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