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 file_start_write(file); 1108 host_err = vfs_iter_write(file, &iter, &pos, flags); 1109 file_end_write(file); 1110 if (host_err < 0) { 1111 nfsd_reset_write_verifier(nn); 1112 trace_nfsd_writeverf_reset(nn, rqstp, host_err); 1113 goto out_nfserr; 1114 } 1115 *cnt = host_err; 1116 nfsd_stats_io_write_add(exp, *cnt); 1117 fsnotify_modify(file); 1118 host_err = filemap_check_wb_err(file->f_mapping, since); 1119 if (host_err < 0) 1120 goto out_nfserr; 1121 1122 if (stable && use_wgather) { 1123 host_err = wait_for_concurrent_writes(file); 1124 if (host_err < 0) { 1125 nfsd_reset_write_verifier(nn); 1126 trace_nfsd_writeverf_reset(nn, rqstp, host_err); 1127 } 1128 } 1129 1130 out_nfserr: 1131 if (host_err >= 0) { 1132 trace_nfsd_write_io_done(rqstp, fhp, offset, *cnt); 1133 nfserr = nfs_ok; 1134 } else { 1135 trace_nfsd_write_err(rqstp, fhp, offset, host_err); 1136 nfserr = nfserrno(host_err); 1137 } 1138 if (restore_flags) 1139 current_restore_flags(pflags, PF_LOCAL_THROTTLE); 1140 return nfserr; 1141 } 1142 1143 /* 1144 * Read data from a file. count must contain the requested read count 1145 * on entry. On return, *count contains the number of bytes actually read. 1146 * N.B. After this call fhp needs an fh_put 1147 */ 1148 __be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp, 1149 loff_t offset, struct kvec *vec, int vlen, unsigned long *count, 1150 u32 *eof) 1151 { 1152 struct nfsd_file *nf; 1153 struct file *file; 1154 __be32 err; 1155 1156 trace_nfsd_read_start(rqstp, fhp, offset, *count); 1157 err = nfsd_file_acquire_gc(rqstp, fhp, NFSD_MAY_READ, &nf); 1158 if (err) 1159 return err; 1160 1161 file = nf->nf_file; 1162 if (file->f_op->splice_read && test_bit(RQ_SPLICE_OK, &rqstp->rq_flags)) 1163 err = nfsd_splice_read(rqstp, fhp, file, offset, count, eof); 1164 else 1165 err = nfsd_readv(rqstp, fhp, file, offset, vec, vlen, count, eof); 1166 1167 nfsd_file_put(nf); 1168 1169 trace_nfsd_read_done(rqstp, fhp, offset, *count); 1170 1171 return err; 1172 } 1173 1174 /* 1175 * Write data to a file. 1176 * The stable flag requests synchronous writes. 1177 * N.B. After this call fhp needs an fh_put 1178 */ 1179 __be32 1180 nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t offset, 1181 struct kvec *vec, int vlen, unsigned long *cnt, int stable, 1182 __be32 *verf) 1183 { 1184 struct nfsd_file *nf; 1185 __be32 err; 1186 1187 trace_nfsd_write_start(rqstp, fhp, offset, *cnt); 1188 1189 err = nfsd_file_acquire_gc(rqstp, fhp, NFSD_MAY_WRITE, &nf); 1190 if (err) 1191 goto out; 1192 1193 err = nfsd_vfs_write(rqstp, fhp, nf, offset, vec, 1194 vlen, cnt, stable, verf); 1195 nfsd_file_put(nf); 1196 out: 1197 trace_nfsd_write_done(rqstp, fhp, offset, *cnt); 1198 return err; 1199 } 1200 1201 /** 1202 * nfsd_commit - Commit pending writes to stable storage 1203 * @rqstp: RPC request being processed 1204 * @fhp: NFS filehandle 1205 * @nf: target file 1206 * @offset: raw offset from beginning of file 1207 * @count: raw count of bytes to sync 1208 * @verf: filled in with the server's current write verifier 1209 * 1210 * Note: we guarantee that data that lies within the range specified 1211 * by the 'offset' and 'count' parameters will be synced. The server 1212 * is permitted to sync data that lies outside this range at the 1213 * same time. 1214 * 1215 * Unfortunately we cannot lock the file to make sure we return full WCC 1216 * data to the client, as locking happens lower down in the filesystem. 1217 * 1218 * Return values: 1219 * An nfsstat value in network byte order. 1220 */ 1221 __be32 1222 nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf, 1223 u64 offset, u32 count, __be32 *verf) 1224 { 1225 __be32 err = nfs_ok; 1226 u64 maxbytes; 1227 loff_t start, end; 1228 struct nfsd_net *nn; 1229 1230 /* 1231 * Convert the client-provided (offset, count) range to a 1232 * (start, end) range. If the client-provided range falls 1233 * outside the maximum file size of the underlying FS, 1234 * clamp the sync range appropriately. 1235 */ 1236 start = 0; 1237 end = LLONG_MAX; 1238 maxbytes = (u64)fhp->fh_dentry->d_sb->s_maxbytes; 1239 if (offset < maxbytes) { 1240 start = offset; 1241 if (count && (offset + count - 1 < maxbytes)) 1242 end = offset + count - 1; 1243 } 1244 1245 nn = net_generic(nf->nf_net, nfsd_net_id); 1246 if (EX_ISSYNC(fhp->fh_export)) { 1247 errseq_t since = READ_ONCE(nf->nf_file->f_wb_err); 1248 int err2; 1249 1250 err2 = vfs_fsync_range(nf->nf_file, start, end, 0); 1251 switch (err2) { 1252 case 0: 1253 nfsd_copy_write_verifier(verf, nn); 1254 err2 = filemap_check_wb_err(nf->nf_file->f_mapping, 1255 since); 1256 err = nfserrno(err2); 1257 break; 1258 case -EINVAL: 1259 err = nfserr_notsupp; 1260 break; 1261 default: 1262 nfsd_reset_write_verifier(nn); 1263 trace_nfsd_writeverf_reset(nn, rqstp, err2); 1264 err = nfserrno(err2); 1265 } 1266 } else 1267 nfsd_copy_write_verifier(verf, nn); 1268 1269 return err; 1270 } 1271 1272 /** 1273 * nfsd_create_setattr - Set a created file's attributes 1274 * @rqstp: RPC transaction being executed 1275 * @fhp: NFS filehandle of parent directory 1276 * @resfhp: NFS filehandle of new object 1277 * @attrs: requested attributes of new object 1278 * 1279 * Returns nfs_ok on success, or an nfsstat in network byte order. 1280 */ 1281 __be32 1282 nfsd_create_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, 1283 struct svc_fh *resfhp, struct nfsd_attrs *attrs) 1284 { 1285 struct iattr *iap = attrs->na_iattr; 1286 __be32 status; 1287 1288 /* 1289 * Mode has already been set by file creation. 1290 */ 1291 iap->ia_valid &= ~ATTR_MODE; 1292 1293 /* 1294 * Setting uid/gid works only for root. Irix appears to 1295 * send along the gid on create when it tries to implement 1296 * setgid directories via NFS: 1297 */ 1298 if (!uid_eq(current_fsuid(), GLOBAL_ROOT_UID)) 1299 iap->ia_valid &= ~(ATTR_UID|ATTR_GID); 1300 1301 /* 1302 * Callers expect new file metadata to be committed even 1303 * if the attributes have not changed. 1304 */ 1305 if (iap->ia_valid) 1306 status = nfsd_setattr(rqstp, resfhp, attrs, 0, (time64_t)0); 1307 else 1308 status = nfserrno(commit_metadata(resfhp)); 1309 1310 /* 1311 * Transactional filesystems had a chance to commit changes 1312 * for both parent and child simultaneously making the 1313 * following commit_metadata a noop in many cases. 1314 */ 1315 if (!status) 1316 status = nfserrno(commit_metadata(fhp)); 1317 1318 /* 1319 * Update the new filehandle to pick up the new attributes. 1320 */ 1321 if (!status) 1322 status = fh_update(resfhp); 1323 1324 return status; 1325 } 1326 1327 /* HPUX client sometimes creates a file in mode 000, and sets size to 0. 1328 * setting size to 0 may fail for some specific file systems by the permission 1329 * checking which requires WRITE permission but the mode is 000. 1330 * we ignore the resizing(to 0) on the just new created file, since the size is 1331 * 0 after file created. 1332 * 1333 * call this only after vfs_create() is called. 1334 * */ 1335 static void 1336 nfsd_check_ignore_resizing(struct iattr *iap) 1337 { 1338 if ((iap->ia_valid & ATTR_SIZE) && (iap->ia_size == 0)) 1339 iap->ia_valid &= ~ATTR_SIZE; 1340 } 1341 1342 /* The parent directory should already be locked: */ 1343 __be32 1344 nfsd_create_locked(struct svc_rqst *rqstp, struct svc_fh *fhp, 1345 struct nfsd_attrs *attrs, 1346 int type, dev_t rdev, struct svc_fh *resfhp) 1347 { 1348 struct dentry *dentry, *dchild; 1349 struct inode *dirp; 1350 struct iattr *iap = attrs->na_iattr; 1351 __be32 err; 1352 int host_err; 1353 1354 dentry = fhp->fh_dentry; 1355 dirp = d_inode(dentry); 1356 1357 dchild = dget(resfhp->fh_dentry); 1358 err = nfsd_permission(rqstp, fhp->fh_export, dentry, NFSD_MAY_CREATE); 1359 if (err) 1360 goto out; 1361 1362 if (!(iap->ia_valid & ATTR_MODE)) 1363 iap->ia_mode = 0; 1364 iap->ia_mode = (iap->ia_mode & S_IALLUGO) | type; 1365 1366 if (!IS_POSIXACL(dirp)) 1367 iap->ia_mode &= ~current_umask(); 1368 1369 err = 0; 1370 switch (type) { 1371 case S_IFREG: 1372 host_err = vfs_create(&init_user_ns, dirp, dchild, iap->ia_mode, true); 1373 if (!host_err) 1374 nfsd_check_ignore_resizing(iap); 1375 break; 1376 case S_IFDIR: 1377 host_err = vfs_mkdir(&init_user_ns, dirp, dchild, iap->ia_mode); 1378 if (!host_err && unlikely(d_unhashed(dchild))) { 1379 struct dentry *d; 1380 d = lookup_one_len(dchild->d_name.name, 1381 dchild->d_parent, 1382 dchild->d_name.len); 1383 if (IS_ERR(d)) { 1384 host_err = PTR_ERR(d); 1385 break; 1386 } 1387 if (unlikely(d_is_negative(d))) { 1388 dput(d); 1389 err = nfserr_serverfault; 1390 goto out; 1391 } 1392 dput(resfhp->fh_dentry); 1393 resfhp->fh_dentry = dget(d); 1394 err = fh_update(resfhp); 1395 dput(dchild); 1396 dchild = d; 1397 if (err) 1398 goto out; 1399 } 1400 break; 1401 case S_IFCHR: 1402 case S_IFBLK: 1403 case S_IFIFO: 1404 case S_IFSOCK: 1405 host_err = vfs_mknod(&init_user_ns, dirp, dchild, 1406 iap->ia_mode, rdev); 1407 break; 1408 default: 1409 printk(KERN_WARNING "nfsd: bad file type %o in nfsd_create\n", 1410 type); 1411 host_err = -EINVAL; 1412 } 1413 if (host_err < 0) 1414 goto out_nfserr; 1415 1416 err = nfsd_create_setattr(rqstp, fhp, resfhp, attrs); 1417 1418 out: 1419 dput(dchild); 1420 return err; 1421 1422 out_nfserr: 1423 err = nfserrno(host_err); 1424 goto out; 1425 } 1426 1427 /* 1428 * Create a filesystem object (regular, directory, special). 1429 * Note that the parent directory is left locked. 1430 * 1431 * N.B. Every call to nfsd_create needs an fh_put for _both_ fhp and resfhp 1432 */ 1433 __be32 1434 nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, 1435 char *fname, int flen, struct nfsd_attrs *attrs, 1436 int type, dev_t rdev, struct svc_fh *resfhp) 1437 { 1438 struct dentry *dentry, *dchild = NULL; 1439 __be32 err; 1440 int host_err; 1441 1442 if (isdotent(fname, flen)) 1443 return nfserr_exist; 1444 1445 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_NOP); 1446 if (err) 1447 return err; 1448 1449 dentry = fhp->fh_dentry; 1450 1451 host_err = fh_want_write(fhp); 1452 if (host_err) 1453 return nfserrno(host_err); 1454 1455 inode_lock_nested(dentry->d_inode, I_MUTEX_PARENT); 1456 dchild = lookup_one_len(fname, dentry, flen); 1457 host_err = PTR_ERR(dchild); 1458 if (IS_ERR(dchild)) { 1459 err = nfserrno(host_err); 1460 goto out_unlock; 1461 } 1462 err = fh_compose(resfhp, fhp->fh_export, dchild, fhp); 1463 /* 1464 * We unconditionally drop our ref to dchild as fh_compose will have 1465 * already grabbed its own ref for it. 1466 */ 1467 dput(dchild); 1468 if (err) 1469 goto out_unlock; 1470 fh_fill_pre_attrs(fhp); 1471 err = nfsd_create_locked(rqstp, fhp, attrs, type, rdev, resfhp); 1472 fh_fill_post_attrs(fhp); 1473 out_unlock: 1474 inode_unlock(dentry->d_inode); 1475 return err; 1476 } 1477 1478 /* 1479 * Read a symlink. On entry, *lenp must contain the maximum path length that 1480 * fits into the buffer. On return, it contains the true length. 1481 * N.B. After this call fhp needs an fh_put 1482 */ 1483 __be32 1484 nfsd_readlink(struct svc_rqst *rqstp, struct svc_fh *fhp, char *buf, int *lenp) 1485 { 1486 __be32 err; 1487 const char *link; 1488 struct path path; 1489 DEFINE_DELAYED_CALL(done); 1490 int len; 1491 1492 err = fh_verify(rqstp, fhp, S_IFLNK, NFSD_MAY_NOP); 1493 if (unlikely(err)) 1494 return err; 1495 1496 path.mnt = fhp->fh_export->ex_path.mnt; 1497 path.dentry = fhp->fh_dentry; 1498 1499 if (unlikely(!d_is_symlink(path.dentry))) 1500 return nfserr_inval; 1501 1502 touch_atime(&path); 1503 1504 link = vfs_get_link(path.dentry, &done); 1505 if (IS_ERR(link)) 1506 return nfserrno(PTR_ERR(link)); 1507 1508 len = strlen(link); 1509 if (len < *lenp) 1510 *lenp = len; 1511 memcpy(buf, link, *lenp); 1512 do_delayed_call(&done); 1513 return 0; 1514 } 1515 1516 /** 1517 * nfsd_symlink - Create a symlink and look up its inode 1518 * @rqstp: RPC transaction being executed 1519 * @fhp: NFS filehandle of parent directory 1520 * @fname: filename of the new symlink 1521 * @flen: length of @fname 1522 * @path: content of the new symlink (NUL-terminated) 1523 * @attrs: requested attributes of new object 1524 * @resfhp: NFS filehandle of new object 1525 * 1526 * N.B. After this call _both_ fhp and resfhp need an fh_put 1527 * 1528 * Returns nfs_ok on success, or an nfsstat in network byte order. 1529 */ 1530 __be32 1531 nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp, 1532 char *fname, int flen, 1533 char *path, struct nfsd_attrs *attrs, 1534 struct svc_fh *resfhp) 1535 { 1536 struct dentry *dentry, *dnew; 1537 __be32 err, cerr; 1538 int host_err; 1539 1540 err = nfserr_noent; 1541 if (!flen || path[0] == '\0') 1542 goto out; 1543 err = nfserr_exist; 1544 if (isdotent(fname, flen)) 1545 goto out; 1546 1547 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE); 1548 if (err) 1549 goto out; 1550 1551 host_err = fh_want_write(fhp); 1552 if (host_err) { 1553 err = nfserrno(host_err); 1554 goto out; 1555 } 1556 1557 dentry = fhp->fh_dentry; 1558 inode_lock_nested(dentry->d_inode, I_MUTEX_PARENT); 1559 dnew = lookup_one_len(fname, dentry, flen); 1560 if (IS_ERR(dnew)) { 1561 err = nfserrno(PTR_ERR(dnew)); 1562 inode_unlock(dentry->d_inode); 1563 goto out_drop_write; 1564 } 1565 fh_fill_pre_attrs(fhp); 1566 host_err = vfs_symlink(&init_user_ns, d_inode(dentry), dnew, path); 1567 err = nfserrno(host_err); 1568 cerr = fh_compose(resfhp, fhp->fh_export, dnew, fhp); 1569 if (!err) 1570 nfsd_create_setattr(rqstp, fhp, resfhp, attrs); 1571 fh_fill_post_attrs(fhp); 1572 inode_unlock(dentry->d_inode); 1573 if (!err) 1574 err = nfserrno(commit_metadata(fhp)); 1575 dput(dnew); 1576 if (err==0) err = cerr; 1577 out_drop_write: 1578 fh_drop_write(fhp); 1579 out: 1580 return err; 1581 } 1582 1583 /* 1584 * Create a hardlink 1585 * N.B. After this call _both_ ffhp and tfhp need an fh_put 1586 */ 1587 __be32 1588 nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp, 1589 char *name, int len, struct svc_fh *tfhp) 1590 { 1591 struct dentry *ddir, *dnew, *dold; 1592 struct inode *dirp; 1593 __be32 err; 1594 int host_err; 1595 1596 err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_CREATE); 1597 if (err) 1598 goto out; 1599 err = fh_verify(rqstp, tfhp, 0, NFSD_MAY_NOP); 1600 if (err) 1601 goto out; 1602 err = nfserr_isdir; 1603 if (d_is_dir(tfhp->fh_dentry)) 1604 goto out; 1605 err = nfserr_perm; 1606 if (!len) 1607 goto out; 1608 err = nfserr_exist; 1609 if (isdotent(name, len)) 1610 goto out; 1611 1612 host_err = fh_want_write(tfhp); 1613 if (host_err) { 1614 err = nfserrno(host_err); 1615 goto out; 1616 } 1617 1618 ddir = ffhp->fh_dentry; 1619 dirp = d_inode(ddir); 1620 inode_lock_nested(dirp, I_MUTEX_PARENT); 1621 1622 dnew = lookup_one_len(name, ddir, len); 1623 if (IS_ERR(dnew)) { 1624 err = nfserrno(PTR_ERR(dnew)); 1625 goto out_unlock; 1626 } 1627 1628 dold = tfhp->fh_dentry; 1629 1630 err = nfserr_noent; 1631 if (d_really_is_negative(dold)) 1632 goto out_dput; 1633 fh_fill_pre_attrs(ffhp); 1634 host_err = vfs_link(dold, &init_user_ns, dirp, dnew, NULL); 1635 fh_fill_post_attrs(ffhp); 1636 inode_unlock(dirp); 1637 if (!host_err) { 1638 err = nfserrno(commit_metadata(ffhp)); 1639 if (!err) 1640 err = nfserrno(commit_metadata(tfhp)); 1641 } else { 1642 if (host_err == -EXDEV && rqstp->rq_vers == 2) 1643 err = nfserr_acces; 1644 else 1645 err = nfserrno(host_err); 1646 } 1647 dput(dnew); 1648 out_drop_write: 1649 fh_drop_write(tfhp); 1650 out: 1651 return err; 1652 1653 out_dput: 1654 dput(dnew); 1655 out_unlock: 1656 inode_unlock(dirp); 1657 goto out_drop_write; 1658 } 1659 1660 static void 1661 nfsd_close_cached_files(struct dentry *dentry) 1662 { 1663 struct inode *inode = d_inode(dentry); 1664 1665 if (inode && S_ISREG(inode->i_mode)) 1666 nfsd_file_close_inode_sync(inode); 1667 } 1668 1669 static bool 1670 nfsd_has_cached_files(struct dentry *dentry) 1671 { 1672 bool ret = false; 1673 struct inode *inode = d_inode(dentry); 1674 1675 if (inode && S_ISREG(inode->i_mode)) 1676 ret = nfsd_file_is_cached(inode); 1677 return ret; 1678 } 1679 1680 /* 1681 * Rename a file 1682 * N.B. After this call _both_ ffhp and tfhp need an fh_put 1683 */ 1684 __be32 1685 nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, 1686 struct svc_fh *tfhp, char *tname, int tlen) 1687 { 1688 struct dentry *fdentry, *tdentry, *odentry, *ndentry, *trap; 1689 struct inode *fdir, *tdir; 1690 __be32 err; 1691 int host_err; 1692 bool close_cached = false; 1693 1694 err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_REMOVE); 1695 if (err) 1696 goto out; 1697 err = fh_verify(rqstp, tfhp, S_IFDIR, NFSD_MAY_CREATE); 1698 if (err) 1699 goto out; 1700 1701 fdentry = ffhp->fh_dentry; 1702 fdir = d_inode(fdentry); 1703 1704 tdentry = tfhp->fh_dentry; 1705 tdir = d_inode(tdentry); 1706 1707 err = nfserr_perm; 1708 if (!flen || isdotent(fname, flen) || !tlen || isdotent(tname, tlen)) 1709 goto out; 1710 1711 retry: 1712 host_err = fh_want_write(ffhp); 1713 if (host_err) { 1714 err = nfserrno(host_err); 1715 goto out; 1716 } 1717 1718 trap = lock_rename(tdentry, fdentry); 1719 fh_fill_pre_attrs(ffhp); 1720 fh_fill_pre_attrs(tfhp); 1721 1722 odentry = lookup_one_len(fname, fdentry, flen); 1723 host_err = PTR_ERR(odentry); 1724 if (IS_ERR(odentry)) 1725 goto out_nfserr; 1726 1727 host_err = -ENOENT; 1728 if (d_really_is_negative(odentry)) 1729 goto out_dput_old; 1730 host_err = -EINVAL; 1731 if (odentry == trap) 1732 goto out_dput_old; 1733 1734 ndentry = lookup_one_len(tname, tdentry, tlen); 1735 host_err = PTR_ERR(ndentry); 1736 if (IS_ERR(ndentry)) 1737 goto out_dput_old; 1738 host_err = -ENOTEMPTY; 1739 if (ndentry == trap) 1740 goto out_dput_new; 1741 1742 host_err = -EXDEV; 1743 if (ffhp->fh_export->ex_path.mnt != tfhp->fh_export->ex_path.mnt) 1744 goto out_dput_new; 1745 if (ffhp->fh_export->ex_path.dentry != tfhp->fh_export->ex_path.dentry) 1746 goto out_dput_new; 1747 1748 if ((ndentry->d_sb->s_export_op->flags & EXPORT_OP_CLOSE_BEFORE_UNLINK) && 1749 nfsd_has_cached_files(ndentry)) { 1750 close_cached = true; 1751 goto out_dput_old; 1752 } else { 1753 struct renamedata rd = { 1754 .old_mnt_userns = &init_user_ns, 1755 .old_dir = fdir, 1756 .old_dentry = odentry, 1757 .new_mnt_userns = &init_user_ns, 1758 .new_dir = tdir, 1759 .new_dentry = ndentry, 1760 }; 1761 int retries; 1762 1763 for (retries = 1;;) { 1764 host_err = vfs_rename(&rd); 1765 if (host_err != -EAGAIN || !retries--) 1766 break; 1767 if (!nfsd_wait_for_delegreturn(rqstp, d_inode(odentry))) 1768 break; 1769 } 1770 if (!host_err) { 1771 host_err = commit_metadata(tfhp); 1772 if (!host_err) 1773 host_err = commit_metadata(ffhp); 1774 } 1775 } 1776 out_dput_new: 1777 dput(ndentry); 1778 out_dput_old: 1779 dput(odentry); 1780 out_nfserr: 1781 err = nfserrno(host_err); 1782 1783 if (!close_cached) { 1784 fh_fill_post_attrs(ffhp); 1785 fh_fill_post_attrs(tfhp); 1786 } 1787 unlock_rename(tdentry, fdentry); 1788 fh_drop_write(ffhp); 1789 1790 /* 1791 * If the target dentry has cached open files, then we need to try to 1792 * close them prior to doing the rename. Flushing delayed fput 1793 * shouldn't be done with locks held however, so we delay it until this 1794 * point and then reattempt the whole shebang. 1795 */ 1796 if (close_cached) { 1797 close_cached = false; 1798 nfsd_close_cached_files(ndentry); 1799 dput(ndentry); 1800 goto retry; 1801 } 1802 out: 1803 return err; 1804 } 1805 1806 /* 1807 * Unlink a file or directory 1808 * N.B. After this call fhp needs an fh_put 1809 */ 1810 __be32 1811 nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, 1812 char *fname, int flen) 1813 { 1814 struct dentry *dentry, *rdentry; 1815 struct inode *dirp; 1816 struct inode *rinode; 1817 __be32 err; 1818 int host_err; 1819 1820 err = nfserr_acces; 1821 if (!flen || isdotent(fname, flen)) 1822 goto out; 1823 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_REMOVE); 1824 if (err) 1825 goto out; 1826 1827 host_err = fh_want_write(fhp); 1828 if (host_err) 1829 goto out_nfserr; 1830 1831 dentry = fhp->fh_dentry; 1832 dirp = d_inode(dentry); 1833 inode_lock_nested(dirp, I_MUTEX_PARENT); 1834 1835 rdentry = lookup_one_len(fname, dentry, flen); 1836 host_err = PTR_ERR(rdentry); 1837 if (IS_ERR(rdentry)) 1838 goto out_unlock; 1839 1840 if (d_really_is_negative(rdentry)) { 1841 dput(rdentry); 1842 host_err = -ENOENT; 1843 goto out_unlock; 1844 } 1845 rinode = d_inode(rdentry); 1846 ihold(rinode); 1847 1848 if (!type) 1849 type = d_inode(rdentry)->i_mode & S_IFMT; 1850 1851 fh_fill_pre_attrs(fhp); 1852 if (type != S_IFDIR) { 1853 int retries; 1854 1855 if (rdentry->d_sb->s_export_op->flags & EXPORT_OP_CLOSE_BEFORE_UNLINK) 1856 nfsd_close_cached_files(rdentry); 1857 1858 for (retries = 1;;) { 1859 host_err = vfs_unlink(&init_user_ns, dirp, rdentry, NULL); 1860 if (host_err != -EAGAIN || !retries--) 1861 break; 1862 if (!nfsd_wait_for_delegreturn(rqstp, rinode)) 1863 break; 1864 } 1865 } else { 1866 host_err = vfs_rmdir(&init_user_ns, dirp, rdentry); 1867 } 1868 fh_fill_post_attrs(fhp); 1869 1870 inode_unlock(dirp); 1871 if (!host_err) 1872 host_err = commit_metadata(fhp); 1873 dput(rdentry); 1874 iput(rinode); /* truncate the inode here */ 1875 1876 out_drop_write: 1877 fh_drop_write(fhp); 1878 out_nfserr: 1879 if (host_err == -EBUSY) { 1880 /* name is mounted-on. There is no perfect 1881 * error status. 1882 */ 1883 if (nfsd_v4client(rqstp)) 1884 err = nfserr_file_open; 1885 else 1886 err = nfserr_acces; 1887 } else { 1888 err = nfserrno(host_err); 1889 } 1890 out: 1891 return err; 1892 out_unlock: 1893 inode_unlock(dirp); 1894 goto out_drop_write; 1895 } 1896 1897 /* 1898 * We do this buffering because we must not call back into the file 1899 * system's ->lookup() method from the filldir callback. That may well 1900 * deadlock a number of file systems. 1901 * 1902 * This is based heavily on the implementation of same in XFS. 1903 */ 1904 struct buffered_dirent { 1905 u64 ino; 1906 loff_t offset; 1907 int namlen; 1908 unsigned int d_type; 1909 char name[]; 1910 }; 1911 1912 struct readdir_data { 1913 struct dir_context ctx; 1914 char *dirent; 1915 size_t used; 1916 int full; 1917 }; 1918 1919 static bool nfsd_buffered_filldir(struct dir_context *ctx, const char *name, 1920 int namlen, loff_t offset, u64 ino, 1921 unsigned int d_type) 1922 { 1923 struct readdir_data *buf = 1924 container_of(ctx, struct readdir_data, ctx); 1925 struct buffered_dirent *de = (void *)(buf->dirent + buf->used); 1926 unsigned int reclen; 1927 1928 reclen = ALIGN(sizeof(struct buffered_dirent) + namlen, sizeof(u64)); 1929 if (buf->used + reclen > PAGE_SIZE) { 1930 buf->full = 1; 1931 return false; 1932 } 1933 1934 de->namlen = namlen; 1935 de->offset = offset; 1936 de->ino = ino; 1937 de->d_type = d_type; 1938 memcpy(de->name, name, namlen); 1939 buf->used += reclen; 1940 1941 return true; 1942 } 1943 1944 static __be32 nfsd_buffered_readdir(struct file *file, struct svc_fh *fhp, 1945 nfsd_filldir_t func, struct readdir_cd *cdp, 1946 loff_t *offsetp) 1947 { 1948 struct buffered_dirent *de; 1949 int host_err; 1950 int size; 1951 loff_t offset; 1952 struct readdir_data buf = { 1953 .ctx.actor = nfsd_buffered_filldir, 1954 .dirent = (void *)__get_free_page(GFP_KERNEL) 1955 }; 1956 1957 if (!buf.dirent) 1958 return nfserrno(-ENOMEM); 1959 1960 offset = *offsetp; 1961 1962 while (1) { 1963 unsigned int reclen; 1964 1965 cdp->err = nfserr_eof; /* will be cleared on successful read */ 1966 buf.used = 0; 1967 buf.full = 0; 1968 1969 host_err = iterate_dir(file, &buf.ctx); 1970 if (buf.full) 1971 host_err = 0; 1972 1973 if (host_err < 0) 1974 break; 1975 1976 size = buf.used; 1977 1978 if (!size) 1979 break; 1980 1981 de = (struct buffered_dirent *)buf.dirent; 1982 while (size > 0) { 1983 offset = de->offset; 1984 1985 if (func(cdp, de->name, de->namlen, de->offset, 1986 de->ino, de->d_type)) 1987 break; 1988 1989 if (cdp->err != nfs_ok) 1990 break; 1991 1992 trace_nfsd_dirent(fhp, de->ino, de->name, de->namlen); 1993 1994 reclen = ALIGN(sizeof(*de) + de->namlen, 1995 sizeof(u64)); 1996 size -= reclen; 1997 de = (struct buffered_dirent *)((char *)de + reclen); 1998 } 1999 if (size > 0) /* We bailed out early */ 2000 break; 2001 2002 offset = vfs_llseek(file, 0, SEEK_CUR); 2003 } 2004 2005 free_page((unsigned long)(buf.dirent)); 2006 2007 if (host_err) 2008 return nfserrno(host_err); 2009 2010 *offsetp = offset; 2011 return cdp->err; 2012 } 2013 2014 /* 2015 * Read entries from a directory. 2016 * The NFSv3/4 verifier we ignore for now. 2017 */ 2018 __be32 2019 nfsd_readdir(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t *offsetp, 2020 struct readdir_cd *cdp, nfsd_filldir_t func) 2021 { 2022 __be32 err; 2023 struct file *file; 2024 loff_t offset = *offsetp; 2025 int may_flags = NFSD_MAY_READ; 2026 2027 /* NFSv2 only supports 32 bit cookies */ 2028 if (rqstp->rq_vers > 2) 2029 may_flags |= NFSD_MAY_64BIT_COOKIE; 2030 2031 err = nfsd_open(rqstp, fhp, S_IFDIR, may_flags, &file); 2032 if (err) 2033 goto out; 2034 2035 offset = vfs_llseek(file, offset, SEEK_SET); 2036 if (offset < 0) { 2037 err = nfserrno((int)offset); 2038 goto out_close; 2039 } 2040 2041 err = nfsd_buffered_readdir(file, fhp, func, cdp, offsetp); 2042 2043 if (err == nfserr_eof || err == nfserr_toosmall) 2044 err = nfs_ok; /* can still be found in ->err */ 2045 out_close: 2046 fput(file); 2047 out: 2048 return err; 2049 } 2050 2051 /* 2052 * Get file system stats 2053 * N.B. After this call fhp needs an fh_put 2054 */ 2055 __be32 2056 nfsd_statfs(struct svc_rqst *rqstp, struct svc_fh *fhp, struct kstatfs *stat, int access) 2057 { 2058 __be32 err; 2059 2060 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP | access); 2061 if (!err) { 2062 struct path path = { 2063 .mnt = fhp->fh_export->ex_path.mnt, 2064 .dentry = fhp->fh_dentry, 2065 }; 2066 if (vfs_statfs(&path, stat)) 2067 err = nfserr_io; 2068 } 2069 return err; 2070 } 2071 2072 static int exp_rdonly(struct svc_rqst *rqstp, struct svc_export *exp) 2073 { 2074 return nfsexp_flags(rqstp, exp) & NFSEXP_READONLY; 2075 } 2076 2077 #ifdef CONFIG_NFSD_V4 2078 /* 2079 * Helper function to translate error numbers. In the case of xattr operations, 2080 * some error codes need to be translated outside of the standard translations. 2081 * 2082 * ENODATA needs to be translated to nfserr_noxattr. 2083 * E2BIG to nfserr_xattr2big. 2084 * 2085 * Additionally, vfs_listxattr can return -ERANGE. This means that the 2086 * file has too many extended attributes to retrieve inside an 2087 * XATTR_LIST_MAX sized buffer. This is a bug in the xattr implementation: 2088 * filesystems will allow the adding of extended attributes until they hit 2089 * their own internal limit. This limit may be larger than XATTR_LIST_MAX. 2090 * So, at that point, the attributes are present and valid, but can't 2091 * be retrieved using listxattr, since the upper level xattr code enforces 2092 * the XATTR_LIST_MAX limit. 2093 * 2094 * This bug means that we need to deal with listxattr returning -ERANGE. The 2095 * best mapping is to return TOOSMALL. 2096 */ 2097 static __be32 2098 nfsd_xattr_errno(int err) 2099 { 2100 switch (err) { 2101 case -ENODATA: 2102 return nfserr_noxattr; 2103 case -E2BIG: 2104 return nfserr_xattr2big; 2105 case -ERANGE: 2106 return nfserr_toosmall; 2107 } 2108 return nfserrno(err); 2109 } 2110 2111 /* 2112 * Retrieve the specified user extended attribute. To avoid always 2113 * having to allocate the maximum size (since we are not getting 2114 * a maximum size from the RPC), do a probe + alloc. Hold a reader 2115 * lock on i_rwsem to prevent the extended attribute from changing 2116 * size while we're doing this. 2117 */ 2118 __be32 2119 nfsd_getxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name, 2120 void **bufp, int *lenp) 2121 { 2122 ssize_t len; 2123 __be32 err; 2124 char *buf; 2125 struct inode *inode; 2126 struct dentry *dentry; 2127 2128 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_READ); 2129 if (err) 2130 return err; 2131 2132 err = nfs_ok; 2133 dentry = fhp->fh_dentry; 2134 inode = d_inode(dentry); 2135 2136 inode_lock_shared(inode); 2137 2138 len = vfs_getxattr(&init_user_ns, dentry, name, NULL, 0); 2139 2140 /* 2141 * Zero-length attribute, just return. 2142 */ 2143 if (len == 0) { 2144 *bufp = NULL; 2145 *lenp = 0; 2146 goto out; 2147 } 2148 2149 if (len < 0) { 2150 err = nfsd_xattr_errno(len); 2151 goto out; 2152 } 2153 2154 if (len > *lenp) { 2155 err = nfserr_toosmall; 2156 goto out; 2157 } 2158 2159 buf = kvmalloc(len, GFP_KERNEL | GFP_NOFS); 2160 if (buf == NULL) { 2161 err = nfserr_jukebox; 2162 goto out; 2163 } 2164 2165 len = vfs_getxattr(&init_user_ns, dentry, name, buf, len); 2166 if (len <= 0) { 2167 kvfree(buf); 2168 buf = NULL; 2169 err = nfsd_xattr_errno(len); 2170 } 2171 2172 *lenp = len; 2173 *bufp = buf; 2174 2175 out: 2176 inode_unlock_shared(inode); 2177 2178 return err; 2179 } 2180 2181 /* 2182 * Retrieve the xattr names. Since we can't know how many are 2183 * user extended attributes, we must get all attributes here, 2184 * and have the XDR encode filter out the "user." ones. 2185 * 2186 * While this could always just allocate an XATTR_LIST_MAX 2187 * buffer, that's a waste, so do a probe + allocate. To 2188 * avoid any changes between the probe and allocate, wrap 2189 * this in inode_lock. 2190 */ 2191 __be32 2192 nfsd_listxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char **bufp, 2193 int *lenp) 2194 { 2195 ssize_t len; 2196 __be32 err; 2197 char *buf; 2198 struct inode *inode; 2199 struct dentry *dentry; 2200 2201 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_READ); 2202 if (err) 2203 return err; 2204 2205 dentry = fhp->fh_dentry; 2206 inode = d_inode(dentry); 2207 *lenp = 0; 2208 2209 inode_lock_shared(inode); 2210 2211 len = vfs_listxattr(dentry, NULL, 0); 2212 if (len <= 0) { 2213 err = nfsd_xattr_errno(len); 2214 goto out; 2215 } 2216 2217 if (len > XATTR_LIST_MAX) { 2218 err = nfserr_xattr2big; 2219 goto out; 2220 } 2221 2222 /* 2223 * We're holding i_rwsem - use GFP_NOFS. 2224 */ 2225 buf = kvmalloc(len, GFP_KERNEL | GFP_NOFS); 2226 if (buf == NULL) { 2227 err = nfserr_jukebox; 2228 goto out; 2229 } 2230 2231 len = vfs_listxattr(dentry, buf, len); 2232 if (len <= 0) { 2233 kvfree(buf); 2234 err = nfsd_xattr_errno(len); 2235 goto out; 2236 } 2237 2238 *lenp = len; 2239 *bufp = buf; 2240 2241 err = nfs_ok; 2242 out: 2243 inode_unlock_shared(inode); 2244 2245 return err; 2246 } 2247 2248 /** 2249 * nfsd_removexattr - Remove an extended attribute 2250 * @rqstp: RPC transaction being executed 2251 * @fhp: NFS filehandle of object with xattr to remove 2252 * @name: name of xattr to remove (NUL-terminate) 2253 * 2254 * Pass in a NULL pointer for delegated_inode, and let the client deal 2255 * with NFS4ERR_DELAY (same as with e.g. setattr and remove). 2256 * 2257 * Returns nfs_ok on success, or an nfsstat in network byte order. 2258 */ 2259 __be32 2260 nfsd_removexattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name) 2261 { 2262 __be32 err; 2263 int ret; 2264 2265 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_WRITE); 2266 if (err) 2267 return err; 2268 2269 ret = fh_want_write(fhp); 2270 if (ret) 2271 return nfserrno(ret); 2272 2273 inode_lock(fhp->fh_dentry->d_inode); 2274 fh_fill_pre_attrs(fhp); 2275 2276 ret = __vfs_removexattr_locked(&init_user_ns, fhp->fh_dentry, 2277 name, NULL); 2278 2279 fh_fill_post_attrs(fhp); 2280 inode_unlock(fhp->fh_dentry->d_inode); 2281 fh_drop_write(fhp); 2282 2283 return nfsd_xattr_errno(ret); 2284 } 2285 2286 __be32 2287 nfsd_setxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name, 2288 void *buf, u32 len, u32 flags) 2289 { 2290 __be32 err; 2291 int ret; 2292 2293 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_WRITE); 2294 if (err) 2295 return err; 2296 2297 ret = fh_want_write(fhp); 2298 if (ret) 2299 return nfserrno(ret); 2300 inode_lock(fhp->fh_dentry->d_inode); 2301 fh_fill_pre_attrs(fhp); 2302 2303 ret = __vfs_setxattr_locked(&init_user_ns, fhp->fh_dentry, name, buf, 2304 len, flags, NULL); 2305 fh_fill_post_attrs(fhp); 2306 inode_unlock(fhp->fh_dentry->d_inode); 2307 fh_drop_write(fhp); 2308 2309 return nfsd_xattr_errno(ret); 2310 } 2311 #endif 2312 2313 /* 2314 * Check for a user's access permissions to this inode. 2315 */ 2316 __be32 2317 nfsd_permission(struct svc_rqst *rqstp, struct svc_export *exp, 2318 struct dentry *dentry, int acc) 2319 { 2320 struct inode *inode = d_inode(dentry); 2321 int err; 2322 2323 if ((acc & NFSD_MAY_MASK) == NFSD_MAY_NOP) 2324 return 0; 2325 #if 0 2326 dprintk("nfsd: permission 0x%x%s%s%s%s%s%s%s mode 0%o%s%s%s\n", 2327 acc, 2328 (acc & NFSD_MAY_READ)? " read" : "", 2329 (acc & NFSD_MAY_WRITE)? " write" : "", 2330 (acc & NFSD_MAY_EXEC)? " exec" : "", 2331 (acc & NFSD_MAY_SATTR)? " sattr" : "", 2332 (acc & NFSD_MAY_TRUNC)? " trunc" : "", 2333 (acc & NFSD_MAY_LOCK)? " lock" : "", 2334 (acc & NFSD_MAY_OWNER_OVERRIDE)? " owneroverride" : "", 2335 inode->i_mode, 2336 IS_IMMUTABLE(inode)? " immut" : "", 2337 IS_APPEND(inode)? " append" : "", 2338 __mnt_is_readonly(exp->ex_path.mnt)? " ro" : ""); 2339 dprintk(" owner %d/%d user %d/%d\n", 2340 inode->i_uid, inode->i_gid, current_fsuid(), current_fsgid()); 2341 #endif 2342 2343 /* Normally we reject any write/sattr etc access on a read-only file 2344 * system. But if it is IRIX doing check on write-access for a 2345 * device special file, we ignore rofs. 2346 */ 2347 if (!(acc & NFSD_MAY_LOCAL_ACCESS)) 2348 if (acc & (NFSD_MAY_WRITE | NFSD_MAY_SATTR | NFSD_MAY_TRUNC)) { 2349 if (exp_rdonly(rqstp, exp) || 2350 __mnt_is_readonly(exp->ex_path.mnt)) 2351 return nfserr_rofs; 2352 if (/* (acc & NFSD_MAY_WRITE) && */ IS_IMMUTABLE(inode)) 2353 return nfserr_perm; 2354 } 2355 if ((acc & NFSD_MAY_TRUNC) && IS_APPEND(inode)) 2356 return nfserr_perm; 2357 2358 if (acc & NFSD_MAY_LOCK) { 2359 /* If we cannot rely on authentication in NLM requests, 2360 * just allow locks, otherwise require read permission, or 2361 * ownership 2362 */ 2363 if (exp->ex_flags & NFSEXP_NOAUTHNLM) 2364 return 0; 2365 else 2366 acc = NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE; 2367 } 2368 /* 2369 * The file owner always gets access permission for accesses that 2370 * would normally be checked at open time. This is to make 2371 * file access work even when the client has done a fchmod(fd, 0). 2372 * 2373 * However, `cp foo bar' should fail nevertheless when bar is 2374 * readonly. A sensible way to do this might be to reject all 2375 * attempts to truncate a read-only file, because a creat() call 2376 * always implies file truncation. 2377 * ... but this isn't really fair. A process may reasonably call 2378 * ftruncate on an open file descriptor on a file with perm 000. 2379 * We must trust the client to do permission checking - using "ACCESS" 2380 * with NFSv3. 2381 */ 2382 if ((acc & NFSD_MAY_OWNER_OVERRIDE) && 2383 uid_eq(inode->i_uid, current_fsuid())) 2384 return 0; 2385 2386 /* This assumes NFSD_MAY_{READ,WRITE,EXEC} == MAY_{READ,WRITE,EXEC} */ 2387 err = inode_permission(&init_user_ns, inode, 2388 acc & (MAY_READ | MAY_WRITE | MAY_EXEC)); 2389 2390 /* Allow read access to binaries even when mode 111 */ 2391 if (err == -EACCES && S_ISREG(inode->i_mode) && 2392 (acc == (NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE) || 2393 acc == (NFSD_MAY_READ | NFSD_MAY_READ_IF_EXEC))) 2394 err = inode_permission(&init_user_ns, inode, MAY_EXEC); 2395 2396 return err? nfserrno(err) : 0; 2397 } 2398