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