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/ima.h> 29 #include <linux/pagemap.h> 30 #include <linux/slab.h> 31 #include <linux/uaccess.h> 32 #include <linux/exportfs.h> 33 #include <linux/writeback.h> 34 #include <linux/security.h> 35 36 #include "xdr3.h" 37 38 #ifdef CONFIG_NFSD_V4 39 #include "../internal.h" 40 #include "acl.h" 41 #include "idmap.h" 42 #include "xdr4.h" 43 #endif /* CONFIG_NFSD_V4 */ 44 45 #include "nfsd.h" 46 #include "vfs.h" 47 #include "filecache.h" 48 #include "trace.h" 49 50 #define NFSDDBG_FACILITY NFSDDBG_FILEOP 51 52 /** 53 * nfserrno - Map Linux errnos to NFS errnos 54 * @errno: POSIX(-ish) error code to be mapped 55 * 56 * Returns the appropriate (net-endian) nfserr_* (or nfs_ok if errno is 0). If 57 * it's an error we don't expect, log it once and return nfserr_io. 58 */ 59 __be32 60 nfserrno (int errno) 61 { 62 static struct { 63 __be32 nfserr; 64 int syserr; 65 } nfs_errtbl[] = { 66 { nfs_ok, 0 }, 67 { nfserr_perm, -EPERM }, 68 { nfserr_noent, -ENOENT }, 69 { nfserr_io, -EIO }, 70 { nfserr_nxio, -ENXIO }, 71 { nfserr_fbig, -E2BIG }, 72 { nfserr_stale, -EBADF }, 73 { nfserr_acces, -EACCES }, 74 { nfserr_exist, -EEXIST }, 75 { nfserr_xdev, -EXDEV }, 76 { nfserr_mlink, -EMLINK }, 77 { nfserr_nodev, -ENODEV }, 78 { nfserr_notdir, -ENOTDIR }, 79 { nfserr_isdir, -EISDIR }, 80 { nfserr_inval, -EINVAL }, 81 { nfserr_fbig, -EFBIG }, 82 { nfserr_nospc, -ENOSPC }, 83 { nfserr_rofs, -EROFS }, 84 { nfserr_mlink, -EMLINK }, 85 { nfserr_nametoolong, -ENAMETOOLONG }, 86 { nfserr_notempty, -ENOTEMPTY }, 87 { nfserr_dquot, -EDQUOT }, 88 { nfserr_stale, -ESTALE }, 89 { nfserr_jukebox, -ETIMEDOUT }, 90 { nfserr_jukebox, -ERESTARTSYS }, 91 { nfserr_jukebox, -EAGAIN }, 92 { nfserr_jukebox, -EWOULDBLOCK }, 93 { nfserr_jukebox, -ENOMEM }, 94 { nfserr_io, -ETXTBSY }, 95 { nfserr_notsupp, -EOPNOTSUPP }, 96 { nfserr_toosmall, -ETOOSMALL }, 97 { nfserr_serverfault, -ESERVERFAULT }, 98 { nfserr_serverfault, -ENFILE }, 99 { nfserr_io, -EREMOTEIO }, 100 { nfserr_stale, -EOPENSTALE }, 101 { nfserr_io, -EUCLEAN }, 102 { nfserr_perm, -ENOKEY }, 103 { nfserr_no_grace, -ENOGRACE}, 104 }; 105 int i; 106 107 for (i = 0; i < ARRAY_SIZE(nfs_errtbl); i++) { 108 if (nfs_errtbl[i].syserr == errno) 109 return nfs_errtbl[i].nfserr; 110 } 111 WARN_ONCE(1, "nfsd: non-standard errno: %d\n", errno); 112 return nfserr_io; 113 } 114 115 /* 116 * Called from nfsd_lookup and encode_dirent. Check if we have crossed 117 * a mount point. 118 * Returns -EAGAIN or -ETIMEDOUT leaving *dpp and *expp unchanged, 119 * or nfs_ok having possibly changed *dpp and *expp 120 */ 121 int 122 nfsd_cross_mnt(struct svc_rqst *rqstp, struct dentry **dpp, 123 struct svc_export **expp) 124 { 125 struct svc_export *exp = *expp, *exp2 = NULL; 126 struct dentry *dentry = *dpp; 127 struct path path = {.mnt = mntget(exp->ex_path.mnt), 128 .dentry = dget(dentry)}; 129 unsigned int follow_flags = 0; 130 int err = 0; 131 132 if (exp->ex_flags & NFSEXP_CROSSMOUNT) 133 follow_flags = LOOKUP_AUTOMOUNT; 134 135 err = follow_down(&path, follow_flags); 136 if (err < 0) 137 goto out; 138 if (path.mnt == exp->ex_path.mnt && path.dentry == dentry && 139 nfsd_mountpoint(dentry, exp) == 2) { 140 /* This is only a mountpoint in some other namespace */ 141 path_put(&path); 142 goto out; 143 } 144 145 exp2 = rqst_exp_get_by_name(rqstp, &path); 146 if (IS_ERR(exp2)) { 147 err = PTR_ERR(exp2); 148 /* 149 * We normally allow NFS clients to continue 150 * "underneath" a mountpoint that is not exported. 151 * The exception is V4ROOT, where no traversal is ever 152 * allowed without an explicit export of the new 153 * directory. 154 */ 155 if (err == -ENOENT && !(exp->ex_flags & NFSEXP_V4ROOT)) 156 err = 0; 157 path_put(&path); 158 goto out; 159 } 160 if (nfsd_v4client(rqstp) || 161 (exp->ex_flags & NFSEXP_CROSSMOUNT) || EX_NOHIDE(exp2)) { 162 /* successfully crossed mount point */ 163 /* 164 * This is subtle: path.dentry is *not* on path.mnt 165 * at this point. The only reason we are safe is that 166 * original mnt is pinned down by exp, so we should 167 * put path *before* putting exp 168 */ 169 *dpp = path.dentry; 170 path.dentry = dentry; 171 *expp = exp2; 172 exp2 = exp; 173 } 174 path_put(&path); 175 exp_put(exp2); 176 out: 177 return err; 178 } 179 180 static void follow_to_parent(struct path *path) 181 { 182 struct dentry *dp; 183 184 while (path->dentry == path->mnt->mnt_root && follow_up(path)) 185 ; 186 dp = dget_parent(path->dentry); 187 dput(path->dentry); 188 path->dentry = dp; 189 } 190 191 static int nfsd_lookup_parent(struct svc_rqst *rqstp, struct dentry *dparent, struct svc_export **exp, struct dentry **dentryp) 192 { 193 struct svc_export *exp2; 194 struct path path = {.mnt = mntget((*exp)->ex_path.mnt), 195 .dentry = dget(dparent)}; 196 197 follow_to_parent(&path); 198 199 exp2 = rqst_exp_parent(rqstp, &path); 200 if (PTR_ERR(exp2) == -ENOENT) { 201 *dentryp = dget(dparent); 202 } else if (IS_ERR(exp2)) { 203 path_put(&path); 204 return PTR_ERR(exp2); 205 } else { 206 *dentryp = dget(path.dentry); 207 exp_put(*exp); 208 *exp = exp2; 209 } 210 path_put(&path); 211 return 0; 212 } 213 214 /* 215 * For nfsd purposes, we treat V4ROOT exports as though there was an 216 * export at *every* directory. 217 * We return: 218 * '1' if this dentry *must* be an export point, 219 * '2' if it might be, if there is really a mount here, and 220 * '0' if there is no chance of an export point here. 221 */ 222 int nfsd_mountpoint(struct dentry *dentry, struct svc_export *exp) 223 { 224 if (!d_inode(dentry)) 225 return 0; 226 if (exp->ex_flags & NFSEXP_V4ROOT) 227 return 1; 228 if (nfsd4_is_junction(dentry)) 229 return 1; 230 if (d_managed(dentry)) 231 /* 232 * Might only be a mountpoint in a different namespace, 233 * but we need to check. 234 */ 235 return 2; 236 return 0; 237 } 238 239 __be32 240 nfsd_lookup_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp, 241 const char *name, unsigned int len, 242 struct svc_export **exp_ret, struct dentry **dentry_ret) 243 { 244 struct svc_export *exp; 245 struct dentry *dparent; 246 struct dentry *dentry; 247 int host_err; 248 249 dprintk("nfsd: nfsd_lookup(fh %s, %.*s)\n", SVCFH_fmt(fhp), len,name); 250 251 dparent = fhp->fh_dentry; 252 exp = exp_get(fhp->fh_export); 253 254 /* Lookup the name, but don't follow links */ 255 if (isdotent(name, len)) { 256 if (len==1) 257 dentry = dget(dparent); 258 else if (dparent != exp->ex_path.dentry) 259 dentry = dget_parent(dparent); 260 else if (!EX_NOHIDE(exp) && !nfsd_v4client(rqstp)) 261 dentry = dget(dparent); /* .. == . just like at / */ 262 else { 263 /* checking mountpoint crossing is very different when stepping up */ 264 host_err = nfsd_lookup_parent(rqstp, dparent, &exp, &dentry); 265 if (host_err) 266 goto out_nfserr; 267 } 268 } else { 269 dentry = lookup_one_len_unlocked(name, dparent, len); 270 host_err = PTR_ERR(dentry); 271 if (IS_ERR(dentry)) 272 goto out_nfserr; 273 if (nfsd_mountpoint(dentry, exp)) { 274 host_err = nfsd_cross_mnt(rqstp, &dentry, &exp); 275 if (host_err) { 276 dput(dentry); 277 goto out_nfserr; 278 } 279 } 280 } 281 *dentry_ret = dentry; 282 *exp_ret = exp; 283 return 0; 284 285 out_nfserr: 286 exp_put(exp); 287 return nfserrno(host_err); 288 } 289 290 /** 291 * nfsd_lookup - look up a single path component for nfsd 292 * 293 * @rqstp: the request context 294 * @fhp: the file handle of the directory 295 * @name: the component name, or %NULL to look up parent 296 * @len: length of name to examine 297 * @resfh: pointer to pre-initialised filehandle to hold result. 298 * 299 * Look up one component of a pathname. 300 * N.B. After this call _both_ fhp and resfh need an fh_put 301 * 302 * If the lookup would cross a mountpoint, and the mounted filesystem 303 * is exported to the client with NFSEXP_NOHIDE, then the lookup is 304 * accepted as it stands and the mounted directory is 305 * returned. Otherwise the covered directory is returned. 306 * NOTE: this mountpoint crossing is not supported properly by all 307 * clients and is explicitly disallowed for NFSv3 308 * 309 */ 310 __be32 311 nfsd_lookup(struct svc_rqst *rqstp, struct svc_fh *fhp, const char *name, 312 unsigned int len, struct svc_fh *resfh) 313 { 314 struct svc_export *exp; 315 struct dentry *dentry; 316 __be32 err; 317 318 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC); 319 if (err) 320 return err; 321 err = nfsd_lookup_dentry(rqstp, fhp, name, len, &exp, &dentry); 322 if (err) 323 return err; 324 err = check_nfsd_access(exp, rqstp); 325 if (err) 326 goto out; 327 /* 328 * Note: we compose the file handle now, but as the 329 * dentry may be negative, it may need to be updated. 330 */ 331 err = fh_compose(resfh, exp, dentry, fhp); 332 if (!err && d_really_is_negative(dentry)) 333 err = nfserr_noent; 334 out: 335 dput(dentry); 336 exp_put(exp); 337 return err; 338 } 339 340 static void 341 commit_reset_write_verifier(struct nfsd_net *nn, struct svc_rqst *rqstp, 342 int err) 343 { 344 switch (err) { 345 case -EAGAIN: 346 case -ESTALE: 347 /* 348 * Neither of these are the result of a problem with 349 * durable storage, so avoid a write verifier reset. 350 */ 351 break; 352 default: 353 nfsd_reset_write_verifier(nn); 354 trace_nfsd_writeverf_reset(nn, rqstp, err); 355 } 356 } 357 358 /* 359 * Commit metadata changes to stable storage. 360 */ 361 static int 362 commit_inode_metadata(struct inode *inode) 363 { 364 const struct export_operations *export_ops = inode->i_sb->s_export_op; 365 366 if (export_ops->commit_metadata) 367 return export_ops->commit_metadata(inode); 368 return sync_inode_metadata(inode, 1); 369 } 370 371 static int 372 commit_metadata(struct svc_fh *fhp) 373 { 374 struct inode *inode = d_inode(fhp->fh_dentry); 375 376 if (!EX_ISSYNC(fhp->fh_export)) 377 return 0; 378 return commit_inode_metadata(inode); 379 } 380 381 /* 382 * Go over the attributes and take care of the small differences between 383 * NFS semantics and what Linux expects. 384 */ 385 static void 386 nfsd_sanitize_attrs(struct inode *inode, struct iattr *iap) 387 { 388 /* Ignore mode updates on symlinks */ 389 if (S_ISLNK(inode->i_mode)) 390 iap->ia_valid &= ~ATTR_MODE; 391 392 /* sanitize the mode change */ 393 if (iap->ia_valid & ATTR_MODE) { 394 iap->ia_mode &= S_IALLUGO; 395 iap->ia_mode |= (inode->i_mode & ~S_IALLUGO); 396 } 397 398 /* Revoke setuid/setgid on chown */ 399 if (!S_ISDIR(inode->i_mode) && 400 ((iap->ia_valid & ATTR_UID) || (iap->ia_valid & ATTR_GID))) { 401 iap->ia_valid |= ATTR_KILL_PRIV; 402 if (iap->ia_valid & ATTR_MODE) { 403 /* we're setting mode too, just clear the s*id bits */ 404 iap->ia_mode &= ~S_ISUID; 405 if (iap->ia_mode & S_IXGRP) 406 iap->ia_mode &= ~S_ISGID; 407 } else { 408 /* set ATTR_KILL_* bits and let VFS handle it */ 409 iap->ia_valid |= ATTR_KILL_SUID; 410 iap->ia_valid |= 411 setattr_should_drop_sgid(&nop_mnt_idmap, inode); 412 } 413 } 414 } 415 416 static __be32 417 nfsd_get_write_access(struct svc_rqst *rqstp, struct svc_fh *fhp, 418 struct iattr *iap) 419 { 420 struct inode *inode = d_inode(fhp->fh_dentry); 421 422 if (iap->ia_size < inode->i_size) { 423 __be32 err; 424 425 err = nfsd_permission(rqstp, fhp->fh_export, fhp->fh_dentry, 426 NFSD_MAY_TRUNC | NFSD_MAY_OWNER_OVERRIDE); 427 if (err) 428 return err; 429 } 430 return nfserrno(get_write_access(inode)); 431 } 432 433 static int __nfsd_setattr(struct dentry *dentry, struct iattr *iap) 434 { 435 int host_err; 436 437 if (iap->ia_valid & ATTR_SIZE) { 438 /* 439 * RFC5661, Section 18.30.4: 440 * Changing the size of a file with SETATTR indirectly 441 * changes the time_modify and change attributes. 442 * 443 * (and similar for the older RFCs) 444 */ 445 struct iattr size_attr = { 446 .ia_valid = ATTR_SIZE | ATTR_CTIME | ATTR_MTIME, 447 .ia_size = iap->ia_size, 448 }; 449 450 if (iap->ia_size < 0) 451 return -EFBIG; 452 453 host_err = notify_change(&nop_mnt_idmap, dentry, &size_attr, NULL); 454 if (host_err) 455 return host_err; 456 iap->ia_valid &= ~ATTR_SIZE; 457 458 /* 459 * Avoid the additional setattr call below if the only other 460 * attribute that the client sends is the mtime, as we update 461 * it as part of the size change above. 462 */ 463 if ((iap->ia_valid & ~ATTR_MTIME) == 0) 464 return 0; 465 } 466 467 if (!iap->ia_valid) 468 return 0; 469 470 iap->ia_valid |= ATTR_CTIME; 471 return notify_change(&nop_mnt_idmap, dentry, iap, NULL); 472 } 473 474 /** 475 * nfsd_setattr - Set various file attributes. 476 * @rqstp: controlling RPC transaction 477 * @fhp: filehandle of target 478 * @attr: attributes to set 479 * @check_guard: set to 1 if guardtime is a valid timestamp 480 * @guardtime: do not act if ctime.tv_sec does not match this timestamp 481 * 482 * This call may adjust the contents of @attr (in particular, this 483 * call may change the bits in the na_iattr.ia_valid field). 484 * 485 * Returns nfs_ok on success, otherwise an NFS status code is 486 * returned. Caller must release @fhp by calling fh_put in either 487 * case. 488 */ 489 __be32 490 nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, 491 struct nfsd_attrs *attr, 492 int check_guard, time64_t guardtime) 493 { 494 struct dentry *dentry; 495 struct inode *inode; 496 struct iattr *iap = attr->na_iattr; 497 int accmode = NFSD_MAY_SATTR; 498 umode_t ftype = 0; 499 __be32 err; 500 int host_err = 0; 501 bool get_write_count; 502 bool size_change = (iap->ia_valid & ATTR_SIZE); 503 int retries; 504 505 if (iap->ia_valid & ATTR_SIZE) { 506 accmode |= NFSD_MAY_WRITE|NFSD_MAY_OWNER_OVERRIDE; 507 ftype = S_IFREG; 508 } 509 510 /* 511 * If utimes(2) and friends are called with times not NULL, we should 512 * not set NFSD_MAY_WRITE bit. Otherwise fh_verify->nfsd_permission 513 * will return EACCES, when the caller's effective UID does not match 514 * the owner of the file, and the caller is not privileged. In this 515 * situation, we should return EPERM(notify_change will return this). 516 */ 517 if (iap->ia_valid & (ATTR_ATIME | ATTR_MTIME)) { 518 accmode |= NFSD_MAY_OWNER_OVERRIDE; 519 if (!(iap->ia_valid & (ATTR_ATIME_SET | ATTR_MTIME_SET))) 520 accmode |= NFSD_MAY_WRITE; 521 } 522 523 /* Callers that do fh_verify should do the fh_want_write: */ 524 get_write_count = !fhp->fh_dentry; 525 526 /* Get inode */ 527 err = fh_verify(rqstp, fhp, ftype, accmode); 528 if (err) 529 return err; 530 if (get_write_count) { 531 host_err = fh_want_write(fhp); 532 if (host_err) 533 goto out; 534 } 535 536 dentry = fhp->fh_dentry; 537 inode = d_inode(dentry); 538 539 nfsd_sanitize_attrs(inode, iap); 540 541 if (check_guard && guardtime != inode_get_ctime_sec(inode)) 542 return nfserr_notsync; 543 544 /* 545 * The size case is special, it changes the file in addition to the 546 * attributes, and file systems don't expect it to be mixed with 547 * "random" attribute changes. We thus split out the size change 548 * into a separate call to ->setattr, and do the rest as a separate 549 * setattr call. 550 */ 551 if (size_change) { 552 err = nfsd_get_write_access(rqstp, fhp, iap); 553 if (err) 554 return err; 555 } 556 557 inode_lock(inode); 558 err = fh_fill_pre_attrs(fhp); 559 if (err) 560 goto out_unlock; 561 for (retries = 1;;) { 562 struct iattr attrs; 563 564 /* 565 * notify_change() can alter its iattr argument, making 566 * @iap unsuitable for submission multiple times. Make a 567 * copy for every loop iteration. 568 */ 569 attrs = *iap; 570 host_err = __nfsd_setattr(dentry, &attrs); 571 if (host_err != -EAGAIN || !retries--) 572 break; 573 if (!nfsd_wait_for_delegreturn(rqstp, inode)) 574 break; 575 } 576 if (attr->na_seclabel && attr->na_seclabel->len) 577 attr->na_labelerr = security_inode_setsecctx(dentry, 578 attr->na_seclabel->data, attr->na_seclabel->len); 579 if (IS_ENABLED(CONFIG_FS_POSIX_ACL) && attr->na_pacl) 580 attr->na_aclerr = set_posix_acl(&nop_mnt_idmap, 581 dentry, ACL_TYPE_ACCESS, 582 attr->na_pacl); 583 if (IS_ENABLED(CONFIG_FS_POSIX_ACL) && 584 !attr->na_aclerr && attr->na_dpacl && S_ISDIR(inode->i_mode)) 585 attr->na_aclerr = set_posix_acl(&nop_mnt_idmap, 586 dentry, ACL_TYPE_DEFAULT, 587 attr->na_dpacl); 588 fh_fill_post_attrs(fhp); 589 out_unlock: 590 inode_unlock(inode); 591 if (size_change) 592 put_write_access(inode); 593 out: 594 if (!host_err) 595 host_err = commit_metadata(fhp); 596 return err != 0 ? err : nfserrno(host_err); 597 } 598 599 #if defined(CONFIG_NFSD_V4) 600 /* 601 * NFS junction information is stored in an extended attribute. 602 */ 603 #define NFSD_JUNCTION_XATTR_NAME XATTR_TRUSTED_PREFIX "junction.nfs" 604 605 /** 606 * nfsd4_is_junction - Test if an object could be an NFS junction 607 * 608 * @dentry: object to test 609 * 610 * Returns 1 if "dentry" appears to contain NFS junction information. 611 * Otherwise 0 is returned. 612 */ 613 int nfsd4_is_junction(struct dentry *dentry) 614 { 615 struct inode *inode = d_inode(dentry); 616 617 if (inode == NULL) 618 return 0; 619 if (inode->i_mode & S_IXUGO) 620 return 0; 621 if (!(inode->i_mode & S_ISVTX)) 622 return 0; 623 if (vfs_getxattr(&nop_mnt_idmap, dentry, NFSD_JUNCTION_XATTR_NAME, 624 NULL, 0) <= 0) 625 return 0; 626 return 1; 627 } 628 629 static struct nfsd4_compound_state *nfsd4_get_cstate(struct svc_rqst *rqstp) 630 { 631 return &((struct nfsd4_compoundres *)rqstp->rq_resp)->cstate; 632 } 633 634 __be32 nfsd4_clone_file_range(struct svc_rqst *rqstp, 635 struct nfsd_file *nf_src, u64 src_pos, 636 struct nfsd_file *nf_dst, u64 dst_pos, 637 u64 count, bool sync) 638 { 639 struct file *src = nf_src->nf_file; 640 struct file *dst = nf_dst->nf_file; 641 errseq_t since; 642 loff_t cloned; 643 __be32 ret = 0; 644 645 since = READ_ONCE(dst->f_wb_err); 646 cloned = vfs_clone_file_range(src, src_pos, dst, dst_pos, count, 0); 647 if (cloned < 0) { 648 ret = nfserrno(cloned); 649 goto out_err; 650 } 651 if (count && cloned != count) { 652 ret = nfserrno(-EINVAL); 653 goto out_err; 654 } 655 if (sync) { 656 loff_t dst_end = count ? dst_pos + count - 1 : LLONG_MAX; 657 int status = vfs_fsync_range(dst, dst_pos, dst_end, 0); 658 659 if (!status) 660 status = filemap_check_wb_err(dst->f_mapping, since); 661 if (!status) 662 status = commit_inode_metadata(file_inode(src)); 663 if (status < 0) { 664 struct nfsd_net *nn = net_generic(nf_dst->nf_net, 665 nfsd_net_id); 666 667 trace_nfsd_clone_file_range_err(rqstp, 668 &nfsd4_get_cstate(rqstp)->save_fh, 669 src_pos, 670 &nfsd4_get_cstate(rqstp)->current_fh, 671 dst_pos, 672 count, status); 673 commit_reset_write_verifier(nn, rqstp, status); 674 ret = nfserrno(status); 675 } 676 } 677 out_err: 678 return ret; 679 } 680 681 ssize_t nfsd_copy_file_range(struct file *src, u64 src_pos, struct file *dst, 682 u64 dst_pos, u64 count) 683 { 684 ssize_t ret; 685 686 /* 687 * Limit copy to 4MB to prevent indefinitely blocking an nfsd 688 * thread and client rpc slot. The choice of 4MB is somewhat 689 * arbitrary. We might instead base this on r/wsize, or make it 690 * tunable, or use a time instead of a byte limit, or implement 691 * asynchronous copy. In theory a client could also recognize a 692 * limit like this and pipeline multiple COPY requests. 693 */ 694 count = min_t(u64, count, 1 << 22); 695 ret = vfs_copy_file_range(src, src_pos, dst, dst_pos, count, 0); 696 697 if (ret == -EOPNOTSUPP || ret == -EXDEV) 698 ret = vfs_copy_file_range(src, src_pos, dst, dst_pos, count, 699 COPY_FILE_SPLICE); 700 return ret; 701 } 702 703 __be32 nfsd4_vfs_fallocate(struct svc_rqst *rqstp, struct svc_fh *fhp, 704 struct file *file, loff_t offset, loff_t len, 705 int flags) 706 { 707 int error; 708 709 if (!S_ISREG(file_inode(file)->i_mode)) 710 return nfserr_inval; 711 712 error = vfs_fallocate(file, flags, offset, len); 713 if (!error) 714 error = commit_metadata(fhp); 715 716 return nfserrno(error); 717 } 718 #endif /* defined(CONFIG_NFSD_V4) */ 719 720 /* 721 * Check server access rights to a file system object 722 */ 723 struct accessmap { 724 u32 access; 725 int how; 726 }; 727 static struct accessmap nfs3_regaccess[] = { 728 { NFS3_ACCESS_READ, NFSD_MAY_READ }, 729 { NFS3_ACCESS_EXECUTE, NFSD_MAY_EXEC }, 730 { NFS3_ACCESS_MODIFY, NFSD_MAY_WRITE|NFSD_MAY_TRUNC }, 731 { NFS3_ACCESS_EXTEND, NFSD_MAY_WRITE }, 732 733 #ifdef CONFIG_NFSD_V4 734 { NFS4_ACCESS_XAREAD, NFSD_MAY_READ }, 735 { NFS4_ACCESS_XAWRITE, NFSD_MAY_WRITE }, 736 { NFS4_ACCESS_XALIST, NFSD_MAY_READ }, 737 #endif 738 739 { 0, 0 } 740 }; 741 742 static struct accessmap nfs3_diraccess[] = { 743 { NFS3_ACCESS_READ, NFSD_MAY_READ }, 744 { NFS3_ACCESS_LOOKUP, NFSD_MAY_EXEC }, 745 { NFS3_ACCESS_MODIFY, NFSD_MAY_EXEC|NFSD_MAY_WRITE|NFSD_MAY_TRUNC}, 746 { NFS3_ACCESS_EXTEND, NFSD_MAY_EXEC|NFSD_MAY_WRITE }, 747 { NFS3_ACCESS_DELETE, NFSD_MAY_REMOVE }, 748 749 #ifdef CONFIG_NFSD_V4 750 { NFS4_ACCESS_XAREAD, NFSD_MAY_READ }, 751 { NFS4_ACCESS_XAWRITE, NFSD_MAY_WRITE }, 752 { NFS4_ACCESS_XALIST, NFSD_MAY_READ }, 753 #endif 754 755 { 0, 0 } 756 }; 757 758 static struct accessmap nfs3_anyaccess[] = { 759 /* Some clients - Solaris 2.6 at least, make an access call 760 * to the server to check for access for things like /dev/null 761 * (which really, the server doesn't care about). So 762 * We provide simple access checking for them, looking 763 * mainly at mode bits, and we make sure to ignore read-only 764 * filesystem checks 765 */ 766 { NFS3_ACCESS_READ, NFSD_MAY_READ }, 767 { NFS3_ACCESS_EXECUTE, NFSD_MAY_EXEC }, 768 { NFS3_ACCESS_MODIFY, NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS }, 769 { NFS3_ACCESS_EXTEND, NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS }, 770 771 { 0, 0 } 772 }; 773 774 __be32 775 nfsd_access(struct svc_rqst *rqstp, struct svc_fh *fhp, u32 *access, u32 *supported) 776 { 777 struct accessmap *map; 778 struct svc_export *export; 779 struct dentry *dentry; 780 u32 query, result = 0, sresult = 0; 781 __be32 error; 782 783 error = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP); 784 if (error) 785 goto out; 786 787 export = fhp->fh_export; 788 dentry = fhp->fh_dentry; 789 790 if (d_is_reg(dentry)) 791 map = nfs3_regaccess; 792 else if (d_is_dir(dentry)) 793 map = nfs3_diraccess; 794 else 795 map = nfs3_anyaccess; 796 797 798 query = *access; 799 for (; map->access; map++) { 800 if (map->access & query) { 801 __be32 err2; 802 803 sresult |= map->access; 804 805 err2 = nfsd_permission(rqstp, export, dentry, map->how); 806 switch (err2) { 807 case nfs_ok: 808 result |= map->access; 809 break; 810 811 /* the following error codes just mean the access was not allowed, 812 * rather than an error occurred */ 813 case nfserr_rofs: 814 case nfserr_acces: 815 case nfserr_perm: 816 /* simply don't "or" in the access bit. */ 817 break; 818 default: 819 error = err2; 820 goto out; 821 } 822 } 823 } 824 *access = result; 825 if (supported) 826 *supported = sresult; 827 828 out: 829 return error; 830 } 831 832 int nfsd_open_break_lease(struct inode *inode, int access) 833 { 834 unsigned int mode; 835 836 if (access & NFSD_MAY_NOT_BREAK_LEASE) 837 return 0; 838 mode = (access & NFSD_MAY_WRITE) ? O_WRONLY : O_RDONLY; 839 return break_lease(inode, mode | O_NONBLOCK); 840 } 841 842 /* 843 * Open an existing file or directory. 844 * The may_flags argument indicates the type of open (read/write/lock) 845 * and additional flags. 846 * N.B. After this call fhp needs an fh_put 847 */ 848 static int 849 __nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type, 850 int may_flags, struct file **filp) 851 { 852 struct path path; 853 struct inode *inode; 854 struct file *file; 855 int flags = O_RDONLY|O_LARGEFILE; 856 int host_err = -EPERM; 857 858 path.mnt = fhp->fh_export->ex_path.mnt; 859 path.dentry = fhp->fh_dentry; 860 inode = d_inode(path.dentry); 861 862 if (IS_APPEND(inode) && (may_flags & NFSD_MAY_WRITE)) 863 goto out; 864 865 if (!inode->i_fop) 866 goto out; 867 868 host_err = nfsd_open_break_lease(inode, may_flags); 869 if (host_err) /* NOMEM or WOULDBLOCK */ 870 goto out; 871 872 if (may_flags & NFSD_MAY_WRITE) { 873 if (may_flags & NFSD_MAY_READ) 874 flags = O_RDWR|O_LARGEFILE; 875 else 876 flags = O_WRONLY|O_LARGEFILE; 877 } 878 879 file = dentry_open(&path, flags, current_cred()); 880 if (IS_ERR(file)) { 881 host_err = PTR_ERR(file); 882 goto out; 883 } 884 885 host_err = ima_file_check(file, may_flags); 886 if (host_err) { 887 fput(file); 888 goto out; 889 } 890 891 if (may_flags & NFSD_MAY_64BIT_COOKIE) 892 file->f_mode |= FMODE_64BITHASH; 893 else 894 file->f_mode |= FMODE_32BITHASH; 895 896 *filp = file; 897 out: 898 return host_err; 899 } 900 901 __be32 902 nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type, 903 int may_flags, struct file **filp) 904 { 905 __be32 err; 906 int host_err; 907 bool retried = false; 908 909 /* 910 * If we get here, then the client has already done an "open", 911 * and (hopefully) checked permission - so allow OWNER_OVERRIDE 912 * in case a chmod has now revoked permission. 913 * 914 * Arguably we should also allow the owner override for 915 * directories, but we never have and it doesn't seem to have 916 * caused anyone a problem. If we were to change this, note 917 * also that our filldir callbacks would need a variant of 918 * lookup_one_len that doesn't check permissions. 919 */ 920 if (type == S_IFREG) 921 may_flags |= NFSD_MAY_OWNER_OVERRIDE; 922 retry: 923 err = fh_verify(rqstp, fhp, type, may_flags); 924 if (!err) { 925 host_err = __nfsd_open(rqstp, fhp, type, may_flags, filp); 926 if (host_err == -EOPENSTALE && !retried) { 927 retried = true; 928 fh_put(fhp); 929 goto retry; 930 } 931 err = nfserrno(host_err); 932 } 933 return err; 934 } 935 936 /** 937 * nfsd_open_verified - Open a regular file for the filecache 938 * @rqstp: RPC request 939 * @fhp: NFS filehandle of the file to open 940 * @may_flags: internal permission flags 941 * @filp: OUT: open "struct file *" 942 * 943 * Returns zero on success, or a negative errno value. 944 */ 945 int 946 nfsd_open_verified(struct svc_rqst *rqstp, struct svc_fh *fhp, int may_flags, 947 struct file **filp) 948 { 949 return __nfsd_open(rqstp, fhp, S_IFREG, may_flags, filp); 950 } 951 952 /* 953 * Grab and keep cached pages associated with a file in the svc_rqst 954 * so that they can be passed to the network sendmsg routines 955 * directly. They will be released after the sending has completed. 956 * 957 * Return values: Number of bytes consumed, or -EIO if there are no 958 * remaining pages in rqstp->rq_pages. 959 */ 960 static int 961 nfsd_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf, 962 struct splice_desc *sd) 963 { 964 struct svc_rqst *rqstp = sd->u.data; 965 struct page *page = buf->page; // may be a compound one 966 unsigned offset = buf->offset; 967 struct page *last_page; 968 969 last_page = page + (offset + sd->len - 1) / PAGE_SIZE; 970 for (page += offset / PAGE_SIZE; page <= last_page; page++) { 971 /* 972 * Skip page replacement when extending the contents of the 973 * current page. But note that we may get two zero_pages in a 974 * row from shmem. 975 */ 976 if (page == *(rqstp->rq_next_page - 1) && 977 offset_in_page(rqstp->rq_res.page_base + 978 rqstp->rq_res.page_len)) 979 continue; 980 if (unlikely(!svc_rqst_replace_page(rqstp, page))) 981 return -EIO; 982 } 983 if (rqstp->rq_res.page_len == 0) // first call 984 rqstp->rq_res.page_base = offset % PAGE_SIZE; 985 rqstp->rq_res.page_len += sd->len; 986 return sd->len; 987 } 988 989 static int nfsd_direct_splice_actor(struct pipe_inode_info *pipe, 990 struct splice_desc *sd) 991 { 992 return __splice_from_pipe(pipe, sd, nfsd_splice_actor); 993 } 994 995 static u32 nfsd_eof_on_read(struct file *file, loff_t offset, ssize_t len, 996 size_t expected) 997 { 998 if (expected != 0 && len == 0) 999 return 1; 1000 if (offset+len >= i_size_read(file_inode(file))) 1001 return 1; 1002 return 0; 1003 } 1004 1005 static __be32 nfsd_finish_read(struct svc_rqst *rqstp, struct svc_fh *fhp, 1006 struct file *file, loff_t offset, 1007 unsigned long *count, u32 *eof, ssize_t host_err) 1008 { 1009 if (host_err >= 0) { 1010 struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id); 1011 1012 nfsd_stats_io_read_add(nn, fhp->fh_export, host_err); 1013 *eof = nfsd_eof_on_read(file, offset, host_err, *count); 1014 *count = host_err; 1015 fsnotify_access(file); 1016 trace_nfsd_read_io_done(rqstp, fhp, offset, *count); 1017 return 0; 1018 } else { 1019 trace_nfsd_read_err(rqstp, fhp, offset, host_err); 1020 return nfserrno(host_err); 1021 } 1022 } 1023 1024 /** 1025 * nfsd_splice_read - Perform a VFS read using a splice pipe 1026 * @rqstp: RPC transaction context 1027 * @fhp: file handle of file to be read 1028 * @file: opened struct file of file to be read 1029 * @offset: starting byte offset 1030 * @count: IN: requested number of bytes; OUT: number of bytes read 1031 * @eof: OUT: set non-zero if operation reached the end of the file 1032 * 1033 * Returns nfs_ok on success, otherwise an nfserr stat value is 1034 * returned. 1035 */ 1036 __be32 nfsd_splice_read(struct svc_rqst *rqstp, struct svc_fh *fhp, 1037 struct file *file, loff_t offset, unsigned long *count, 1038 u32 *eof) 1039 { 1040 struct splice_desc sd = { 1041 .len = 0, 1042 .total_len = *count, 1043 .pos = offset, 1044 .u.data = rqstp, 1045 }; 1046 ssize_t host_err; 1047 1048 trace_nfsd_read_splice(rqstp, fhp, offset, *count); 1049 host_err = rw_verify_area(READ, file, &offset, *count); 1050 if (!host_err) 1051 host_err = splice_direct_to_actor(file, &sd, 1052 nfsd_direct_splice_actor); 1053 return nfsd_finish_read(rqstp, fhp, file, offset, count, eof, host_err); 1054 } 1055 1056 /** 1057 * nfsd_iter_read - Perform a VFS read using an iterator 1058 * @rqstp: RPC transaction context 1059 * @fhp: file handle of file to be read 1060 * @file: opened struct file of file to be read 1061 * @offset: starting byte offset 1062 * @count: IN: requested number of bytes; OUT: number of bytes read 1063 * @base: offset in first page of read buffer 1064 * @eof: OUT: set non-zero if operation reached the end of the file 1065 * 1066 * Some filesystems or situations cannot use nfsd_splice_read. This 1067 * function is the slightly less-performant fallback for those cases. 1068 * 1069 * Returns nfs_ok on success, otherwise an nfserr stat value is 1070 * returned. 1071 */ 1072 __be32 nfsd_iter_read(struct svc_rqst *rqstp, struct svc_fh *fhp, 1073 struct file *file, loff_t offset, unsigned long *count, 1074 unsigned int base, u32 *eof) 1075 { 1076 unsigned long v, total; 1077 struct iov_iter iter; 1078 loff_t ppos = offset; 1079 struct page *page; 1080 ssize_t host_err; 1081 1082 v = 0; 1083 total = *count; 1084 while (total) { 1085 page = *(rqstp->rq_next_page++); 1086 rqstp->rq_vec[v].iov_base = page_address(page) + base; 1087 rqstp->rq_vec[v].iov_len = min_t(size_t, total, PAGE_SIZE - base); 1088 total -= rqstp->rq_vec[v].iov_len; 1089 ++v; 1090 base = 0; 1091 } 1092 WARN_ON_ONCE(v > ARRAY_SIZE(rqstp->rq_vec)); 1093 1094 trace_nfsd_read_vector(rqstp, fhp, offset, *count); 1095 iov_iter_kvec(&iter, ITER_DEST, rqstp->rq_vec, v, *count); 1096 host_err = vfs_iter_read(file, &iter, &ppos, 0); 1097 return nfsd_finish_read(rqstp, fhp, file, offset, count, eof, host_err); 1098 } 1099 1100 /* 1101 * Gathered writes: If another process is currently writing to the file, 1102 * there's a high chance this is another nfsd (triggered by a bulk write 1103 * from a client's biod). Rather than syncing the file with each write 1104 * request, we sleep for 10 msec. 1105 * 1106 * I don't know if this roughly approximates C. Juszak's idea of 1107 * gathered writes, but it's a nice and simple solution (IMHO), and it 1108 * seems to work:-) 1109 * 1110 * Note: we do this only in the NFSv2 case, since v3 and higher have a 1111 * better tool (separate unstable writes and commits) for solving this 1112 * problem. 1113 */ 1114 static int wait_for_concurrent_writes(struct file *file) 1115 { 1116 struct inode *inode = file_inode(file); 1117 static ino_t last_ino; 1118 static dev_t last_dev; 1119 int err = 0; 1120 1121 if (atomic_read(&inode->i_writecount) > 1 1122 || (last_ino == inode->i_ino && last_dev == inode->i_sb->s_dev)) { 1123 dprintk("nfsd: write defer %d\n", task_pid_nr(current)); 1124 msleep(10); 1125 dprintk("nfsd: write resume %d\n", task_pid_nr(current)); 1126 } 1127 1128 if (inode->i_state & I_DIRTY) { 1129 dprintk("nfsd: write sync %d\n", task_pid_nr(current)); 1130 err = vfs_fsync(file, 0); 1131 } 1132 last_ino = inode->i_ino; 1133 last_dev = inode->i_sb->s_dev; 1134 return err; 1135 } 1136 1137 __be32 1138 nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf, 1139 loff_t offset, struct kvec *vec, int vlen, 1140 unsigned long *cnt, int stable, 1141 __be32 *verf) 1142 { 1143 struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id); 1144 struct file *file = nf->nf_file; 1145 struct super_block *sb = file_inode(file)->i_sb; 1146 struct svc_export *exp; 1147 struct iov_iter iter; 1148 errseq_t since; 1149 __be32 nfserr; 1150 int host_err; 1151 int use_wgather; 1152 loff_t pos = offset; 1153 unsigned long exp_op_flags = 0; 1154 unsigned int pflags = current->flags; 1155 rwf_t flags = 0; 1156 bool restore_flags = false; 1157 1158 trace_nfsd_write_opened(rqstp, fhp, offset, *cnt); 1159 1160 if (sb->s_export_op) 1161 exp_op_flags = sb->s_export_op->flags; 1162 1163 if (test_bit(RQ_LOCAL, &rqstp->rq_flags) && 1164 !(exp_op_flags & EXPORT_OP_REMOTE_FS)) { 1165 /* 1166 * We want throttling in balance_dirty_pages() 1167 * and shrink_inactive_list() to only consider 1168 * the backingdev we are writing to, so that nfs to 1169 * localhost doesn't cause nfsd to lock up due to all 1170 * the client's dirty pages or its congested queue. 1171 */ 1172 current->flags |= PF_LOCAL_THROTTLE; 1173 restore_flags = true; 1174 } 1175 1176 exp = fhp->fh_export; 1177 use_wgather = (rqstp->rq_vers == 2) && EX_WGATHER(exp); 1178 1179 if (!EX_ISSYNC(exp)) 1180 stable = NFS_UNSTABLE; 1181 1182 if (stable && !use_wgather) 1183 flags |= RWF_SYNC; 1184 1185 iov_iter_kvec(&iter, ITER_SOURCE, vec, vlen, *cnt); 1186 since = READ_ONCE(file->f_wb_err); 1187 if (verf) 1188 nfsd_copy_write_verifier(verf, nn); 1189 host_err = vfs_iter_write(file, &iter, &pos, flags); 1190 if (host_err < 0) { 1191 commit_reset_write_verifier(nn, rqstp, host_err); 1192 goto out_nfserr; 1193 } 1194 *cnt = host_err; 1195 nfsd_stats_io_write_add(nn, exp, *cnt); 1196 fsnotify_modify(file); 1197 host_err = filemap_check_wb_err(file->f_mapping, since); 1198 if (host_err < 0) 1199 goto out_nfserr; 1200 1201 if (stable && use_wgather) { 1202 host_err = wait_for_concurrent_writes(file); 1203 if (host_err < 0) 1204 commit_reset_write_verifier(nn, rqstp, host_err); 1205 } 1206 1207 out_nfserr: 1208 if (host_err >= 0) { 1209 trace_nfsd_write_io_done(rqstp, fhp, offset, *cnt); 1210 nfserr = nfs_ok; 1211 } else { 1212 trace_nfsd_write_err(rqstp, fhp, offset, host_err); 1213 nfserr = nfserrno(host_err); 1214 } 1215 if (restore_flags) 1216 current_restore_flags(pflags, PF_LOCAL_THROTTLE); 1217 return nfserr; 1218 } 1219 1220 /** 1221 * nfsd_read_splice_ok - check if spliced reading is supported 1222 * @rqstp: RPC transaction context 1223 * 1224 * Return values: 1225 * %true: nfsd_splice_read() may be used 1226 * %false: nfsd_splice_read() must not be used 1227 * 1228 * NFS READ normally uses splice to send data in-place. However the 1229 * data in cache can change after the reply's MIC is computed but 1230 * before the RPC reply is sent. To prevent the client from 1231 * rejecting the server-computed MIC in this somewhat rare case, do 1232 * not use splice with the GSS integrity and privacy services. 1233 */ 1234 bool nfsd_read_splice_ok(struct svc_rqst *rqstp) 1235 { 1236 switch (svc_auth_flavor(rqstp)) { 1237 case RPC_AUTH_GSS_KRB5I: 1238 case RPC_AUTH_GSS_KRB5P: 1239 return false; 1240 } 1241 return true; 1242 } 1243 1244 /** 1245 * nfsd_read - Read data from a file 1246 * @rqstp: RPC transaction context 1247 * @fhp: file handle of file to be read 1248 * @offset: starting byte offset 1249 * @count: IN: requested number of bytes; OUT: number of bytes read 1250 * @eof: OUT: set non-zero if operation reached the end of the file 1251 * 1252 * The caller must verify that there is enough space in @rqstp.rq_res 1253 * to perform this operation. 1254 * 1255 * N.B. After this call fhp needs an fh_put 1256 * 1257 * Returns nfs_ok on success, otherwise an nfserr stat value is 1258 * returned. 1259 */ 1260 __be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp, 1261 loff_t offset, unsigned long *count, u32 *eof) 1262 { 1263 struct nfsd_file *nf; 1264 struct file *file; 1265 __be32 err; 1266 1267 trace_nfsd_read_start(rqstp, fhp, offset, *count); 1268 err = nfsd_file_acquire_gc(rqstp, fhp, NFSD_MAY_READ, &nf); 1269 if (err) 1270 return err; 1271 1272 file = nf->nf_file; 1273 if (file->f_op->splice_read && nfsd_read_splice_ok(rqstp)) 1274 err = nfsd_splice_read(rqstp, fhp, file, offset, count, eof); 1275 else 1276 err = nfsd_iter_read(rqstp, fhp, file, offset, count, 0, eof); 1277 1278 nfsd_file_put(nf); 1279 trace_nfsd_read_done(rqstp, fhp, offset, *count); 1280 return err; 1281 } 1282 1283 /* 1284 * Write data to a file. 1285 * The stable flag requests synchronous writes. 1286 * N.B. After this call fhp needs an fh_put 1287 */ 1288 __be32 1289 nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t offset, 1290 struct kvec *vec, int vlen, unsigned long *cnt, int stable, 1291 __be32 *verf) 1292 { 1293 struct nfsd_file *nf; 1294 __be32 err; 1295 1296 trace_nfsd_write_start(rqstp, fhp, offset, *cnt); 1297 1298 err = nfsd_file_acquire_gc(rqstp, fhp, NFSD_MAY_WRITE, &nf); 1299 if (err) 1300 goto out; 1301 1302 err = nfsd_vfs_write(rqstp, fhp, nf, offset, vec, 1303 vlen, cnt, stable, verf); 1304 nfsd_file_put(nf); 1305 out: 1306 trace_nfsd_write_done(rqstp, fhp, offset, *cnt); 1307 return err; 1308 } 1309 1310 /** 1311 * nfsd_commit - Commit pending writes to stable storage 1312 * @rqstp: RPC request being processed 1313 * @fhp: NFS filehandle 1314 * @nf: target file 1315 * @offset: raw offset from beginning of file 1316 * @count: raw count of bytes to sync 1317 * @verf: filled in with the server's current write verifier 1318 * 1319 * Note: we guarantee that data that lies within the range specified 1320 * by the 'offset' and 'count' parameters will be synced. The server 1321 * is permitted to sync data that lies outside this range at the 1322 * same time. 1323 * 1324 * Unfortunately we cannot lock the file to make sure we return full WCC 1325 * data to the client, as locking happens lower down in the filesystem. 1326 * 1327 * Return values: 1328 * An nfsstat value in network byte order. 1329 */ 1330 __be32 1331 nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf, 1332 u64 offset, u32 count, __be32 *verf) 1333 { 1334 __be32 err = nfs_ok; 1335 u64 maxbytes; 1336 loff_t start, end; 1337 struct nfsd_net *nn; 1338 1339 /* 1340 * Convert the client-provided (offset, count) range to a 1341 * (start, end) range. If the client-provided range falls 1342 * outside the maximum file size of the underlying FS, 1343 * clamp the sync range appropriately. 1344 */ 1345 start = 0; 1346 end = LLONG_MAX; 1347 maxbytes = (u64)fhp->fh_dentry->d_sb->s_maxbytes; 1348 if (offset < maxbytes) { 1349 start = offset; 1350 if (count && (offset + count - 1 < maxbytes)) 1351 end = offset + count - 1; 1352 } 1353 1354 nn = net_generic(nf->nf_net, nfsd_net_id); 1355 if (EX_ISSYNC(fhp->fh_export)) { 1356 errseq_t since = READ_ONCE(nf->nf_file->f_wb_err); 1357 int err2; 1358 1359 err2 = vfs_fsync_range(nf->nf_file, start, end, 0); 1360 switch (err2) { 1361 case 0: 1362 nfsd_copy_write_verifier(verf, nn); 1363 err2 = filemap_check_wb_err(nf->nf_file->f_mapping, 1364 since); 1365 err = nfserrno(err2); 1366 break; 1367 case -EINVAL: 1368 err = nfserr_notsupp; 1369 break; 1370 default: 1371 commit_reset_write_verifier(nn, rqstp, err2); 1372 err = nfserrno(err2); 1373 } 1374 } else 1375 nfsd_copy_write_verifier(verf, nn); 1376 1377 return err; 1378 } 1379 1380 /** 1381 * nfsd_create_setattr - Set a created file's attributes 1382 * @rqstp: RPC transaction being executed 1383 * @fhp: NFS filehandle of parent directory 1384 * @resfhp: NFS filehandle of new object 1385 * @attrs: requested attributes of new object 1386 * 1387 * Returns nfs_ok on success, or an nfsstat in network byte order. 1388 */ 1389 __be32 1390 nfsd_create_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, 1391 struct svc_fh *resfhp, struct nfsd_attrs *attrs) 1392 { 1393 struct iattr *iap = attrs->na_iattr; 1394 __be32 status; 1395 1396 /* 1397 * Mode has already been set by file creation. 1398 */ 1399 iap->ia_valid &= ~ATTR_MODE; 1400 1401 /* 1402 * Setting uid/gid works only for root. Irix appears to 1403 * send along the gid on create when it tries to implement 1404 * setgid directories via NFS: 1405 */ 1406 if (!uid_eq(current_fsuid(), GLOBAL_ROOT_UID)) 1407 iap->ia_valid &= ~(ATTR_UID|ATTR_GID); 1408 1409 /* 1410 * Callers expect new file metadata to be committed even 1411 * if the attributes have not changed. 1412 */ 1413 if (iap->ia_valid) 1414 status = nfsd_setattr(rqstp, resfhp, attrs, 0, (time64_t)0); 1415 else 1416 status = nfserrno(commit_metadata(resfhp)); 1417 1418 /* 1419 * Transactional filesystems had a chance to commit changes 1420 * for both parent and child simultaneously making the 1421 * following commit_metadata a noop in many cases. 1422 */ 1423 if (!status) 1424 status = nfserrno(commit_metadata(fhp)); 1425 1426 /* 1427 * Update the new filehandle to pick up the new attributes. 1428 */ 1429 if (!status) 1430 status = fh_update(resfhp); 1431 1432 return status; 1433 } 1434 1435 /* HPUX client sometimes creates a file in mode 000, and sets size to 0. 1436 * setting size to 0 may fail for some specific file systems by the permission 1437 * checking which requires WRITE permission but the mode is 000. 1438 * we ignore the resizing(to 0) on the just new created file, since the size is 1439 * 0 after file created. 1440 * 1441 * call this only after vfs_create() is called. 1442 * */ 1443 static void 1444 nfsd_check_ignore_resizing(struct iattr *iap) 1445 { 1446 if ((iap->ia_valid & ATTR_SIZE) && (iap->ia_size == 0)) 1447 iap->ia_valid &= ~ATTR_SIZE; 1448 } 1449 1450 /* The parent directory should already be locked: */ 1451 __be32 1452 nfsd_create_locked(struct svc_rqst *rqstp, struct svc_fh *fhp, 1453 struct nfsd_attrs *attrs, 1454 int type, dev_t rdev, struct svc_fh *resfhp) 1455 { 1456 struct dentry *dentry, *dchild; 1457 struct inode *dirp; 1458 struct iattr *iap = attrs->na_iattr; 1459 __be32 err; 1460 int host_err; 1461 1462 dentry = fhp->fh_dentry; 1463 dirp = d_inode(dentry); 1464 1465 dchild = dget(resfhp->fh_dentry); 1466 err = nfsd_permission(rqstp, fhp->fh_export, dentry, NFSD_MAY_CREATE); 1467 if (err) 1468 goto out; 1469 1470 if (!(iap->ia_valid & ATTR_MODE)) 1471 iap->ia_mode = 0; 1472 iap->ia_mode = (iap->ia_mode & S_IALLUGO) | type; 1473 1474 if (!IS_POSIXACL(dirp)) 1475 iap->ia_mode &= ~current_umask(); 1476 1477 err = 0; 1478 switch (type) { 1479 case S_IFREG: 1480 host_err = vfs_create(&nop_mnt_idmap, dirp, dchild, 1481 iap->ia_mode, true); 1482 if (!host_err) 1483 nfsd_check_ignore_resizing(iap); 1484 break; 1485 case S_IFDIR: 1486 host_err = vfs_mkdir(&nop_mnt_idmap, dirp, dchild, iap->ia_mode); 1487 if (!host_err && unlikely(d_unhashed(dchild))) { 1488 struct dentry *d; 1489 d = lookup_one_len(dchild->d_name.name, 1490 dchild->d_parent, 1491 dchild->d_name.len); 1492 if (IS_ERR(d)) { 1493 host_err = PTR_ERR(d); 1494 break; 1495 } 1496 if (unlikely(d_is_negative(d))) { 1497 dput(d); 1498 err = nfserr_serverfault; 1499 goto out; 1500 } 1501 dput(resfhp->fh_dentry); 1502 resfhp->fh_dentry = dget(d); 1503 err = fh_update(resfhp); 1504 dput(dchild); 1505 dchild = d; 1506 if (err) 1507 goto out; 1508 } 1509 break; 1510 case S_IFCHR: 1511 case S_IFBLK: 1512 case S_IFIFO: 1513 case S_IFSOCK: 1514 host_err = vfs_mknod(&nop_mnt_idmap, dirp, dchild, 1515 iap->ia_mode, rdev); 1516 break; 1517 default: 1518 printk(KERN_WARNING "nfsd: bad file type %o in nfsd_create\n", 1519 type); 1520 host_err = -EINVAL; 1521 } 1522 if (host_err < 0) 1523 goto out_nfserr; 1524 1525 err = nfsd_create_setattr(rqstp, fhp, resfhp, attrs); 1526 1527 out: 1528 dput(dchild); 1529 return err; 1530 1531 out_nfserr: 1532 err = nfserrno(host_err); 1533 goto out; 1534 } 1535 1536 /* 1537 * Create a filesystem object (regular, directory, special). 1538 * Note that the parent directory is left locked. 1539 * 1540 * N.B. Every call to nfsd_create needs an fh_put for _both_ fhp and resfhp 1541 */ 1542 __be32 1543 nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, 1544 char *fname, int flen, struct nfsd_attrs *attrs, 1545 int type, dev_t rdev, struct svc_fh *resfhp) 1546 { 1547 struct dentry *dentry, *dchild = NULL; 1548 __be32 err; 1549 int host_err; 1550 1551 if (isdotent(fname, flen)) 1552 return nfserr_exist; 1553 1554 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_NOP); 1555 if (err) 1556 return err; 1557 1558 dentry = fhp->fh_dentry; 1559 1560 host_err = fh_want_write(fhp); 1561 if (host_err) 1562 return nfserrno(host_err); 1563 1564 inode_lock_nested(dentry->d_inode, I_MUTEX_PARENT); 1565 dchild = lookup_one_len(fname, dentry, flen); 1566 host_err = PTR_ERR(dchild); 1567 if (IS_ERR(dchild)) { 1568 err = nfserrno(host_err); 1569 goto out_unlock; 1570 } 1571 err = fh_compose(resfhp, fhp->fh_export, dchild, fhp); 1572 /* 1573 * We unconditionally drop our ref to dchild as fh_compose will have 1574 * already grabbed its own ref for it. 1575 */ 1576 dput(dchild); 1577 if (err) 1578 goto out_unlock; 1579 err = fh_fill_pre_attrs(fhp); 1580 if (err != nfs_ok) 1581 goto out_unlock; 1582 err = nfsd_create_locked(rqstp, fhp, attrs, type, rdev, resfhp); 1583 fh_fill_post_attrs(fhp); 1584 out_unlock: 1585 inode_unlock(dentry->d_inode); 1586 return err; 1587 } 1588 1589 /* 1590 * Read a symlink. On entry, *lenp must contain the maximum path length that 1591 * fits into the buffer. On return, it contains the true length. 1592 * N.B. After this call fhp needs an fh_put 1593 */ 1594 __be32 1595 nfsd_readlink(struct svc_rqst *rqstp, struct svc_fh *fhp, char *buf, int *lenp) 1596 { 1597 __be32 err; 1598 const char *link; 1599 struct path path; 1600 DEFINE_DELAYED_CALL(done); 1601 int len; 1602 1603 err = fh_verify(rqstp, fhp, S_IFLNK, NFSD_MAY_NOP); 1604 if (unlikely(err)) 1605 return err; 1606 1607 path.mnt = fhp->fh_export->ex_path.mnt; 1608 path.dentry = fhp->fh_dentry; 1609 1610 if (unlikely(!d_is_symlink(path.dentry))) 1611 return nfserr_inval; 1612 1613 touch_atime(&path); 1614 1615 link = vfs_get_link(path.dentry, &done); 1616 if (IS_ERR(link)) 1617 return nfserrno(PTR_ERR(link)); 1618 1619 len = strlen(link); 1620 if (len < *lenp) 1621 *lenp = len; 1622 memcpy(buf, link, *lenp); 1623 do_delayed_call(&done); 1624 return 0; 1625 } 1626 1627 /** 1628 * nfsd_symlink - Create a symlink and look up its inode 1629 * @rqstp: RPC transaction being executed 1630 * @fhp: NFS filehandle of parent directory 1631 * @fname: filename of the new symlink 1632 * @flen: length of @fname 1633 * @path: content of the new symlink (NUL-terminated) 1634 * @attrs: requested attributes of new object 1635 * @resfhp: NFS filehandle of new object 1636 * 1637 * N.B. After this call _both_ fhp and resfhp need an fh_put 1638 * 1639 * Returns nfs_ok on success, or an nfsstat in network byte order. 1640 */ 1641 __be32 1642 nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp, 1643 char *fname, int flen, 1644 char *path, struct nfsd_attrs *attrs, 1645 struct svc_fh *resfhp) 1646 { 1647 struct dentry *dentry, *dnew; 1648 __be32 err, cerr; 1649 int host_err; 1650 1651 err = nfserr_noent; 1652 if (!flen || path[0] == '\0') 1653 goto out; 1654 err = nfserr_exist; 1655 if (isdotent(fname, flen)) 1656 goto out; 1657 1658 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE); 1659 if (err) 1660 goto out; 1661 1662 host_err = fh_want_write(fhp); 1663 if (host_err) { 1664 err = nfserrno(host_err); 1665 goto out; 1666 } 1667 1668 dentry = fhp->fh_dentry; 1669 inode_lock_nested(dentry->d_inode, I_MUTEX_PARENT); 1670 dnew = lookup_one_len(fname, dentry, flen); 1671 if (IS_ERR(dnew)) { 1672 err = nfserrno(PTR_ERR(dnew)); 1673 inode_unlock(dentry->d_inode); 1674 goto out_drop_write; 1675 } 1676 err = fh_fill_pre_attrs(fhp); 1677 if (err != nfs_ok) 1678 goto out_unlock; 1679 host_err = vfs_symlink(&nop_mnt_idmap, d_inode(dentry), dnew, path); 1680 err = nfserrno(host_err); 1681 cerr = fh_compose(resfhp, fhp->fh_export, dnew, fhp); 1682 if (!err) 1683 nfsd_create_setattr(rqstp, fhp, resfhp, attrs); 1684 fh_fill_post_attrs(fhp); 1685 out_unlock: 1686 inode_unlock(dentry->d_inode); 1687 if (!err) 1688 err = nfserrno(commit_metadata(fhp)); 1689 dput(dnew); 1690 if (err==0) err = cerr; 1691 out_drop_write: 1692 fh_drop_write(fhp); 1693 out: 1694 return err; 1695 } 1696 1697 /* 1698 * Create a hardlink 1699 * N.B. After this call _both_ ffhp and tfhp need an fh_put 1700 */ 1701 __be32 1702 nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp, 1703 char *name, int len, struct svc_fh *tfhp) 1704 { 1705 struct dentry *ddir, *dnew, *dold; 1706 struct inode *dirp; 1707 __be32 err; 1708 int host_err; 1709 1710 err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_CREATE); 1711 if (err) 1712 goto out; 1713 err = fh_verify(rqstp, tfhp, 0, NFSD_MAY_NOP); 1714 if (err) 1715 goto out; 1716 err = nfserr_isdir; 1717 if (d_is_dir(tfhp->fh_dentry)) 1718 goto out; 1719 err = nfserr_perm; 1720 if (!len) 1721 goto out; 1722 err = nfserr_exist; 1723 if (isdotent(name, len)) 1724 goto out; 1725 1726 host_err = fh_want_write(tfhp); 1727 if (host_err) { 1728 err = nfserrno(host_err); 1729 goto out; 1730 } 1731 1732 ddir = ffhp->fh_dentry; 1733 dirp = d_inode(ddir); 1734 inode_lock_nested(dirp, I_MUTEX_PARENT); 1735 1736 dnew = lookup_one_len(name, ddir, len); 1737 if (IS_ERR(dnew)) { 1738 err = nfserrno(PTR_ERR(dnew)); 1739 goto out_unlock; 1740 } 1741 1742 dold = tfhp->fh_dentry; 1743 1744 err = nfserr_noent; 1745 if (d_really_is_negative(dold)) 1746 goto out_dput; 1747 err = fh_fill_pre_attrs(ffhp); 1748 if (err != nfs_ok) 1749 goto out_dput; 1750 host_err = vfs_link(dold, &nop_mnt_idmap, dirp, dnew, NULL); 1751 fh_fill_post_attrs(ffhp); 1752 inode_unlock(dirp); 1753 if (!host_err) { 1754 err = nfserrno(commit_metadata(ffhp)); 1755 if (!err) 1756 err = nfserrno(commit_metadata(tfhp)); 1757 } else { 1758 if (host_err == -EXDEV && rqstp->rq_vers == 2) 1759 err = nfserr_acces; 1760 else 1761 err = nfserrno(host_err); 1762 } 1763 dput(dnew); 1764 out_drop_write: 1765 fh_drop_write(tfhp); 1766 out: 1767 return err; 1768 1769 out_dput: 1770 dput(dnew); 1771 out_unlock: 1772 inode_unlock(dirp); 1773 goto out_drop_write; 1774 } 1775 1776 static void 1777 nfsd_close_cached_files(struct dentry *dentry) 1778 { 1779 struct inode *inode = d_inode(dentry); 1780 1781 if (inode && S_ISREG(inode->i_mode)) 1782 nfsd_file_close_inode_sync(inode); 1783 } 1784 1785 static bool 1786 nfsd_has_cached_files(struct dentry *dentry) 1787 { 1788 bool ret = false; 1789 struct inode *inode = d_inode(dentry); 1790 1791 if (inode && S_ISREG(inode->i_mode)) 1792 ret = nfsd_file_is_cached(inode); 1793 return ret; 1794 } 1795 1796 /* 1797 * Rename a file 1798 * N.B. After this call _both_ ffhp and tfhp need an fh_put 1799 */ 1800 __be32 1801 nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, 1802 struct svc_fh *tfhp, char *tname, int tlen) 1803 { 1804 struct dentry *fdentry, *tdentry, *odentry, *ndentry, *trap; 1805 struct inode *fdir, *tdir; 1806 __be32 err; 1807 int host_err; 1808 bool close_cached = false; 1809 1810 err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_REMOVE); 1811 if (err) 1812 goto out; 1813 err = fh_verify(rqstp, tfhp, S_IFDIR, NFSD_MAY_CREATE); 1814 if (err) 1815 goto out; 1816 1817 fdentry = ffhp->fh_dentry; 1818 fdir = d_inode(fdentry); 1819 1820 tdentry = tfhp->fh_dentry; 1821 tdir = d_inode(tdentry); 1822 1823 err = nfserr_perm; 1824 if (!flen || isdotent(fname, flen) || !tlen || isdotent(tname, tlen)) 1825 goto out; 1826 1827 err = (rqstp->rq_vers == 2) ? nfserr_acces : nfserr_xdev; 1828 if (ffhp->fh_export->ex_path.mnt != tfhp->fh_export->ex_path.mnt) 1829 goto out; 1830 if (ffhp->fh_export->ex_path.dentry != tfhp->fh_export->ex_path.dentry) 1831 goto out; 1832 1833 retry: 1834 host_err = fh_want_write(ffhp); 1835 if (host_err) { 1836 err = nfserrno(host_err); 1837 goto out; 1838 } 1839 1840 trap = lock_rename(tdentry, fdentry); 1841 if (IS_ERR(trap)) { 1842 err = (rqstp->rq_vers == 2) ? nfserr_acces : nfserr_xdev; 1843 goto out; 1844 } 1845 err = fh_fill_pre_attrs(ffhp); 1846 if (err != nfs_ok) 1847 goto out_unlock; 1848 err = fh_fill_pre_attrs(tfhp); 1849 if (err != nfs_ok) 1850 goto out_unlock; 1851 1852 odentry = lookup_one_len(fname, fdentry, flen); 1853 host_err = PTR_ERR(odentry); 1854 if (IS_ERR(odentry)) 1855 goto out_nfserr; 1856 1857 host_err = -ENOENT; 1858 if (d_really_is_negative(odentry)) 1859 goto out_dput_old; 1860 host_err = -EINVAL; 1861 if (odentry == trap) 1862 goto out_dput_old; 1863 1864 ndentry = lookup_one_len(tname, tdentry, tlen); 1865 host_err = PTR_ERR(ndentry); 1866 if (IS_ERR(ndentry)) 1867 goto out_dput_old; 1868 host_err = -ENOTEMPTY; 1869 if (ndentry == trap) 1870 goto out_dput_new; 1871 1872 if ((ndentry->d_sb->s_export_op->flags & EXPORT_OP_CLOSE_BEFORE_UNLINK) && 1873 nfsd_has_cached_files(ndentry)) { 1874 close_cached = true; 1875 goto out_dput_old; 1876 } else { 1877 struct renamedata rd = { 1878 .old_mnt_idmap = &nop_mnt_idmap, 1879 .old_dir = fdir, 1880 .old_dentry = odentry, 1881 .new_mnt_idmap = &nop_mnt_idmap, 1882 .new_dir = tdir, 1883 .new_dentry = ndentry, 1884 }; 1885 int retries; 1886 1887 for (retries = 1;;) { 1888 host_err = vfs_rename(&rd); 1889 if (host_err != -EAGAIN || !retries--) 1890 break; 1891 if (!nfsd_wait_for_delegreturn(rqstp, d_inode(odentry))) 1892 break; 1893 } 1894 if (!host_err) { 1895 host_err = commit_metadata(tfhp); 1896 if (!host_err) 1897 host_err = commit_metadata(ffhp); 1898 } 1899 } 1900 out_dput_new: 1901 dput(ndentry); 1902 out_dput_old: 1903 dput(odentry); 1904 out_nfserr: 1905 err = nfserrno(host_err); 1906 1907 if (!close_cached) { 1908 fh_fill_post_attrs(ffhp); 1909 fh_fill_post_attrs(tfhp); 1910 } 1911 out_unlock: 1912 unlock_rename(tdentry, fdentry); 1913 fh_drop_write(ffhp); 1914 1915 /* 1916 * If the target dentry has cached open files, then we need to 1917 * try to close them prior to doing the rename. Final fput 1918 * shouldn't be done with locks held however, so we delay it 1919 * until this point and then reattempt the whole shebang. 1920 */ 1921 if (close_cached) { 1922 close_cached = false; 1923 nfsd_close_cached_files(ndentry); 1924 dput(ndentry); 1925 goto retry; 1926 } 1927 out: 1928 return err; 1929 } 1930 1931 /* 1932 * Unlink a file or directory 1933 * N.B. After this call fhp needs an fh_put 1934 */ 1935 __be32 1936 nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, 1937 char *fname, int flen) 1938 { 1939 struct dentry *dentry, *rdentry; 1940 struct inode *dirp; 1941 struct inode *rinode; 1942 __be32 err; 1943 int host_err; 1944 1945 err = nfserr_acces; 1946 if (!flen || isdotent(fname, flen)) 1947 goto out; 1948 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_REMOVE); 1949 if (err) 1950 goto out; 1951 1952 host_err = fh_want_write(fhp); 1953 if (host_err) 1954 goto out_nfserr; 1955 1956 dentry = fhp->fh_dentry; 1957 dirp = d_inode(dentry); 1958 inode_lock_nested(dirp, I_MUTEX_PARENT); 1959 1960 rdentry = lookup_one_len(fname, dentry, flen); 1961 host_err = PTR_ERR(rdentry); 1962 if (IS_ERR(rdentry)) 1963 goto out_unlock; 1964 1965 if (d_really_is_negative(rdentry)) { 1966 dput(rdentry); 1967 host_err = -ENOENT; 1968 goto out_unlock; 1969 } 1970 rinode = d_inode(rdentry); 1971 err = fh_fill_pre_attrs(fhp); 1972 if (err != nfs_ok) 1973 goto out_unlock; 1974 1975 ihold(rinode); 1976 if (!type) 1977 type = d_inode(rdentry)->i_mode & S_IFMT; 1978 1979 if (type != S_IFDIR) { 1980 int retries; 1981 1982 if (rdentry->d_sb->s_export_op->flags & EXPORT_OP_CLOSE_BEFORE_UNLINK) 1983 nfsd_close_cached_files(rdentry); 1984 1985 for (retries = 1;;) { 1986 host_err = vfs_unlink(&nop_mnt_idmap, dirp, rdentry, NULL); 1987 if (host_err != -EAGAIN || !retries--) 1988 break; 1989 if (!nfsd_wait_for_delegreturn(rqstp, rinode)) 1990 break; 1991 } 1992 } else { 1993 host_err = vfs_rmdir(&nop_mnt_idmap, dirp, rdentry); 1994 } 1995 fh_fill_post_attrs(fhp); 1996 1997 inode_unlock(dirp); 1998 if (!host_err) 1999 host_err = commit_metadata(fhp); 2000 dput(rdentry); 2001 iput(rinode); /* truncate the inode here */ 2002 2003 out_drop_write: 2004 fh_drop_write(fhp); 2005 out_nfserr: 2006 if (host_err == -EBUSY) { 2007 /* name is mounted-on. There is no perfect 2008 * error status. 2009 */ 2010 if (nfsd_v4client(rqstp)) 2011 err = nfserr_file_open; 2012 else 2013 err = nfserr_acces; 2014 } else { 2015 err = nfserrno(host_err); 2016 } 2017 out: 2018 return err; 2019 out_unlock: 2020 inode_unlock(dirp); 2021 goto out_drop_write; 2022 } 2023 2024 /* 2025 * We do this buffering because we must not call back into the file 2026 * system's ->lookup() method from the filldir callback. That may well 2027 * deadlock a number of file systems. 2028 * 2029 * This is based heavily on the implementation of same in XFS. 2030 */ 2031 struct buffered_dirent { 2032 u64 ino; 2033 loff_t offset; 2034 int namlen; 2035 unsigned int d_type; 2036 char name[]; 2037 }; 2038 2039 struct readdir_data { 2040 struct dir_context ctx; 2041 char *dirent; 2042 size_t used; 2043 int full; 2044 }; 2045 2046 static bool nfsd_buffered_filldir(struct dir_context *ctx, const char *name, 2047 int namlen, loff_t offset, u64 ino, 2048 unsigned int d_type) 2049 { 2050 struct readdir_data *buf = 2051 container_of(ctx, struct readdir_data, ctx); 2052 struct buffered_dirent *de = (void *)(buf->dirent + buf->used); 2053 unsigned int reclen; 2054 2055 reclen = ALIGN(sizeof(struct buffered_dirent) + namlen, sizeof(u64)); 2056 if (buf->used + reclen > PAGE_SIZE) { 2057 buf->full = 1; 2058 return false; 2059 } 2060 2061 de->namlen = namlen; 2062 de->offset = offset; 2063 de->ino = ino; 2064 de->d_type = d_type; 2065 memcpy(de->name, name, namlen); 2066 buf->used += reclen; 2067 2068 return true; 2069 } 2070 2071 static __be32 nfsd_buffered_readdir(struct file *file, struct svc_fh *fhp, 2072 nfsd_filldir_t func, struct readdir_cd *cdp, 2073 loff_t *offsetp) 2074 { 2075 struct buffered_dirent *de; 2076 int host_err; 2077 int size; 2078 loff_t offset; 2079 struct readdir_data buf = { 2080 .ctx.actor = nfsd_buffered_filldir, 2081 .dirent = (void *)__get_free_page(GFP_KERNEL) 2082 }; 2083 2084 if (!buf.dirent) 2085 return nfserrno(-ENOMEM); 2086 2087 offset = *offsetp; 2088 2089 while (1) { 2090 unsigned int reclen; 2091 2092 cdp->err = nfserr_eof; /* will be cleared on successful read */ 2093 buf.used = 0; 2094 buf.full = 0; 2095 2096 host_err = iterate_dir(file, &buf.ctx); 2097 if (buf.full) 2098 host_err = 0; 2099 2100 if (host_err < 0) 2101 break; 2102 2103 size = buf.used; 2104 2105 if (!size) 2106 break; 2107 2108 de = (struct buffered_dirent *)buf.dirent; 2109 while (size > 0) { 2110 offset = de->offset; 2111 2112 if (func(cdp, de->name, de->namlen, de->offset, 2113 de->ino, de->d_type)) 2114 break; 2115 2116 if (cdp->err != nfs_ok) 2117 break; 2118 2119 trace_nfsd_dirent(fhp, de->ino, de->name, de->namlen); 2120 2121 reclen = ALIGN(sizeof(*de) + de->namlen, 2122 sizeof(u64)); 2123 size -= reclen; 2124 de = (struct buffered_dirent *)((char *)de + reclen); 2125 } 2126 if (size > 0) /* We bailed out early */ 2127 break; 2128 2129 offset = vfs_llseek(file, 0, SEEK_CUR); 2130 } 2131 2132 free_page((unsigned long)(buf.dirent)); 2133 2134 if (host_err) 2135 return nfserrno(host_err); 2136 2137 *offsetp = offset; 2138 return cdp->err; 2139 } 2140 2141 /** 2142 * nfsd_readdir - Read entries from a directory 2143 * @rqstp: RPC transaction context 2144 * @fhp: NFS file handle of directory to be read 2145 * @offsetp: OUT: seek offset of final entry that was read 2146 * @cdp: OUT: an eof error value 2147 * @func: entry filler actor 2148 * 2149 * This implementation ignores the NFSv3/4 verifier cookie. 2150 * 2151 * NB: normal system calls hold file->f_pos_lock when calling 2152 * ->iterate_shared and ->llseek, but nfsd_readdir() does not. 2153 * Because the struct file acquired here is not visible to other 2154 * threads, it's internal state does not need mutex protection. 2155 * 2156 * Returns nfs_ok on success, otherwise an nfsstat code is 2157 * returned. 2158 */ 2159 __be32 2160 nfsd_readdir(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t *offsetp, 2161 struct readdir_cd *cdp, nfsd_filldir_t func) 2162 { 2163 __be32 err; 2164 struct file *file; 2165 loff_t offset = *offsetp; 2166 int may_flags = NFSD_MAY_READ; 2167 2168 /* NFSv2 only supports 32 bit cookies */ 2169 if (rqstp->rq_vers > 2) 2170 may_flags |= NFSD_MAY_64BIT_COOKIE; 2171 2172 err = nfsd_open(rqstp, fhp, S_IFDIR, may_flags, &file); 2173 if (err) 2174 goto out; 2175 2176 offset = vfs_llseek(file, offset, SEEK_SET); 2177 if (offset < 0) { 2178 err = nfserrno((int)offset); 2179 goto out_close; 2180 } 2181 2182 err = nfsd_buffered_readdir(file, fhp, func, cdp, offsetp); 2183 2184 if (err == nfserr_eof || err == nfserr_toosmall) 2185 err = nfs_ok; /* can still be found in ->err */ 2186 out_close: 2187 nfsd_filp_close(file); 2188 out: 2189 return err; 2190 } 2191 2192 /** 2193 * nfsd_filp_close: close a file synchronously 2194 * @fp: the file to close 2195 * 2196 * nfsd_filp_close() is similar in behaviour to filp_close(). 2197 * The difference is that if this is the final close on the 2198 * file, the that finalisation happens immediately, rather then 2199 * being handed over to a work_queue, as it the case for 2200 * filp_close(). 2201 * When a user-space process closes a file (even when using 2202 * filp_close() the finalisation happens before returning to 2203 * userspace, so it is effectively synchronous. When a kernel thread 2204 * uses file_close(), on the other hand, the handling is completely 2205 * asynchronous. This means that any cost imposed by that finalisation 2206 * is not imposed on the nfsd thread, and nfsd could potentually 2207 * close files more quickly than the work queue finalises the close, 2208 * which would lead to unbounded growth in the queue. 2209 * 2210 * In some contexts is it not safe to synchronously wait for 2211 * close finalisation (see comment for __fput_sync()), but nfsd 2212 * does not match those contexts. In partcilarly it does not, at the 2213 * time that this function is called, hold and locks and no finalisation 2214 * of any file, socket, or device driver would have any cause to wait 2215 * for nfsd to make progress. 2216 */ 2217 void nfsd_filp_close(struct file *fp) 2218 { 2219 get_file(fp); 2220 filp_close(fp, NULL); 2221 __fput_sync(fp); 2222 } 2223 2224 /* 2225 * Get file system stats 2226 * N.B. After this call fhp needs an fh_put 2227 */ 2228 __be32 2229 nfsd_statfs(struct svc_rqst *rqstp, struct svc_fh *fhp, struct kstatfs *stat, int access) 2230 { 2231 __be32 err; 2232 2233 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP | access); 2234 if (!err) { 2235 struct path path = { 2236 .mnt = fhp->fh_export->ex_path.mnt, 2237 .dentry = fhp->fh_dentry, 2238 }; 2239 if (vfs_statfs(&path, stat)) 2240 err = nfserr_io; 2241 } 2242 return err; 2243 } 2244 2245 static int exp_rdonly(struct svc_rqst *rqstp, struct svc_export *exp) 2246 { 2247 return nfsexp_flags(rqstp, exp) & NFSEXP_READONLY; 2248 } 2249 2250 #ifdef CONFIG_NFSD_V4 2251 /* 2252 * Helper function to translate error numbers. In the case of xattr operations, 2253 * some error codes need to be translated outside of the standard translations. 2254 * 2255 * ENODATA needs to be translated to nfserr_noxattr. 2256 * E2BIG to nfserr_xattr2big. 2257 * 2258 * Additionally, vfs_listxattr can return -ERANGE. This means that the 2259 * file has too many extended attributes to retrieve inside an 2260 * XATTR_LIST_MAX sized buffer. This is a bug in the xattr implementation: 2261 * filesystems will allow the adding of extended attributes until they hit 2262 * their own internal limit. This limit may be larger than XATTR_LIST_MAX. 2263 * So, at that point, the attributes are present and valid, but can't 2264 * be retrieved using listxattr, since the upper level xattr code enforces 2265 * the XATTR_LIST_MAX limit. 2266 * 2267 * This bug means that we need to deal with listxattr returning -ERANGE. The 2268 * best mapping is to return TOOSMALL. 2269 */ 2270 static __be32 2271 nfsd_xattr_errno(int err) 2272 { 2273 switch (err) { 2274 case -ENODATA: 2275 return nfserr_noxattr; 2276 case -E2BIG: 2277 return nfserr_xattr2big; 2278 case -ERANGE: 2279 return nfserr_toosmall; 2280 } 2281 return nfserrno(err); 2282 } 2283 2284 /* 2285 * Retrieve the specified user extended attribute. To avoid always 2286 * having to allocate the maximum size (since we are not getting 2287 * a maximum size from the RPC), do a probe + alloc. Hold a reader 2288 * lock on i_rwsem to prevent the extended attribute from changing 2289 * size while we're doing this. 2290 */ 2291 __be32 2292 nfsd_getxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name, 2293 void **bufp, int *lenp) 2294 { 2295 ssize_t len; 2296 __be32 err; 2297 char *buf; 2298 struct inode *inode; 2299 struct dentry *dentry; 2300 2301 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_READ); 2302 if (err) 2303 return err; 2304 2305 err = nfs_ok; 2306 dentry = fhp->fh_dentry; 2307 inode = d_inode(dentry); 2308 2309 inode_lock_shared(inode); 2310 2311 len = vfs_getxattr(&nop_mnt_idmap, dentry, name, NULL, 0); 2312 2313 /* 2314 * Zero-length attribute, just return. 2315 */ 2316 if (len == 0) { 2317 *bufp = NULL; 2318 *lenp = 0; 2319 goto out; 2320 } 2321 2322 if (len < 0) { 2323 err = nfsd_xattr_errno(len); 2324 goto out; 2325 } 2326 2327 if (len > *lenp) { 2328 err = nfserr_toosmall; 2329 goto out; 2330 } 2331 2332 buf = kvmalloc(len, GFP_KERNEL); 2333 if (buf == NULL) { 2334 err = nfserr_jukebox; 2335 goto out; 2336 } 2337 2338 len = vfs_getxattr(&nop_mnt_idmap, dentry, name, buf, len); 2339 if (len <= 0) { 2340 kvfree(buf); 2341 buf = NULL; 2342 err = nfsd_xattr_errno(len); 2343 } 2344 2345 *lenp = len; 2346 *bufp = buf; 2347 2348 out: 2349 inode_unlock_shared(inode); 2350 2351 return err; 2352 } 2353 2354 /* 2355 * Retrieve the xattr names. Since we can't know how many are 2356 * user extended attributes, we must get all attributes here, 2357 * and have the XDR encode filter out the "user." ones. 2358 * 2359 * While this could always just allocate an XATTR_LIST_MAX 2360 * buffer, that's a waste, so do a probe + allocate. To 2361 * avoid any changes between the probe and allocate, wrap 2362 * this in inode_lock. 2363 */ 2364 __be32 2365 nfsd_listxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char **bufp, 2366 int *lenp) 2367 { 2368 ssize_t len; 2369 __be32 err; 2370 char *buf; 2371 struct inode *inode; 2372 struct dentry *dentry; 2373 2374 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_READ); 2375 if (err) 2376 return err; 2377 2378 dentry = fhp->fh_dentry; 2379 inode = d_inode(dentry); 2380 *lenp = 0; 2381 2382 inode_lock_shared(inode); 2383 2384 len = vfs_listxattr(dentry, NULL, 0); 2385 if (len <= 0) { 2386 err = nfsd_xattr_errno(len); 2387 goto out; 2388 } 2389 2390 if (len > XATTR_LIST_MAX) { 2391 err = nfserr_xattr2big; 2392 goto out; 2393 } 2394 2395 buf = kvmalloc(len, GFP_KERNEL); 2396 if (buf == NULL) { 2397 err = nfserr_jukebox; 2398 goto out; 2399 } 2400 2401 len = vfs_listxattr(dentry, buf, len); 2402 if (len <= 0) { 2403 kvfree(buf); 2404 err = nfsd_xattr_errno(len); 2405 goto out; 2406 } 2407 2408 *lenp = len; 2409 *bufp = buf; 2410 2411 err = nfs_ok; 2412 out: 2413 inode_unlock_shared(inode); 2414 2415 return err; 2416 } 2417 2418 /** 2419 * nfsd_removexattr - Remove an extended attribute 2420 * @rqstp: RPC transaction being executed 2421 * @fhp: NFS filehandle of object with xattr to remove 2422 * @name: name of xattr to remove (NUL-terminate) 2423 * 2424 * Pass in a NULL pointer for delegated_inode, and let the client deal 2425 * with NFS4ERR_DELAY (same as with e.g. setattr and remove). 2426 * 2427 * Returns nfs_ok on success, or an nfsstat in network byte order. 2428 */ 2429 __be32 2430 nfsd_removexattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name) 2431 { 2432 __be32 err; 2433 int ret; 2434 2435 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_WRITE); 2436 if (err) 2437 return err; 2438 2439 ret = fh_want_write(fhp); 2440 if (ret) 2441 return nfserrno(ret); 2442 2443 inode_lock(fhp->fh_dentry->d_inode); 2444 err = fh_fill_pre_attrs(fhp); 2445 if (err != nfs_ok) 2446 goto out_unlock; 2447 ret = __vfs_removexattr_locked(&nop_mnt_idmap, fhp->fh_dentry, 2448 name, NULL); 2449 err = nfsd_xattr_errno(ret); 2450 fh_fill_post_attrs(fhp); 2451 out_unlock: 2452 inode_unlock(fhp->fh_dentry->d_inode); 2453 fh_drop_write(fhp); 2454 2455 return err; 2456 } 2457 2458 __be32 2459 nfsd_setxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name, 2460 void *buf, u32 len, u32 flags) 2461 { 2462 __be32 err; 2463 int ret; 2464 2465 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_WRITE); 2466 if (err) 2467 return err; 2468 2469 ret = fh_want_write(fhp); 2470 if (ret) 2471 return nfserrno(ret); 2472 inode_lock(fhp->fh_dentry->d_inode); 2473 err = fh_fill_pre_attrs(fhp); 2474 if (err != nfs_ok) 2475 goto out_unlock; 2476 ret = __vfs_setxattr_locked(&nop_mnt_idmap, fhp->fh_dentry, 2477 name, buf, len, flags, NULL); 2478 fh_fill_post_attrs(fhp); 2479 err = nfsd_xattr_errno(ret); 2480 out_unlock: 2481 inode_unlock(fhp->fh_dentry->d_inode); 2482 fh_drop_write(fhp); 2483 return err; 2484 } 2485 #endif 2486 2487 /* 2488 * Check for a user's access permissions to this inode. 2489 */ 2490 __be32 2491 nfsd_permission(struct svc_rqst *rqstp, struct svc_export *exp, 2492 struct dentry *dentry, int acc) 2493 { 2494 struct inode *inode = d_inode(dentry); 2495 int err; 2496 2497 if ((acc & NFSD_MAY_MASK) == NFSD_MAY_NOP) 2498 return 0; 2499 #if 0 2500 dprintk("nfsd: permission 0x%x%s%s%s%s%s%s%s mode 0%o%s%s%s\n", 2501 acc, 2502 (acc & NFSD_MAY_READ)? " read" : "", 2503 (acc & NFSD_MAY_WRITE)? " write" : "", 2504 (acc & NFSD_MAY_EXEC)? " exec" : "", 2505 (acc & NFSD_MAY_SATTR)? " sattr" : "", 2506 (acc & NFSD_MAY_TRUNC)? " trunc" : "", 2507 (acc & NFSD_MAY_LOCK)? " lock" : "", 2508 (acc & NFSD_MAY_OWNER_OVERRIDE)? " owneroverride" : "", 2509 inode->i_mode, 2510 IS_IMMUTABLE(inode)? " immut" : "", 2511 IS_APPEND(inode)? " append" : "", 2512 __mnt_is_readonly(exp->ex_path.mnt)? " ro" : ""); 2513 dprintk(" owner %d/%d user %d/%d\n", 2514 inode->i_uid, inode->i_gid, current_fsuid(), current_fsgid()); 2515 #endif 2516 2517 /* Normally we reject any write/sattr etc access on a read-only file 2518 * system. But if it is IRIX doing check on write-access for a 2519 * device special file, we ignore rofs. 2520 */ 2521 if (!(acc & NFSD_MAY_LOCAL_ACCESS)) 2522 if (acc & (NFSD_MAY_WRITE | NFSD_MAY_SATTR | NFSD_MAY_TRUNC)) { 2523 if (exp_rdonly(rqstp, exp) || 2524 __mnt_is_readonly(exp->ex_path.mnt)) 2525 return nfserr_rofs; 2526 if (/* (acc & NFSD_MAY_WRITE) && */ IS_IMMUTABLE(inode)) 2527 return nfserr_perm; 2528 } 2529 if ((acc & NFSD_MAY_TRUNC) && IS_APPEND(inode)) 2530 return nfserr_perm; 2531 2532 if (acc & NFSD_MAY_LOCK) { 2533 /* If we cannot rely on authentication in NLM requests, 2534 * just allow locks, otherwise require read permission, or 2535 * ownership 2536 */ 2537 if (exp->ex_flags & NFSEXP_NOAUTHNLM) 2538 return 0; 2539 else 2540 acc = NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE; 2541 } 2542 /* 2543 * The file owner always gets access permission for accesses that 2544 * would normally be checked at open time. This is to make 2545 * file access work even when the client has done a fchmod(fd, 0). 2546 * 2547 * However, `cp foo bar' should fail nevertheless when bar is 2548 * readonly. A sensible way to do this might be to reject all 2549 * attempts to truncate a read-only file, because a creat() call 2550 * always implies file truncation. 2551 * ... but this isn't really fair. A process may reasonably call 2552 * ftruncate on an open file descriptor on a file with perm 000. 2553 * We must trust the client to do permission checking - using "ACCESS" 2554 * with NFSv3. 2555 */ 2556 if ((acc & NFSD_MAY_OWNER_OVERRIDE) && 2557 uid_eq(inode->i_uid, current_fsuid())) 2558 return 0; 2559 2560 /* This assumes NFSD_MAY_{READ,WRITE,EXEC} == MAY_{READ,WRITE,EXEC} */ 2561 err = inode_permission(&nop_mnt_idmap, inode, 2562 acc & (MAY_READ | MAY_WRITE | MAY_EXEC)); 2563 2564 /* Allow read access to binaries even when mode 111 */ 2565 if (err == -EACCES && S_ISREG(inode->i_mode) && 2566 (acc == (NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE) || 2567 acc == (NFSD_MAY_READ | NFSD_MAY_READ_IF_EXEC))) 2568 err = inode_permission(&nop_mnt_idmap, inode, MAY_EXEC); 2569 2570 return err? nfserrno(err) : 0; 2571 } 2572