1 /* 2 * File operations used by nfsd. Some of these have been ripped from 3 * other parts of the kernel because they weren't exported, others 4 * are partial duplicates with added or changed functionality. 5 * 6 * Note that several functions dget() the dentry upon which they want 7 * to act, most notably those that create directory entries. Response 8 * dentry's are dput()'d if necessary in the release callback. 9 * So if you notice code paths that apparently fail to dput() the 10 * dentry, don't worry--they have been taken care of. 11 * 12 * Copyright (C) 1995-1999 Olaf Kirch <okir@monad.swb.de> 13 * Zerocpy NFS support (C) 2002 Hirokazu Takahashi <taka@valinux.co.jp> 14 */ 15 16 #include <linux/fs.h> 17 #include <linux/file.h> 18 #include <linux/splice.h> 19 #include <linux/falloc.h> 20 #include <linux/fcntl.h> 21 #include <linux/namei.h> 22 #include <linux/delay.h> 23 #include <linux/fsnotify.h> 24 #include <linux/posix_acl_xattr.h> 25 #include <linux/xattr.h> 26 #include <linux/jhash.h> 27 #include <linux/ima.h> 28 #include <linux/slab.h> 29 #include <linux/uaccess.h> 30 #include <linux/exportfs.h> 31 #include <linux/writeback.h> 32 #include <linux/security.h> 33 34 #ifdef CONFIG_NFSD_V3 35 #include "xdr3.h" 36 #endif /* CONFIG_NFSD_V3 */ 37 38 #ifdef CONFIG_NFSD_V4 39 #include "../internal.h" 40 #include "acl.h" 41 #include "idmap.h" 42 #endif /* CONFIG_NFSD_V4 */ 43 44 #include "nfsd.h" 45 #include "vfs.h" 46 #include "trace.h" 47 48 #define NFSDDBG_FACILITY NFSDDBG_FILEOP 49 50 51 /* 52 * This is a cache of readahead params that help us choose the proper 53 * readahead strategy. Initially, we set all readahead parameters to 0 54 * and let the VFS handle things. 55 * If you increase the number of cached files very much, you'll need to 56 * add a hash table here. 57 */ 58 struct raparms { 59 struct raparms *p_next; 60 unsigned int p_count; 61 ino_t p_ino; 62 dev_t p_dev; 63 int p_set; 64 struct file_ra_state p_ra; 65 unsigned int p_hindex; 66 }; 67 68 struct raparm_hbucket { 69 struct raparms *pb_head; 70 spinlock_t pb_lock; 71 } ____cacheline_aligned_in_smp; 72 73 #define RAPARM_HASH_BITS 4 74 #define RAPARM_HASH_SIZE (1<<RAPARM_HASH_BITS) 75 #define RAPARM_HASH_MASK (RAPARM_HASH_SIZE-1) 76 static struct raparm_hbucket raparm_hash[RAPARM_HASH_SIZE]; 77 78 /* 79 * Called from nfsd_lookup and encode_dirent. Check if we have crossed 80 * a mount point. 81 * Returns -EAGAIN or -ETIMEDOUT leaving *dpp and *expp unchanged, 82 * or nfs_ok having possibly changed *dpp and *expp 83 */ 84 int 85 nfsd_cross_mnt(struct svc_rqst *rqstp, struct dentry **dpp, 86 struct svc_export **expp) 87 { 88 struct svc_export *exp = *expp, *exp2 = NULL; 89 struct dentry *dentry = *dpp; 90 struct path path = {.mnt = mntget(exp->ex_path.mnt), 91 .dentry = dget(dentry)}; 92 int err = 0; 93 94 err = follow_down(&path); 95 if (err < 0) 96 goto out; 97 if (path.mnt == exp->ex_path.mnt && path.dentry == dentry && 98 nfsd_mountpoint(dentry, exp) == 2) { 99 /* This is only a mountpoint in some other namespace */ 100 path_put(&path); 101 goto out; 102 } 103 104 exp2 = rqst_exp_get_by_name(rqstp, &path); 105 if (IS_ERR(exp2)) { 106 err = PTR_ERR(exp2); 107 /* 108 * We normally allow NFS clients to continue 109 * "underneath" a mountpoint that is not exported. 110 * The exception is V4ROOT, where no traversal is ever 111 * allowed without an explicit export of the new 112 * directory. 113 */ 114 if (err == -ENOENT && !(exp->ex_flags & NFSEXP_V4ROOT)) 115 err = 0; 116 path_put(&path); 117 goto out; 118 } 119 if (nfsd_v4client(rqstp) || 120 (exp->ex_flags & NFSEXP_CROSSMOUNT) || EX_NOHIDE(exp2)) { 121 /* successfully crossed mount point */ 122 /* 123 * This is subtle: path.dentry is *not* on path.mnt 124 * at this point. The only reason we are safe is that 125 * original mnt is pinned down by exp, so we should 126 * put path *before* putting exp 127 */ 128 *dpp = path.dentry; 129 path.dentry = dentry; 130 *expp = exp2; 131 exp2 = exp; 132 } 133 path_put(&path); 134 exp_put(exp2); 135 out: 136 return err; 137 } 138 139 static void follow_to_parent(struct path *path) 140 { 141 struct dentry *dp; 142 143 while (path->dentry == path->mnt->mnt_root && follow_up(path)) 144 ; 145 dp = dget_parent(path->dentry); 146 dput(path->dentry); 147 path->dentry = dp; 148 } 149 150 static int nfsd_lookup_parent(struct svc_rqst *rqstp, struct dentry *dparent, struct svc_export **exp, struct dentry **dentryp) 151 { 152 struct svc_export *exp2; 153 struct path path = {.mnt = mntget((*exp)->ex_path.mnt), 154 .dentry = dget(dparent)}; 155 156 follow_to_parent(&path); 157 158 exp2 = rqst_exp_parent(rqstp, &path); 159 if (PTR_ERR(exp2) == -ENOENT) { 160 *dentryp = dget(dparent); 161 } else if (IS_ERR(exp2)) { 162 path_put(&path); 163 return PTR_ERR(exp2); 164 } else { 165 *dentryp = dget(path.dentry); 166 exp_put(*exp); 167 *exp = exp2; 168 } 169 path_put(&path); 170 return 0; 171 } 172 173 /* 174 * For nfsd purposes, we treat V4ROOT exports as though there was an 175 * export at *every* directory. 176 * We return: 177 * '1' if this dentry *must* be an export point, 178 * '2' if it might be, if there is really a mount here, and 179 * '0' if there is no chance of an export point here. 180 */ 181 int nfsd_mountpoint(struct dentry *dentry, struct svc_export *exp) 182 { 183 if (!d_inode(dentry)) 184 return 0; 185 if (exp->ex_flags & NFSEXP_V4ROOT) 186 return 1; 187 if (nfsd4_is_junction(dentry)) 188 return 1; 189 if (d_mountpoint(dentry)) 190 /* 191 * Might only be a mountpoint in a different namespace, 192 * but we need to check. 193 */ 194 return 2; 195 return 0; 196 } 197 198 __be32 199 nfsd_lookup_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp, 200 const char *name, unsigned int len, 201 struct svc_export **exp_ret, struct dentry **dentry_ret) 202 { 203 struct svc_export *exp; 204 struct dentry *dparent; 205 struct dentry *dentry; 206 int host_err; 207 208 dprintk("nfsd: nfsd_lookup(fh %s, %.*s)\n", SVCFH_fmt(fhp), len,name); 209 210 dparent = fhp->fh_dentry; 211 exp = exp_get(fhp->fh_export); 212 213 /* Lookup the name, but don't follow links */ 214 if (isdotent(name, len)) { 215 if (len==1) 216 dentry = dget(dparent); 217 else if (dparent != exp->ex_path.dentry) 218 dentry = dget_parent(dparent); 219 else if (!EX_NOHIDE(exp) && !nfsd_v4client(rqstp)) 220 dentry = dget(dparent); /* .. == . just like at / */ 221 else { 222 /* checking mountpoint crossing is very different when stepping up */ 223 host_err = nfsd_lookup_parent(rqstp, dparent, &exp, &dentry); 224 if (host_err) 225 goto out_nfserr; 226 } 227 } else { 228 /* 229 * In the nfsd4_open() case, this may be held across 230 * subsequent open and delegation acquisition which may 231 * need to take the child's i_mutex: 232 */ 233 fh_lock_nested(fhp, I_MUTEX_PARENT); 234 dentry = lookup_one_len(name, dparent, len); 235 host_err = PTR_ERR(dentry); 236 if (IS_ERR(dentry)) 237 goto out_nfserr; 238 if (nfsd_mountpoint(dentry, exp)) { 239 /* 240 * We don't need the i_mutex after all. It's 241 * still possible we could open this (regular 242 * files can be mountpoints too), but the 243 * i_mutex is just there to prevent renames of 244 * something that we might be about to delegate, 245 * and a mountpoint won't be renamed: 246 */ 247 fh_unlock(fhp); 248 if ((host_err = nfsd_cross_mnt(rqstp, &dentry, &exp))) { 249 dput(dentry); 250 goto out_nfserr; 251 } 252 } 253 } 254 *dentry_ret = dentry; 255 *exp_ret = exp; 256 return 0; 257 258 out_nfserr: 259 exp_put(exp); 260 return nfserrno(host_err); 261 } 262 263 /* 264 * Look up one component of a pathname. 265 * N.B. After this call _both_ fhp and resfh need an fh_put 266 * 267 * If the lookup would cross a mountpoint, and the mounted filesystem 268 * is exported to the client with NFSEXP_NOHIDE, then the lookup is 269 * accepted as it stands and the mounted directory is 270 * returned. Otherwise the covered directory is returned. 271 * NOTE: this mountpoint crossing is not supported properly by all 272 * clients and is explicitly disallowed for NFSv3 273 * NeilBrown <neilb@cse.unsw.edu.au> 274 */ 275 __be32 276 nfsd_lookup(struct svc_rqst *rqstp, struct svc_fh *fhp, const char *name, 277 unsigned int len, struct svc_fh *resfh) 278 { 279 struct svc_export *exp; 280 struct dentry *dentry; 281 __be32 err; 282 283 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC); 284 if (err) 285 return err; 286 err = nfsd_lookup_dentry(rqstp, fhp, name, len, &exp, &dentry); 287 if (err) 288 return err; 289 err = check_nfsd_access(exp, rqstp); 290 if (err) 291 goto out; 292 /* 293 * Note: we compose the file handle now, but as the 294 * dentry may be negative, it may need to be updated. 295 */ 296 err = fh_compose(resfh, exp, dentry, fhp); 297 if (!err && d_really_is_negative(dentry)) 298 err = nfserr_noent; 299 out: 300 dput(dentry); 301 exp_put(exp); 302 return err; 303 } 304 305 /* 306 * Commit metadata changes to stable storage. 307 */ 308 static int 309 commit_metadata(struct svc_fh *fhp) 310 { 311 struct inode *inode = d_inode(fhp->fh_dentry); 312 const struct export_operations *export_ops = inode->i_sb->s_export_op; 313 314 if (!EX_ISSYNC(fhp->fh_export)) 315 return 0; 316 317 if (export_ops->commit_metadata) 318 return export_ops->commit_metadata(inode); 319 return sync_inode_metadata(inode, 1); 320 } 321 322 /* 323 * Go over the attributes and take care of the small differences between 324 * NFS semantics and what Linux expects. 325 */ 326 static void 327 nfsd_sanitize_attrs(struct inode *inode, struct iattr *iap) 328 { 329 /* sanitize the mode change */ 330 if (iap->ia_valid & ATTR_MODE) { 331 iap->ia_mode &= S_IALLUGO; 332 iap->ia_mode |= (inode->i_mode & ~S_IALLUGO); 333 } 334 335 /* Revoke setuid/setgid on chown */ 336 if (!S_ISDIR(inode->i_mode) && 337 ((iap->ia_valid & ATTR_UID) || (iap->ia_valid & ATTR_GID))) { 338 iap->ia_valid |= ATTR_KILL_PRIV; 339 if (iap->ia_valid & ATTR_MODE) { 340 /* we're setting mode too, just clear the s*id bits */ 341 iap->ia_mode &= ~S_ISUID; 342 if (iap->ia_mode & S_IXGRP) 343 iap->ia_mode &= ~S_ISGID; 344 } else { 345 /* set ATTR_KILL_* bits and let VFS handle it */ 346 iap->ia_valid |= (ATTR_KILL_SUID | ATTR_KILL_SGID); 347 } 348 } 349 } 350 351 static __be32 352 nfsd_get_write_access(struct svc_rqst *rqstp, struct svc_fh *fhp, 353 struct iattr *iap) 354 { 355 struct inode *inode = d_inode(fhp->fh_dentry); 356 int host_err; 357 358 if (iap->ia_size < inode->i_size) { 359 __be32 err; 360 361 err = nfsd_permission(rqstp, fhp->fh_export, fhp->fh_dentry, 362 NFSD_MAY_TRUNC | NFSD_MAY_OWNER_OVERRIDE); 363 if (err) 364 return err; 365 } 366 367 host_err = get_write_access(inode); 368 if (host_err) 369 goto out_nfserrno; 370 371 host_err = locks_verify_truncate(inode, NULL, iap->ia_size); 372 if (host_err) 373 goto out_put_write_access; 374 return 0; 375 376 out_put_write_access: 377 put_write_access(inode); 378 out_nfserrno: 379 return nfserrno(host_err); 380 } 381 382 /* 383 * Set various file attributes. After this call fhp needs an fh_put. 384 */ 385 __be32 386 nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap, 387 int check_guard, time_t guardtime) 388 { 389 struct dentry *dentry; 390 struct inode *inode; 391 int accmode = NFSD_MAY_SATTR; 392 umode_t ftype = 0; 393 __be32 err; 394 int host_err; 395 bool get_write_count; 396 bool size_change = (iap->ia_valid & ATTR_SIZE); 397 398 if (iap->ia_valid & (ATTR_ATIME | ATTR_MTIME | ATTR_SIZE)) 399 accmode |= NFSD_MAY_WRITE|NFSD_MAY_OWNER_OVERRIDE; 400 if (iap->ia_valid & ATTR_SIZE) 401 ftype = S_IFREG; 402 403 /* Callers that do fh_verify should do the fh_want_write: */ 404 get_write_count = !fhp->fh_dentry; 405 406 /* Get inode */ 407 err = fh_verify(rqstp, fhp, ftype, accmode); 408 if (err) 409 return err; 410 if (get_write_count) { 411 host_err = fh_want_write(fhp); 412 if (host_err) 413 goto out; 414 } 415 416 dentry = fhp->fh_dentry; 417 inode = d_inode(dentry); 418 419 /* Ignore any mode updates on symlinks */ 420 if (S_ISLNK(inode->i_mode)) 421 iap->ia_valid &= ~ATTR_MODE; 422 423 if (!iap->ia_valid) 424 return 0; 425 426 nfsd_sanitize_attrs(inode, iap); 427 428 if (check_guard && guardtime != inode->i_ctime.tv_sec) 429 return nfserr_notsync; 430 431 /* 432 * The size case is special, it changes the file in addition to the 433 * attributes, and file systems don't expect it to be mixed with 434 * "random" attribute changes. We thus split out the size change 435 * into a separate call to ->setattr, and do the rest as a separate 436 * setattr call. 437 */ 438 if (size_change) { 439 err = nfsd_get_write_access(rqstp, fhp, iap); 440 if (err) 441 return err; 442 } 443 444 fh_lock(fhp); 445 if (size_change) { 446 /* 447 * RFC5661, Section 18.30.4: 448 * Changing the size of a file with SETATTR indirectly 449 * changes the time_modify and change attributes. 450 * 451 * (and similar for the older RFCs) 452 */ 453 struct iattr size_attr = { 454 .ia_valid = ATTR_SIZE | ATTR_CTIME | ATTR_MTIME, 455 .ia_size = iap->ia_size, 456 }; 457 458 host_err = notify_change(dentry, &size_attr, NULL); 459 if (host_err) 460 goto out_unlock; 461 iap->ia_valid &= ~ATTR_SIZE; 462 463 /* 464 * Avoid the additional setattr call below if the only other 465 * attribute that the client sends is the mtime, as we update 466 * it as part of the size change above. 467 */ 468 if ((iap->ia_valid & ~ATTR_MTIME) == 0) 469 goto out_unlock; 470 } 471 472 iap->ia_valid |= ATTR_CTIME; 473 host_err = notify_change(dentry, iap, NULL); 474 475 out_unlock: 476 fh_unlock(fhp); 477 if (size_change) 478 put_write_access(inode); 479 out: 480 if (!host_err) 481 host_err = commit_metadata(fhp); 482 return nfserrno(host_err); 483 } 484 485 #if defined(CONFIG_NFSD_V4) 486 /* 487 * NFS junction information is stored in an extended attribute. 488 */ 489 #define NFSD_JUNCTION_XATTR_NAME XATTR_TRUSTED_PREFIX "junction.nfs" 490 491 /** 492 * nfsd4_is_junction - Test if an object could be an NFS junction 493 * 494 * @dentry: object to test 495 * 496 * Returns 1 if "dentry" appears to contain NFS junction information. 497 * Otherwise 0 is returned. 498 */ 499 int nfsd4_is_junction(struct dentry *dentry) 500 { 501 struct inode *inode = d_inode(dentry); 502 503 if (inode == NULL) 504 return 0; 505 if (inode->i_mode & S_IXUGO) 506 return 0; 507 if (!(inode->i_mode & S_ISVTX)) 508 return 0; 509 if (vfs_getxattr(dentry, NFSD_JUNCTION_XATTR_NAME, NULL, 0) <= 0) 510 return 0; 511 return 1; 512 } 513 #ifdef CONFIG_NFSD_V4_SECURITY_LABEL 514 __be32 nfsd4_set_nfs4_label(struct svc_rqst *rqstp, struct svc_fh *fhp, 515 struct xdr_netobj *label) 516 { 517 __be32 error; 518 int host_error; 519 struct dentry *dentry; 520 521 error = fh_verify(rqstp, fhp, 0 /* S_IFREG */, NFSD_MAY_SATTR); 522 if (error) 523 return error; 524 525 dentry = fhp->fh_dentry; 526 527 inode_lock(d_inode(dentry)); 528 host_error = security_inode_setsecctx(dentry, label->data, label->len); 529 inode_unlock(d_inode(dentry)); 530 return nfserrno(host_error); 531 } 532 #else 533 __be32 nfsd4_set_nfs4_label(struct svc_rqst *rqstp, struct svc_fh *fhp, 534 struct xdr_netobj *label) 535 { 536 return nfserr_notsupp; 537 } 538 #endif 539 540 __be32 nfsd4_clone_file_range(struct file *src, u64 src_pos, struct file *dst, 541 u64 dst_pos, u64 count) 542 { 543 return nfserrno(do_clone_file_range(src, src_pos, dst, dst_pos, count)); 544 } 545 546 ssize_t nfsd_copy_file_range(struct file *src, u64 src_pos, struct file *dst, 547 u64 dst_pos, u64 count) 548 { 549 550 /* 551 * Limit copy to 4MB to prevent indefinitely blocking an nfsd 552 * thread and client rpc slot. The choice of 4MB is somewhat 553 * arbitrary. We might instead base this on r/wsize, or make it 554 * tunable, or use a time instead of a byte limit, or implement 555 * asynchronous copy. In theory a client could also recognize a 556 * limit like this and pipeline multiple COPY requests. 557 */ 558 count = min_t(u64, count, 1 << 22); 559 return vfs_copy_file_range(src, src_pos, dst, dst_pos, count, 0); 560 } 561 562 __be32 nfsd4_vfs_fallocate(struct svc_rqst *rqstp, struct svc_fh *fhp, 563 struct file *file, loff_t offset, loff_t len, 564 int flags) 565 { 566 int error; 567 568 if (!S_ISREG(file_inode(file)->i_mode)) 569 return nfserr_inval; 570 571 error = vfs_fallocate(file, flags, offset, len); 572 if (!error) 573 error = commit_metadata(fhp); 574 575 return nfserrno(error); 576 } 577 #endif /* defined(CONFIG_NFSD_V4) */ 578 579 #ifdef CONFIG_NFSD_V3 580 /* 581 * Check server access rights to a file system object 582 */ 583 struct accessmap { 584 u32 access; 585 int how; 586 }; 587 static struct accessmap nfs3_regaccess[] = { 588 { NFS3_ACCESS_READ, NFSD_MAY_READ }, 589 { NFS3_ACCESS_EXECUTE, NFSD_MAY_EXEC }, 590 { NFS3_ACCESS_MODIFY, NFSD_MAY_WRITE|NFSD_MAY_TRUNC }, 591 { NFS3_ACCESS_EXTEND, NFSD_MAY_WRITE }, 592 593 { 0, 0 } 594 }; 595 596 static struct accessmap nfs3_diraccess[] = { 597 { NFS3_ACCESS_READ, NFSD_MAY_READ }, 598 { NFS3_ACCESS_LOOKUP, NFSD_MAY_EXEC }, 599 { NFS3_ACCESS_MODIFY, NFSD_MAY_EXEC|NFSD_MAY_WRITE|NFSD_MAY_TRUNC}, 600 { NFS3_ACCESS_EXTEND, NFSD_MAY_EXEC|NFSD_MAY_WRITE }, 601 { NFS3_ACCESS_DELETE, NFSD_MAY_REMOVE }, 602 603 { 0, 0 } 604 }; 605 606 static struct accessmap nfs3_anyaccess[] = { 607 /* Some clients - Solaris 2.6 at least, make an access call 608 * to the server to check for access for things like /dev/null 609 * (which really, the server doesn't care about). So 610 * We provide simple access checking for them, looking 611 * mainly at mode bits, and we make sure to ignore read-only 612 * filesystem checks 613 */ 614 { NFS3_ACCESS_READ, NFSD_MAY_READ }, 615 { NFS3_ACCESS_EXECUTE, NFSD_MAY_EXEC }, 616 { NFS3_ACCESS_MODIFY, NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS }, 617 { NFS3_ACCESS_EXTEND, NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS }, 618 619 { 0, 0 } 620 }; 621 622 __be32 623 nfsd_access(struct svc_rqst *rqstp, struct svc_fh *fhp, u32 *access, u32 *supported) 624 { 625 struct accessmap *map; 626 struct svc_export *export; 627 struct dentry *dentry; 628 u32 query, result = 0, sresult = 0; 629 __be32 error; 630 631 error = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP); 632 if (error) 633 goto out; 634 635 export = fhp->fh_export; 636 dentry = fhp->fh_dentry; 637 638 if (d_is_reg(dentry)) 639 map = nfs3_regaccess; 640 else if (d_is_dir(dentry)) 641 map = nfs3_diraccess; 642 else 643 map = nfs3_anyaccess; 644 645 646 query = *access; 647 for (; map->access; map++) { 648 if (map->access & query) { 649 __be32 err2; 650 651 sresult |= map->access; 652 653 err2 = nfsd_permission(rqstp, export, dentry, map->how); 654 switch (err2) { 655 case nfs_ok: 656 result |= map->access; 657 break; 658 659 /* the following error codes just mean the access was not allowed, 660 * rather than an error occurred */ 661 case nfserr_rofs: 662 case nfserr_acces: 663 case nfserr_perm: 664 /* simply don't "or" in the access bit. */ 665 break; 666 default: 667 error = err2; 668 goto out; 669 } 670 } 671 } 672 *access = result; 673 if (supported) 674 *supported = sresult; 675 676 out: 677 return error; 678 } 679 #endif /* CONFIG_NFSD_V3 */ 680 681 static int nfsd_open_break_lease(struct inode *inode, int access) 682 { 683 unsigned int mode; 684 685 if (access & NFSD_MAY_NOT_BREAK_LEASE) 686 return 0; 687 mode = (access & NFSD_MAY_WRITE) ? O_WRONLY : O_RDONLY; 688 return break_lease(inode, mode | O_NONBLOCK); 689 } 690 691 /* 692 * Open an existing file or directory. 693 * The may_flags argument indicates the type of open (read/write/lock) 694 * and additional flags. 695 * N.B. After this call fhp needs an fh_put 696 */ 697 __be32 698 nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type, 699 int may_flags, struct file **filp) 700 { 701 struct path path; 702 struct inode *inode; 703 struct file *file; 704 int flags = O_RDONLY|O_LARGEFILE; 705 __be32 err; 706 int host_err = 0; 707 708 validate_process_creds(); 709 710 /* 711 * If we get here, then the client has already done an "open", 712 * and (hopefully) checked permission - so allow OWNER_OVERRIDE 713 * in case a chmod has now revoked permission. 714 * 715 * Arguably we should also allow the owner override for 716 * directories, but we never have and it doesn't seem to have 717 * caused anyone a problem. If we were to change this, note 718 * also that our filldir callbacks would need a variant of 719 * lookup_one_len that doesn't check permissions. 720 */ 721 if (type == S_IFREG) 722 may_flags |= NFSD_MAY_OWNER_OVERRIDE; 723 err = fh_verify(rqstp, fhp, type, may_flags); 724 if (err) 725 goto out; 726 727 path.mnt = fhp->fh_export->ex_path.mnt; 728 path.dentry = fhp->fh_dentry; 729 inode = d_inode(path.dentry); 730 731 /* Disallow write access to files with the append-only bit set 732 * or any access when mandatory locking enabled 733 */ 734 err = nfserr_perm; 735 if (IS_APPEND(inode) && (may_flags & NFSD_MAY_WRITE)) 736 goto out; 737 /* 738 * We must ignore files (but only files) which might have mandatory 739 * locks on them because there is no way to know if the accesser has 740 * the lock. 741 */ 742 if (S_ISREG((inode)->i_mode) && mandatory_lock(inode)) 743 goto out; 744 745 if (!inode->i_fop) 746 goto out; 747 748 host_err = nfsd_open_break_lease(inode, may_flags); 749 if (host_err) /* NOMEM or WOULDBLOCK */ 750 goto out_nfserr; 751 752 if (may_flags & NFSD_MAY_WRITE) { 753 if (may_flags & NFSD_MAY_READ) 754 flags = O_RDWR|O_LARGEFILE; 755 else 756 flags = O_WRONLY|O_LARGEFILE; 757 } 758 759 file = dentry_open(&path, flags, current_cred()); 760 if (IS_ERR(file)) { 761 host_err = PTR_ERR(file); 762 goto out_nfserr; 763 } 764 765 host_err = ima_file_check(file, may_flags, 0); 766 if (host_err) { 767 fput(file); 768 goto out_nfserr; 769 } 770 771 if (may_flags & NFSD_MAY_64BIT_COOKIE) 772 file->f_mode |= FMODE_64BITHASH; 773 else 774 file->f_mode |= FMODE_32BITHASH; 775 776 *filp = file; 777 out_nfserr: 778 err = nfserrno(host_err); 779 out: 780 validate_process_creds(); 781 return err; 782 } 783 784 struct raparms * 785 nfsd_init_raparms(struct file *file) 786 { 787 struct inode *inode = file_inode(file); 788 dev_t dev = inode->i_sb->s_dev; 789 ino_t ino = inode->i_ino; 790 struct raparms *ra, **rap, **frap = NULL; 791 int depth = 0; 792 unsigned int hash; 793 struct raparm_hbucket *rab; 794 795 hash = jhash_2words(dev, ino, 0xfeedbeef) & RAPARM_HASH_MASK; 796 rab = &raparm_hash[hash]; 797 798 spin_lock(&rab->pb_lock); 799 for (rap = &rab->pb_head; (ra = *rap); rap = &ra->p_next) { 800 if (ra->p_ino == ino && ra->p_dev == dev) 801 goto found; 802 depth++; 803 if (ra->p_count == 0) 804 frap = rap; 805 } 806 depth = nfsdstats.ra_size; 807 if (!frap) { 808 spin_unlock(&rab->pb_lock); 809 return NULL; 810 } 811 rap = frap; 812 ra = *frap; 813 ra->p_dev = dev; 814 ra->p_ino = ino; 815 ra->p_set = 0; 816 ra->p_hindex = hash; 817 found: 818 if (rap != &rab->pb_head) { 819 *rap = ra->p_next; 820 ra->p_next = rab->pb_head; 821 rab->pb_head = ra; 822 } 823 ra->p_count++; 824 nfsdstats.ra_depth[depth*10/nfsdstats.ra_size]++; 825 spin_unlock(&rab->pb_lock); 826 827 if (ra->p_set) 828 file->f_ra = ra->p_ra; 829 return ra; 830 } 831 832 void nfsd_put_raparams(struct file *file, struct raparms *ra) 833 { 834 struct raparm_hbucket *rab = &raparm_hash[ra->p_hindex]; 835 836 spin_lock(&rab->pb_lock); 837 ra->p_ra = file->f_ra; 838 ra->p_set = 1; 839 ra->p_count--; 840 spin_unlock(&rab->pb_lock); 841 } 842 843 /* 844 * Grab and keep cached pages associated with a file in the svc_rqst 845 * so that they can be passed to the network sendmsg/sendpage routines 846 * directly. They will be released after the sending has completed. 847 */ 848 static int 849 nfsd_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf, 850 struct splice_desc *sd) 851 { 852 struct svc_rqst *rqstp = sd->u.data; 853 struct page **pp = rqstp->rq_next_page; 854 struct page *page = buf->page; 855 size_t size; 856 857 size = sd->len; 858 859 if (rqstp->rq_res.page_len == 0) { 860 get_page(page); 861 put_page(*rqstp->rq_next_page); 862 *(rqstp->rq_next_page++) = page; 863 rqstp->rq_res.page_base = buf->offset; 864 rqstp->rq_res.page_len = size; 865 } else if (page != pp[-1]) { 866 get_page(page); 867 if (*rqstp->rq_next_page) 868 put_page(*rqstp->rq_next_page); 869 *(rqstp->rq_next_page++) = page; 870 rqstp->rq_res.page_len += size; 871 } else 872 rqstp->rq_res.page_len += size; 873 874 return size; 875 } 876 877 static int nfsd_direct_splice_actor(struct pipe_inode_info *pipe, 878 struct splice_desc *sd) 879 { 880 return __splice_from_pipe(pipe, sd, nfsd_splice_actor); 881 } 882 883 static __be32 884 nfsd_finish_read(struct file *file, unsigned long *count, int host_err) 885 { 886 if (host_err >= 0) { 887 nfsdstats.io_read += host_err; 888 *count = host_err; 889 fsnotify_access(file); 890 return 0; 891 } else 892 return nfserrno(host_err); 893 } 894 895 __be32 nfsd_splice_read(struct svc_rqst *rqstp, 896 struct file *file, loff_t offset, unsigned long *count) 897 { 898 struct splice_desc sd = { 899 .len = 0, 900 .total_len = *count, 901 .pos = offset, 902 .u.data = rqstp, 903 }; 904 int host_err; 905 906 rqstp->rq_next_page = rqstp->rq_respages + 1; 907 host_err = splice_direct_to_actor(file, &sd, nfsd_direct_splice_actor); 908 return nfsd_finish_read(file, count, host_err); 909 } 910 911 __be32 nfsd_readv(struct file *file, loff_t offset, struct kvec *vec, int vlen, 912 unsigned long *count) 913 { 914 struct iov_iter iter; 915 int host_err; 916 917 iov_iter_kvec(&iter, READ | ITER_KVEC, vec, vlen, *count); 918 host_err = vfs_iter_read(file, &iter, &offset, 0); 919 920 return nfsd_finish_read(file, count, host_err); 921 } 922 923 /* 924 * Gathered writes: If another process is currently writing to the file, 925 * there's a high chance this is another nfsd (triggered by a bulk write 926 * from a client's biod). Rather than syncing the file with each write 927 * request, we sleep for 10 msec. 928 * 929 * I don't know if this roughly approximates C. Juszak's idea of 930 * gathered writes, but it's a nice and simple solution (IMHO), and it 931 * seems to work:-) 932 * 933 * Note: we do this only in the NFSv2 case, since v3 and higher have a 934 * better tool (separate unstable writes and commits) for solving this 935 * problem. 936 */ 937 static int wait_for_concurrent_writes(struct file *file) 938 { 939 struct inode *inode = file_inode(file); 940 static ino_t last_ino; 941 static dev_t last_dev; 942 int err = 0; 943 944 if (atomic_read(&inode->i_writecount) > 1 945 || (last_ino == inode->i_ino && last_dev == inode->i_sb->s_dev)) { 946 dprintk("nfsd: write defer %d\n", task_pid_nr(current)); 947 msleep(10); 948 dprintk("nfsd: write resume %d\n", task_pid_nr(current)); 949 } 950 951 if (inode->i_state & I_DIRTY) { 952 dprintk("nfsd: write sync %d\n", task_pid_nr(current)); 953 err = vfs_fsync(file, 0); 954 } 955 last_ino = inode->i_ino; 956 last_dev = inode->i_sb->s_dev; 957 return err; 958 } 959 960 __be32 961 nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file, 962 loff_t offset, struct kvec *vec, int vlen, 963 unsigned long *cnt, int stable) 964 { 965 struct svc_export *exp; 966 struct iov_iter iter; 967 __be32 err = 0; 968 int host_err; 969 int use_wgather; 970 loff_t pos = offset; 971 unsigned int pflags = current->flags; 972 int flags = 0; 973 974 if (test_bit(RQ_LOCAL, &rqstp->rq_flags)) 975 /* 976 * We want less throttling in balance_dirty_pages() 977 * and shrink_inactive_list() so that nfs to 978 * localhost doesn't cause nfsd to lock up due to all 979 * the client's dirty pages or its congested queue. 980 */ 981 current->flags |= PF_LESS_THROTTLE; 982 983 exp = fhp->fh_export; 984 use_wgather = (rqstp->rq_vers == 2) && EX_WGATHER(exp); 985 986 if (!EX_ISSYNC(exp)) 987 stable = NFS_UNSTABLE; 988 989 if (stable && !use_wgather) 990 flags |= RWF_SYNC; 991 992 iov_iter_kvec(&iter, WRITE | ITER_KVEC, vec, vlen, *cnt); 993 host_err = vfs_iter_write(file, &iter, &pos, flags); 994 if (host_err < 0) 995 goto out_nfserr; 996 *cnt = host_err; 997 nfsdstats.io_write += host_err; 998 fsnotify_modify(file); 999 1000 if (stable && use_wgather) 1001 host_err = wait_for_concurrent_writes(file); 1002 1003 out_nfserr: 1004 dprintk("nfsd: write complete host_err=%d\n", host_err); 1005 if (host_err >= 0) 1006 err = 0; 1007 else 1008 err = nfserrno(host_err); 1009 if (test_bit(RQ_LOCAL, &rqstp->rq_flags)) 1010 current_restore_flags(pflags, PF_LESS_THROTTLE); 1011 return err; 1012 } 1013 1014 /* 1015 * Read data from a file. count must contain the requested read count 1016 * on entry. On return, *count contains the number of bytes actually read. 1017 * N.B. After this call fhp needs an fh_put 1018 */ 1019 __be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp, 1020 loff_t offset, struct kvec *vec, int vlen, unsigned long *count) 1021 { 1022 struct file *file; 1023 struct raparms *ra; 1024 __be32 err; 1025 1026 trace_read_start(rqstp, fhp, offset, vlen); 1027 err = nfsd_open(rqstp, fhp, S_IFREG, NFSD_MAY_READ, &file); 1028 if (err) 1029 return err; 1030 1031 ra = nfsd_init_raparms(file); 1032 1033 trace_read_opened(rqstp, fhp, offset, vlen); 1034 1035 if (file->f_op->splice_read && test_bit(RQ_SPLICE_OK, &rqstp->rq_flags)) 1036 err = nfsd_splice_read(rqstp, file, offset, count); 1037 else 1038 err = nfsd_readv(file, offset, vec, vlen, count); 1039 1040 trace_read_io_done(rqstp, fhp, offset, vlen); 1041 1042 if (ra) 1043 nfsd_put_raparams(file, ra); 1044 fput(file); 1045 1046 trace_read_done(rqstp, fhp, offset, vlen); 1047 1048 return err; 1049 } 1050 1051 /* 1052 * Write data to a file. 1053 * The stable flag requests synchronous writes. 1054 * N.B. After this call fhp needs an fh_put 1055 */ 1056 __be32 1057 nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t offset, 1058 struct kvec *vec, int vlen, unsigned long *cnt, int stable) 1059 { 1060 struct file *file = NULL; 1061 __be32 err = 0; 1062 1063 trace_write_start(rqstp, fhp, offset, vlen); 1064 1065 err = nfsd_open(rqstp, fhp, S_IFREG, NFSD_MAY_WRITE, &file); 1066 if (err) 1067 goto out; 1068 1069 trace_write_opened(rqstp, fhp, offset, vlen); 1070 err = nfsd_vfs_write(rqstp, fhp, file, offset, vec, vlen, cnt, stable); 1071 trace_write_io_done(rqstp, fhp, offset, vlen); 1072 fput(file); 1073 out: 1074 trace_write_done(rqstp, fhp, offset, vlen); 1075 return err; 1076 } 1077 1078 #ifdef CONFIG_NFSD_V3 1079 /* 1080 * Commit all pending writes to stable storage. 1081 * 1082 * Note: we only guarantee that data that lies within the range specified 1083 * by the 'offset' and 'count' parameters will be synced. 1084 * 1085 * Unfortunately we cannot lock the file to make sure we return full WCC 1086 * data to the client, as locking happens lower down in the filesystem. 1087 */ 1088 __be32 1089 nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp, 1090 loff_t offset, unsigned long count) 1091 { 1092 struct file *file; 1093 loff_t end = LLONG_MAX; 1094 __be32 err = nfserr_inval; 1095 1096 if (offset < 0) 1097 goto out; 1098 if (count != 0) { 1099 end = offset + (loff_t)count - 1; 1100 if (end < offset) 1101 goto out; 1102 } 1103 1104 err = nfsd_open(rqstp, fhp, S_IFREG, 1105 NFSD_MAY_WRITE|NFSD_MAY_NOT_BREAK_LEASE, &file); 1106 if (err) 1107 goto out; 1108 if (EX_ISSYNC(fhp->fh_export)) { 1109 int err2 = vfs_fsync_range(file, offset, end, 0); 1110 1111 if (err2 != -EINVAL) 1112 err = nfserrno(err2); 1113 else 1114 err = nfserr_notsupp; 1115 } 1116 1117 fput(file); 1118 out: 1119 return err; 1120 } 1121 #endif /* CONFIG_NFSD_V3 */ 1122 1123 static __be32 1124 nfsd_create_setattr(struct svc_rqst *rqstp, struct svc_fh *resfhp, 1125 struct iattr *iap) 1126 { 1127 /* 1128 * Mode has already been set earlier in create: 1129 */ 1130 iap->ia_valid &= ~ATTR_MODE; 1131 /* 1132 * Setting uid/gid works only for root. Irix appears to 1133 * send along the gid on create when it tries to implement 1134 * setgid directories via NFS: 1135 */ 1136 if (!uid_eq(current_fsuid(), GLOBAL_ROOT_UID)) 1137 iap->ia_valid &= ~(ATTR_UID|ATTR_GID); 1138 if (iap->ia_valid) 1139 return nfsd_setattr(rqstp, resfhp, iap, 0, (time_t)0); 1140 /* Callers expect file metadata to be committed here */ 1141 return nfserrno(commit_metadata(resfhp)); 1142 } 1143 1144 /* HPUX client sometimes creates a file in mode 000, and sets size to 0. 1145 * setting size to 0 may fail for some specific file systems by the permission 1146 * checking which requires WRITE permission but the mode is 000. 1147 * we ignore the resizing(to 0) on the just new created file, since the size is 1148 * 0 after file created. 1149 * 1150 * call this only after vfs_create() is called. 1151 * */ 1152 static void 1153 nfsd_check_ignore_resizing(struct iattr *iap) 1154 { 1155 if ((iap->ia_valid & ATTR_SIZE) && (iap->ia_size == 0)) 1156 iap->ia_valid &= ~ATTR_SIZE; 1157 } 1158 1159 /* The parent directory should already be locked: */ 1160 __be32 1161 nfsd_create_locked(struct svc_rqst *rqstp, struct svc_fh *fhp, 1162 char *fname, int flen, struct iattr *iap, 1163 int type, dev_t rdev, struct svc_fh *resfhp) 1164 { 1165 struct dentry *dentry, *dchild; 1166 struct inode *dirp; 1167 __be32 err; 1168 __be32 err2; 1169 int host_err; 1170 1171 dentry = fhp->fh_dentry; 1172 dirp = d_inode(dentry); 1173 1174 dchild = dget(resfhp->fh_dentry); 1175 if (!fhp->fh_locked) { 1176 WARN_ONCE(1, "nfsd_create: parent %pd2 not locked!\n", 1177 dentry); 1178 err = nfserr_io; 1179 goto out; 1180 } 1181 1182 err = nfsd_permission(rqstp, fhp->fh_export, dentry, NFSD_MAY_CREATE); 1183 if (err) 1184 goto out; 1185 1186 if (!(iap->ia_valid & ATTR_MODE)) 1187 iap->ia_mode = 0; 1188 iap->ia_mode = (iap->ia_mode & S_IALLUGO) | type; 1189 1190 err = 0; 1191 host_err = 0; 1192 switch (type) { 1193 case S_IFREG: 1194 host_err = vfs_create(dirp, dchild, iap->ia_mode, true); 1195 if (!host_err) 1196 nfsd_check_ignore_resizing(iap); 1197 break; 1198 case S_IFDIR: 1199 host_err = vfs_mkdir(dirp, dchild, iap->ia_mode); 1200 break; 1201 case S_IFCHR: 1202 case S_IFBLK: 1203 case S_IFIFO: 1204 case S_IFSOCK: 1205 host_err = vfs_mknod(dirp, dchild, iap->ia_mode, rdev); 1206 break; 1207 default: 1208 printk(KERN_WARNING "nfsd: bad file type %o in nfsd_create\n", 1209 type); 1210 host_err = -EINVAL; 1211 } 1212 if (host_err < 0) 1213 goto out_nfserr; 1214 1215 err = nfsd_create_setattr(rqstp, resfhp, iap); 1216 1217 /* 1218 * nfsd_create_setattr already committed the child. Transactional 1219 * filesystems had a chance to commit changes for both parent and 1220 * child simultaneously making the following commit_metadata a 1221 * noop. 1222 */ 1223 err2 = nfserrno(commit_metadata(fhp)); 1224 if (err2) 1225 err = err2; 1226 /* 1227 * Update the file handle to get the new inode info. 1228 */ 1229 if (!err) 1230 err = fh_update(resfhp); 1231 out: 1232 dput(dchild); 1233 return err; 1234 1235 out_nfserr: 1236 err = nfserrno(host_err); 1237 goto out; 1238 } 1239 1240 /* 1241 * Create a filesystem object (regular, directory, special). 1242 * Note that the parent directory is left locked. 1243 * 1244 * N.B. Every call to nfsd_create needs an fh_put for _both_ fhp and resfhp 1245 */ 1246 __be32 1247 nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, 1248 char *fname, int flen, struct iattr *iap, 1249 int type, dev_t rdev, struct svc_fh *resfhp) 1250 { 1251 struct dentry *dentry, *dchild = NULL; 1252 struct inode *dirp; 1253 __be32 err; 1254 int host_err; 1255 1256 if (isdotent(fname, flen)) 1257 return nfserr_exist; 1258 1259 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_NOP); 1260 if (err) 1261 return err; 1262 1263 dentry = fhp->fh_dentry; 1264 dirp = d_inode(dentry); 1265 1266 host_err = fh_want_write(fhp); 1267 if (host_err) 1268 return nfserrno(host_err); 1269 1270 fh_lock_nested(fhp, I_MUTEX_PARENT); 1271 dchild = lookup_one_len(fname, dentry, flen); 1272 host_err = PTR_ERR(dchild); 1273 if (IS_ERR(dchild)) 1274 return nfserrno(host_err); 1275 err = fh_compose(resfhp, fhp->fh_export, dchild, fhp); 1276 /* 1277 * We unconditionally drop our ref to dchild as fh_compose will have 1278 * already grabbed its own ref for it. 1279 */ 1280 dput(dchild); 1281 if (err) 1282 return err; 1283 return nfsd_create_locked(rqstp, fhp, fname, flen, iap, type, 1284 rdev, resfhp); 1285 } 1286 1287 #ifdef CONFIG_NFSD_V3 1288 1289 /* 1290 * NFSv3 and NFSv4 version of nfsd_create 1291 */ 1292 __be32 1293 do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, 1294 char *fname, int flen, struct iattr *iap, 1295 struct svc_fh *resfhp, int createmode, u32 *verifier, 1296 bool *truncp, bool *created) 1297 { 1298 struct dentry *dentry, *dchild = NULL; 1299 struct inode *dirp; 1300 __be32 err; 1301 int host_err; 1302 __u32 v_mtime=0, v_atime=0; 1303 1304 err = nfserr_perm; 1305 if (!flen) 1306 goto out; 1307 err = nfserr_exist; 1308 if (isdotent(fname, flen)) 1309 goto out; 1310 if (!(iap->ia_valid & ATTR_MODE)) 1311 iap->ia_mode = 0; 1312 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC); 1313 if (err) 1314 goto out; 1315 1316 dentry = fhp->fh_dentry; 1317 dirp = d_inode(dentry); 1318 1319 host_err = fh_want_write(fhp); 1320 if (host_err) 1321 goto out_nfserr; 1322 1323 fh_lock_nested(fhp, I_MUTEX_PARENT); 1324 1325 /* 1326 * Compose the response file handle. 1327 */ 1328 dchild = lookup_one_len(fname, dentry, flen); 1329 host_err = PTR_ERR(dchild); 1330 if (IS_ERR(dchild)) 1331 goto out_nfserr; 1332 1333 /* If file doesn't exist, check for permissions to create one */ 1334 if (d_really_is_negative(dchild)) { 1335 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE); 1336 if (err) 1337 goto out; 1338 } 1339 1340 err = fh_compose(resfhp, fhp->fh_export, dchild, fhp); 1341 if (err) 1342 goto out; 1343 1344 if (nfsd_create_is_exclusive(createmode)) { 1345 /* solaris7 gets confused (bugid 4218508) if these have 1346 * the high bit set, so just clear the high bits. If this is 1347 * ever changed to use different attrs for storing the 1348 * verifier, then do_open_lookup() will also need to be fixed 1349 * accordingly. 1350 */ 1351 v_mtime = verifier[0]&0x7fffffff; 1352 v_atime = verifier[1]&0x7fffffff; 1353 } 1354 1355 if (d_really_is_positive(dchild)) { 1356 err = 0; 1357 1358 switch (createmode) { 1359 case NFS3_CREATE_UNCHECKED: 1360 if (! d_is_reg(dchild)) 1361 goto out; 1362 else if (truncp) { 1363 /* in nfsv4, we need to treat this case a little 1364 * differently. we don't want to truncate the 1365 * file now; this would be wrong if the OPEN 1366 * fails for some other reason. furthermore, 1367 * if the size is nonzero, we should ignore it 1368 * according to spec! 1369 */ 1370 *truncp = (iap->ia_valid & ATTR_SIZE) && !iap->ia_size; 1371 } 1372 else { 1373 iap->ia_valid &= ATTR_SIZE; 1374 goto set_attr; 1375 } 1376 break; 1377 case NFS3_CREATE_EXCLUSIVE: 1378 if ( d_inode(dchild)->i_mtime.tv_sec == v_mtime 1379 && d_inode(dchild)->i_atime.tv_sec == v_atime 1380 && d_inode(dchild)->i_size == 0 ) { 1381 if (created) 1382 *created = 1; 1383 break; 1384 } 1385 case NFS4_CREATE_EXCLUSIVE4_1: 1386 if ( d_inode(dchild)->i_mtime.tv_sec == v_mtime 1387 && d_inode(dchild)->i_atime.tv_sec == v_atime 1388 && d_inode(dchild)->i_size == 0 ) { 1389 if (created) 1390 *created = 1; 1391 goto set_attr; 1392 } 1393 /* fallthru */ 1394 case NFS3_CREATE_GUARDED: 1395 err = nfserr_exist; 1396 } 1397 fh_drop_write(fhp); 1398 goto out; 1399 } 1400 1401 host_err = vfs_create(dirp, dchild, iap->ia_mode, true); 1402 if (host_err < 0) { 1403 fh_drop_write(fhp); 1404 goto out_nfserr; 1405 } 1406 if (created) 1407 *created = 1; 1408 1409 nfsd_check_ignore_resizing(iap); 1410 1411 if (nfsd_create_is_exclusive(createmode)) { 1412 /* Cram the verifier into atime/mtime */ 1413 iap->ia_valid = ATTR_MTIME|ATTR_ATIME 1414 | ATTR_MTIME_SET|ATTR_ATIME_SET; 1415 /* XXX someone who knows this better please fix it for nsec */ 1416 iap->ia_mtime.tv_sec = v_mtime; 1417 iap->ia_atime.tv_sec = v_atime; 1418 iap->ia_mtime.tv_nsec = 0; 1419 iap->ia_atime.tv_nsec = 0; 1420 } 1421 1422 set_attr: 1423 err = nfsd_create_setattr(rqstp, resfhp, iap); 1424 1425 /* 1426 * nfsd_create_setattr already committed the child 1427 * (and possibly also the parent). 1428 */ 1429 if (!err) 1430 err = nfserrno(commit_metadata(fhp)); 1431 1432 /* 1433 * Update the filehandle to get the new inode info. 1434 */ 1435 if (!err) 1436 err = fh_update(resfhp); 1437 1438 out: 1439 fh_unlock(fhp); 1440 if (dchild && !IS_ERR(dchild)) 1441 dput(dchild); 1442 fh_drop_write(fhp); 1443 return err; 1444 1445 out_nfserr: 1446 err = nfserrno(host_err); 1447 goto out; 1448 } 1449 #endif /* CONFIG_NFSD_V3 */ 1450 1451 /* 1452 * Read a symlink. On entry, *lenp must contain the maximum path length that 1453 * fits into the buffer. On return, it contains the true length. 1454 * N.B. After this call fhp needs an fh_put 1455 */ 1456 __be32 1457 nfsd_readlink(struct svc_rqst *rqstp, struct svc_fh *fhp, char *buf, int *lenp) 1458 { 1459 __be32 err; 1460 const char *link; 1461 struct path path; 1462 DEFINE_DELAYED_CALL(done); 1463 int len; 1464 1465 err = fh_verify(rqstp, fhp, S_IFLNK, NFSD_MAY_NOP); 1466 if (unlikely(err)) 1467 return err; 1468 1469 path.mnt = fhp->fh_export->ex_path.mnt; 1470 path.dentry = fhp->fh_dentry; 1471 1472 if (unlikely(!d_is_symlink(path.dentry))) 1473 return nfserr_inval; 1474 1475 touch_atime(&path); 1476 1477 link = vfs_get_link(path.dentry, &done); 1478 if (IS_ERR(link)) 1479 return nfserrno(PTR_ERR(link)); 1480 1481 len = strlen(link); 1482 if (len < *lenp) 1483 *lenp = len; 1484 memcpy(buf, link, *lenp); 1485 do_delayed_call(&done); 1486 return 0; 1487 } 1488 1489 /* 1490 * Create a symlink and look up its inode 1491 * N.B. After this call _both_ fhp and resfhp need an fh_put 1492 */ 1493 __be32 1494 nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp, 1495 char *fname, int flen, 1496 char *path, 1497 struct svc_fh *resfhp) 1498 { 1499 struct dentry *dentry, *dnew; 1500 __be32 err, cerr; 1501 int host_err; 1502 1503 err = nfserr_noent; 1504 if (!flen || path[0] == '\0') 1505 goto out; 1506 err = nfserr_exist; 1507 if (isdotent(fname, flen)) 1508 goto out; 1509 1510 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE); 1511 if (err) 1512 goto out; 1513 1514 host_err = fh_want_write(fhp); 1515 if (host_err) 1516 goto out_nfserr; 1517 1518 fh_lock(fhp); 1519 dentry = fhp->fh_dentry; 1520 dnew = lookup_one_len(fname, dentry, flen); 1521 host_err = PTR_ERR(dnew); 1522 if (IS_ERR(dnew)) 1523 goto out_nfserr; 1524 1525 host_err = vfs_symlink(d_inode(dentry), dnew, path); 1526 err = nfserrno(host_err); 1527 if (!err) 1528 err = nfserrno(commit_metadata(fhp)); 1529 fh_unlock(fhp); 1530 1531 fh_drop_write(fhp); 1532 1533 cerr = fh_compose(resfhp, fhp->fh_export, dnew, fhp); 1534 dput(dnew); 1535 if (err==0) err = cerr; 1536 out: 1537 return err; 1538 1539 out_nfserr: 1540 err = nfserrno(host_err); 1541 goto out; 1542 } 1543 1544 /* 1545 * Create a hardlink 1546 * N.B. After this call _both_ ffhp and tfhp need an fh_put 1547 */ 1548 __be32 1549 nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp, 1550 char *name, int len, struct svc_fh *tfhp) 1551 { 1552 struct dentry *ddir, *dnew, *dold; 1553 struct inode *dirp; 1554 __be32 err; 1555 int host_err; 1556 1557 err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_CREATE); 1558 if (err) 1559 goto out; 1560 err = fh_verify(rqstp, tfhp, 0, NFSD_MAY_NOP); 1561 if (err) 1562 goto out; 1563 err = nfserr_isdir; 1564 if (d_is_dir(tfhp->fh_dentry)) 1565 goto out; 1566 err = nfserr_perm; 1567 if (!len) 1568 goto out; 1569 err = nfserr_exist; 1570 if (isdotent(name, len)) 1571 goto out; 1572 1573 host_err = fh_want_write(tfhp); 1574 if (host_err) { 1575 err = nfserrno(host_err); 1576 goto out; 1577 } 1578 1579 fh_lock_nested(ffhp, I_MUTEX_PARENT); 1580 ddir = ffhp->fh_dentry; 1581 dirp = d_inode(ddir); 1582 1583 dnew = lookup_one_len(name, ddir, len); 1584 host_err = PTR_ERR(dnew); 1585 if (IS_ERR(dnew)) 1586 goto out_nfserr; 1587 1588 dold = tfhp->fh_dentry; 1589 1590 err = nfserr_noent; 1591 if (d_really_is_negative(dold)) 1592 goto out_dput; 1593 host_err = vfs_link(dold, dirp, dnew, NULL); 1594 if (!host_err) { 1595 err = nfserrno(commit_metadata(ffhp)); 1596 if (!err) 1597 err = nfserrno(commit_metadata(tfhp)); 1598 } else { 1599 if (host_err == -EXDEV && rqstp->rq_vers == 2) 1600 err = nfserr_acces; 1601 else 1602 err = nfserrno(host_err); 1603 } 1604 out_dput: 1605 dput(dnew); 1606 out_unlock: 1607 fh_unlock(ffhp); 1608 fh_drop_write(tfhp); 1609 out: 1610 return err; 1611 1612 out_nfserr: 1613 err = nfserrno(host_err); 1614 goto out_unlock; 1615 } 1616 1617 /* 1618 * Rename a file 1619 * N.B. After this call _both_ ffhp and tfhp need an fh_put 1620 */ 1621 __be32 1622 nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, 1623 struct svc_fh *tfhp, char *tname, int tlen) 1624 { 1625 struct dentry *fdentry, *tdentry, *odentry, *ndentry, *trap; 1626 struct inode *fdir, *tdir; 1627 __be32 err; 1628 int host_err; 1629 1630 err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_REMOVE); 1631 if (err) 1632 goto out; 1633 err = fh_verify(rqstp, tfhp, S_IFDIR, NFSD_MAY_CREATE); 1634 if (err) 1635 goto out; 1636 1637 fdentry = ffhp->fh_dentry; 1638 fdir = d_inode(fdentry); 1639 1640 tdentry = tfhp->fh_dentry; 1641 tdir = d_inode(tdentry); 1642 1643 err = nfserr_perm; 1644 if (!flen || isdotent(fname, flen) || !tlen || isdotent(tname, tlen)) 1645 goto out; 1646 1647 host_err = fh_want_write(ffhp); 1648 if (host_err) { 1649 err = nfserrno(host_err); 1650 goto out; 1651 } 1652 1653 /* cannot use fh_lock as we need deadlock protective ordering 1654 * so do it by hand */ 1655 trap = lock_rename(tdentry, fdentry); 1656 ffhp->fh_locked = tfhp->fh_locked = true; 1657 fill_pre_wcc(ffhp); 1658 fill_pre_wcc(tfhp); 1659 1660 odentry = lookup_one_len(fname, fdentry, flen); 1661 host_err = PTR_ERR(odentry); 1662 if (IS_ERR(odentry)) 1663 goto out_nfserr; 1664 1665 host_err = -ENOENT; 1666 if (d_really_is_negative(odentry)) 1667 goto out_dput_old; 1668 host_err = -EINVAL; 1669 if (odentry == trap) 1670 goto out_dput_old; 1671 1672 ndentry = lookup_one_len(tname, tdentry, tlen); 1673 host_err = PTR_ERR(ndentry); 1674 if (IS_ERR(ndentry)) 1675 goto out_dput_old; 1676 host_err = -ENOTEMPTY; 1677 if (ndentry == trap) 1678 goto out_dput_new; 1679 1680 host_err = -EXDEV; 1681 if (ffhp->fh_export->ex_path.mnt != tfhp->fh_export->ex_path.mnt) 1682 goto out_dput_new; 1683 if (ffhp->fh_export->ex_path.dentry != tfhp->fh_export->ex_path.dentry) 1684 goto out_dput_new; 1685 1686 host_err = vfs_rename(fdir, odentry, tdir, ndentry, NULL, 0); 1687 if (!host_err) { 1688 host_err = commit_metadata(tfhp); 1689 if (!host_err) 1690 host_err = commit_metadata(ffhp); 1691 } 1692 out_dput_new: 1693 dput(ndentry); 1694 out_dput_old: 1695 dput(odentry); 1696 out_nfserr: 1697 err = nfserrno(host_err); 1698 /* 1699 * We cannot rely on fh_unlock on the two filehandles, 1700 * as that would do the wrong thing if the two directories 1701 * were the same, so again we do it by hand. 1702 */ 1703 fill_post_wcc(ffhp); 1704 fill_post_wcc(tfhp); 1705 unlock_rename(tdentry, fdentry); 1706 ffhp->fh_locked = tfhp->fh_locked = false; 1707 fh_drop_write(ffhp); 1708 1709 out: 1710 return err; 1711 } 1712 1713 /* 1714 * Unlink a file or directory 1715 * N.B. After this call fhp needs an fh_put 1716 */ 1717 __be32 1718 nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, 1719 char *fname, int flen) 1720 { 1721 struct dentry *dentry, *rdentry; 1722 struct inode *dirp; 1723 __be32 err; 1724 int host_err; 1725 1726 err = nfserr_acces; 1727 if (!flen || isdotent(fname, flen)) 1728 goto out; 1729 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_REMOVE); 1730 if (err) 1731 goto out; 1732 1733 host_err = fh_want_write(fhp); 1734 if (host_err) 1735 goto out_nfserr; 1736 1737 fh_lock_nested(fhp, I_MUTEX_PARENT); 1738 dentry = fhp->fh_dentry; 1739 dirp = d_inode(dentry); 1740 1741 rdentry = lookup_one_len(fname, dentry, flen); 1742 host_err = PTR_ERR(rdentry); 1743 if (IS_ERR(rdentry)) 1744 goto out_nfserr; 1745 1746 if (d_really_is_negative(rdentry)) { 1747 dput(rdentry); 1748 err = nfserr_noent; 1749 goto out; 1750 } 1751 1752 if (!type) 1753 type = d_inode(rdentry)->i_mode & S_IFMT; 1754 1755 if (type != S_IFDIR) 1756 host_err = vfs_unlink(dirp, rdentry, NULL); 1757 else 1758 host_err = vfs_rmdir(dirp, rdentry); 1759 if (!host_err) 1760 host_err = commit_metadata(fhp); 1761 dput(rdentry); 1762 1763 out_nfserr: 1764 err = nfserrno(host_err); 1765 out: 1766 return err; 1767 } 1768 1769 /* 1770 * We do this buffering because we must not call back into the file 1771 * system's ->lookup() method from the filldir callback. That may well 1772 * deadlock a number of file systems. 1773 * 1774 * This is based heavily on the implementation of same in XFS. 1775 */ 1776 struct buffered_dirent { 1777 u64 ino; 1778 loff_t offset; 1779 int namlen; 1780 unsigned int d_type; 1781 char name[]; 1782 }; 1783 1784 struct readdir_data { 1785 struct dir_context ctx; 1786 char *dirent; 1787 size_t used; 1788 int full; 1789 }; 1790 1791 static int nfsd_buffered_filldir(struct dir_context *ctx, const char *name, 1792 int namlen, loff_t offset, u64 ino, 1793 unsigned int d_type) 1794 { 1795 struct readdir_data *buf = 1796 container_of(ctx, struct readdir_data, ctx); 1797 struct buffered_dirent *de = (void *)(buf->dirent + buf->used); 1798 unsigned int reclen; 1799 1800 reclen = ALIGN(sizeof(struct buffered_dirent) + namlen, sizeof(u64)); 1801 if (buf->used + reclen > PAGE_SIZE) { 1802 buf->full = 1; 1803 return -EINVAL; 1804 } 1805 1806 de->namlen = namlen; 1807 de->offset = offset; 1808 de->ino = ino; 1809 de->d_type = d_type; 1810 memcpy(de->name, name, namlen); 1811 buf->used += reclen; 1812 1813 return 0; 1814 } 1815 1816 static __be32 nfsd_buffered_readdir(struct file *file, nfsd_filldir_t func, 1817 struct readdir_cd *cdp, loff_t *offsetp) 1818 { 1819 struct buffered_dirent *de; 1820 int host_err; 1821 int size; 1822 loff_t offset; 1823 struct readdir_data buf = { 1824 .ctx.actor = nfsd_buffered_filldir, 1825 .dirent = (void *)__get_free_page(GFP_KERNEL) 1826 }; 1827 1828 if (!buf.dirent) 1829 return nfserrno(-ENOMEM); 1830 1831 offset = *offsetp; 1832 1833 while (1) { 1834 unsigned int reclen; 1835 1836 cdp->err = nfserr_eof; /* will be cleared on successful read */ 1837 buf.used = 0; 1838 buf.full = 0; 1839 1840 host_err = iterate_dir(file, &buf.ctx); 1841 if (buf.full) 1842 host_err = 0; 1843 1844 if (host_err < 0) 1845 break; 1846 1847 size = buf.used; 1848 1849 if (!size) 1850 break; 1851 1852 de = (struct buffered_dirent *)buf.dirent; 1853 while (size > 0) { 1854 offset = de->offset; 1855 1856 if (func(cdp, de->name, de->namlen, de->offset, 1857 de->ino, de->d_type)) 1858 break; 1859 1860 if (cdp->err != nfs_ok) 1861 break; 1862 1863 reclen = ALIGN(sizeof(*de) + de->namlen, 1864 sizeof(u64)); 1865 size -= reclen; 1866 de = (struct buffered_dirent *)((char *)de + reclen); 1867 } 1868 if (size > 0) /* We bailed out early */ 1869 break; 1870 1871 offset = vfs_llseek(file, 0, SEEK_CUR); 1872 } 1873 1874 free_page((unsigned long)(buf.dirent)); 1875 1876 if (host_err) 1877 return nfserrno(host_err); 1878 1879 *offsetp = offset; 1880 return cdp->err; 1881 } 1882 1883 /* 1884 * Read entries from a directory. 1885 * The NFSv3/4 verifier we ignore for now. 1886 */ 1887 __be32 1888 nfsd_readdir(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t *offsetp, 1889 struct readdir_cd *cdp, nfsd_filldir_t func) 1890 { 1891 __be32 err; 1892 struct file *file; 1893 loff_t offset = *offsetp; 1894 int may_flags = NFSD_MAY_READ; 1895 1896 /* NFSv2 only supports 32 bit cookies */ 1897 if (rqstp->rq_vers > 2) 1898 may_flags |= NFSD_MAY_64BIT_COOKIE; 1899 1900 err = nfsd_open(rqstp, fhp, S_IFDIR, may_flags, &file); 1901 if (err) 1902 goto out; 1903 1904 offset = vfs_llseek(file, offset, SEEK_SET); 1905 if (offset < 0) { 1906 err = nfserrno((int)offset); 1907 goto out_close; 1908 } 1909 1910 err = nfsd_buffered_readdir(file, func, cdp, offsetp); 1911 1912 if (err == nfserr_eof || err == nfserr_toosmall) 1913 err = nfs_ok; /* can still be found in ->err */ 1914 out_close: 1915 fput(file); 1916 out: 1917 return err; 1918 } 1919 1920 /* 1921 * Get file system stats 1922 * N.B. After this call fhp needs an fh_put 1923 */ 1924 __be32 1925 nfsd_statfs(struct svc_rqst *rqstp, struct svc_fh *fhp, struct kstatfs *stat, int access) 1926 { 1927 __be32 err; 1928 1929 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP | access); 1930 if (!err) { 1931 struct path path = { 1932 .mnt = fhp->fh_export->ex_path.mnt, 1933 .dentry = fhp->fh_dentry, 1934 }; 1935 if (vfs_statfs(&path, stat)) 1936 err = nfserr_io; 1937 } 1938 return err; 1939 } 1940 1941 static int exp_rdonly(struct svc_rqst *rqstp, struct svc_export *exp) 1942 { 1943 return nfsexp_flags(rqstp, exp) & NFSEXP_READONLY; 1944 } 1945 1946 /* 1947 * Check for a user's access permissions to this inode. 1948 */ 1949 __be32 1950 nfsd_permission(struct svc_rqst *rqstp, struct svc_export *exp, 1951 struct dentry *dentry, int acc) 1952 { 1953 struct inode *inode = d_inode(dentry); 1954 int err; 1955 1956 if ((acc & NFSD_MAY_MASK) == NFSD_MAY_NOP) 1957 return 0; 1958 #if 0 1959 dprintk("nfsd: permission 0x%x%s%s%s%s%s%s%s mode 0%o%s%s%s\n", 1960 acc, 1961 (acc & NFSD_MAY_READ)? " read" : "", 1962 (acc & NFSD_MAY_WRITE)? " write" : "", 1963 (acc & NFSD_MAY_EXEC)? " exec" : "", 1964 (acc & NFSD_MAY_SATTR)? " sattr" : "", 1965 (acc & NFSD_MAY_TRUNC)? " trunc" : "", 1966 (acc & NFSD_MAY_LOCK)? " lock" : "", 1967 (acc & NFSD_MAY_OWNER_OVERRIDE)? " owneroverride" : "", 1968 inode->i_mode, 1969 IS_IMMUTABLE(inode)? " immut" : "", 1970 IS_APPEND(inode)? " append" : "", 1971 __mnt_is_readonly(exp->ex_path.mnt)? " ro" : ""); 1972 dprintk(" owner %d/%d user %d/%d\n", 1973 inode->i_uid, inode->i_gid, current_fsuid(), current_fsgid()); 1974 #endif 1975 1976 /* Normally we reject any write/sattr etc access on a read-only file 1977 * system. But if it is IRIX doing check on write-access for a 1978 * device special file, we ignore rofs. 1979 */ 1980 if (!(acc & NFSD_MAY_LOCAL_ACCESS)) 1981 if (acc & (NFSD_MAY_WRITE | NFSD_MAY_SATTR | NFSD_MAY_TRUNC)) { 1982 if (exp_rdonly(rqstp, exp) || 1983 __mnt_is_readonly(exp->ex_path.mnt)) 1984 return nfserr_rofs; 1985 if (/* (acc & NFSD_MAY_WRITE) && */ IS_IMMUTABLE(inode)) 1986 return nfserr_perm; 1987 } 1988 if ((acc & NFSD_MAY_TRUNC) && IS_APPEND(inode)) 1989 return nfserr_perm; 1990 1991 if (acc & NFSD_MAY_LOCK) { 1992 /* If we cannot rely on authentication in NLM requests, 1993 * just allow locks, otherwise require read permission, or 1994 * ownership 1995 */ 1996 if (exp->ex_flags & NFSEXP_NOAUTHNLM) 1997 return 0; 1998 else 1999 acc = NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE; 2000 } 2001 /* 2002 * The file owner always gets access permission for accesses that 2003 * would normally be checked at open time. This is to make 2004 * file access work even when the client has done a fchmod(fd, 0). 2005 * 2006 * However, `cp foo bar' should fail nevertheless when bar is 2007 * readonly. A sensible way to do this might be to reject all 2008 * attempts to truncate a read-only file, because a creat() call 2009 * always implies file truncation. 2010 * ... but this isn't really fair. A process may reasonably call 2011 * ftruncate on an open file descriptor on a file with perm 000. 2012 * We must trust the client to do permission checking - using "ACCESS" 2013 * with NFSv3. 2014 */ 2015 if ((acc & NFSD_MAY_OWNER_OVERRIDE) && 2016 uid_eq(inode->i_uid, current_fsuid())) 2017 return 0; 2018 2019 /* This assumes NFSD_MAY_{READ,WRITE,EXEC} == MAY_{READ,WRITE,EXEC} */ 2020 err = inode_permission(inode, acc & (MAY_READ|MAY_WRITE|MAY_EXEC)); 2021 2022 /* Allow read access to binaries even when mode 111 */ 2023 if (err == -EACCES && S_ISREG(inode->i_mode) && 2024 (acc == (NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE) || 2025 acc == (NFSD_MAY_READ | NFSD_MAY_READ_IF_EXEC))) 2026 err = inode_permission(inode, MAY_EXEC); 2027 2028 return err? nfserrno(err) : 0; 2029 } 2030 2031 void 2032 nfsd_racache_shutdown(void) 2033 { 2034 struct raparms *raparm, *last_raparm; 2035 unsigned int i; 2036 2037 dprintk("nfsd: freeing readahead buffers.\n"); 2038 2039 for (i = 0; i < RAPARM_HASH_SIZE; i++) { 2040 raparm = raparm_hash[i].pb_head; 2041 while(raparm) { 2042 last_raparm = raparm; 2043 raparm = raparm->p_next; 2044 kfree(last_raparm); 2045 } 2046 raparm_hash[i].pb_head = NULL; 2047 } 2048 } 2049 /* 2050 * Initialize readahead param cache 2051 */ 2052 int 2053 nfsd_racache_init(int cache_size) 2054 { 2055 int i; 2056 int j = 0; 2057 int nperbucket; 2058 struct raparms **raparm = NULL; 2059 2060 2061 if (raparm_hash[0].pb_head) 2062 return 0; 2063 nperbucket = DIV_ROUND_UP(cache_size, RAPARM_HASH_SIZE); 2064 nperbucket = max(2, nperbucket); 2065 cache_size = nperbucket * RAPARM_HASH_SIZE; 2066 2067 dprintk("nfsd: allocating %d readahead buffers.\n", cache_size); 2068 2069 for (i = 0; i < RAPARM_HASH_SIZE; i++) { 2070 spin_lock_init(&raparm_hash[i].pb_lock); 2071 2072 raparm = &raparm_hash[i].pb_head; 2073 for (j = 0; j < nperbucket; j++) { 2074 *raparm = kzalloc(sizeof(struct raparms), GFP_KERNEL); 2075 if (!*raparm) 2076 goto out_nomem; 2077 raparm = &(*raparm)->p_next; 2078 } 2079 *raparm = NULL; 2080 } 2081 2082 nfsdstats.ra_size = cache_size; 2083 return 0; 2084 2085 out_nomem: 2086 dprintk("nfsd: kmalloc failed, freeing readahead buffers\n"); 2087 nfsd_racache_shutdown(); 2088 return -ENOMEM; 2089 } 2090