTR_LEN(name, len), dparent); 274 host_err = PTR_ERR(dentry); 275 if (IS_ERR(dentry)) 276 goto out_nfserr; 277 if (nfsd_mountpoint(dentry, exp)) { 278 host_err = nfsd_cross_mnt(rqstp, &dentry, &exp); 279 if (host_err) { 280 dput(dentry); 281 goto out_nfserr; 282 } 283 } 284 } 285 *dentry_ret = dentry; 286 *exp_ret = exp; 287 return 0; 288 289out_nfserr: 290 exp_put(exp); 291 return nfserrno(host_err); 292} 293 294/** 295 * nfsd_lookup - look up a single path component for nfsd 296 * 297 * @rqstp: the request context 298 * @fhp: the file handle of the directory 299 * @name: the component name, or %NULL to look up parent 300 * @len: length of name to examine 301 * @resfh: pointer to pre-initialised filehandle to hold result. 302 * 303 * Look up one component of a pathname. 304 * N.B. After this call _both_ fhp and resfh need an fh_put 305 * 306 * If the lookup would cross a mountpoint, and the mounted filesystem 307 * is exported to the client with NFSEXP_NOHIDE, then the lookup is 308 * accepted as it stands and the mounted directory is 309 * returned. Otherwise the covered directory is returned. 310 * NOTE: this mountpoint crossing is not supported properly by all 311 * clients and is explicitly disallowed for NFSv3 312 * 313 */ 314__be32 315nfsd_lookup(struct svc_rqst *rqstp, struct svc_fh *fhp, const char *name, 316 unsigned int len, struct svc_fh *resfh) 317{ 318 struct svc_export *exp; 319 struct dentry *dentry; 320 __be32 err; 321 322 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC); 323 if (err) 324 return err; 325 err = nfsd_lookup_dentry(rqstp, fhp, name, len, &exp, &dentry); 326 if (err) 327 return err; 328 err = check_nfsd_access(exp, rqstp, false); 329 if (err) 330 goto out; 331 /* 332 * Note: we compose the file handle now, but as the 333 * dentry may be negative, it may need to be updated. 334 */ 335 err = fh_compose(resfh, exp, dentry, fhp); 336 if (!err && d_really_is_negative(dentry)) 337 err = nfserr_noent; 338out: 339 dput(dentry); 340 exp_put(exp); 341 return err; 342} 343 344static void 345commit_reset_write_verifier(struct nfsd_net *nn, struct svc_rqst *rqstp, 346 int err) 347{ 348 switch (err) { 349 case -EAGAIN: 350 case -ESTALE: 351 /* 352 * Neither of these are the result of a problem with 353 * durable storage, so avoid a write verifier reset. 354 */ 355 break; 356 default: 357 nfsd_reset_write_verifier(nn); 358 trace_nfsd_writeverf_reset(nn, rqstp, err); 359 } 360} 361 362/* 363 * Commit metadata changes to stable storage. 364 */ 365static int 366commit_inode_metadata(struct inode *inode) 367{ 368 const struct export_operations *export_ops = inode->i_sb->s_export_op; 369 370 if (export_ops->commit_metadata) 371 return export_ops->commit_metadata(inode); 372 return sync_inode_metadata(inode, 1); 373} 374 375static int 376commit_metadata(struct svc_fh *fhp) 377{ 378 struct inode *inode = d_inode(fhp->fh_dentry); 379 380 if (!EX_ISSYNC(fhp->fh_export)) 381 return 0; 382 return commit_inode_metadata(inode); 383} 384 385/* 386 * Go over the attributes and take care of the small differences between 387 * NFS semantics and what Linux expects. 388 */ 389static void 390nfsd_sanitize_attrs(struct inode *inode, struct iattr *iap) 391{ 392 /* Ignore mode updates on symlinks */ 393 if (S_ISLNK(inode->i_mode)) 394 iap->ia_valid &= ~ATTR_MODE; 395 396 /* sanitize the mode change */ 397 if (iap->ia_valid & ATTR_MODE) { 398 iap->ia_mode &= S_IALLUGO; 399 iap->ia_mode |= (inode->i_mode & ~S_IALLUGO); 400 } 401 402 /* Revoke setuid/setgid on chown */ 403 if (!S_ISDIR(inode->i_mode) && 404 ((iap->ia_valid & ATTR_UID) || (iap->ia_valid & ATTR_GID))) { 405 iap->ia_valid |= ATTR_KILL_PRIV; 406 if (iap->ia_valid & ATTR_MODE) { 407 /* we're setting mode too, just clear the s*id bits */ 408 iap->ia_mode &= ~S_ISUID; 409 if (iap->ia_mode & S_IXGRP) 410 iap->ia_mode &= ~S_ISGID; 411 } else { 412 /* set ATTR_KILL_* bits and let VFS handle it */ 413 iap->ia_valid |= ATTR_KILL_SUID; 414 iap->ia_valid |= 415 setattr_should_drop_sgid(&nop_mnt_idmap, inode); 416 } 417 } 418} 419 420static __be32 421nfsd_get_write_access(struct svc_rqst *rqstp, struct svc_fh *fhp, 422 struct iattr *iap) 423{ 424 struct inode *inode = d_inode(fhp->fh_dentry); 425 426 if (iap->ia_size < inode->i_size) { 427 __be32 err; 428 429 err = nfsd_permission(&rqstp->rq_cred, 430 fhp->fh_export, fhp->fh_dentry, 431 NFSD_MAY_TRUNC | NFSD_MAY_OWNER_OVERRIDE); 432 if (err) 433 return err; 434 } 435 return nfserrno(get_write_access(inode)); 436} 437 438static int __nfsd_setattr(struct dentry *dentry, struct iattr *iap) 439{ 440 int host_err; 441 442 if (iap->ia_valid & ATTR_SIZE) { 443 /* 444 * RFC5661, Section 18.30.4: 445 * Changing the size of a file with SETATTR indirectly 446 * changes the time_modify and change attributes. 447 * 448 * (and similar for the older RFCs) 449 */ 450 struct iattr size_attr = { 451 .ia_valid = ATTR_SIZE | ATTR_CTIME | ATTR_MTIME, 452 .ia_size = iap->ia_size, 453 }; 454 455 if (iap->ia_size < 0) 456 return -EFBIG; 457 458 host_err = notify_change(&nop_mnt_idmap, dentry, &size_attr, NULL); 459 if (host_err) 460 return host_err; 461 iap->ia_valid &= ~ATTR_SIZE; 462 463 /* 464 * Avoid the additional setattr call below if the only other 465 * attribute that the client sends is the mtime, as we update 466 * it as part of the size change above. 467 */ 468 if ((iap->ia_valid & ~ATTR_MTIME) == 0) 469 return 0; 470 } 471 472 if ((iap->ia_valid & ~ATTR_DELEG) == 0) 473 return 0; 474 475 /* 476 * If ATTR_DELEG is set, then this is an update from a client that 477 * holds a delegation. If this is an update for only the atime, the 478 * ctime should not be changed. If the update contains the mtime 479 * too, then ATTR_CTIME should already be set. 480 */ 481 if (!(iap->ia_valid & ATTR_DELEG)) 482 iap->ia_valid |= ATTR_CTIME; 483 484 return notify_change(&nop_mnt_idmap, dentry, iap, NULL); 485} 486 487/** 488 * nfsd_setattr - Set various file attributes. 489 * @rqstp: controlling RPC transaction 490 * @fhp: filehandle of target 491 * @attr: attributes to set 492 * @guardtime: do not act if ctime.tv_sec does not match this timestamp 493 * 494 * This call may adjust the contents of @attr (in particular, this 495 * call may change the bits in the na_iattr.ia_valid field). 496 * 497 * Returns nfs_ok on success, otherwise an NFS status code is 498 * returned. Caller must release @fhp by calling fh_put in either 499 * case. 500 */ 501__be32 502nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, 503 struct nfsd_attrs *attr, const struct timespec64 *guardtime) 504{ 505 struct dentry *dentry; 506 struct inode *inode; 507 struct iattr *iap = attr->na_iattr; 508 int accmode = NFSD_MAY_SATTR; 509 umode_t ftype = 0; 510 __be32 err; 511 int host_err = 0; 512 bool get_write_count; 513 bool size_change = (iap->ia_valid & ATTR_SIZE); 514 int retries; 515 516 trace_nfsd_vfs_setattr(rqstp, fhp, iap, guardtime); 517 518 if (iap->ia_valid & ATTR_SIZE) { 519 accmode |= NFSD_MAY_WRITE|NFSD_MAY_OWNER_OVERRIDE; 520 ftype = S_IFREG; 521 } 522 523 /* 524 * If utimes(2) and friends are called with times not NULL, we should 525 * not set NFSD_MAY_WRITE bit. Otherwise fh_verify->nfsd_permission 526 * will return EACCES, when the caller's effective UID does not match 527 * the owner of the file, and the caller is not privileged. In this 528 * situation, we should return EPERM(notify_change will return this). 529 */ 530 if (iap->ia_valid & (ATTR_ATIME | ATTR_MTIME)) { 531 accmode |= NFSD_MAY_OWNER_OVERRIDE; 532 if (!(iap->ia_valid & (ATTR_ATIME_SET | ATTR_MTIME_SET))) 533 accmode |= NFSD_MAY_WRITE; 534 } 535 536 /* Callers that do fh_verify should do the fh_want_write: */ 537 get_write_count = !fhp->fh_dentry; 538 539 /* Get inode */ 540 err = fh_verify(rqstp, fhp, ftype, accmode); 541 if (err) 542 return err; 543 if (get_write_count) { 544 host_err = fh_want_write(fhp); 545 if (host_err) 546 goto out; 547 } 548 549 dentry = fhp->fh_dentry; 550 inode = d_inode(dentry); 551 552 nfsd_sanitize_attrs(inode, iap); 553 554 /* 555 * The size case is special, it changes the file in addition to the 556 * attributes, and file systems don't expect it to be mixed with 557 * "random" attribute changes. We thus split out the size change 558 * into a separate call to ->setattr, and do the rest as a separate 559 * setattr call. 560 */ 561 if (size_change) { 562 err = nfsd_get_write_access(rqstp, fhp, iap); 563 if (err) 564 return err; 565 } 566 567 inode_lock(inode); 568 err = fh_fill_pre_attrs(fhp); 569 if (err) 570 goto out_unlock; 571 572 if (guardtime) { 573 struct timespec64 ctime = inode_get_ctime(inode); 574 if ((u32)guardtime->tv_sec != (u32)ctime.tv_sec || 575 guardtime->tv_nsec != ctime.tv_nsec) { 576 err = nfserr_notsync; 577 goto out_fill_attrs; 578 } 579 } 580 581 for (retries = 1;;) { 582 struct iattr attrs; 583 584 /* 585 * notify_change() can alter its iattr argument, making 586 * @iap unsuitable for submission multiple times. Make a 587 * copy for every loop iteration. 588 */ 589 attrs = *iap; 590 host_err = __nfsd_setattr(dentry, &attrs); 591 if (host_err != -EAGAIN || !retries--) 592 break; 593 if (!nfsd_wait_for_delegreturn(rqstp, inode)) 594 break; 595 } 596 if (attr->na_seclabel && attr->na_seclabel->len) 597 attr->na_labelerr = security_inode_setsecctx(dentry, 598 attr->na_seclabel->data, attr->na_seclabel->len); 599 if (IS_ENABLED(CONFIG_FS_POSIX_ACL) && attr->na_pacl) 600 attr->na_aclerr = set_posix_acl(&nop_mnt_idmap, 601 dentry, ACL_TYPE_ACCESS, 602 attr->na_pacl); 603 if (IS_ENABLED(CONFIG_FS_POSIX_ACL) && 604 !attr->na_aclerr && attr->na_dpacl && S_ISDIR(inode->i_mode)) 605 attr->na_aclerr = set_posix_acl(&nop_mnt_idmap, 606 dentry, ACL_TYPE_DEFAULT, 607 attr->na_dpacl); 608out_fill_attrs: 609 /* 610 * RFC 1813 Section 3.3.2 does not mandate that an NFS server 611 * returns wcc_data for SETATTR. Some client implementations 612 * depend on receiving wcc_data, however, to sort out partial 613 * updates (eg., the client requested that size and mode be 614 * modified, but the server changed only the file mode). 615 */ 616 fh_fill_post_attrs(fhp); 617out_unlock: 618 inode_unlock(inode); 619 if (size_change) 620 put_write_access(inode); 621out: 622 if (!host_err) 623 host_err = commit_metadata(fhp); 624 return err != 0 ? err : nfserrno(host_err); 625} 626 627#if defined(CONFIG_NFSD_V4) 628/* 629 * NFS junction information is stored in an extended attribute. 630 */ 631#define NFSD_JUNCTION_XATTR_NAME XATTR_TRUSTED_PREFIX "junction.nfs" 632 633/** 634 * nfsd4_is_junction - Test if an object could be an NFS junction 635 * 636 * @dentry: object to test 637 * 638 * Returns 1 if "dentry" appears to contain NFS junction information. 639 * Otherwise 0 is returned. 640 */ 641int nfsd4_is_junction(struct dentry *dentry) 642{ 643 struct inode *inode = d_inode(dentry); 644 645 if (inode == NULL) 646 return 0; 647 if (inode->i_mode & S_IXUGO) 648 return 0; 649 if (!(inode->i_mode & S_ISVTX)) 650 return 0; 651 if (vfs_getxattr(&nop_mnt_idmap, dentry, NFSD_JUNCTION_XATTR_NAME, 652 NULL, 0) <= 0) 653 return 0; 654 return 1; 655} 656 657static struct nfsd4_compound_state *nfsd4_get_cstate(struct svc_rqst *rqstp) 658{ 659 return &((struct nfsd4_compoundres *)rqstp->rq_resp)->cstate; 660} 661 662__be32 nfsd4_clone_file_range(struct svc_rqst *rqstp, 663 struct nfsd_file *nf_src, u64 src_pos, 664 struct nfsd_file *nf_dst, u64 dst_pos, 665 u64 count, bool sync) 666{ 667 struct file *src = nf_src->nf_file; 668 struct file *dst = nf_dst->nf_file; 669 errseq_t since; 670 loff_t cloned; 671 __be32 ret = 0; 672 673 since = READ_ONCE(dst->f_wb_err); 674 cloned = vfs_clone_file_range(src, src_pos, dst, dst_pos, count, 0); 675 if (cloned < 0) { 676 ret = nfserrno(cloned); 677 goto out_err; 678 } 679 if (count && cloned != count) { 680 ret = nfserrno(-EINVAL); 681 goto out_err; 682 } 683 if (sync) { 684 loff_t dst_end = count ? dst_pos + count - 1 : LLONG_MAX; 685 int status = vfs_fsync_range(dst, dst_pos, dst_end, 0); 686 687 if (!status) 688 status = filemap_check_wb_err(dst->f_mapping, since); 689 if (!status) 690 status = commit_inode_metadata(file_inode(src)); 691 if (status < 0) { 692 struct nfsd_net *nn = net_generic(nf_dst->nf_net, 693 nfsd_net_id); 694 695 trace_nfsd_clone_file_range_err(rqstp, 696 &nfsd4_get_cstate(rqstp)->save_fh, 697 src_pos, 698 &nfsd4_get_cstate(rqstp)->current_fh, 699 dst_pos, 700 count, status); 701 commit_reset_write_verifier(nn, rqstp, status); 702 ret = nfserrno(status); 703 } 704 } 705out_err: 706 return ret; 707} 708 709ssize_t nfsd_copy_file_range(struct file *src, u64 src_pos, struct file *dst, 710 u64 dst_pos, u64 count) 711{ 712 ssize_t ret; 713 714 /* 715 * Limit copy to 4MB to prevent indefinitely blocking an nfsd 716 * thread and client rpc slot. The choice of 4MB is somewhat 717 * arbitrary. We might instead base this on r/wsize, or make it 718 * tunable, or use a time instead of a byte limit, or implement 719 * asynchronous copy. In theory a client could also recognize a 720 * limit like this and pipeline multiple COPY requests. 721 */ 722 count = min_t(u64, count, 1 << 22); 723 ret = vfs_copy_file_range(src, src_pos, dst, dst_pos, count, 0); 724 725 if (ret == -EOPNOTSUPP || ret == -EXDEV) 726 ret = vfs_copy_file_range(src, src_pos, dst, dst_pos, count, 727 COPY_FILE_SPLICE); 728 return ret; 729} 730 731__be32 nfsd4_vfs_fallocate(struct svc_rqst *rqstp, struct svc_fh *fhp, 732 struct file *file, loff_t offset, loff_t len, 733 int flags) 734{ 735 int error; 736 737 if (!S_ISREG(file_inode(file)->i_mode)) 738 return nfserr_inval; 739 740 error = vfs_fallocate(file, flags, offset, len); 741 if (!error) 742 error = commit_metadata(fhp); 743 744 return nfserrno(error); 745} 746#endif /* defined(CONFIG_NFSD_V4) */ 747 748/* 749 * Check server access rights to a file system object 750 */ 751struct accessmap { 752 u32 access; 753 int how; 754}; 755static struct accessmap nfs3_regaccess[] = { 756 { NFS3_ACCESS_READ, NFSD_MAY_READ }, 757 { NFS3_ACCESS_EXECUTE, NFSD_MAY_EXEC }, 758 { NFS3_ACCESS_MODIFY, NFSD_MAY_WRITE|NFSD_MAY_TRUNC }, 759 { NFS3_ACCESS_EXTEND, NFSD_MAY_WRITE }, 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_diraccess[] = { 771 { NFS3_ACCESS_READ, NFSD_MAY_READ }, 772 { NFS3_ACCESS_LOOKUP, NFSD_MAY_EXEC }, 773 { NFS3_ACCESS_MODIFY, NFSD_MAY_EXEC|NFSD_MAY_WRITE|NFSD_MAY_TRUNC}, 774 { NFS3_ACCESS_EXTEND, NFSD_MAY_EXEC|NFSD_MAY_WRITE }, 775 { NFS3_ACCESS_DELETE, NFSD_MAY_REMOVE }, 776 777#ifdef CONFIG_NFSD_V4 778 { NFS4_ACCESS_XAREAD, NFSD_MAY_READ }, 779 { NFS4_ACCESS_XAWRITE, NFSD_MAY_WRITE }, 780 { NFS4_ACCESS_XALIST, NFSD_MAY_READ }, 781#endif 782 783 { 0, 0 } 784}; 785 786static struct accessmap nfs3_anyaccess[] = { 787 /* Some clients - Solaris 2.6 at least, make an access call 788 * to the server to check for access for things like /dev/null 789 * (which really, the server doesn't care about). So 790 * We provide simple access checking for them, looking 791 * mainly at mode bits, and we make sure to ignore read-only 792 * filesystem checks 793 */ 794 { NFS3_ACCESS_READ, NFSD_MAY_READ }, 795 { NFS3_ACCESS_EXECUTE, NFSD_MAY_EXEC }, 796 { NFS3_ACCESS_MODIFY, NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS }, 797 { NFS3_ACCESS_EXTEND, NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS }, 798 799 { 0, 0 } 800}; 801 802__be32 803nfsd_access(struct svc_rqst *rqstp, struct svc_fh *fhp, u32 *access, u32 *supported) 804{ 805 struct accessmap *map; 806 struct svc_export *export; 807 struct dentry *dentry; 808 u32 query, result = 0, sresult = 0; 809 __be32 error; 810 811 error = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP); 812 if (error) 813 goto out; 814 815 export = fhp->fh_export; 816 dentry = fhp->fh_dentry; 817 818 if (d_is_reg(dentry)) 819 map = nfs3_regaccess; 820 else if (d_is_dir(dentry)) 821 map = nfs3_diraccess; 822 else 823 map = nfs3_anyaccess; 824 825 826 query = *access; 827 for (; map->access; map++) { 828 if (map->access & query) { 829 __be32 err2; 830 831 sresult |= map->access; 832 833 err2 = nfsd_permission(&rqstp->rq_cred, export, 834 dentry, map->how); 835 switch (err2) { 836 case nfs_ok: 837 result |= map->access; 838 break; 839 840 /* the following error codes just mean the access was not allowed, 841 * rather than an error occurred */ 842 case nfserr_rofs: 843 case nfserr_acces: 844 case nfserr_perm: 845 /* simply don't "or" in the access bit. */ 846 break; 847 default: 848 error = err2; 849 goto out; 850 } 851 } 852 } 853 *access = result; 854 if (supported) 855 *supported = sresult; 856 857 out: 858 return error; 859} 860 861int nfsd_open_break_lease(struct inode *inode, int access) 862{ 863 unsigned int mode; 864 865 if (access & NFSD_MAY_NOT_BREAK_LEASE) 866 return 0; 867 mode = (access & NFSD_MAY_WRITE) ? O_WRONLY : O_RDONLY; 868 return break_lease(inode, mode | O_NONBLOCK); 869} 870 871/* 872 * Open an existing file or directory. 873 * The may_flags argument indicates the type of open (read/write/lock) 874 * and additional flags. 875 * N.B. After this call fhp needs an fh_put 876 */ 877static int 878__nfsd_open(struct svc_fh *fhp, umode_t type, int may_flags, struct file **filp) 879{ 880 struct path path; 881 struct inode *inode; 882 struct file *file; 883 int flags = O_RDONLY|O_LARGEFILE; 884 int host_err = -EPERM; 885 886 path.mnt = fhp->fh_export->ex_path.mnt; 887 path.dentry = fhp->fh_dentry; 888 inode = d_inode(path.dentry); 889 890 if (IS_APPEND(inode) && (may_flags & NFSD_MAY_WRITE)) 891 goto out; 892 893 if (!inode->i_fop) 894 goto out; 895 896 host_err = nfsd_open_break_lease(inode, may_flags); 897 if (host_err) /* NOMEM or WOULDBLOCK */ 898 goto out; 899 900 if (may_flags & NFSD_MAY_WRITE) { 901 if (may_flags & NFSD_MAY_READ) 902 flags = O_RDWR|O_LARGEFILE; 903 else 904 flags = O_WRONLY|O_LARGEFILE; 905 } 906 907 file = dentry_open(&path, flags, current_cred()); 908 if (IS_ERR(file)) { 909 host_err = PTR_ERR(file); 910 goto out; 911 } 912 913 host_err = security_file_post_open(file, may_flags); 914 if (host_err) { 915 fput(file); 916 goto out; 917 } 918 919 *filp = file; 920out: 921 return host_err; 922} 923 924__be32 925nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type, 926 int may_flags, struct file **filp) 927{ 928 __be32 err; 929 int host_err; 930 bool retried = false; 931 932 /* 933 * If we get here, then the client has already done an "open", 934 * and (hopefully) checked permission - so allow OWNER_OVERRIDE 935 * in case a chmod has now revoked permission. 936 * 937 * Arguably we should also allow the owner override for 938 * directories, but we never have and it doesn't seem to have 939 * caused anyone a problem. If we were to change this, note 940 * also that our filldir callbacks would need a variant of 941 * lookup_one_positive_unlocked() that doesn't check permissions. 942 */ 943 if (type == S_IFREG) 944 may_flags |= NFSD_MAY_OWNER_OVERRIDE; 945retry: 946 err = fh_verify(rqstp, fhp, type, may_flags); 947 if (!err) { 948 host_err = __nfsd_open(fhp, type, may_flags, filp); 949 if (host_err == -EOPENSTALE && !retried) { 950 retried = true; 951 fh_put(fhp); 952 goto retry; 953 } 954 err = nfserrno(host_err); 955 } 956 return err; 957} 958 959/** 960 * nfsd_open_verified - Open a regular file for the filecache 961 * @fhp: NFS filehandle of the file to open 962 * @type: S_IFMT inode type allowed (0 means any type is allowed) 963 * @may_flags: internal permission flags 964 * @filp: OUT: open "struct file *" 965 * 966 * Returns zero on success, or a negative errno value. 967 */ 968int 969nfsd_open_verified(struct svc_fh *fhp, umode_t type, int may_flags, struct file **filp) 970{ 971 return __nfsd_open(fhp, type, may_flags, filp); 972} 973 974/* 975 * Grab and keep cached pages associated with a file in the svc_rqst 976 * so that they can be passed to the network sendmsg routines 977 * directly. They will be released after the sending has completed. 978 * 979 * Return values: Number of bytes consumed, or -EIO if there are no 980 * remaining pages in rqstp->rq_pages. 981 */ 982static int 983nfsd_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf, 984 struct splice_desc *sd) 985{ 986 struct svc_rqst *rqstp = sd->u.data; 987 struct page *page = buf->page; // may be a compound one 988 unsigned offset = buf->offset; 989 struct page *last_page; 990 991 last_page = page + (offset + sd->len - 1) / PAGE_SIZE; 992 for (page += offset / PAGE_SIZE; page <= last_page; page++) { 993 /* 994 * Skip page replacement when extending the contents of the 995 * current page. But note that we may get two zero_pages in a 996 * row from shmem. 997 */ 998 if (page == *(rqstp->rq_next_page - 1) && 999 offset_in_page(rqstp->rq_res.page_base + 1000 rqstp->rq_res.page_len)) 1001 continue; 1002 if (unlikely(!svc_rqst_replace_page(rqstp, page))) 1003 return -EIO; 1004 } 1005 if (rqstp->rq_res.page_len == 0) // first call 1006 rqstp->rq_res.page_base = offset % PAGE_SIZE; 1007 rqstp->rq_res.page_len += sd->len; 1008 return sd->len; 1009} 1010 1011static int nfsd_direct_splice_actor(struct pipe_inode_info *pipe, 1012 struct splice_desc *sd) 1013{ 1014 return __splice_from_pipe(pipe, sd, nfsd_splice_actor); 1015} 1016 1017static u32 nfsd_eof_on_read(struct file *file, loff_t offset, ssize_t len, 1018 size_t expected) 1019{ 1020 if (expected != 0 && len == 0) 1021 return 1; 1022 if (offset+len >= i_size_read(file_inode(file))) 1023 return 1; 1024 return 0; 1025} 1026 1027static __be32 nfsd_finish_read(struct svc_rqst *rqstp, struct svc_fh *fhp, 1028 struct file *file, loff_t offset, 1029 unsigned long *count, u32 *eof, ssize_t host_err) 1030{ 1031 if (host_err >= 0) { 1032 struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id); 1033 1034 nfsd_stats_io_read_add(nn, fhp->fh_export, host_err); 1035 *eof = nfsd_eof_on_read(file, offset, host_err, *count); 1036 *count = host_err; 1037 fsnotify_access(file); 1038 trace_nfsd_read_io_done(rqstp, fhp, offset, *count); 1039 return 0; 1040 } else { 1041 trace_nfsd_read_err(rqstp, fhp, offset, host_err); 1042 return nfserrno(host_err); 1043 } 1044} 1045 1046/** 1047 * nfsd_splice_read - Perform a VFS read using a splice pipe 1048 * @rqstp: RPC transaction context 1049 * @fhp: file handle of file to be read 1050 * @file: opened struct file of file to be read 1051 * @offset: starting byte offset 1052 * @count: IN: requested number of bytes; OUT: number of bytes read 1053 * @eof: OUT: set non-zero if operation reached the end of the file 1054 * 1055 * Returns nfs_ok on success, otherwise an nfserr stat value is 1056 * returned. 1057 */ 1058__be32 nfsd_splice_read(struct svc_rqst *rqstp, struct svc_fh *fhp, 1059 struct file *file, loff_t offset, unsigned long *count, 1060 u32 *eof) 1061{ 1062 struct splice_desc sd = { 1063 .len = 0, 1064 .total_len = *count, 1065 .pos = offset, 1066 .u.data = rqstp, 1067 }; 1068 ssize_t host_err; 1069 1070 trace_nfsd_read_splice(rqstp, fhp, offset, *count); 1071 host_err = rw_verify_area(READ, file, &offset, *count); 1072 if (!host_err) 1073 host_err = splice_direct_to_actor(file, &sd, 1074 nfsd_direct_splice_actor); 1075 return nfsd_finish_read(rqstp, fhp, file, offset, count, eof, host_err); 1076} 1077 1078/* 1079 * The byte range of the client's READ request is expanded on both ends 1080 * until it meets the underlying file system's direct I/O alignment 1081 * requirements. After the internal read is complete, the byte range of 1082 * the NFS READ payload is reduced to the byte range that was originally 1083 * requested. 1084 * 1085 * Note that a direct read can be done only when the xdr_buf containing 1086 * the NFS READ reply does not already have contents in its .pages array. 1087 * This is due to potentially restrictive alignment requirements on the 1088 * read buffer. When .page_len and @base are zero, the .pages array is 1089 * guaranteed to be page-aligned. 1090 */ 1091static noinline_for_stack __be32 1092nfsd_direct_read(struct svc_rqst *rqstp, struct svc_fh *fhp, 1093 struct nfsd_file *nf, loff_t offset, unsigned long *count, 1094 u32 *eof) 1095{ 1096 u64 dio_start, dio_end; 1097 unsigned long v, total; 1098 struct iov_iter iter; 1099 struct kiocb kiocb; 1100 ssize_t host_err; 1101 size_t len; 1102 1103 init_sync_kiocb(&kiocb, nf->nf_file); 1104 kiocb.ki_flags |= IOCB_DIRECT; 1105 1106 /* Read a properly-aligned region of bytes into rq_bvec */ 1107 dio_start = round_down(offset, nf->nf_dio_read_offset_align); 1108 dio_end = round_up((u64)offset + *count, nf->nf_dio_read_offset_align); 1109 1110 kiocb.ki_pos = dio_start; 1111 1112 v = 0; 1113 total = dio_end - dio_start; 1114 while (total && v < rqstp->rq_maxpages && 1115 rqstp->rq_next_page < rqstp->rq_page_end) { 1116 len = min_t(size_t, total, PAGE_SIZE); 1117 bvec_set_page(&rqstp->rq_bvec[v], *rqstp->rq_next_page, 1118 len, 0); 1119 1120 total -= len; 1121 ++rqstp->rq_next_page; 1122 ++v; 1123 } 1124 1125 trace_nfsd_read_direct(rqstp, fhp, offset, *count - total); 1126 iov_iter_bvec(&iter, ITER_DEST, rqstp->rq_bvec, v, 1127 dio_end - dio_start - total); 1128 1129 host_err = vfs_iocb_iter_read(nf->nf_file, &kiocb, &iter); 1130 if (host_err >= 0) { 1131 unsigned int pad = offset - dio_start; 1132 1133 /* The returned payload starts after the pad */ 1134 rqstp->rq_res.page_base = pad; 1135 1136 /* Compute the count of bytes to be returned */ 1137 if (host_err > pad + *count) 1138 host_err = *count; 1139 else if (host_err > pad) 1140 host_err -= pad; 1141 else 1142 host_err = 0; 1143 } else if (unlikely(host_err == -EINVAL)) { 1144 struct inode *inode = d_inode(fhp->fh_dentry); 1145 1146 pr_info_ratelimited("nfsd: Direct I/O alignment failure on %s/%ld\n", 1147 inode->i_sb->s_id, inode->i_ino); 1148 host_err = -ESERVERFAULT; 1149 } 1150 1151 return nfsd_finish_read(rqstp, fhp, nf->nf_file, offset, count, 1152 eof, host_err); 1153} 1154 1155/** 1156 * nfsd_iter_read - Perform a VFS read using an iterator 1157 * @rqstp: RPC transaction context 1158 * @fhp: file handle of file to be read 1159 * @nf: opened struct nfsd_file of file to be read 1160 * @offset: starting byte offset 1161 * @count: IN: requested number of bytes; OUT: number of bytes read 1162 * @base: offset in first page of read buffer 1163 * @eof: OUT: set non-zero if operation reached the end of the file 1164 * 1165 * Some filesystems or situations cannot use nfsd_splice_read. This 1166 * function is the slightly less-performant fallback for those cases. 1167 * 1168 * Returns nfs_ok on success, otherwise an nfserr stat value is 1169 * returned. 1170 */ 1171__be32 nfsd_iter_read(struct svc_rqst *rqstp, struct svc_fh *fhp, 1172 struct nfsd_file *nf, loff_t offset, unsigned long *count, 1173 unsigned int base, u32 *eof) 1174{ 1175 struct file *file = nf->nf_file; 1176 unsigned long v, total; 1177 struct iov_iter iter; 1178 struct kiocb kiocb; 1179 ssize_t host_err; 1180 size_t len; 1181 1182 init_sync_kiocb(&kiocb, file); 1183 1184 switch (nfsd_io_cache_read) { 1185 case NFSD_IO_BUFFERED: 1186 break; 1187 case NFSD_IO_DIRECT: 1188 /* When dio_read_offset_align is zero, dio is not supported */ 1189 if (nf->nf_dio_read_offset_align && !rqstp->rq_res.page_len) 1190 return nfsd_direct_read(rqstp, fhp, nf, offset, 1191 count, eof); 1192 fallthrough; 1193 case NFSD_IO_DONTCACHE: 1194 if (file->f_op->fop_flags & FOP_DONTCACHE) 1195 kiocb.ki_flags = IOCB_DONTCACHE; 1196 break; 1197 } 1198 1199 kiocb.ki_pos = offset; 1200 1201 v = 0; 1202 total = *count; 1203 while (total && v < rqstp->rq_maxpages && 1204 rqstp->rq_next_page < rqstp->rq_page_end) { 1205 len = min_t(size_t, total, PAGE_SIZE - base); 1206 bvec_set_page(&rqstp->rq_bvec[v], *rqstp->rq_next_page, 1207 len, base); 1208 1209 total -= len; 1210 ++rqstp->rq_next_page; 1211 ++v; 1212 base = 0; 1213 } 1214 1215 trace_nfsd_read_vector(rqstp, fhp, offset, *count - total); 1216 iov_iter_bvec(&iter, ITER_DEST, rqstp->rq_bvec, v, *count - total); 1217 host_err = vfs_iocb_iter_read(file, &kiocb, &iter); 1218 return nfsd_finish_read(rqstp, fhp, file, offset, count, eof, host_err); 1219} 1220 1221/* 1222 * Gathered writes: If another process is currently writing to the file, 1223 * there's a high chance this is another nfsd (triggered by a bulk write 1224 * from a client's biod). Rather than syncing the file with each write 1225 * request, we sleep for 10 msec. 1226 * 1227 * I don't know if this roughly approximates C. Juszak's idea of 1228 * gathered writes, but it's a nice and simple solution (IMHO), and it 1229 * seems to work:-) 1230 * 1231 * Note: we do this only in the NFSv2 case, since v3 and higher have a 1232 * better tool (separate unstable writes and commits) for solving this 1233 * problem. 1234 */ 1235static int wait_for_concurrent_writes(struct file *file) 1236{ 1237 struct inode *inode = file_inode(file); 1238 static ino_t last_ino; 1239 static dev_t last_dev; 1240 int err = 0; 1241 1242 if (atomic_read(&inode->i_writecount) > 1 1243 || (last_ino == inode->i_ino && last_dev == inode->i_sb->s_dev)) { 1244 dprintk("nfsd: write defer %d\n", task_pid_nr(current)); 1245 msleep(10); 1246 dprintk("nfsd: write resume %d\n", task_pid_nr(current)); 1247 } 1248 1249 if (inode_state_read_once(inode) & I_DIRTY) { 1250 dprintk("nfsd: write sync %d\n", task_pid_nr(current)); 1251 err = vfs_fsync(file, 0); 1252 } 1253 last_ino = inode->i_ino; 1254 last_dev = inode->i_sb->s_dev; 1255 return err; 1256} 1257 1258struct nfsd_write_dio_seg { 1259 struct iov_iter iter; 1260 int flags; 1261}; 1262 1263static unsigned long 1264iov_iter_bvec_offset(const struct iov_iter *iter) 1265{ 1266 return (unsigned long)(iter->bvec->bv_offset + iter->iov_offset); 1267} 1268 1269static void 1270nfsd_write_dio_seg_init(struct nfsd_write_dio_seg *segment, 1271 struct bio_vec *bvec, unsigned int nvecs, 1272 unsigned long total, size_t start, size_t len, 1273 struct kiocb *iocb) 1274{ 1275 iov_iter_bvec(&segment->iter, ITER_SOURCE, bvec, nvecs, total); 1276 if (start) 1277 iov_iter_advance(&segment->iter, start); 1278 iov_iter_truncate(&segment->iter, len); 1279 segment->flags = iocb->ki_flags; 1280} 1281 1282static unsigned int 1283nfsd_write_dio_iters_init(struct nfsd_file *nf, struct bio_vec *bvec, 1284 unsigned int nvecs, struct kiocb *iocb, 1285 unsigned long total, 1286 struct nfsd_write_dio_seg segments[3]) 1287{ 1288 u32 offset_align = nf->nf_dio_offset_align; 1289 loff_t prefix_end, orig_end, middle_end; 1290 u32 mem_align = nf->nf_dio_mem_align; 1291 size_t prefix, middle, suffix; 1292 loff_t offset = iocb->ki_pos; 1293 unsigned int nsegs = 0; 1294 1295 /* 1296 * Check if direct I/O is feasible for this write request. 1297 * If alignments are not available, the write is too small, 1298 * or no alignment can be found, fall back to buffered I/O. 1299 */ 1300 if (unlikely(!mem_align || !offset_align) || 1301 unlikely(total < max(offset_align, mem_align))) 1302 goto no_dio; 1303 1304 prefix_end = round_up(offset, offset_align); 1305 orig_end = offset + total; 1306 middle_end = round_down(orig_end, offset_align); 1307 1308 prefix = prefix_end - offset; 1309 middle = middle_end - prefix_end; 1310 suffix = orig_end - middle_end; 1311 1312 if (!middle) 1313 goto no_dio; 1314 1315 if (prefix) 1316 nfsd_write_dio_seg_init(&segments[nsegs++], bvec, 1317 nvecs, total, 0, prefix, iocb); 1318 1319 nfsd_write_dio_seg_init(&segments[nsegs], bvec, nvecs, 1320 total, prefix, middle, iocb); 1321 1322 /* 1323 * Check if the bvec iterator is aligned for direct I/O. 1324 * 1325 * bvecs generated from RPC receive buffers are contiguous: After 1326 * the first bvec, all subsequent bvecs start at bv_offset zero 1327 * (page-aligned). Therefore, only the first bvec is checked. 1328 */ 1329 if (iov_iter_bvec_offset(&segments[nsegs].iter) & (mem_align - 1)) 1330 goto no_dio; 1331 segments[nsegs].flags |= IOCB_DIRECT; 1332 nsegs++; 1333 1334 if (suffix) 1335 nfsd_write_dio_seg_init(&segments[nsegs++], bvec, nvecs, total, 1336 prefix + middle, suffix, iocb); 1337 1338 return nsegs; 1339 1340no_dio: 1341 /* No DIO alignment possible - pack into single non-DIO segment. */ 1342 nfsd_write_dio_seg_init(&segments[0], bvec, nvecs, total, 0, 1343 total, iocb); 1344 return 1; 1345} 1346 1347static noinline_for_stack int 1348nfsd_direct_write(struct svc_rqst *rqstp, struct svc_fh *fhp, 1349 struct nfsd_file *nf, unsigned int nvecs, 1350 unsigned long *cnt, struct kiocb *kiocb) 1351{ 1352 struct nfsd_write_dio_seg segments[3]; 1353 struct file *file = nf->nf_file; 1354 unsigned int nsegs, i; 1355 ssize_t host_err; 1356 1357 nsegs = nfsd_write_dio_iters_init(nf, rqstp->rq_bvec, nvecs, 1358 kiocb, *cnt, segments); 1359 1360 *cnt = 0; 1361 for (i = 0; i < nsegs; i++) { 1362 kiocb->ki_flags = segments[i].flags; 1363 if (kiocb->ki_flags & IOCB_DIRECT) 1364 trace_nfsd_write_direct(rqstp, fhp, kiocb->ki_pos, 1365 segments[i].iter.count); 1366 else { 1367 trace_nfsd_write_vector(rqstp, fhp, kiocb->ki_pos, 1368 segments[i].iter.count); 1369 /* 1370 * Mark the I/O buffer as evict-able to reduce 1371 * memory contention. 1372 */ 1373 if (nf->nf_file->f_op->fop_flags & FOP_DONTCACHE) 1374 kiocb->ki_flags |= IOCB_DONTCACHE; 1375 } 1376 1377 host_err = vfs_iocb_iter_write(file, kiocb, &segments[i].iter); 1378 if (host_err < 0) 1379 return host_err; 1380 *cnt += host_err; 1381 if (host_err < segments[i].iter.count) 1382 break; /* partial write */ 1383 } 1384 1385 return 0; 1386} 1387 1388/** 1389 * nfsd_vfs_write - write data to an already-open file 1390 * @rqstp: RPC execution context 1391 * @fhp: File handle of file to write into 1392 * @nf: An open file matching @fhp 1393 * @offset: Byte offset of start 1394 * @payload: xdr_buf containing the write payload 1395 * @cnt: IN: number of bytes to write, OUT: number of bytes actually written 1396 * @stable: An NFS stable_how value 1397 * @verf: NFS WRITE verifier 1398 * 1399 * Upon return, caller must invoke fh_put on @fhp. 1400 * 1401 * Return values: 1402 * An nfsstat value in network byte order. 1403 */ 1404__be32 1405nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, 1406 struct nfsd_file *nf, loff_t offset, 1407 const struct xdr_buf *payload, unsigned long *cnt, 1408 int stable, __be32 *verf) 1409{ 1410 struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id); 1411 struct file *file = nf->nf_file; 1412 struct super_block *sb = file_inode(file)->i_sb; 1413 struct kiocb kiocb; 1414 struct svc_export *exp; 1415 struct iov_iter iter; 1416 errseq_t since; 1417 __be32 nfserr; 1418 int host_err; 1419 unsigned long exp_op_flags = 0; 1420 unsigned int pflags = current->flags; 1421 bool restore_flags = false; 1422 unsigned int nvecs; 1423 1424 trace_nfsd_write_opened(rqstp, fhp, offset, *cnt); 1425 1426 if (sb->s_export_op) 1427 exp_op_flags = sb->s_export_op->flags; 1428 1429 if (test_bit(RQ_LOCAL, &rqstp->rq_flags) && 1430 !(exp_op_flags & EXPORT_OP_REMOTE_FS)) { 1431 /* 1432 * We want throttling in balance_dirty_pages() 1433 * and shrink_inactive_list() to only consider 1434 * the backingdev we are writing to, so that nfs to 1435 * localhost doesn't cause nfsd to lock up due to all 1436 * the client's dirty pages or its congested queue. 1437 */ 1438 current->flags |= PF_LOCAL_THROTTLE; 1439 restore_flags = true; 1440 } 1441 1442 exp = fhp->fh_export; 1443 1444 if (!EX_ISSYNC(exp)) 1445 stable = NFS_UNSTABLE; 1446 init_sync_kiocb(&kiocb, file); 1447 kiocb.ki_pos = offset; 1448 if (likely(!fhp->fh_use_wgather)) { 1449 switch (stable) { 1450 case NFS_FILE_SYNC: 1451 /* persist data and timestamps */ 1452 kiocb.ki_flags |= IOCB_DSYNC | IOCB_SYNC; 1453 break; 1454 case NFS_DATA_SYNC: 1455 /* persist data only */ 1456 kiocb.ki_flags |= IOCB_DSYNC; 1457 break; 1458 } 1459 } 1460 1461 nvecs = xdr_buf_to_bvec(rqstp->rq_bvec, rqstp->rq_maxpages, payload); 1462 1463 since = READ_ONCE(file->f_wb_err); 1464 if (verf) 1465 nfsd_copy_write_verifier(verf, nn); 1466 1467 switch (nfsd_io_cache_write) { 1468 case NFSD_IO_DIRECT: 1469 host_err = nfsd_direct_write(rqstp, fhp, nf, nvecs, 1470 cnt, &kiocb); 1471 break; 1472 case NFSD_IO_DONTCACHE: 1473 if (file->f_op->fop_flags & FOP_DONTCACHE) 1474 kiocb.ki_flags |= IOCB_DONTCACHE; 1475 fallthrough; 1476 case NFSD_IO_BUFFERED: 1477 iov_iter_bvec(&iter, ITER_SOURCE, rqstp->rq_bvec, nvecs, *cnt); 1478 host_err = vfs_iocb_iter_write(file, &kiocb, &iter); 1479 if (host_err < 0) 1480 break; 1481 *cnt = host_err; 1482 break; 1483 } 1484 if (host_err < 0) { 1485 commit_reset_write_verifier(nn, rqstp, host_err); 1486 goto out_nfserr; 1487 } 1488 nfsd_stats_io_write_add(nn, exp, *cnt); 1489 fsnotify_modify(file); 1490 host_err = filemap_check_wb_err(file->f_mapping, since); 1491 if (host_err < 0) 1492 goto out_nfserr; 1493 1494 if (stable && fhp->fh_use_wgather) { 1495 host_err = wait_for_concurrent_writes(file); 1496 if (host_err < 0) 1497 commit_reset_write_verifier(nn, rqstp, host_err); 1498 } 1499 1500out_nfserr: 1501 if (host_err >= 0) { 1502 trace_nfsd_write_io_done(rqstp, fhp, offset, *cnt); 1503 nfserr = nfs_ok; 1504 } else { 1505 trace_nfsd_write_err(rqstp, fhp, offset, host_err); 1506 nfserr = nfserrno(host_err); 1507 } 1508 if (restore_flags) 1509 current_restore_flags(pflags, PF_LOCAL_THROTTLE); 1510 return nfserr; 1511} 1512 1513/** 1514 * nfsd_read_splice_ok - check if spliced reading is supported 1515 * @rqstp: RPC transaction context 1516 * 1517 * Return values: 1518 * %true: nfsd_splice_read() may be used 1519 * %false: nfsd_splice_read() must not be used 1520 * 1521 * NFS READ normally uses splice to send data in-place. However the 1522 * data in cache can change after the reply's MIC is computed but 1523 * before the RPC reply is sent. To prevent the client from 1524 * rejecting the server-computed MIC in this somewhat rare case, do 1525 * not use splice with the GSS integrity and privacy services. 1526 */ 1527bool nfsd_read_splice_ok(struct svc_rqst *rqstp) 1528{ 1529 if (nfsd_disable_splice_read) 1530 return false; 1531 switch (svc_auth_flavor(rqstp)) { 1532 case RPC_AUTH_GSS_KRB5I: 1533 case RPC_AUTH_GSS_KRB5P: 1534 return false; 1535 } 1536 return true; 1537} 1538 1539/** 1540 * nfsd_read - Read data from a file 1541 * @rqstp: RPC transaction context 1542 * @fhp: file handle of file to be read 1543 * @offset: starting byte offset 1544 * @count: IN: requested number of bytes; OUT: number of bytes read 1545 * @eof: OUT: set non-zero if operation reached the end of the file 1546 * 1547 * The caller must verify that there is enough space in @rqstp.rq_res 1548 * to perform this operation. 1549 * 1550 * N.B. After this call fhp needs an fh_put 1551 * 1552 * Returns nfs_ok on success, otherwise an nfserr stat value is 1553 * returned. 1554 */ 1555__be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp, 1556 loff_t offset, unsigned long *count, u32 *eof) 1557{ 1558 struct nfsd_file *nf; 1559 struct file *file; 1560 __be32 err; 1561 1562 trace_nfsd_read_start(rqstp, fhp, offset, *count); 1563 err = nfsd_file_acquire_gc(rqstp, fhp, NFSD_MAY_READ, &nf); 1564 if (err) 1565 return err; 1566 1567 file = nf->nf_file; 1568 if (file->f_op->splice_read && nfsd_read_splice_ok(rqstp)) 1569 err = nfsd_splice_read(rqstp, fhp, file, offset, count, eof); 1570 else 1571 err = nfsd_iter_read(rqstp, fhp, nf, offset, count, 0, eof); 1572 1573 nfsd_file_put(nf); 1574 trace_nfsd_read_done(rqstp, fhp, offset, *count); 1575 return err; 1576} 1577 1578/** 1579 * nfsd_write - open a file and write data to it 1580 * @rqstp: RPC execution context 1581 * @fhp: File handle of file to write into; nfsd_write() may modify it 1582 * @offset: Byte offset of start 1583 * @payload: xdr_buf containing the write payload 1584 * @cnt: IN: number of bytes to write, OUT: number of bytes actually written 1585 * @stable: An NFS stable_how value 1586 * @verf: NFS WRITE verifier 1587 * 1588 * Upon return, caller must invoke fh_put on @fhp. 1589 * 1590 * Return values: 1591 * An nfsstat value in network byte order. 1592 */ 1593__be32 1594nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t offset, 1595 const struct xdr_buf *payload, unsigned long *cnt, int stable, 1596 __be32 *verf) 1597{ 1598 struct nfsd_file *nf; 1599 __be32 err; 1600 1601 trace_nfsd_write_start(rqstp, fhp, offset, *cnt); 1602 1603 err = nfsd_file_acquire_gc(rqstp, fhp, NFSD_MAY_WRITE, &nf); 1604 if (err) 1605 goto out; 1606 1607 err = nfsd_vfs_write(rqstp, fhp, nf, offset, payload, cnt, 1608 stable, verf); 1609 nfsd_file_put(nf); 1610out: 1611 trace_nfsd_write_done(rqstp, fhp, offset, *cnt); 1612 return err; 1613} 1614 1615/** 1616 * nfsd_commit - Commit pending writes to stable storage 1617 * @rqstp: RPC request being processed 1618 * @fhp: NFS filehandle 1619 * @nf: target file 1620 * @offset: raw offset from beginning of file 1621 * @count: raw count of bytes to sync 1622 * @verf: filled in with the server's current write verifier 1623 * 1624 * Note: we guarantee that data that lies within the range specified 1625 * by the 'offset' and 'count' parameters will be synced. The server 1626 * is permitted to sync data that lies outside this range at the 1627 * same time. 1628 * 1629 * Unfortunately we cannot lock the file to make sure we return full WCC 1630 * data to the client, as locking happens lower down in the filesystem. 1631 * 1632 * Return values: 1633 * An nfsstat value in network byte order. 1634 */ 1635__be32 1636nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf, 1637 u64 offset, u32 count, __be32 *verf) 1638{ 1639 __be32 err = nfs_ok; 1640 u64 maxbytes; 1641 loff_t start, end; 1642 struct nfsd_net *nn; 1643 1644 trace_nfsd_commit_start(rqstp, fhp, offset, count); 1645 1646 /* 1647 * Convert the client-provided (offset, count) range to a 1648 * (start, end) range. If the client-provided range falls 1649 * outside the maximum file size of the underlying FS, 1650 * clamp the sync range appropriately. 1651 */ 1652 start = 0; 1653 end = LLONG_MAX; 1654 maxbytes = (u64)fhp->fh_dentry->d_sb->s_maxbytes; 1655 if (offset < maxbytes) { 1656 start = offset; 1657 if (count && (offset + count - 1 < maxbytes)) 1658 end = offset + count - 1; 1659 } 1660 1661 nn = net_generic(nf->nf_net, nfsd_net_id); 1662 if (EX_ISSYNC(fhp->fh_export)) { 1663 errseq_t since = READ_ONCE(nf->nf_file->f_wb_err); 1664 int err2; 1665 1666 err2 = vfs_fsync_range(nf->nf_file, start, end, 0); 1667 switch (err2) { 1668 case 0: 1669 nfsd_copy_write_verifier(verf, nn); 1670 err2 = filemap_check_wb_err(nf->nf_file->f_mapping, 1671 since); 1672 err = nfserrno(err2); 1673 break; 1674 case -EINVAL: 1675 err = nfserr_notsupp; 1676 break; 1677 default: 1678 commit_reset_write_verifier(nn, rqstp, err2); 1679 err = nfserrno(err2); 1680 } 1681 } else 1682 nfsd_copy_write_verifier(verf, nn); 1683 1684 trace_nfsd_commit_done(rqstp, fhp, offset, count); 1685 return err; 1686} 1687 1688/** 1689 * nfsd_create_setattr - Set a created file's attributes 1690 * @rqstp: RPC transaction being executed 1691 * @fhp: NFS filehandle of parent directory 1692 * @resfhp: NFS filehandle of new object 1693 * @attrs: requested attributes of new object 1694 * 1695 * Returns nfs_ok on success, or an nfsstat in network byte order. 1696 */ 1697__be32 1698nfsd_create_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, 1699 struct svc_fh *resfhp, struct nfsd_attrs *attrs) 1700{ 1701 struct iattr *iap = attrs->na_iattr; 1702 __be32 status; 1703 1704 /* 1705 * Mode has already been set by file creation. 1706 */ 1707 iap->ia_valid &= ~ATTR_MODE; 1708 1709 /* 1710 * Setting uid/gid works only for root. Irix appears to 1711 * send along the gid on create when it tries to implement 1712 * setgid directories via NFS: 1713 */ 1714 if (!uid_eq(current_fsuid(), GLOBAL_ROOT_UID)) 1715 iap->ia_valid &= ~(ATTR_UID|ATTR_GID); 1716 1717 /* 1718 * Callers expect new file metadata to be committed even 1719 * if the attributes have not changed. 1720 */ 1721 if (nfsd_attrs_valid(attrs)) 1722 status = nfsd_setattr(rqstp, resfhp, attrs, NULL); 1723 else 1724 status = nfserrno(commit_metadata(resfhp)); 1725 1726 /* 1727 * Transactional filesystems had a chance to commit changes 1728 * for both parent and child simultaneously making the 1729 * following commit_metadata a noop in many cases. 1730 */ 1731 if (!status) 1732 status = nfserrno(commit_metadata(fhp)); 1733 1734 /* 1735 * Update the new filehandle to pick up the new attributes. 1736 */ 1737 if (!status) 1738 status = fh_update(resfhp); 1739 1740 return status; 1741} 1742 1743/* HPUX client sometimes creates a file in mode 000, and sets size to 0. 1744 * setting size to 0 may fail for some specific file systems by the permission 1745 * checking which requires WRITE permission but the mode is 000. 1746 * we ignore the resizing(to 0) on the just new created file, since the size is 1747 * 0 after file created. 1748 * 1749 * call this only after vfs_create() is called. 1750 * */ 1751static void 1752nfsd_check_ignore_resizing(struct iattr *iap) 1753{ 1754 if ((iap->ia_valid & ATTR_SIZE) && (iap->ia_size == 0)) 1755 iap->ia_valid &= ~ATTR_SIZE; 1756} 1757 1758/* The parent directory should already be locked - we will unlock */ 1759__be32 1760nfsd_create_locked(struct svc_rqst *rqstp, struct svc_fh *fhp, 1761 struct nfsd_attrs *attrs, 1762 int type, dev_t rdev, struct svc_fh *resfhp) 1763{ 1764 struct dentry *dentry, *dchild; 1765 struct inode *dirp; 1766 struct iattr *iap = attrs->na_iattr; 1767 __be32 err; 1768 int host_err = 0; 1769 1770 dentry = fhp->fh_dentry; 1771 dirp = d_inode(dentry); 1772 1773 dchild = dget(resfhp->fh_dentry); 1774 err = nfsd_permission(&rqstp->rq_cred, fhp->fh_export, dentry, 1775 NFSD_MAY_CREATE); 1776 if (err) 1777 goto out; 1778 1779 if (!(iap->ia_valid & ATTR_MODE)) 1780 iap->ia_mode = 0; 1781 iap->ia_mode = (iap->ia_mode & S_IALLUGO) | type; 1782 1783 if (!IS_POSIXACL(dirp)) 1784 iap->ia_mode &= ~current_umask(); 1785 1786 err = 0; 1787 switch (type) { 1788 case S_IFREG: 1789 host_err = vfs_create(&nop_mnt_idmap, dchild, iap->ia_mode, NULL); 1790 if (!host_err) 1791 nfsd_check_ignore_resizing(iap); 1792 break; 1793 case S_IFDIR: 1794 dchild = vfs_mkdir(&nop_mnt_idmap, dirp, dchild, iap->ia_mode, NULL); 1795 if (IS_ERR(dchild)) { 1796 host_err = PTR_ERR(dchild); 1797 } else if (d_is_negative(dchild)) { 1798 err = nfserr_serverfault; 1799 goto out; 1800 } else if (unlikely(dchild != resfhp->fh_dentry)) { 1801 dput(resfhp->fh_dentry); 1802 resfhp->fh_dentry = dget(dchild); 1803 } 1804 break; 1805 case S_IFCHR: 1806 case S_IFBLK: 1807 case S_IFIFO: 1808 case S_IFSOCK: 1809 host_err = vfs_mknod(&nop_mnt_idmap, dirp, dchild, 1810 iap->ia_mode, rdev, NULL); 1811 break; 1812 default: 1813 printk(KERN_WARNING "nfsd: bad file type %o in nfsd_create\n", 1814 type); 1815 host_err = -EINVAL; 1816 } 1817 if (host_err < 0) 1818 goto out_nfserr; 1819 1820 err = nfsd_create_setattr(rqstp, fhp, resfhp, attrs); 1821 1822out: 1823 if (!err) 1824 fh_fill_post_attrs(fhp); 1825 end_creating(dchild); 1826 return err; 1827 1828out_nfserr: 1829 err = nfserrno(host_err); 1830 goto out; 1831} 1832 1833/* 1834 * Create a filesystem object (regular, directory, special). 1835 * Note that the parent directory is left locked. 1836 * 1837 * N.B. Every call to nfsd_create needs an fh_put for _both_ fhp and resfhp 1838 */ 1839__be32 1840nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, 1841 char *fname, int flen, struct nfsd_attrs *attrs, 1842 int type, dev_t rdev, struct svc_fh *resfhp) 1843{ 1844 struct dentry *dentry, *dchild = NULL; 1845 __be32 err; 1846 int host_err; 1847 1848 trace_nfsd_vfs_create(rqstp, fhp, type, fname, flen); 1849 1850 if (isdotent(fname, flen)) 1851 return nfserr_exist; 1852 1853 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_NOP); 1854 if (err) 1855 return err; 1856 1857 dentry = fhp->fh_dentry; 1858 1859 host_err = fh_want_write(fhp); 1860 if (host_err) 1861 return nfserrno(host_err); 1862 1863 dchild = start_creating(&nop_mnt_idmap, dentry, &QSTR_LEN(fname, flen)); 1864 host_err = PTR_ERR(dchild); 1865 if (IS_ERR(dchild)) 1866 return nfserrno(host_err); 1867 1868 err = fh_compose(resfhp, fhp->fh_export, dchild, fhp); 1869 if (err) 1870 goto out_unlock; 1871 err = fh_fill_pre_attrs(fhp); 1872 if (err != nfs_ok) 1873 goto out_unlock; 1874 err = nfsd_create_locked(rqstp, fhp, attrs, type, rdev, resfhp); 1875 /* nfsd_create_locked() unlocked the parent */ 1876 dput(dchild); 1877 return err; 1878 1879out_unlock: 1880 end_creating(dchild); 1881 return err; 1882} 1883 1884/* 1885 * Read a symlink. On entry, *lenp must contain the maximum path length that 1886 * fits into the buffer. On return, it contains the true length. 1887 * N.B. After this call fhp needs an fh_put 1888 */ 1889__be32 1890nfsd_readlink(struct svc_rqst *rqstp, struct svc_fh *fhp, char *buf, int *lenp) 1891{ 1892 __be32 err; 1893 const char *link; 1894 struct path path; 1895 DEFINE_DELAYED_CALL(done); 1896 int len; 1897 1898 err = fh_verify(rqstp, fhp, S_IFLNK, NFSD_MAY_NOP); 1899 if (unlikely(err)) 1900 return err; 1901 1902 path.mnt = fhp->fh_export->ex_path.mnt; 1903 path.dentry = fhp->fh_dentry; 1904 1905 if (unlikely(!d_is_symlink(path.dentry))) 1906 return nfserr_inval; 1907 1908 touch_atime(&path); 1909 1910 link = vfs_get_link(path.dentry, &done); 1911 if (IS_ERR(link)) 1912 return nfserrno(PTR_ERR(link)); 1913 1914 len = strlen(link); 1915 if (len < *lenp) 1916 *lenp = len; 1917 memcpy(buf, link, *lenp); 1918 do_delayed_call(&done); 1919 return 0; 1920} 1921 1922/** 1923 * nfsd_symlink - Create a symlink and look up its inode 1924 * @rqstp: RPC transaction being executed 1925 * @fhp: NFS filehandle of parent directory 1926 * @fname: filename of the new symlink 1927 * @flen: length of @fname 1928 * @path: content of the new symlink (NUL-terminated) 1929 * @attrs: requested attributes of new object 1930 * @resfhp: NFS filehandle of new object 1931 * 1932 * N.B. After this call _both_ fhp and resfhp need an fh_put 1933 * 1934 * Returns nfs_ok on success, or an nfsstat in network byte order. 1935 */ 1936__be32 1937nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp, 1938 char *fname, int flen, 1939 char *path, struct nfsd_attrs *attrs, 1940 struct svc_fh *resfhp) 1941{ 1942 struct dentry *dentry, *dnew; 1943 __be32 err, cerr; 1944 int host_err; 1945 1946 trace_nfsd_vfs_symlink(rqstp, fhp, fname, flen, path); 1947 1948 err = nfserr_noent; 1949 if (!flen || path[0] == '\0') 1950 goto out; 1951 err = nfserr_exist; 1952 if (isdotent(fname, flen)) 1953 goto out; 1954 1955 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE); 1956 if (err) 1957 goto out; 1958 1959 host_err = fh_want_write(fhp); 1960 if (host_err) { 1961 err = nfserrno(host_err); 1962 goto out; 1963 } 1964 1965 dentry = fhp->fh_dentry; 1966 dnew = start_creating(&nop_mnt_idmap, dentry, &QSTR_LEN(fname, flen)); 1967 if (IS_ERR(dnew)) { 1968 err = nfserrno(PTR_ERR(dnew)); 1969 goto out_drop_write; 1970 } 1971 err = fh_fill_pre_attrs(fhp); 1972 if (err != nfs_ok) 1973 goto out_unlock; 1974 host_err = vfs_symlink(&nop_mnt_idmap, d_inode(dentry), dnew, path, NULL); 1975 err = nfserrno(host_err); 1976 cerr = fh_compose(resfhp, fhp->fh_export, dnew, fhp); 1977 if (!err) 1978 nfsd_create_setattr(rqstp, fhp, resfhp, attrs); 1979 fh_fill_post_attrs(fhp); 1980out_unlock: 1981 end_creating(dnew); 1982 if (!err) 1983 err = nfserrno(commit_metadata(fhp)); 1984 if (!err) 1985 err = cerr; 1986out_drop_write: 1987 fh_drop_write(fhp); 1988out: 1989 return err; 1990} 1991 1992/** 1993 * nfsd_link - create a link 1994 * @rqstp: RPC transaction context 1995 * @ffhp: the file handle of the directory where the new link is to be created 1996 * @name: the filename of the new link 1997 * @len: the length of @name in octets 1998 * @tfhp: the file handle of an existing file object 1999 * 2000 * After this call _both_ ffhp and tfhp need an fh_put. 2001 * 2002 * Returns a generic NFS status code in network byte-order. 2003 */ 2004__be32 2005nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp, 2006 char *name, int len, struct svc_fh *tfhp) 2007{ 2008 struct dentry *ddir, *dnew, *dold; 2009 struct inode *dirp; 2010 int type; 2011 __be32 err; 2012 int host_err; 2013 2014 trace_nfsd_vfs_link(rqstp, ffhp, tfhp, name, len); 2015 2016 err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_CREATE); 2017 if (err) 2018 goto out; 2019 err = fh_verify(rqstp, tfhp, 0, NFSD_MAY_NOP); 2020 if (err) 2021 goto out; 2022 err = nfserr_isdir; 2023 if (d_is_dir(tfhp->fh_dentry)) 2024 goto out; 2025 err = nfserr_perm; 2026 if (!len) 2027 goto out; 2028 err = nfserr_exist; 2029 if (isdotent(name, len)) 2030 goto out; 2031 2032 err = nfs_ok; 2033 type = d_inode(tfhp->fh_dentry)->i_mode & S_IFMT; 2034 host_err = fh_want_write(tfhp); 2035 if (host_err) 2036 goto out; 2037 2038 ddir = ffhp->fh_dentry; 2039 dirp = d_inode(ddir); 2040 dnew = start_creating(&nop_mnt_idmap, ddir, &QSTR_LEN(name, len)); 2041 2042 if (IS_ERR(dnew)) { 2043 host_err = PTR_ERR(dnew); 2044 goto out_drop_write; 2045 } 2046 2047 dold = tfhp->fh_dentry; 2048 2049 err = nfserr_noent; 2050 if (d_really_is_negative(dold)) 2051 goto out_unlock; 2052 err = fh_fill_pre_attrs(ffhp); 2053 if (err != nfs_ok) 2054 goto out_unlock; 2055 host_err = vfs_link(dold, &nop_mnt_idmap, dirp, dnew, NULL); 2056 fh_fill_post_attrs(ffhp); 2057out_unlock: 2058 end_creating(dnew); 2059 if (!host_err) { 2060 host_err = commit_metadata(ffhp); 2061 if (!host_err) 2062 host_err = commit_metadata(tfhp); 2063 } 2064 2065out_drop_write: 2066 fh_drop_write(tfhp); 2067 if (host_err == -EBUSY) { 2068 /* 2069 * See RFC 8881 Section 18.9.4 para 1-2: NFSv4 LINK 2070 * wants a status unique to the object type. 2071 */ 2072 if (type != S_IFDIR) 2073 err = nfserr_file_open; 2074 else 2075 err = nfserr_acces; 2076 } 2077out: 2078 return err != nfs_ok ? err : nfserrno(host_err); 2079} 2080 2081static void 2082nfsd_close_cached_files(struct dentry *dentry) 2083{ 2084 struct inode *inode = d_inode(dentry); 2085 2086 if (inode && S_ISREG(inode->i_mode)) 2087 nfsd_file_close_inode_sync(inode); 2088} 2089 2090static bool 2091nfsd_has_cached_files(struct dentry *dentry) 2092{ 2093 bool ret = false; 2094 struct inode *inode = d_inode(dentry); 2095 2096 if (inode && S_ISREG(inode->i_mode)) 2097 ret = nfsd_file_is_cached(inode); 2098 return ret; 2099} 2100 2101/** 2102 * nfsd_rename - rename a directory entry 2103 * @rqstp: RPC transaction context 2104 * @ffhp: the file handle of parent directory containing the entry to be renamed 2105 * @fname: the filename of directory entry to be renamed 2106 * @flen: the length of @fname in octets 2107 * @tfhp: the file handle of parent directory to contain the renamed entry 2108 * @tname: the filename of the new entry 2109 * @tlen: the length of @tlen in octets 2110 * 2111 * After this call _both_ ffhp and tfhp need an fh_put. 2112 * 2113 * Returns a generic NFS status code in network byte-order. 2114 */ 2115__be32 2116nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, 2117 struct svc_fh *tfhp, char *tname, int tlen) 2118{ 2119 struct dentry *fdentry, *tdentry; 2120 int type = S_IFDIR; 2121 struct renamedata rd = {}; 2122 __be32 err; 2123 int host_err; 2124 struct dentry *close_cached; 2125 2126 trace_nfsd_vfs_rename(rqstp, ffhp, tfhp, fname, flen, tname, tlen); 2127 2128 err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_REMOVE); 2129 if (err) 2130 goto out; 2131 err = fh_verify(rqstp, tfhp, S_IFDIR, NFSD_MAY_CREATE); 2132 if (err) 2133 goto out; 2134 2135 fdentry = ffhp->fh_dentry; 2136 2137 tdentry = tfhp->fh_dentry; 2138 2139 err = nfserr_perm; 2140 if (!flen || isdotent(fname, flen) || !tlen || isdotent(tname, tlen)) 2141 goto out; 2142 2143 err = nfserr_xdev; 2144 if (ffhp->fh_export->ex_path.mnt != tfhp->fh_export->ex_path.mnt) 2145 goto out; 2146 if (ffhp->fh_export->ex_path.dentry != tfhp->fh_export->ex_path.dentry) 2147 goto out; 2148 2149retry: 2150 close_cached = NULL; 2151 host_err = fh_want_write(ffhp); 2152 if (host_err) { 2153 err = nfserrno(host_err); 2154 goto out; 2155 } 2156 2157 rd.mnt_idmap = &nop_mnt_idmap; 2158 rd.old_parent = fdentry; 2159 rd.new_parent = tdentry; 2160 2161 host_err = start_renaming(&rd, 0, &QSTR_LEN(fname, flen), 2162 &QSTR_LEN(tname, tlen)); 2163 2164 if (host_err) { 2165 err = nfserrno(host_err); 2166 goto out_want_write; 2167 } 2168 err = fh_fill_pre_attrs(ffhp); 2169 if (err != nfs_ok) 2170 goto out_unlock; 2171 err = fh_fill_pre_attrs(tfhp); 2172 if (err != nfs_ok) 2173 goto out_unlock; 2174 2175 type = d_inode(rd.old_dentry)->i_mode & S_IFMT; 2176 2177 if (d_inode(rd.new_dentry)) 2178 type = d_inode(rd.new_dentry)->i_mode & S_IFMT; 2179 2180 if ((rd.new_dentry->d_sb->s_export_op->flags & EXPORT_OP_CLOSE_BEFORE_UNLINK) && 2181 nfsd_has_cached_files(rd.new_dentry)) { 2182 close_cached = dget(rd.new_dentry); 2183 goto out_unlock; 2184 } else { 2185 int retries; 2186 2187 for (retries = 1;;) { 2188 host_err = vfs_rename(&rd); 2189 if (host_err != -EAGAIN || !retries--) 2190 break; 2191 if (!nfsd_wait_for_delegreturn(rqstp, d_inode(rd.old_dentry))) 2192 break; 2193 } 2194 if (!host_err) { 2195 host_err = commit_metadata(tfhp); 2196 if (!host_err) 2197 host_err = commit_metadata(ffhp); 2198 } 2199 } 2200 if (host_err == -EBUSY) { 2201 /* 2202 * See RFC 8881 Section 18.26.4 para 1-3: NFSv4 RENAME 2203 * wants a status unique to the object type. 2204 */ 2205 if (type != S_IFDIR) 2206 err = nfserr_file_open; 2207 else 2208 err = nfserr_acces; 2209 } else { 2210 err = nfserrno(host_err); 2211 } 2212 2213 if (!close_cached) { 2214 fh_fill_post_attrs(ffhp); 2215 fh_fill_post_attrs(tfhp); 2216 } 2217out_unlock: 2218 end_renaming(&rd); 2219out_want_write: 2220 fh_drop_write(ffhp); 2221 2222 /* 2223 * If the target dentry has cached open files, then we need to 2224 * try to close them prior to doing the rename. Final fput 2225 * shouldn't be done with locks held however, so we delay it 2226 * until this point and then reattempt the whole shebang. 2227 */ 2228 if (close_cached) { 2229 nfsd_close_cached_files(close_cached); 2230 dput(close_cached); 2231 goto retry; 2232 } 2233out: 2234 return err; 2235} 2236 2237/** 2238 * nfsd_unlink - remove a directory entry 2239 * @rqstp: RPC transaction context 2240 * @fhp: the file handle of the parent directory to be modified 2241 * @type: enforced file type of the object to be removed 2242 * @fname: the name of directory entry to be removed 2243 * @flen: length of @fname in octets 2244 * 2245 * After this call fhp needs an fh_put. 2246 * 2247 * Returns a generic NFS status code in network byte-order. 2248 */ 2249__be32 2250nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, 2251 char *fname, int flen) 2252{ 2253 struct dentry *dentry, *rdentry; 2254 struct inode *dirp; 2255 struct inode *rinode = NULL; 2256 __be32 err; 2257 int host_err; 2258 2259 trace_nfsd_vfs_unlink(rqstp, fhp, fname, flen); 2260 2261 err = nfserr_acces; 2262 if (!flen || isdotent(fname, flen)) 2263 goto out; 2264 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_REMOVE); 2265 if (err) 2266 goto out; 2267 2268 host_err = fh_want_write(fhp); 2269 if (host_err) 2270 goto out_nfserr; 2271 2272 dentry = fhp->fh_dentry; 2273 dirp = d_inode(dentry); 2274 2275 rdentry = start_removing(&nop_mnt_idmap, dentry, &QSTR_LEN(fname, flen)); 2276 2277 host_err = PTR_ERR(rdentry); 2278 if (IS_ERR(rdentry)) 2279 goto out_drop_write; 2280 2281 err = fh_fill_pre_attrs(fhp); 2282 if (err != nfs_ok) 2283 goto out_unlock; 2284 2285 rinode = d_inode(rdentry); 2286 /* Prevent truncation until after locks dropped */ 2287 ihold(rinode); 2288 2289 if (!type) 2290 type = d_inode(rdentry)->i_mode & S_IFMT; 2291 2292 if (type != S_IFDIR) { 2293 int retries; 2294 2295 if (rdentry->d_sb->s_export_op->flags & EXPORT_OP_CLOSE_BEFORE_UNLINK) 2296 nfsd_close_cached_files(rdentry); 2297 2298 for (retries = 1;;) { 2299 host_err = vfs_unlink(&nop_mnt_idmap, dirp, rdentry, NULL); 2300 if (host_err != -EAGAIN || !retries--) 2301 break; 2302 if (!nfsd_wait_for_delegreturn(rqstp, rinode)) 2303 break; 2304 } 2305 } else { 2306 host_err = vfs_rmdir(&nop_mnt_idmap, dirp, rdentry, NULL); 2307 } 2308 fh_fill_post_attrs(fhp); 2309 2310out_unlock: 2311 end_removing(rdentry); 2312 if (!err && !host_err) 2313 host_err = commit_metadata(fhp); 2314 iput(rinode); /* truncate the inode here */ 2315 2316out_drop_write: 2317 fh_drop_write(fhp); 2318out_nfserr: 2319 if (host_err == -EBUSY) { 2320 /* 2321 * See RFC 8881 Section 18.25.4 para 4: NFSv4 REMOVE 2322 * wants a status unique to the object type. 2323 */ 2324 if (type != S_IFDIR) 2325 err = nfserr_file_open; 2326 else 2327 err = nfserr_acces; 2328 } 2329out: 2330 return err != nfs_ok ? err : nfserrno(host_err); 2331} 2332 2333/* 2334 * We do this buffering because we must not call back into the file 2335 * system's ->lookup() method from the filldir callback. That may well 2336 * deadlock a number of file systems. 2337 * 2338 * This is based heavily on the implementation of same in XFS. 2339 */ 2340struct buffered_dirent { 2341 u64 ino; 2342 loff_t offset; 2343 int namlen; 2344 unsigned int d_type; 2345 char name[]; 2346}; 2347 2348struct readdir_data { 2349 struct dir_context ctx; 2350 char *dirent; 2351 size_t used; 2352 int full; 2353}; 2354 2355static bool nfsd_buffered_filldir(struct dir_context *ctx, const char *name, 2356 int namlen, loff_t offset, u64 ino, 2357 unsigned int d_type) 2358{ 2359 struct readdir_data *buf = 2360 container_of(ctx, struct readdir_data, ctx); 2361 struct buffered_dirent *de = (void *)(buf->dirent + buf->used); 2362 unsigned int reclen; 2363 2364 reclen = ALIGN(sizeof(struct buffered_dirent) + namlen, sizeof(u64)); 2365 if (buf->used + reclen > PAGE_SIZE) { 2366 buf->full = 1; 2367 return false; 2368 } 2369 2370 de->namlen = namlen; 2371 de->offset = offset; 2372 de->ino = ino; 2373 de->d_type = d_type; 2374 memcpy(de->name, name, namlen); 2375 buf->used += reclen; 2376 2377 return true; 2378} 2379 2380static __be32 nfsd_buffered_readdir(struct file *file, struct svc_fh *fhp, 2381 nfsd_filldir_t func, struct readdir_cd *cdp, 2382 loff_t *offsetp) 2383{ 2384 struct buffered_dirent *de; 2385 int host_err; 2386 int size; 2387 loff_t offset; 2388 struct readdir_data buf = { 2389 .ctx.actor = nfsd_buffered_filldir, 2390 .dirent = (void *)__get_free_page(GFP_KERNEL) 2391 }; 2392 2393 if (!buf.dirent) 2394 return nfserrno(-ENOMEM); 2395 2396 offset = *offsetp; 2397 2398 while (1) { 2399 unsigned int reclen; 2400 2401 cdp->err = nfserr_eof; /* will be cleared on successful read */ 2402 buf.used = 0; 2403 buf.full = 0; 2404 2405 host_err = iterate_dir(file, &buf.ctx); 2406 if (buf.full) 2407 host_err = 0; 2408 2409 if (host_err < 0) 2410 break; 2411 2412 size = buf.used; 2413 2414 if (!size) 2415 break; 2416 2417 de = (struct buffered_dirent *)buf.dirent; 2418 while (size > 0) { 2419 offset = de->offset; 2420 2421 if (func(cdp, de->name, de->namlen, de->offset, 2422 de->ino, de->d_type)) 2423 break; 2424 2425 if (cdp->err != nfs_ok) 2426 break; 2427 2428 trace_nfsd_dirent(fhp, de->ino, de->name, de->namlen); 2429 2430 reclen = ALIGN(sizeof(*de) + de->namlen, 2431 sizeof(u64)); 2432 size -= reclen; 2433 de = (struct buffered_dirent *)((char *)de + reclen); 2434 } 2435 if (size > 0) /* We bailed out early */ 2436 break; 2437 2438 offset = vfs_llseek(file, 0, SEEK_CUR); 2439 } 2440 2441 free_page((unsigned long)(buf.dirent)); 2442 2443 if (host_err) 2444 return nfserrno(host_err); 2445 2446 *offsetp = offset; 2447 return cdp->err; 2448} 2449 2450/** 2451 * nfsd_readdir - Read entries from a directory 2452 * @rqstp: RPC transaction context 2453 * @fhp: NFS file handle of directory to be read 2454 * @offsetp: OUT: seek offset of final entry that was read 2455 * @cdp: OUT: an eof error value 2456 * @func: entry filler actor 2457 * 2458 * This implementation ignores the NFSv3/4 verifier cookie. 2459 * 2460 * NB: normal system calls hold file->f_pos_lock when calling 2461 * ->iterate_shared and ->llseek, but nfsd_readdir() does not. 2462 * Because the struct file acquired here is not visible to other 2463 * threads, it's internal state does not need mutex protection. 2464 * 2465 * Returns nfs_ok on success, otherwise an nfsstat code is 2466 * returned. 2467 */ 2468__be32 2469nfsd_readdir(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t *offsetp, 2470 struct readdir_cd *cdp, nfsd_filldir_t func) 2471{ 2472 __be32 err; 2473 struct file *file; 2474 loff_t offset = *offsetp; 2475 int may_flags = NFSD_MAY_READ; 2476 2477 err = nfsd_open(rqstp, fhp, S_IFDIR, may_flags, &file); 2478 if (err) 2479 goto out; 2480 2481 if (fhp->fh_64bit_cookies) 2482 file->f_mode |= FMODE_64BITHASH; 2483 else 2484 file->f_mode |= FMODE_32BITHASH; 2485 2486 offset = vfs_llseek(file, offset, SEEK_SET); 2487 if (offset < 0) { 2488 err = nfserrno((int)offset); 2489 goto out_close; 2490 } 2491 2492 err = nfsd_buffered_readdir(file, fhp, func, cdp, offsetp); 2493 2494 if (err == nfserr_eof || err == nfserr_toosmall) 2495 err = nfs_ok; /* can still be found in ->err */ 2496out_close: 2497 nfsd_filp_close(file); 2498out: 2499 return err; 2500} 2501 2502/** 2503 * nfsd_filp_close: close a file synchronously 2504 * @fp: the file to close 2505 * 2506 * nfsd_filp_close() is similar in behaviour to filp_close(). 2507 * The difference is that if this is the final close on the 2508 * file, the that finalisation happens immediately, rather then 2509 * being handed over to a work_queue, as it the case for 2510 * filp_close(). 2511 * When a user-space process closes a file (even when using 2512 * filp_close() the finalisation happens before returning to 2513 * userspace, so it is effectively synchronous. When a kernel thread 2514 * uses file_close(), on the other hand, the handling is completely 2515 * asynchronous. This means that any cost imposed by that finalisation 2516 * is not imposed on the nfsd thread, and nfsd could potentually 2517 * close files more quickly than the work queue finalises the close, 2518 * which would lead to unbounded growth in the queue. 2519 * 2520 * In some contexts is it not safe to synchronously wait for 2521 * close finalisation (see comment for __fput_sync()), but nfsd 2522 * does not match those contexts. In partcilarly it does not, at the 2523 * time that this function is called, hold and locks and no finalisation 2524 * of any file, socket, or device driver would have any cause to wait 2525 * for nfsd to make progress. 2526 */ 2527void nfsd_filp_close(struct file *fp) 2528{ 2529 get_file(fp); 2530 filp_close(fp, NULL); 2531 __fput_sync(fp); 2532} 2533 2534/* 2535 * Get file system stats 2536 * N.B. After this call fhp needs an fh_put 2537 */ 2538__be32 2539nfsd_statfs(struct svc_rqst *rqstp, struct svc_fh *fhp, struct kstatfs *stat, int access) 2540{ 2541 __be32 err; 2542 2543 trace_nfsd_vfs_statfs(rqstp, fhp); 2544 2545 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP | access); 2546 if (!err) { 2547 struct path path = { 2548 .mnt = fhp->fh_export->ex_path.mnt, 2549 .dentry = fhp->fh_dentry, 2550 }; 2551 if (vfs_statfs(&path, stat)) 2552 err = nfserr_io; 2553 } 2554 return err; 2555} 2556 2557static int exp_rdonly(struct svc_cred *cred, struct svc_export *exp) 2558{ 2559 return nfsexp_flags(cred, exp) & NFSEXP_READONLY; 2560} 2561 2562#ifdef CONFIG_NFSD_V4 2563/* 2564 * Helper function to translate error numbers. In the case of xattr operations, 2565 * some error codes need to be translated outside of the standard translations. 2566 * 2567 * ENODATA needs to be translated to nfserr_noxattr. 2568 * E2BIG to nfserr_xattr2big. 2569 * 2570 * Additionally, vfs_listxattr can return -ERANGE. This means that the 2571 * file has too many extended attributes to retrieve inside an 2572 * XATTR_LIST_MAX sized buffer. This is a bug in the xattr implementation: 2573 * filesystems will allow the adding of extended attributes until they hit 2574 * their own internal limit. This limit may be larger than XATTR_LIST_MAX. 2575 * So, at that point, the attributes are present and valid, but can't 2576 * be retrieved using listxattr, since the upper level xattr code enforces 2577 * the XATTR_LIST_MAX limit. 2578 * 2579 * This bug means that we need to deal with listxattr returning -ERANGE. The 2580 * best mapping is to return TOOSMALL. 2581 */ 2582static __be32 2583nfsd_xattr_errno(int err) 2584{ 2585 switch (err) { 2586 case -ENODATA: 2587 return nfserr_noxattr; 2588 case -E2BIG: 2589 return nfserr_xattr2big; 2590 case -ERANGE: 2591 return nfserr_toosmall; 2592 } 2593 return nfserrno(err); 2594} 2595 2596/* 2597 * Retrieve the specified user extended attribute. To avoid always 2598 * having to allocate the maximum size (since we are not getting 2599 * a maximum size from the RPC), do a probe + alloc. Hold a reader 2600 * lock on i_rwsem to prevent the extended attribute from changing 2601 * size while we're doing this. 2602 */ 2603__be32 2604nfsd_getxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name, 2605 void **bufp, int *lenp) 2606{ 2607 ssize_t len; 2608 __be32 err; 2609 char *buf; 2610 struct inode *inode; 2611 struct dentry *dentry; 2612 2613 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_READ); 2614 if (err) 2615 return err; 2616 2617 err = nfs_ok; 2618 dentry = fhp->fh_dentry; 2619 inode = d_inode(dentry); 2620 2621 inode_lock_shared(inode); 2622 2623 len = vfs_getxattr(&nop_mnt_idmap, dentry, name, NULL, 0); 2624 2625 /* 2626 * Zero-length attribute, just return. 2627 */ 2628 if (len == 0) { 2629 *bufp = NULL; 2630 *lenp = 0; 2631 goto out; 2632 } 2633 2634 if (len < 0) { 2635 err = nfsd_xattr_errno(len); 2636 goto out; 2637 } 2638 2639 if (len > *lenp) { 2640 err = nfserr_toosmall; 2641 goto out; 2642 } 2643 2644 buf = kvmalloc(len, GFP_KERNEL); 2645 if (buf == NULL) { 2646 err = nfserr_jukebox; 2647 goto out; 2648 } 2649 2650 len = vfs_getxattr(&nop_mnt_idmap, dentry, name, buf, len); 2651 if (len <= 0) { 2652 kvfree(buf); 2653 buf = NULL; 2654 err = nfsd_xattr_errno(len); 2655 } 2656 2657 *lenp = len; 2658 *bufp = buf; 2659 2660out: 2661 inode_unlock_shared(inode); 2662 2663 return err; 2664} 2665 2666/* 2667 * Retrieve the xattr names. Since we can't know how many are 2668 * user extended attributes, we must get all attributes here, 2669 * and have the XDR encode filter out the "user." ones. 2670 * 2671 * While this could always just allocate an XATTR_LIST_MAX 2672 * buffer, that's a waste, so do a probe + allocate. To 2673 * avoid any changes between the probe and allocate, wrap 2674 * this in inode_lock. 2675 */ 2676__be32 2677nfsd_listxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char **bufp, 2678 int *lenp) 2679{ 2680 ssize_t len; 2681 __be32 err; 2682 char *buf; 2683 struct inode *inode; 2684 struct dentry *dentry; 2685 2686 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_READ); 2687 if (err) 2688 return err; 2689 2690 dentry = fhp->fh_dentry; 2691 inode = d_inode(dentry); 2692 *lenp = 0; 2693 2694 inode_lock_shared(inode); 2695 2696 len = vfs_listxattr(dentry, NULL, 0); 2697 if (len <= 0) { 2698 err = nfsd_xattr_errno(len); 2699 goto out; 2700 } 2701 2702 if (len > XATTR_LIST_MAX) { 2703 err = nfserr_xattr2big; 2704 goto out; 2705 } 2706 2707 buf = kvmalloc(len, GFP_KERNEL); 2708 if (buf == NULL) { 2709 err = nfserr_jukebox; 2710 goto out; 2711 } 2712 2713 len = vfs_listxattr(dentry, buf, len); 2714 if (len <= 0) { 2715 kvfree(buf); 2716 err = nfsd_xattr_errno(len); 2717 goto out; 2718 } 2719 2720 *lenp = len; 2721 *bufp = buf; 2722 2723 err = nfs_ok; 2724out: 2725 inode_unlock_shared(inode); 2726 2727 return err; 2728} 2729 2730/** 2731 * nfsd_removexattr - Remove an extended attribute 2732 * @rqstp: RPC transaction being executed 2733 * @fhp: NFS filehandle of object with xattr to remove 2734 * @name: name of xattr to remove (NUL-terminate) 2735 * 2736 * Pass in a NULL pointer for delegated_inode, and let the client deal 2737 * with NFS4ERR_DELAY (same as with e.g. setattr and remove). 2738 * 2739 * Returns nfs_ok on success, or an nfsstat in network byte order. 2740 */ 2741__be32 2742nfsd_removexattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name) 2743{ 2744 __be32 err; 2745 int ret; 2746 2747 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_WRITE); 2748 if (err) 2749 return err; 2750 2751 ret = fh_want_write(fhp); 2752 if (ret) 2753 return nfserrno(ret); 2754 2755 inode_lock(fhp->fh_dentry->d_inode); 2756 err = fh_fill_pre_attrs(fhp); 2757 if (err != nfs_ok) 2758 goto out_unlock; 2759 ret = __vfs_removexattr_locked(&nop_mnt_idmap, fhp->fh_dentry, 2760 name, NULL); 2761 err = nfsd_xattr_errno(ret); 2762 fh_fill_post_attrs(fhp); 2763out_unlock: 2764 inode_unlock(fhp->fh_dentry->d_inode); 2765 fh_drop_write(fhp); 2766 2767 return err; 2768} 2769 2770__be32 2771nfsd_setxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name, 2772 void *buf, u32 len, u32 flags) 2773{ 2774 __be32 err; 2775 int ret; 2776 2777 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_WRITE); 2778 if (err) 2779 return err; 2780 2781 ret = fh_want_write(fhp); 2782 if (ret) 2783 return nfserrno(ret); 2784 inode_lock(fhp->fh_dentry->d_inode); 2785 err = fh_fill_pre_attrs(fhp); 2786 if (err != nfs_ok) 2787 goto out_unlock; 2788 ret = __vfs_setxattr_locked(&nop_mnt_idmap, fhp->fh_dentry, 2789 name, buf, len, flags, NULL); 2790 fh_fill_post_attrs(fhp); 2791 err = nfsd_xattr_errno(ret); 2792out_unlock: 2793 inode_unlock(fhp->fh_dentry->d_inode); 2794 fh_drop_write(fhp); 2795 return err; 2796} 2797#endif 2798 2799/* 2800 * Check for a user's access permissions to this inode. 2801 */ 2802__be32 2803nfsd_permission(struct svc_cred *cred, struct svc_export *exp, 2804 struct dentry *dentry, int acc) 2805{ 2806 struct inode *inode = d_inode(dentry); 2807 int err; 2808 2809 if ((acc & NFSD_MAY_MASK) == NFSD_MAY_NOP) 2810 return 0; 2811#if 0 2812 dprintk("nfsd: permission 0x%x%s%s%s%s%s%s%s mode 0%o%s%s%s\n", 2813 acc, 2814 (acc & NFSD_MAY_READ)? " read" : "", 2815 (acc & NFSD_MAY_WRITE)? " write" : "", 2816 (acc & NFSD_MAY_EXEC)? " exec" : "", 2817 (acc & NFSD_MAY_SATTR)? " sattr" : "", 2818 (acc & NFSD_MAY_TRUNC)? " trunc" : "", 2819 (acc & NFSD_MAY_NLM)? " nlm" : "", 2820 (acc & NFSD_MAY_OWNER_OVERRIDE)? " owneroverride" : "", 2821 inode->i_mode, 2822 IS_IMMUTABLE(inode)? " immut" : "", 2823 IS_APPEND(inode)? " append" : "", 2824 __mnt_is_readonly(exp->ex_path.mnt)? " ro" : ""); 2825 dprintk(" owner %d/%d user %d/%d\n", 2826 inode->i_uid, inode->i_gid, current_fsuid(), current_fsgid()); 2827#endif 2828 2829 /* Normally we reject any write/sattr etc access on a read-only file 2830 * system. But if it is IRIX doing check on write-access for a 2831 * device special file, we ignore rofs. 2832 */ 2833 if (!(acc & NFSD_MAY_LOCAL_ACCESS)) 2834 if (acc & (NFSD_MAY_WRITE | NFSD_MAY_SATTR | NFSD_MAY_TRUNC)) { 2835 if (exp_rdonly(cred, exp) || 2836 __mnt_is_readonly(exp->ex_path.mnt)) 2837 return nfserr_rofs; 2838 if (/* (acc & NFSD_MAY_WRITE) && */ IS_IMMUTABLE(inode)) 2839 return nfserr_perm; 2840 } 2841 if ((acc & NFSD_MAY_TRUNC) && IS_APPEND(inode)) 2842 return nfserr_perm; 2843 2844 /* 2845 * The file owner always gets access permission for accesses that 2846 * would normally be checked at open time. This is to make 2847 * file access work even when the client has done a fchmod(fd, 0). 2848 * 2849 * However, `cp foo bar' should fail nevertheless when bar is 2850 * readonly. A sensible way to do this might be to reject all 2851 * attempts to truncate a read-only file, because a creat() call 2852 * always implies file truncation. 2853 * ... but this isn't really fair. A process may reasonably call 2854 * ftruncate on an open file descriptor on a file with perm 000. 2855 * We must trust the client to do permission checking - using "ACCESS" 2856 * with NFSv3. 2857 */ 2858 if ((acc & NFSD_MAY_OWNER_OVERRIDE) && 2859 uid_eq(inode->i_uid, current_fsuid())) 2860 return 0; 2861 2862 /* This assumes NFSD_MAY_{READ,WRITE,EXEC} == MAY_{READ,WRITE,EXEC} */ 2863 err = inode_permission(&nop_mnt_idmap, inode, 2864 acc & (MAY_READ | MAY_WRITE | MAY_EXEC)); 2865 2866 /* Allow read access to binaries even when mode 111 */ 2867 if (err == -EACCES && S_ISREG(inode->i_mode) && 2868 (((acc & NFSD_MAY_MASK) == NFSD_MAY_READ) && 2869 (acc & (NFSD_MAY_OWNER_OVERRIDE | NFSD_MAY_READ_IF_EXEC)))) 2870 err = inode_permission(&nop_mnt_idmap, inode, MAY_EXEC); 2871 2872 return err? nfserrno(err) : 0; 2873}
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