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