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