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/pagemap.h>
29 #include <linux/slab.h>
30 #include <linux/uaccess.h>
31 #include <linux/exportfs.h>
32 #include <linux/writeback.h>
33 #include <linux/security.h>
34
35 #include "xdr3.h"
36
37 #ifdef CONFIG_NFSD_V4
38 #include "../internal.h"
39 #include "acl.h"
40 #include "idmap.h"
41 #include "xdr4.h"
42 #endif /* CONFIG_NFSD_V4 */
43
44 #include "nfsd.h"
45 #include "vfs.h"
46 #include "filecache.h"
47 #include "trace.h"
48
49 #define NFSDDBG_FACILITY NFSDDBG_FILEOP
50
51 /**
52 * nfserrno - Map Linux errnos to NFS errnos
53 * @errno: POSIX(-ish) error code to be mapped
54 *
55 * Returns the appropriate (net-endian) nfserr_* (or nfs_ok if errno is 0). If
56 * it's an error we don't expect, log it once and return nfserr_io.
57 */
58 __be32
59 nfserrno (int errno)
60 {
61 static struct {
62 __be32 nfserr;
63 int syserr;
64 } nfs_errtbl[] = {
65 { nfs_ok, 0 },
66 { nfserr_perm, -EPERM },
67 { nfserr_noent, -ENOENT },
68 { nfserr_io, -EIO },
69 { nfserr_nxio, -ENXIO },
70 { nfserr_fbig, -E2BIG },
71 { nfserr_stale, -EBADF },
72 { nfserr_acces, -EACCES },
73 { nfserr_exist, -EEXIST },
74 { nfserr_xdev, -EXDEV },
75 { nfserr_mlink, -EMLINK },
76 { nfserr_nodev, -ENODEV },
77 { nfserr_notdir, -ENOTDIR },
78 { nfserr_isdir, -EISDIR },
79 { nfserr_inval, -EINVAL },
80 { nfserr_fbig, -EFBIG },
81 { nfserr_nospc, -ENOSPC },
82 { nfserr_rofs, -EROFS },
83 { nfserr_mlink, -EMLINK },
84 { nfserr_nametoolong, -ENAMETOOLONG },
85 { nfserr_notempty, -ENOTEMPTY },
86 { nfserr_dquot, -EDQUOT },
87 { nfserr_stale, -ESTALE },
88 { nfserr_jukebox, -ETIMEDOUT },
89 { nfserr_jukebox, -ERESTARTSYS },
90 { nfserr_jukebox, -EAGAIN },
91 { nfserr_jukebox, -EWOULDBLOCK },
92 { nfserr_jukebox, -ENOMEM },
93 { nfserr_io, -ETXTBSY },
94 { nfserr_notsupp, -EOPNOTSUPP },
95 { nfserr_toosmall, -ETOOSMALL },
96 { nfserr_serverfault, -ESERVERFAULT },
97 { nfserr_serverfault, -ENFILE },
98 { nfserr_io, -EREMOTEIO },
99 { nfserr_stale, -EOPENSTALE },
100 { nfserr_io, -EUCLEAN },
101 { nfserr_perm, -ENOKEY },
102 { nfserr_no_grace, -ENOGRACE},
103 { nfserr_io, -EBADMSG },
104 };
105 int i;
106
107 for (i = 0; i < ARRAY_SIZE(nfs_errtbl); i++) {
108 if (nfs_errtbl[i].syserr == errno)
109 return nfs_errtbl[i].nfserr;
110 }
111 WARN_ONCE(1, "nfsd: non-standard errno: %d\n", errno);
112 return nfserr_io;
113 }
114
115 /*
116 * Called from nfsd_lookup and encode_dirent. Check if we have crossed
117 * a mount point.
118 * Returns -EAGAIN or -ETIMEDOUT leaving *dpp and *expp unchanged,
119 * or nfs_ok having possibly changed *dpp and *expp
120 */
121 int
122 nfsd_cross_mnt(struct svc_rqst *rqstp, struct dentry **dpp,
123 struct svc_export **expp)
124 {
125 struct svc_export *exp = *expp, *exp2 = NULL;
126 struct dentry *dentry = *dpp;
127 struct path path = {.mnt = mntget(exp->ex_path.mnt),
128 .dentry = dget(dentry)};
129 unsigned int follow_flags = 0;
130 int err = 0;
131
132 if (exp->ex_flags & NFSEXP_CROSSMOUNT)
133 follow_flags = LOOKUP_AUTOMOUNT;
134
135 err = follow_down(&path, follow_flags);
136 if (err < 0)
137 goto out;
138 if (path.mnt == exp->ex_path.mnt && path.dentry == dentry &&
139 nfsd_mountpoint(dentry, exp) == 2) {
140 /* This is only a mountpoint in some other namespace */
141 path_put(&path);
142 goto out;
143 }
144
145 exp2 = rqst_exp_get_by_name(rqstp, &path);
146 if (IS_ERR(exp2)) {
147 err = PTR_ERR(exp2);
148 /*
149 * We normally allow NFS clients to continue
150 * "underneath" a mountpoint that is not exported.
151 * The exception is V4ROOT, where no traversal is ever
152 * allowed without an explicit export of the new
153 * directory.
154 */
155 if (err == -ENOENT && !(exp->ex_flags & NFSEXP_V4ROOT))
156 err = 0;
157 path_put(&path);
158 goto out;
159 }
160 if (nfsd_v4client(rqstp) ||
161 (exp->ex_flags & NFSEXP_CROSSMOUNT) || EX_NOHIDE(exp2)) {
162 /* successfully crossed mount point */
163 /*
164 * This is subtle: path.dentry is *not* on path.mnt
165 * at this point. The only reason we are safe is that
166 * original mnt is pinned down by exp, so we should
167 * put path *before* putting exp
168 */
169 *dpp = path.dentry;
170 path.dentry = dentry;
171 *expp = exp2;
172 exp2 = exp;
173 }
174 path_put(&path);
175 exp_put(exp2);
176 out:
177 return err;
178 }
179
180 static void follow_to_parent(struct path *path)
181 {
182 struct dentry *dp;
183
184 while (path->dentry == path->mnt->mnt_root && follow_up(path))
185 ;
186 dp = dget_parent(path->dentry);
187 dput(path->dentry);
188 path->dentry = dp;
189 }
190
191 static int nfsd_lookup_parent(struct svc_rqst *rqstp, struct dentry *dparent, struct svc_export **exp, struct dentry **dentryp)
192 {
193 struct svc_export *exp2;
194 struct path path = {.mnt = mntget((*exp)->ex_path.mnt),
195 .dentry = dget(dparent)};
196
197 follow_to_parent(&path);
198
199 exp2 = rqst_exp_parent(rqstp, &path);
200 if (PTR_ERR(exp2) == -ENOENT) {
201 *dentryp = dget(dparent);
202 } else if (IS_ERR(exp2)) {
203 path_put(&path);
204 return PTR_ERR(exp2);
205 } else {
206 *dentryp = dget(path.dentry);
207 exp_put(*exp);
208 *exp = exp2;
209 }
210 path_put(&path);
211 return 0;
212 }
213
214 /*
215 * For nfsd purposes, we treat V4ROOT exports as though there was an
216 * export at *every* directory.
217 * We return:
218 * '1' if this dentry *must* be an export point,
219 * '2' if it might be, if there is really a mount here, and
220 * '' if there is no chance of an export point here.
221 */
222 int nfsd_mountpoint(struct dentry *dentry, struct svc_export *exp)
223 {
224 if (!d_inode(dentry))
225 return 0;
226 if (exp->ex_flags & NFSEXP_V4ROOT)
227 return 1;
228 if (nfsd4_is_junction(dentry))
229 return 1;
230 if (d_managed(dentry))
231 /*
232 * Might only be a mountpoint in a different namespace,
233 * but we need to check.
234 */
235 return 2;
236 return 0;
237 }
238
239 __be32
240 nfsd_lookup_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp,
241 const char *name, unsigned int len,
242 struct svc_export **exp_ret, struct dentry **dentry_ret)
243 {
244 struct svc_export *exp;
245 struct dentry *dparent;
246 struct dentry *dentry;
247 int host_err;
248
249 dprintk("nfsd: nfsd_lookup(fh %s, %.*s)\n", SVCFH_fmt(fhp), len,name);
250
251 dparent = fhp->fh_dentry;
252 exp = exp_get(fhp->fh_export);
253
254 /* Lookup the name, but don't follow links */
255 if (isdotent(name, len)) {
256 if (len==1)
257 dentry = dget(dparent);
258 else if (dparent != exp->ex_path.dentry)
259 dentry = dget_parent(dparent);
260 else if (!EX_NOHIDE(exp) && !nfsd_v4client(rqstp))
261 dentry = dget(dparent); /* .. == . just like at / */
262 else {
263 /* checking mountpoint crossing is very different when stepping up */
264 host_err = nfsd_lookup_parent(rqstp, dparent, &exp, &dentry);
265 if (host_err)
266 goto out_nfserr;
267 }
268 } else {
269 dentry = lookup_one_len_unlocked(name, dparent, len);
270 host_err = PTR_ERR(dentry);
271 if (IS_ERR(dentry))
272 goto out_nfserr;
273 if (nfsd_mountpoint(dentry, exp)) {
274 host_err = nfsd_cross_mnt(rqstp, &dentry, &exp);
275 if (host_err) {
276 dput(dentry);
277 goto out_nfserr;
278 }
279 }
280 }
281 *dentry_ret = dentry;
282 *exp_ret = exp;
283 return 0;
284
285 out_nfserr:
286 exp_put(exp);
287 return nfserrno(host_err);
288 }
289
290 /**
291 * nfsd_lookup - look up a single path component for nfsd
292 *
293 * @rqstp: the request context
294 * @fhp: the file handle of the directory
295 * @name: the component name, or %NULL to look up parent
296 * @len: length of name to examine
297 * @resfh: pointer to pre-initialised filehandle to hold result.
298 *
299 * Look up one component of a pathname.
300 * N.B. After this call _both_ fhp and resfh need an fh_put
301 *
302 * If the lookup would cross a mountpoint, and the mounted filesystem
303 * is exported to the client with NFSEXP_NOHIDE, then the lookup is
304 * accepted as it stands and the mounted directory is
305 * returned. Otherwise the covered directory is returned.
306 * NOTE: this mountpoint crossing is not supported properly by all
307 * clients and is explicitly disallowed for NFSv3
308 *
309 */
310 __be32
311 nfsd_lookup(struct svc_rqst *rqstp, struct svc_fh *fhp, const char *name,
312 unsigned int len, struct svc_fh *resfh)
313 {
314 struct svc_export *exp;
315 struct dentry *dentry;
316 __be32 err;
317
318 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC);
319 if (err)
320 return err;
321 err = nfsd_lookup_dentry(rqstp, fhp, name, len, &exp, &dentry);
322 if (err)
323 return err;
324 err = check_nfsd_access(exp, rqstp);
325 if (err)
326 goto out;
327 /*
328 * Note: we compose the file handle now, but as the
329 * dentry may be negative, it may need to be updated.
330 */
331 err = fh_compose(resfh, exp, dentry, fhp);
332 if (!err && d_really_is_negative(dentry))
333 err = nfserr_noent;
334 out:
335 dput(dentry);
336 exp_put(exp);
337 return err;
338 }
339
340 static void
341 commit_reset_write_verifier(struct nfsd_net *nn, struct svc_rqst *rqstp,
342 int err)
343 {
344 switch (err) {
345 case -EAGAIN:
346 case -ESTALE:
347 /*
348 * Neither of these are the result of a problem with
349 * durable storage, so avoid a write verifier reset.
350 */
351 break;
352 default:
353 nfsd_reset_write_verifier(nn);
354 trace_nfsd_writeverf_reset(nn, rqstp, err);
355 }
356 }
357
358 /*
359 * Commit metadata changes to stable storage.
360 */
361 static int
362 commit_inode_metadata(struct inode *inode)
363 {
364 const struct export_operations *export_ops = inode->i_sb->s_export_op;
365
366 if (export_ops->commit_metadata)
367 return export_ops->commit_metadata(inode);
368 return sync_inode_metadata(inode, 1);
369 }
370
371 static int
372 commit_metadata(struct svc_fh *fhp)
373 {
374 struct inode *inode = d_inode(fhp->fh_dentry);
375
376 if (!EX_ISSYNC(fhp->fh_export))
377 return 0;
378 return commit_inode_metadata(inode);
379 }
380
381 /*
382 * Go over the attributes and take care of the small differences between
383 * NFS semantics and what Linux expects.
384 */
385 static void
386 nfsd_sanitize_attrs(struct inode *inode, struct iattr *iap)
387 {
388 /* Ignore mode updates on symlinks */
389 if (S_ISLNK(inode->i_mode))
390 iap->ia_valid &= ~ATTR_MODE;
391
392 /* sanitize the mode change */
393 if (iap->ia_valid & ATTR_MODE) {
394 iap->ia_mode &= S_IALLUGO;
395 iap->ia_mode |= (inode->i_mode & ~S_IALLUGO);
396 }
397
398 /* Revoke setuid/setgid on chown */
399 if (!S_ISDIR(inode->i_mode) &&
400 ((iap->ia_valid & ATTR_UID) || (iap->ia_valid & ATTR_GID))) {
401 iap->ia_valid |= ATTR_KILL_PRIV;
402 if (iap->ia_valid & ATTR_MODE) {
403 /* we're setting mode too, just clear the s*id bits */
404 iap->ia_mode &= ~S_ISUID;
405 if (iap->ia_mode & S_IXGRP)
406 iap->ia_mode &= ~S_ISGID;
407 } else {
408 /* set ATTR_KILL_* bits and let VFS handle it */
409 iap->ia_valid |= ATTR_KILL_SUID;
410 iap->ia_valid |=
411 setattr_should_drop_sgid(&nop_mnt_idmap, inode);
412 }
413 }
414 }
415
416 static __be32
417 nfsd_get_write_access(struct svc_rqst *rqstp, struct svc_fh *fhp,
418 struct iattr *iap)
419 {
420 struct inode *inode = d_inode(fhp->fh_dentry);
421
422 if (iap->ia_size < inode->i_size) {
423 __be32 err;
424
425 err = nfsd_permission(rqstp, fhp->fh_export, fhp->fh_dentry,
426 NFSD_MAY_TRUNC | NFSD_MAY_OWNER_OVERRIDE);
427 if (err)
428 return err;
429 }
430 return nfserrno(get_write_access(inode));
431 }
432
433 static int __nfsd_setattr(struct dentry *dentry, struct iattr *iap)
434 {
435 int host_err;
436
437 if (iap->ia_valid & ATTR_SIZE) {
438 /*
439 * RFC5661, Section 18.30.4:
440 * Changing the size of a file with SETATTR indirectly
441 * changes the time_modify and change attributes.
442 *
443 * (and similar for the older RFCs)
444 */
445 struct iattr size_attr = {
446 .ia_valid = ATTR_SIZE | ATTR_CTIME | ATTR_MTIME,
447 .ia_size = iap->ia_size,
448 };
449
450 if (iap->ia_size < 0)
451 return -EFBIG;
452
453 host_err = notify_change(&nop_mnt_idmap, dentry, &size_attr, NULL);
454 if (host_err)
455 return host_err;
456 iap->ia_valid &= ~ATTR_SIZE;
457
458 /*
459 * Avoid the additional setattr call below if the only other
460 * attribute that the client sends is the mtime, as we update
461 * it as part of the size change above.
462 */
463 if ((iap->ia_valid & ~ATTR_MTIME) == 0)
464 return 0;
465 }
466
467 if (!iap->ia_valid)
468 return 0;
469
470 iap->ia_valid |= ATTR_CTIME;
471 return notify_change(&nop_mnt_idmap, dentry, iap, NULL);
472 }
473
474 /**
475 * nfsd_setattr - Set various file attributes.
476 * @rqstp: controlling RPC transaction
477 * @fhp: filehandle of target
478 * @attr: attributes to set
479 * @guardtime: do not act if ctime.tv_sec does not match this timestamp
480 *
481 * This call may adjust the contents of @attr (in particular, this
482 * call may change the bits in the na_iattr.ia_valid field).
483 *
484 * Returns nfs_ok on success, otherwise an NFS status code is
485 * returned. Caller must release @fhp by calling fh_put in either
486 * case.
487 */
488 __be32
489 nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp,
490 struct nfsd_attrs *attr, const struct timespec64 *guardtime)
491 {
492 struct dentry *dentry;
493 struct inode *inode;
494 struct iattr *iap = attr->na_iattr;
495 int accmode = NFSD_MAY_SATTR;
496 umode_t ftype = 0;
497 __be32 err;
498 int host_err = 0;
499 bool get_write_count;
500 bool size_change = (iap->ia_valid & ATTR_SIZE);
501 int retries;
502
503 if (iap->ia_valid & ATTR_SIZE) {
504 accmode |= NFSD_MAY_WRITE|NFSD_MAY_OWNER_OVERRIDE;
505 ftype = S_IFREG;
506 }
507
508 /*
509 * If utimes(2) and friends are called with times not NULL, we should
510 * not set NFSD_MAY_WRITE bit. Otherwise fh_verify->nfsd_permission
511 * will return EACCES, when the caller's effective UID does not match
512 * the owner of the file, and the caller is not privileged. In this
513 * situation, we should return EPERM(notify_change will return this).
514 */
515 if (iap->ia_valid & (ATTR_ATIME | ATTR_MTIME)) {
516 accmode |= NFSD_MAY_OWNER_OVERRIDE;
517 if (!(iap->ia_valid & (ATTR_ATIME_SET | ATTR_MTIME_SET)))
518 accmode |= NFSD_MAY_WRITE;
519 }
520
521 /* Callers that do fh_verify should do the fh_want_write: */
522 get_write_count = !fhp->fh_dentry;
523
524 /* Get inode */
525 err = fh_verify(rqstp, fhp, ftype, accmode);
526 if (err)
527 return err;
528 if (get_write_count) {
529 host_err = fh_want_write(fhp);
530 if (host_err)
531 goto out;
532 }
533
534 dentry = fhp->fh_dentry;
535 inode = d_inode(dentry);
536
537 nfsd_sanitize_attrs(inode, iap);
538
539 /*
540 * The size case is special, it changes the file in addition to the
541 * attributes, and file systems don't expect it to be mixed with
542 * "random" attribute changes. We thus split out the size change
543 * into a separate call to ->setattr, and do the rest as a separate
544 * setattr call.
545 */
546 if (size_change) {
547 err = nfsd_get_write_access(rqstp, fhp, iap);
548 if (err)
549 return err;
550 }
551
552 inode_lock(inode);
553 err = fh_fill_pre_attrs(fhp);
554 if (err)
555 goto out_unlock;
556
557 if (guardtime) {
558 struct timespec64 ctime = inode_get_ctime(inode);
559 if ((u32)guardtime->tv_sec != (u32)ctime.tv_sec ||
560 guardtime->tv_nsec != ctime.tv_nsec) {
561 err = nfserr_notsync;
562 goto out_fill_attrs;
563 }
564 }
565
566 for (retries = 1;;) {
567 struct iattr attrs;
568
569 /*
570 * notify_change() can alter its iattr argument, making
571 * @iap unsuitable for submission multiple times. Make a
572 * copy for every loop iteration.
573 */
574 attrs = *iap;
575 host_err = __nfsd_setattr(dentry, &attrs);
576 if (host_err != -EAGAIN || !retries--)
577 break;
578 if (!nfsd_wait_for_delegreturn(rqstp, inode))
579 break;
580 }
581 if (attr->na_seclabel && attr->na_seclabel->len)
582 attr->na_labelerr = security_inode_setsecctx(dentry,
583 attr->na_seclabel->data, attr->na_seclabel->len);
584 if (IS_ENABLED(CONFIG_FS_POSIX_ACL) && attr->na_pacl)
585 attr->na_aclerr = set_posix_acl(&nop_mnt_idmap,
586 dentry, ACL_TYPE_ACCESS,
587 attr->na_pacl);
588 if (IS_ENABLED(CONFIG_FS_POSIX_ACL) &&
589 !attr->na_aclerr && attr->na_dpacl && S_ISDIR(inode->i_mode))
590 attr->na_aclerr = set_posix_acl(&nop_mnt_idmap,
591 dentry, ACL_TYPE_DEFAULT,
592 attr->na_dpacl);
593 out_fill_attrs:
594 /*
595 * RFC 1813 Section 3.3.2 does not mandate that an NFS server
596 * returns wcc_data for SETATTR. Some client implementations
597 * depend on receiving wcc_data, however, to sort out partial
598 * updates (eg., the client requested that size and mode be
599 * modified, but the server changed only the file mode).
600 */
601 fh_fill_post_attrs(fhp);
602 out_unlock:
603 inode_unlock(inode);
604 if (size_change)
605 put_write_access(inode);
606 out:
607 if (!host_err)
608 host_err = commit_metadata(fhp);
609 return err != 0 ? err : nfserrno(host_err);
610 }
611
612 #if defined(CONFIG_NFSD_V4)
613 /*
614 * NFS junction information is stored in an extended attribute.
615 */
616 #define NFSD_JUNCTION_XATTR_NAME XATTR_TRUSTED_PREFIX "junction.nfs"
617
618 /**
619 * nfsd4_is_junction - Test if an object could be an NFS junction
620 *
621 * @dentry: object to test
622 *
623 * Returns 1 if "dentry" appears to contain NFS junction information.
624 * Otherwise 0 is returned.
625 */
626 int nfsd4_is_junction(struct dentry *dentry)
627 {
628 struct inode *inode = d_inode(dentry);
629
630 if (inode == NULL)
631 return 0;
632 if (inode->i_mode & S_IXUGO)
633 return 0;
634 if (!(inode->i_mode & S_ISVTX))
635 return 0;
636 if (vfs_getxattr(&nop_mnt_idmap, dentry, NFSD_JUNCTION_XATTR_NAME,
637 NULL, 0) <= 0)
638 return 0;
639 return 1;
640 }
641
642 static struct nfsd4_compound_state *nfsd4_get_cstate(struct svc_rqst *rqstp)
643 {
644 return &((struct nfsd4_compoundres *)rqstp->rq_resp)->cstate;
645 }
646
647 __be32 nfsd4_clone_file_range(struct svc_rqst *rqstp,
648 struct nfsd_file *nf_src, u64 src_pos,
649 struct nfsd_file *nf_dst, u64 dst_pos,
650 u64 count, bool sync)
651 {
652 struct file *src = nf_src->nf_file;
653 struct file *dst = nf_dst->nf_file;
654 errseq_t since;
655 loff_t cloned;
656 __be32 ret = 0;
657
658 since = READ_ONCE(dst->f_wb_err);
659 cloned = vfs_clone_file_range(src, src_pos, dst, dst_pos, count, 0);
660 if (cloned < 0) {
661 ret = nfserrno(cloned);
662 goto out_err;
663 }
664 if (count && cloned != count) {
665 ret = nfserrno(-EINVAL);
666 goto out_err;
667 }
668 if (sync) {
669 loff_t dst_end = count ? dst_pos + count - 1 : LLONG_MAX;
670 int status = vfs_fsync_range(dst, dst_pos, dst_end, 0);
671
672 if (!status)
673 status = filemap_check_wb_err(dst->f_mapping, since);
674 if (!status)
675 status = commit_inode_metadata(file_inode(src));
676 if (status < 0) {
677 struct nfsd_net *nn = net_generic(nf_dst->nf_net,
678 nfsd_net_id);
679
680 trace_nfsd_clone_file_range_err(rqstp,
681 &nfsd4_get_cstate(rqstp)->save_fh,
682 src_pos,
683 &nfsd4_get_cstate(rqstp)->current_fh,
684 dst_pos,
685 count, status);
686 commit_reset_write_verifier(nn, rqstp, status);
687 ret = nfserrno(status);
688 }
689 }
690 out_err:
691 return ret;
692 }
693
694 ssize_t nfsd_copy_file_range(struct file *src, u64 src_pos, struct file *dst,
695 u64 dst_pos, u64 count)
696 {
697 ssize_t ret;
698
699 /*
700 * Limit copy to 4MB to prevent indefinitely blocking an nfsd
701 * thread and client rpc slot. The choice of 4MB is somewhat
702 * arbitrary. We might instead base this on r/wsize, or make it
703 * tunable, or use a time instead of a byte limit, or implement
704 * asynchronous copy. In theory a client could also recognize a
705 * limit like this and pipeline multiple COPY requests.
706 */
707 count = min_t(u64, count, 1 << 22);
708 ret = vfs_copy_file_range(src, src_pos, dst, dst_pos, count, 0);
709
710 if (ret == -EOPNOTSUPP || ret == -EXDEV)
711 ret = vfs_copy_file_range(src, src_pos, dst, dst_pos, count,
712 COPY_FILE_SPLICE);
713 return ret;
714 }
715
716 __be32 nfsd4_vfs_fallocate(struct svc_rqst *rqstp, struct svc_fh *fhp,
717 struct file *file, loff_t offset, loff_t len,
718 int flags)
719 {
720 int error;
721
722 if (!S_ISREG(file_inode(file)->i_mode))
723 return nfserr_inval;
724
725 error = vfs_fallocate(file, flags, offset, len);
726 if (!error)
727 error = commit_metadata(fhp);
728
729 return nfserrno(error);
730 }
731 #endif /* defined(CONFIG_NFSD_V4) */
732
733 /*
734 * Check server access rights to a file system object
735 */
736 struct accessmap {
737 u32 access;
738 int how;
739 };
740 static struct accessmap nfs3_regaccess[] = {
741 { NFS3_ACCESS_READ, NFSD_MAY_READ },
742 { NFS3_ACCESS_EXECUTE, NFSD_MAY_EXEC },
743 { NFS3_ACCESS_MODIFY, NFSD_MAY_WRITE|NFSD_MAY_TRUNC },
744 { NFS3_ACCESS_EXTEND, NFSD_MAY_WRITE },
745
746 #ifdef CONFIG_NFSD_V4
747 { NFS4_ACCESS_XAREAD, NFSD_MAY_READ },
748 { NFS4_ACCESS_XAWRITE, NFSD_MAY_WRITE },
749 { NFS4_ACCESS_XALIST, NFSD_MAY_READ },
750 #endif
751
752 { 0, 0 }
753 };
754
755 static struct accessmap nfs3_diraccess[] = {
756 { NFS3_ACCESS_READ, NFSD_MAY_READ },
757 { NFS3_ACCESS_LOOKUP, NFSD_MAY_EXEC },
758 { NFS3_ACCESS_MODIFY, NFSD_MAY_EXEC|NFSD_MAY_WRITE|NFSD_MAY_TRUNC},
759 { NFS3_ACCESS_EXTEND, NFSD_MAY_EXEC|NFSD_MAY_WRITE },
760 { NFS3_ACCESS_DELETE, NFSD_MAY_REMOVE },
761
762 #ifdef CONFIG_NFSD_V4
763 { NFS4_ACCESS_XAREAD, NFSD_MAY_READ },
764 { NFS4_ACCESS_XAWRITE, NFSD_MAY_WRITE },
765 { NFS4_ACCESS_XALIST, NFSD_MAY_READ },
766 #endif
767
768 { 0, 0 }
769 };
770
771 static struct accessmap nfs3_anyaccess[] = {
772 /* Some clients - Solaris 2.6 at least, make an access call
773 * to the server to check for access for things like /dev/null
774 * (which really, the server doesn't care about). So
775 * We provide simple access checking for them, looking
776 * mainly at mode bits, and we make sure to ignore read-only
777 * filesystem checks
778 */
779 { NFS3_ACCESS_READ, NFSD_MAY_READ },
780 { NFS3_ACCESS_EXECUTE, NFSD_MAY_EXEC },
781 { NFS3_ACCESS_MODIFY, NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS },
782 { NFS3_ACCESS_EXTEND, NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS },
783
784 { 0, 0 }
785 };
786
787 __be32
788 nfsd_access(struct svc_rqst *rqstp, struct svc_fh *fhp, u32 *access, u32 *supported)
789 {
790 struct accessmap *map;
791 struct svc_export *export;
792 struct dentry *dentry;
793 u32 query, result = 0, sresult = 0;
794 __be32 error;
795
796 error = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP);
797 if (error)
798 goto out;
799
800 export = fhp->fh_export;
801 dentry = fhp->fh_dentry;
802
803 if (d_is_reg(dentry))
804 map = nfs3_regaccess;
805 else if (d_is_dir(dentry))
806 map = nfs3_diraccess;
807 else
808 map = nfs3_anyaccess;
809
810
811 query = *access;
812 for (; map->access; map++) {
813 if (map->access & query) {
814 __be32 err2;
815
816 sresult |= map->access;
817
818 err2 = nfsd_permission(rqstp, export, dentry, map->how);
819 switch (err2) {
820 case nfs_ok:
821 result |= map->access;
822 break;
823
824 /* the following error codes just mean the access was not allowed,
825 * rather than an error occurred */
826 case nfserr_rofs:
827 case nfserr_acces:
828 case nfserr_perm:
829 /* simply don't "or" in the access bit. */
830 break;
831 default:
832 error = err2;
833 goto out;
834 }
835 }
836 }
837 *access = result;
838 if (supported)
839 *supported = sresult;
840
841 out:
842 return error;
843 }
844
845 int nfsd_open_break_lease(struct inode *inode, int access)
846 {
847 unsigned int mode;
848
849 if (access & NFSD_MAY_NOT_BREAK_LEASE)
850 return 0;
851 mode = (access & NFSD_MAY_WRITE) ? O_WRONLY : O_RDONLY;
852 return break_lease(inode, mode | O_NONBLOCK);
853 }
854
855 /*
856 * Open an existing file or directory.
857 * The may_flags argument indicates the type of open (read/write/lock)
858 * and additional flags.
859 * N.B. After this call fhp needs an fh_put
860 */
861 static int
862 __nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type,
863 int may_flags, struct file **filp)
864 {
865 struct path path;
866 struct inode *inode;
867 struct file *file;
868 int flags = O_RDONLY|O_LARGEFILE;
869 int host_err = -EPERM;
870
871 path.mnt = fhp->fh_export->ex_path.mnt;
872 path.dentry = fhp->fh_dentry;
873 inode = d_inode(path.dentry);
874
875 if (IS_APPEND(inode) && (may_flags & NFSD_MAY_WRITE))
876 goto out;
877
878 if (!inode->i_fop)
879 goto out;
880
881 host_err = nfsd_open_break_lease(inode, may_flags);
882 if (host_err) /* NOMEM or WOULDBLOCK */
883 goto out;
884
885 if (may_flags & NFSD_MAY_WRITE) {
886 if (may_flags & NFSD_MAY_READ)
887 flags = O_RDWR|O_LARGEFILE;
888 else
889 flags = O_WRONLY|O_LARGEFILE;
890 }
891
892 file = dentry_open(&path, flags, current_cred());
893 if (IS_ERR(file)) {
894 host_err = PTR_ERR(file);
895 goto out;
896 }
897
898 host_err = security_file_post_open(file, may_flags);
899 if (host_err) {
900 fput(file);
901 goto out;
902 }
903
904 if (may_flags & NFSD_MAY_64BIT_COOKIE)
905 file->f_mode |= FMODE_64BITHASH;
906 else
907 file->f_mode |= FMODE_32BITHASH;
908
909 *filp = file;
910 out:
911 return host_err;
912 }
913
914 __be32
915 nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type,
916 int may_flags, struct file **filp)
917 {
918 __be32 err;
919 int host_err;
920 bool retried = false;
921
922 /*
923 * If we get here, then the client has already done an "open",
924 * and (hopefully) checked permission - so allow OWNER_OVERRIDE
925 * in case a chmod has now revoked permission.
926 *
927 * Arguably we should also allow the owner override for
928 * directories, but we never have and it doesn't seem to have
929 * caused anyone a problem. If we were to change this, note
930 * also that our filldir callbacks would need a variant of
931 * lookup_one_len that doesn't check permissions.
932 */
933 if (type == S_IFREG)
934 may_flags |= NFSD_MAY_OWNER_OVERRIDE;
935 retry:
936 err = fh_verify(rqstp, fhp, type, may_flags);
937 if (!err) {
938 host_err = __nfsd_open(rqstp, fhp, type, may_flags, filp);
939 if (host_err == -EOPENSTALE && !retried) {
940 retried = true;
941 fh_put(fhp);
942 goto retry;
943 }
944 err = nfserrno(host_err);
945 }
946 return err;
947 }
948
949 /**
950 * nfsd_open_verified - Open a regular file for the filecache
951 * @rqstp: RPC request
952 * @fhp: NFS filehandle of the file to open
953 * @may_flags: internal permission flags
954 * @filp: OUT: open "struct file *"
955 *
956 * Returns zero on success, or a negative errno value.
957 */
958 int
959 nfsd_open_verified(struct svc_rqst *rqstp, struct svc_fh *fhp, int may_flags,
960 struct file **filp)
961 {
962 return __nfsd_open(rqstp, fhp, S_IFREG, may_flags, filp);
963 }
964
965 /*
966 * Grab and keep cached pages associated with a file in the svc_rqst
967 * so that they can be passed to the network sendmsg routines
968 * directly. They will be released after the sending has completed.
969 *
970 * Return values: Number of bytes consumed, or -EIO if there are no
971 * remaining pages in rqstp->rq_pages.
972 */
973 static int
974 nfsd_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
975 struct splice_desc *sd)
976 {
977 struct svc_rqst *rqstp = sd->u.data;
978 struct page *page = buf->page; // may be a compound one
979 unsigned offset = buf->offset;
980 struct page *last_page;
981
982 last_page = page + (offset + sd->len - 1) / PAGE_SIZE;
983 for (page += offset / PAGE_SIZE; page <= last_page; page++) {
984 /*
985 * Skip page replacement when extending the contents of the
986 * current page. But note that we may get two zero_pages in a
987 * row from shmem.
988 */
989 if (page == *(rqstp->rq_next_page - 1) &&
990 offset_in_page(rqstp->rq_res.page_base +
991 rqstp->rq_res.page_len))
992 continue;
993 if (unlikely(!svc_rqst_replace_page(rqstp, page)))
994 return -EIO;
995 }
996 if (rqstp->rq_res.page_len == 0) // first call
997 rqstp->rq_res.page_base = offset % PAGE_SIZE;
998 rqstp->rq_res.page_len += sd->len;
999 return sd->len;
1000 }
1001
1002 static int nfsd_direct_splice_actor(struct pipe_inode_info *pipe,
1003 struct splice_desc *sd)
1004 {
1005 return __splice_from_pipe(pipe, sd, nfsd_splice_actor);
1006 }
1007
1008 static u32 nfsd_eof_on_read(struct file *file, loff_t offset, ssize_t len,
1009 size_t expected)
1010 {
1011 if (expected != 0 && len == 0)
1012 return 1;
1013 if (offset+len >= i_size_read(file_inode(file)))
1014 return 1;
1015 return 0;
1016 }
1017
1018 static __be32 nfsd_finish_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
1019 struct file *file, loff_t offset,
1020 unsigned long *count, u32 *eof, ssize_t host_err)
1021 {
1022 if (host_err >= 0) {
1023 struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
1024
1025 nfsd_stats_io_read_add(nn, fhp->fh_export, host_err);
1026 *eof = nfsd_eof_on_read(file, offset, host_err, *count);
1027 *count = host_err;
1028 fsnotify_access(file);
1029 trace_nfsd_read_io_done(rqstp, fhp, offset, *count);
1030 return 0;
1031 } else {
1032 trace_nfsd_read_err(rqstp, fhp, offset, host_err);
1033 return nfserrno(host_err);
1034 }
1035 }
1036
1037 /**
1038 * nfsd_splice_read - Perform a VFS read using a splice pipe
1039 * @rqstp: RPC transaction context
1040 * @fhp: file handle of file to be read
1041 * @file: opened struct file of file to be read
1042 * @offset: starting byte offset
1043 * @count: IN: requested number of bytes; OUT: number of bytes read
1044 * @eof: OUT: set non-zero if operation reached the end of the file
1045 *
1046 * Returns nfs_ok on success, otherwise an nfserr stat value is
1047 * returned.
1048 */
1049 __be32 nfsd_splice_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
1050 struct file *file, loff_t offset, unsigned long *count,
1051 u32 *eof)
1052 {
1053 struct splice_desc sd = {
1054 .len = 0,
1055 .total_len = *count,
1056 .pos = offset,
1057 .u.data = rqstp,
1058 };
1059 ssize_t host_err;
1060
1061 trace_nfsd_read_splice(rqstp, fhp, offset, *count);
1062 host_err = rw_verify_area(READ, file, &offset, *count);
1063 if (!host_err)
1064 host_err = splice_direct_to_actor(file, &sd,
1065 nfsd_direct_splice_actor);
1066 return nfsd_finish_read(rqstp, fhp, file, offset, count, eof, host_err);
1067 }
1068
1069 /**
1070 * nfsd_iter_read - Perform a VFS read using an iterator
1071 * @rqstp: RPC transaction context
1072 * @fhp: file handle of file to be read
1073 * @file: opened struct file of file to be read
1074 * @offset: starting byte offset
1075 * @count: IN: requested number of bytes; OUT: number of bytes read
1076 * @base: offset in first page of read buffer
1077 * @eof: OUT: set non-zero if operation reached the end of the file
1078 *
1079 * Some filesystems or situations cannot use nfsd_splice_read. This
1080 * function is the slightly less-performant fallback for those cases.
1081 *
1082 * Returns nfs_ok on success, otherwise an nfserr stat value is
1083 * returned.
1084 */
1085 __be32 nfsd_iter_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
1086 struct file *file, loff_t offset, unsigned long *count,
1087 unsigned int base, u32 *eof)
1088 {
1089 unsigned long v, total;
1090 struct iov_iter iter;
1091 loff_t ppos = offset;
1092 struct page *page;
1093 ssize_t host_err;
1094
1095 v = 0;
1096 total = *count;
1097 while (total) {
1098 page = *(rqstp->rq_next_page++);
1099 rqstp->rq_vec[v].iov_base = page_address(page) + base;
1100 rqstp->rq_vec[v].iov_len = min_t(size_t, total, PAGE_SIZE - base);
1101 total -= rqstp->rq_vec[v].iov_len;
1102 ++v;
1103 base = 0;
1104 }
1105 WARN_ON_ONCE(v > ARRAY_SIZE(rqstp->rq_vec));
1106
1107 trace_nfsd_read_vector(rqstp, fhp, offset, *count);
1108 iov_iter_kvec(&iter, ITER_DEST, rqstp->rq_vec, v, *count);
1109 host_err = vfs_iter_read(file, &iter, &ppos, 0);
1110 return nfsd_finish_read(rqstp, fhp, file, offset, count, eof, host_err);
1111 }
1112
1113 /*
1114 * Gathered writes: If another process is currently writing to the file,
1115 * there's a high chance this is another nfsd (triggered by a bulk write
1116 * from a client's biod). Rather than syncing the file with each write
1117 * request, we sleep for 10 msec.
1118 *
1119 * I don't know if this roughly approximates C. Juszak's idea of
1120 * gathered writes, but it's a nice and simple solution (IMHO), and it
1121 * seems to work:-)
1122 *
1123 * Note: we do this only in the NFSv2 case, since v3 and higher have a
1124 * better tool (separate unstable writes and commits) for solving this
1125 * problem.
1126 */
1127 static int wait_for_concurrent_writes(struct file *file)
1128 {
1129 struct inode *inode = file_inode(file);
1130 static ino_t last_ino;
1131 static dev_t last_dev;
1132 int err = 0;
1133
1134 if (atomic_read(&inode->i_writecount) > 1
1135 || (last_ino == inode->i_ino && last_dev == inode->i_sb->s_dev)) {
1136 dprintk("nfsd: write defer %d\n", task_pid_nr(current));
1137 msleep(10);
1138 dprintk("nfsd: write resume %d\n", task_pid_nr(current));
1139 }
1140
1141 if (inode->i_state & I_DIRTY) {
1142 dprintk("nfsd: write sync %d\n", task_pid_nr(current));
1143 err = vfs_fsync(file, 0);
1144 }
1145 last_ino = inode->i_ino;
1146 last_dev = inode->i_sb->s_dev;
1147 return err;
1148 }
1149
1150 __be32
1151 nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf,
1152 loff_t offset, struct kvec *vec, int vlen,
1153 unsigned long *cnt, int stable,
1154 __be32 *verf)
1155 {
1156 struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
1157 struct file *file = nf->nf_file;
1158 struct super_block *sb = file_inode(file)->i_sb;
1159 struct svc_export *exp;
1160 struct iov_iter iter;
1161 errseq_t since;
1162 __be32 nfserr;
1163 int host_err;
1164 int use_wgather;
1165 loff_t pos = offset;
1166 unsigned long exp_op_flags = 0;
1167 unsigned int pflags = current->flags;
1168 rwf_t flags = 0;
1169 bool restore_flags = false;
1170
1171 trace_nfsd_write_opened(rqstp, fhp, offset, *cnt);
1172
1173 if (sb->s_export_op)
1174 exp_op_flags = sb->s_export_op->flags;
1175
1176 if (test_bit(RQ_LOCAL, &rqstp->rq_flags) &&
1177 !(exp_op_flags & EXPORT_OP_REMOTE_FS)) {
1178 /*
1179 * We want throttling in balance_dirty_pages()
1180 * and shrink_inactive_list() to only consider
1181 * the backingdev we are writing to, so that nfs to
1182 * localhost doesn't cause nfsd to lock up due to all
1183 * the client's dirty pages or its congested queue.
1184 */
1185 current->flags |= PF_LOCAL_THROTTLE;
1186 restore_flags = true;
1187 }
1188
1189 exp = fhp->fh_export;
1190 use_wgather = (rqstp->rq_vers == 2) && EX_WGATHER(exp);
1191
1192 if (!EX_ISSYNC(exp))
1193 stable = NFS_UNSTABLE;
1194
1195 if (stable && !use_wgather)
1196 flags |= RWF_SYNC;
1197
1198 iov_iter_kvec(&iter, ITER_SOURCE, vec, vlen, *cnt);
1199 since = READ_ONCE(file->f_wb_err);
1200 if (verf)
1201 nfsd_copy_write_verifier(verf, nn);
1202 host_err = vfs_iter_write(file, &iter, &pos, flags);
1203 if (host_err < 0) {
1204 commit_reset_write_verifier(nn, rqstp, host_err);
1205 goto out_nfserr;
1206 }
1207 *cnt = host_err;
1208 nfsd_stats_io_write_add(nn, exp, *cnt);
1209 fsnotify_modify(file);
1210 host_err = filemap_check_wb_err(file->f_mapping, since);
1211 if (host_err < 0)
1212 goto out_nfserr;
1213
1214 if (stable && use_wgather) {
1215 host_err = wait_for_concurrent_writes(file);
1216 if (host_err < 0)
1217 commit_reset_write_verifier(nn, rqstp, host_err);
1218 }
1219
1220 out_nfserr:
1221 if (host_err >= 0) {
1222 trace_nfsd_write_io_done(rqstp, fhp, offset, *cnt);
1223 nfserr = nfs_ok;
1224 } else {
1225 trace_nfsd_write_err(rqstp, fhp, offset, host_err);
1226 nfserr = nfserrno(host_err);
1227 }
1228 if (restore_flags)
1229 current_restore_flags(pflags, PF_LOCAL_THROTTLE);
1230 return nfserr;
1231 }
1232
1233 /**
1234 * nfsd_read_splice_ok - check if spliced reading is supported
1235 * @rqstp: RPC transaction context
1236 *
1237 * Return values:
1238 * %true: nfsd_splice_read() may be used
1239 * %false: nfsd_splice_read() must not be used
1240 *
1241 * NFS READ normally uses splice to send data in-place. However the
1242 * data in cache can change after the reply's MIC is computed but
1243 * before the RPC reply is sent. To prevent the client from
1244 * rejecting the server-computed MIC in this somewhat rare case, do
1245 * not use splice with the GSS integrity and privacy services.
1246 */
1247 bool nfsd_read_splice_ok(struct svc_rqst *rqstp)
1248 {
1249 switch (svc_auth_flavor(rqstp)) {
1250 case RPC_AUTH_GSS_KRB5I:
1251 case RPC_AUTH_GSS_KRB5P:
1252 return false;
1253 }
1254 return true;
1255 }
1256
1257 /**
1258 * nfsd_read - Read data from a file
1259 * @rqstp: RPC transaction context
1260 * @fhp: file handle of file to be read
1261 * @offset: starting byte offset
1262 * @count: IN: requested number of bytes; OUT: number of bytes read
1263 * @eof: OUT: set non-zero if operation reached the end of the file
1264 *
1265 * The caller must verify that there is enough space in @rqstp.rq_res
1266 * to perform this operation.
1267 *
1268 * N.B. After this call fhp needs an fh_put
1269 *
1270 * Returns nfs_ok on success, otherwise an nfserr stat value is
1271 * returned.
1272 */
1273 __be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
1274 loff_t offset, unsigned long *count, u32 *eof)
1275 {
1276 struct nfsd_file *nf;
1277 struct file *file;
1278 __be32 err;
1279
1280 trace_nfsd_read_start(rqstp, fhp, offset, *count);
1281 err = nfsd_file_acquire_gc(rqstp, fhp, NFSD_MAY_READ, &nf);
1282 if (err)
1283 return err;
1284
1285 file = nf->nf_file;
1286 if (file->f_op->splice_read && nfsd_read_splice_ok(rqstp))
1287 err = nfsd_splice_read(rqstp, fhp, file, offset, count, eof);
1288 else
1289 err = nfsd_iter_read(rqstp, fhp, file, offset, count, 0, eof);
1290
1291 nfsd_file_put(nf);
1292 trace_nfsd_read_done(rqstp, fhp, offset, *count);
1293 return err;
1294 }
1295
1296 /*
1297 * Write data to a file.
1298 * The stable flag requests synchronous writes.
1299 * N.B. After this call fhp needs an fh_put
1300 */
1301 __be32
1302 nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t offset,
1303 struct kvec *vec, int vlen, unsigned long *cnt, int stable,
1304 __be32 *verf)
1305 {
1306 struct nfsd_file *nf;
1307 __be32 err;
1308
1309 trace_nfsd_write_start(rqstp, fhp, offset, *cnt);
1310
1311 err = nfsd_file_acquire_gc(rqstp, fhp, NFSD_MAY_WRITE, &nf);
1312 if (err)
1313 goto out;
1314
1315 err = nfsd_vfs_write(rqstp, fhp, nf, offset, vec,
1316 vlen, cnt, stable, verf);
1317 nfsd_file_put(nf);
1318 out:
1319 trace_nfsd_write_done(rqstp, fhp, offset, *cnt);
1320 return err;
1321 }
1322
1323 /**
1324 * nfsd_commit - Commit pending writes to stable storage
1325 * @rqstp: RPC request being processed
1326 * @fhp: NFS filehandle
1327 * @nf: target file
1328 * @offset: raw offset from beginning of file
1329 * @count: raw count of bytes to sync
1330 * @verf: filled in with the server's current write verifier
1331 *
1332 * Note: we guarantee that data that lies within the range specified
1333 * by the 'offset' and 'count' parameters will be synced. The server
1334 * is permitted to sync data that lies outside this range at the
1335 * same time.
1336 *
1337 * Unfortunately we cannot lock the file to make sure we return full WCC
1338 * data to the client, as locking happens lower down in the filesystem.
1339 *
1340 * Return values:
1341 * An nfsstat value in network byte order.
1342 */
1343 __be32
1344 nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf,
1345 u64 offset, u32 count, __be32 *verf)
1346 {
1347 __be32 err = nfs_ok;
1348 u64 maxbytes;
1349 loff_t start, end;
1350 struct nfsd_net *nn;
1351
1352 /*
1353 * Convert the client-provided (offset, count) range to a
1354 * (start, end) range. If the client-provided range falls
1355 * outside the maximum file size of the underlying FS,
1356 * clamp the sync range appropriately.
1357 */
1358 start = 0;
1359 end = LLONG_MAX;
1360 maxbytes = (u64)fhp->fh_dentry->d_sb->s_maxbytes;
1361 if (offset < maxbytes) {
1362 start = offset;
1363 if (count && (offset + count - 1 < maxbytes))
1364 end = offset + count - 1;
1365 }
1366
1367 nn = net_generic(nf->nf_net, nfsd_net_id);
1368 if (EX_ISSYNC(fhp->fh_export)) {
1369 errseq_t since = READ_ONCE(nf->nf_file->f_wb_err);
1370 int err2;
1371
1372 err2 = vfs_fsync_range(nf->nf_file, start, end, 0);
1373 switch (err2) {
1374 case 0:
1375 nfsd_copy_write_verifier(verf, nn);
1376 err2 = filemap_check_wb_err(nf->nf_file->f_mapping,
1377 since);
1378 err = nfserrno(err2);
1379 break;
1380 case -EINVAL:
1381 err = nfserr_notsupp;
1382 break;
1383 default:
1384 commit_reset_write_verifier(nn, rqstp, err2);
1385 err = nfserrno(err2);
1386 }
1387 } else
1388 nfsd_copy_write_verifier(verf, nn);
1389
1390 return err;
1391 }
1392
1393 /**
1394 * nfsd_create_setattr - Set a created file's attributes
1395 * @rqstp: RPC transaction being executed
1396 * @fhp: NFS filehandle of parent directory
1397 * @resfhp: NFS filehandle of new object
1398 * @attrs: requested attributes of new object
1399 *
1400 * Returns nfs_ok on success, or an nfsstat in network byte order.
1401 */
1402 __be32
1403 nfsd_create_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp,
1404 struct svc_fh *resfhp, struct nfsd_attrs *attrs)
1405 {
1406 struct iattr *iap = attrs->na_iattr;
1407 __be32 status;
1408
1409 /*
1410 * Mode has already been set by file creation.
1411 */
1412 iap->ia_valid &= ~ATTR_MODE;
1413
1414 /*
1415 * Setting uid/gid works only for root. Irix appears to
1416 * send along the gid on create when it tries to implement
1417 * setgid directories via NFS:
1418 */
1419 if (!uid_eq(current_fsuid(), GLOBAL_ROOT_UID))
1420 iap->ia_valid &= ~(ATTR_UID|ATTR_GID);
1421
1422 /*
1423 * Callers expect new file metadata to be committed even
1424 * if the attributes have not changed.
1425 */
1426 if (nfsd_attrs_valid(attrs))
1427 status = nfsd_setattr(rqstp, resfhp, attrs, NULL);
1428 else
1429 status = nfserrno(commit_metadata(resfhp));
1430
1431 /*
1432 * Transactional filesystems had a chance to commit changes
1433 * for both parent and child simultaneously making the
1434 * following commit_metadata a noop in many cases.
1435 */
1436 if (!status)
1437 status = nfserrno(commit_metadata(fhp));
1438
1439 /*
1440 * Update the new filehandle to pick up the new attributes.
1441 */
1442 if (!status)
1443 status = fh_update(resfhp);
1444
1445 return status;
1446 }
1447
1448 /* HPUX client sometimes creates a file in mode 000, and sets size to 0.
1449 * setting size to 0 may fail for some specific file systems by the permission
1450 * checking which requires WRITE permission but the mode is 000.
1451 * we ignore the resizing(to 0) on the just new created file, since the size is
1452 * 0 after file created.
1453 *
1454 * call this only after vfs_create() is called.
1455 * */
1456 static void
1457 nfsd_check_ignore_resizing(struct iattr *iap)
1458 {
1459 if ((iap->ia_valid & ATTR_SIZE) && (iap->ia_size == 0))
1460 iap->ia_valid &= ~ATTR_SIZE;
1461 }
1462
1463 /* The parent directory should already be locked: */
1464 __be32
1465 nfsd_create_locked(struct svc_rqst *rqstp, struct svc_fh *fhp,
1466 struct nfsd_attrs *attrs,
1467 int type, dev_t rdev, struct svc_fh *resfhp)
1468 {
1469 struct dentry *dentry, *dchild;
1470 struct inode *dirp;
1471 struct iattr *iap = attrs->na_iattr;
1472 __be32 err;
1473 int host_err;
1474
1475 dentry = fhp->fh_dentry;
1476 dirp = d_inode(dentry);
1477
1478 dchild = dget(resfhp->fh_dentry);
1479 err = nfsd_permission(rqstp, fhp->fh_export, dentry, NFSD_MAY_CREATE);
1480 if (err)
1481 goto out;
1482
1483 if (!(iap->ia_valid & ATTR_MODE))
1484 iap->ia_mode = 0;
1485 iap->ia_mode = (iap->ia_mode & S_IALLUGO) | type;
1486
1487 if (!IS_POSIXACL(dirp))
1488 iap->ia_mode &= ~current_umask();
1489
1490 err = 0;
1491 switch (type) {
1492 case S_IFREG:
1493 host_err = vfs_create(&nop_mnt_idmap, dirp, dchild,
1494 iap->ia_mode, true);
1495 if (!host_err)
1496 nfsd_check_ignore_resizing(iap);
1497 break;
1498 case S_IFDIR:
1499 host_err = vfs_mkdir(&nop_mnt_idmap, dirp, dchild, iap->ia_mode);
1500 if (!host_err && unlikely(d_unhashed(dchild))) {
1501 struct dentry *d;
1502 d = lookup_one_len(dchild->d_name.name,
1503 dchild->d_parent,
1504 dchild->d_name.len);
1505 if (IS_ERR(d)) {
1506 host_err = PTR_ERR(d);
1507 break;
1508 }
1509 if (unlikely(d_is_negative(d))) {
1510 dput(d);
1511 err = nfserr_serverfault;
1512 goto out;
1513 }
1514 dput(resfhp->fh_dentry);
1515 resfhp->fh_dentry = dget(d);
1516 err = fh_update(resfhp);
1517 dput(dchild);
1518 dchild = d;
1519 if (err)
1520 goto out;
1521 }
1522 break;
1523 case S_IFCHR:
1524 case S_IFBLK:
1525 case S_IFIFO:
1526 case S_IFSOCK:
1527 host_err = vfs_mknod(&nop_mnt_idmap, dirp, dchild,
1528 iap->ia_mode, rdev);
1529 break;
1530 default:
1531 printk(KERN_WARNING "nfsd: bad file type %o in nfsd_create\n",
1532 type);
1533 host_err = -EINVAL;
1534 }
1535 if (host_err < 0)
1536 goto out_nfserr;
1537
1538 err = nfsd_create_setattr(rqstp, fhp, resfhp, attrs);
1539
1540 out:
1541 dput(dchild);
1542 return err;
1543
1544 out_nfserr:
1545 err = nfserrno(host_err);
1546 goto out;
1547 }
1548
1549 /*
1550 * Create a filesystem object (regular, directory, special).
1551 * Note that the parent directory is left locked.
1552 *
1553 * N.B. Every call to nfsd_create needs an fh_put for _both_ fhp and resfhp
1554 */
1555 __be32
1556 nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
1557 char *fname, int flen, struct nfsd_attrs *attrs,
1558 int type, dev_t rdev, struct svc_fh *resfhp)
1559 {
1560 struct dentry *dentry, *dchild = NULL;
1561 __be32 err;
1562 int host_err;
1563
1564 if (isdotent(fname, flen))
1565 return nfserr_exist;
1566
1567 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_NOP);
1568 if (err)
1569 return err;
1570
1571 dentry = fhp->fh_dentry;
1572
1573 host_err = fh_want_write(fhp);
1574 if (host_err)
1575 return nfserrno(host_err);
1576
1577 inode_lock_nested(dentry->d_inode, I_MUTEX_PARENT);
1578 dchild = lookup_one_len(fname, dentry, flen);
1579 host_err = PTR_ERR(dchild);
1580 if (IS_ERR(dchild)) {
1581 err = nfserrno(host_err);
1582 goto out_unlock;
1583 }
1584 err = fh_compose(resfhp, fhp->fh_export, dchild, fhp);
1585 /*
1586 * We unconditionally drop our ref to dchild as fh_compose will have
1587 * already grabbed its own ref for it.
1588 */
1589 dput(dchild);
1590 if (err)
1591 goto out_unlock;
1592 err = fh_fill_pre_attrs(fhp);
1593 if (err != nfs_ok)
1594 goto out_unlock;
1595 err = nfsd_create_locked(rqstp, fhp, attrs, type, rdev, resfhp);
1596 fh_fill_post_attrs(fhp);
1597 out_unlock:
1598 inode_unlock(dentry->d_inode);
1599 return err;
1600 }
1601
1602 /*
1603 * Read a symlink. On entry, *lenp must contain the maximum path length that
1604 * fits into the buffer. On return, it contains the true length.
1605 * N.B. After this call fhp needs an fh_put
1606 */
1607 __be32
1608 nfsd_readlink(struct svc_rqst *rqstp, struct svc_fh *fhp, char *buf, int *lenp)
1609 {
1610 __be32 err;
1611 const char *link;
1612 struct path path;
1613 DEFINE_DELAYED_CALL(done);
1614 int len;
1615
1616 err = fh_verify(rqstp, fhp, S_IFLNK, NFSD_MAY_NOP);
1617 if (unlikely(err))
1618 return err;
1619
1620 path.mnt = fhp->fh_export->ex_path.mnt;
1621 path.dentry = fhp->fh_dentry;
1622
1623 if (unlikely(!d_is_symlink(path.dentry)))
1624 return nfserr_inval;
1625
1626 touch_atime(&path);
1627
1628 link = vfs_get_link(path.dentry, &done);
1629 if (IS_ERR(link))
1630 return nfserrno(PTR_ERR(link));
1631
1632 len = strlen(link);
1633 if (len < *lenp)
1634 *lenp = len;
1635 memcpy(buf, link, *lenp);
1636 do_delayed_call(&done);
1637 return 0;
1638 }
1639
1640 /**
1641 * nfsd_symlink - Create a symlink and look up its inode
1642 * @rqstp: RPC transaction being executed
1643 * @fhp: NFS filehandle of parent directory
1644 * @fname: filename of the new symlink
1645 * @flen: length of @fname
1646 * @path: content of the new symlink (NUL-terminated)
1647 * @attrs: requested attributes of new object
1648 * @resfhp: NFS filehandle of new object
1649 *
1650 * N.B. After this call _both_ fhp and resfhp need an fh_put
1651 *
1652 * Returns nfs_ok on success, or an nfsstat in network byte order.
1653 */
1654 __be32
1655 nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp,
1656 char *fname, int flen,
1657 char *path, struct nfsd_attrs *attrs,
1658 struct svc_fh *resfhp)
1659 {
1660 struct dentry *dentry, *dnew;
1661 __be32 err, cerr;
1662 int host_err;
1663
1664 err = nfserr_noent;
1665 if (!flen || path[0] == '\0')
1666 goto out;
1667 err = nfserr_exist;
1668 if (isdotent(fname, flen))
1669 goto out;
1670
1671 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
1672 if (err)
1673 goto out;
1674
1675 host_err = fh_want_write(fhp);
1676 if (host_err) {
1677 err = nfserrno(host_err);
1678 goto out;
1679 }
1680
1681 dentry = fhp->fh_dentry;
1682 inode_lock_nested(dentry->d_inode, I_MUTEX_PARENT);
1683 dnew = lookup_one_len(fname, dentry, flen);
1684 if (IS_ERR(dnew)) {
1685 err = nfserrno(PTR_ERR(dnew));
1686 inode_unlock(dentry->d_inode);
1687 goto out_drop_write;
1688 }
1689 err = fh_fill_pre_attrs(fhp);
1690 if (err != nfs_ok)
1691 goto out_unlock;
1692 host_err = vfs_symlink(&nop_mnt_idmap, d_inode(dentry), dnew, path);
1693 err = nfserrno(host_err);
1694 cerr = fh_compose(resfhp, fhp->fh_export, dnew, fhp);
1695 if (!err)
1696 nfsd_create_setattr(rqstp, fhp, resfhp, attrs);
1697 fh_fill_post_attrs(fhp);
1698 out_unlock:
1699 inode_unlock(dentry->d_inode);
1700 if (!err)
1701 err = nfserrno(commit_metadata(fhp));
1702 dput(dnew);
1703 if (err==0) err = cerr;
1704 out_drop_write:
1705 fh_drop_write(fhp);
1706 out:
1707 return err;
1708 }
1709
1710 /*
1711 * Create a hardlink
1712 * N.B. After this call _both_ ffhp and tfhp need an fh_put
1713 */
1714 __be32
1715 nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp,
1716 char *name, int len, struct svc_fh *tfhp)
1717 {
1718 struct dentry *ddir, *dnew, *dold;
1719 struct inode *dirp;
1720 __be32 err;
1721 int host_err;
1722
1723 err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_CREATE);
1724 if (err)
1725 goto out;
1726 err = fh_verify(rqstp, tfhp, 0, NFSD_MAY_NOP);
1727 if (err)
1728 goto out;
1729 err = nfserr_isdir;
1730 if (d_is_dir(tfhp->fh_dentry))
1731 goto out;
1732 err = nfserr_perm;
1733 if (!len)
1734 goto out;
1735 err = nfserr_exist;
1736 if (isdotent(name, len))
1737 goto out;
1738
1739 host_err = fh_want_write(tfhp);
1740 if (host_err) {
1741 err = nfserrno(host_err);
1742 goto out;
1743 }
1744
1745 ddir = ffhp->fh_dentry;
1746 dirp = d_inode(ddir);
1747 inode_lock_nested(dirp, I_MUTEX_PARENT);
1748
1749 dnew = lookup_one_len(name, ddir, len);
1750 if (IS_ERR(dnew)) {
1751 err = nfserrno(PTR_ERR(dnew));
1752 goto out_unlock;
1753 }
1754
1755 dold = tfhp->fh_dentry;
1756
1757 err = nfserr_noent;
1758 if (d_really_is_negative(dold))
1759 goto out_dput;
1760 err = fh_fill_pre_attrs(ffhp);
1761 if (err != nfs_ok)
1762 goto out_dput;
1763 host_err = vfs_link(dold, &nop_mnt_idmap, dirp, dnew, NULL);
1764 fh_fill_post_attrs(ffhp);
1765 inode_unlock(dirp);
1766 if (!host_err) {
1767 err = nfserrno(commit_metadata(ffhp));
1768 if (!err)
1769 err = nfserrno(commit_metadata(tfhp));
1770 } else {
1771 if (host_err == -EXDEV && rqstp->rq_vers == 2)
1772 err = nfserr_acces;
1773 else
1774 err = nfserrno(host_err);
1775 }
1776 dput(dnew);
1777 out_drop_write:
1778 fh_drop_write(tfhp);
1779 out:
1780 return err;
1781
1782 out_dput:
1783 dput(dnew);
1784 out_unlock:
1785 inode_unlock(dirp);
1786 goto out_drop_write;
1787 }
1788
1789 static void
1790 nfsd_close_cached_files(struct dentry *dentry)
1791 {
1792 struct inode *inode = d_inode(dentry);
1793
1794 if (inode && S_ISREG(inode->i_mode))
1795 nfsd_file_close_inode_sync(inode);
1796 }
1797
1798 static bool
1799 nfsd_has_cached_files(struct dentry *dentry)
1800 {
1801 bool ret = false;
1802 struct inode *inode = d_inode(dentry);
1803
1804 if (inode && S_ISREG(inode->i_mode))
1805 ret = nfsd_file_is_cached(inode);
1806 return ret;
1807 }
1808
1809 /*
1810 * Rename a file
1811 * N.B. After this call _both_ ffhp and tfhp need an fh_put
1812 */
1813 __be32
1814 nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
1815 struct svc_fh *tfhp, char *tname, int tlen)
1816 {
1817 struct dentry *fdentry, *tdentry, *odentry, *ndentry, *trap;
1818 struct inode *fdir, *tdir;
1819 __be32 err;
1820 int host_err;
1821 bool close_cached = false;
1822
1823 err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_REMOVE);
1824 if (err)
1825 goto out;
1826 err = fh_verify(rqstp, tfhp, S_IFDIR, NFSD_MAY_CREATE);
1827 if (err)
1828 goto out;
1829
1830 fdentry = ffhp->fh_dentry;
1831 fdir = d_inode(fdentry);
1832
1833 tdentry = tfhp->fh_dentry;
1834 tdir = d_inode(tdentry);
1835
1836 err = nfserr_perm;
1837 if (!flen || isdotent(fname, flen) || !tlen || isdotent(tname, tlen))
1838 goto out;
1839
1840 err = (rqstp->rq_vers == 2) ? nfserr_acces : nfserr_xdev;
1841 if (ffhp->fh_export->ex_path.mnt != tfhp->fh_export->ex_path.mnt)
1842 goto out;
1843 if (ffhp->fh_export->ex_path.dentry != tfhp->fh_export->ex_path.dentry)
1844 goto out;
1845
1846 retry:
1847 host_err = fh_want_write(ffhp);
1848 if (host_err) {
1849 err = nfserrno(host_err);
1850 goto out;
1851 }
1852
1853 trap = lock_rename(tdentry, fdentry);
1854 if (IS_ERR(trap)) {
1855 err = (rqstp->rq_vers == 2) ? nfserr_acces : nfserr_xdev;
1856 goto out_want_write;
1857 }
1858 err = fh_fill_pre_attrs(ffhp);
1859 if (err != nfs_ok)
1860 goto out_unlock;
1861 err = fh_fill_pre_attrs(tfhp);
1862 if (err != nfs_ok)
1863 goto out_unlock;
1864
1865 odentry = lookup_one_len(fname, fdentry, flen);
1866 host_err = PTR_ERR(odentry);
1867 if (IS_ERR(odentry))
1868 goto out_nfserr;
1869
1870 host_err = -ENOENT;
1871 if (d_really_is_negative(odentry))
1872 goto out_dput_old;
1873 host_err = -EINVAL;
1874 if (odentry == trap)
1875 goto out_dput_old;
1876
1877 ndentry = lookup_one_len(tname, tdentry, tlen);
1878 host_err = PTR_ERR(ndentry);
1879 if (IS_ERR(ndentry))
1880 goto out_dput_old;
1881 host_err = -ENOTEMPTY;
1882 if (ndentry == trap)
1883 goto out_dput_new;
1884
1885 if ((ndentry->d_sb->s_export_op->flags & EXPORT_OP_CLOSE_BEFORE_UNLINK) &&
1886 nfsd_has_cached_files(ndentry)) {
1887 close_cached = true;
1888 goto out_dput_old;
1889 } else {
1890 struct renamedata rd = {
1891 .old_mnt_idmap = &nop_mnt_idmap,
1892 .old_dir = fdir,
1893 .old_dentry = odentry,
1894 .new_mnt_idmap = &nop_mnt_idmap,
1895 .new_dir = tdir,
1896 .new_dentry = ndentry,
1897 };
1898 int retries;
1899
1900 for (retries = 1;;) {
1901 host_err = vfs_rename(&rd);
1902 if (host_err != -EAGAIN || !retries--)
1903 break;
1904 if (!nfsd_wait_for_delegreturn(rqstp, d_inode(odentry)))
1905 break;
1906 }
1907 if (!host_err) {
1908 host_err = commit_metadata(tfhp);
1909 if (!host_err)
1910 host_err = commit_metadata(ffhp);
1911 }
1912 }
1913 out_dput_new:
1914 dput(ndentry);
1915 out_dput_old:
1916 dput(odentry);
1917 out_nfserr:
1918 err = nfserrno(host_err);
1919
1920 if (!close_cached) {
1921 fh_fill_post_attrs(ffhp);
1922 fh_fill_post_attrs(tfhp);
1923 }
1924 out_unlock:
1925 unlock_rename(tdentry, fdentry);
1926 out_want_write:
1927 fh_drop_write(ffhp);
1928
1929 /*
1930 * If the target dentry has cached open files, then we need to
1931 * try to close them prior to doing the rename. Final fput
1932 * shouldn't be done with locks held however, so we delay it
1933 * until this point and then reattempt the whole shebang.
1934 */
1935 if (close_cached) {
1936 close_cached = false;
1937 nfsd_close_cached_files(ndentry);
1938 dput(ndentry);
1939 goto retry;
1940 }
1941 out:
1942 return err;
1943 }
1944
1945 /*
1946 * Unlink a file or directory
1947 * N.B. After this call fhp needs an fh_put
1948 */
1949 __be32
1950 nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
1951 char *fname, int flen)
1952 {
1953 struct dentry *dentry, *rdentry;
1954 struct inode *dirp;
1955 struct inode *rinode;
1956 __be32 err;
1957 int host_err;
1958
1959 err = nfserr_acces;
1960 if (!flen || isdotent(fname, flen))
1961 goto out;
1962 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_REMOVE);
1963 if (err)
1964 goto out;
1965
1966 host_err = fh_want_write(fhp);
1967 if (host_err)
1968 goto out_nfserr;
1969
1970 dentry = fhp->fh_dentry;
1971 dirp = d_inode(dentry);
1972 inode_lock_nested(dirp, I_MUTEX_PARENT);
1973
1974 rdentry = lookup_one_len(fname, dentry, flen);
1975 host_err = PTR_ERR(rdentry);
1976 if (IS_ERR(rdentry))
1977 goto out_unlock;
1978
1979 if (d_really_is_negative(rdentry)) {
1980 dput(rdentry);
1981 host_err = -ENOENT;
1982 goto out_unlock;
1983 }
1984 rinode = d_inode(rdentry);
1985 err = fh_fill_pre_attrs(fhp);
1986 if (err != nfs_ok)
1987 goto out_unlock;
1988
1989 ihold(rinode);
1990 if (!type)
1991 type = d_inode(rdentry)->i_mode & S_IFMT;
1992
1993 if (type != S_IFDIR) {
1994 int retries;
1995
1996 if (rdentry->d_sb->s_export_op->flags & EXPORT_OP_CLOSE_BEFORE_UNLINK)
1997 nfsd_close_cached_files(rdentry);
1998
1999 for (retries = 1;;) {
2000 host_err = vfs_unlink(&nop_mnt_idmap, dirp, rdentry, NULL);
2001 if (host_err != -EAGAIN || !retries--)
2002 break;
2003 if (!nfsd_wait_for_delegreturn(rqstp, rinode))
2004 break;
2005 }
2006 } else {
2007 host_err = vfs_rmdir(&nop_mnt_idmap, dirp, rdentry);
2008 }
2009 fh_fill_post_attrs(fhp);
2010
2011 inode_unlock(dirp);
2012 if (!host_err)
2013 host_err = commit_metadata(fhp);
2014 dput(rdentry);
2015 iput(rinode); /* truncate the inode here */
2016
2017 out_drop_write:
2018 fh_drop_write(fhp);
2019 out_nfserr:
2020 if (host_err == -EBUSY) {
2021 /* name is mounted-on. There is no perfect
2022 * error status.
2023 */
2024 if (nfsd_v4client(rqstp))
2025 err = nfserr_file_open;
2026 else
2027 err = nfserr_acces;
2028 } else {
2029 err = nfserrno(host_err);
2030 }
2031 out:
2032 return err;
2033 out_unlock:
2034 inode_unlock(dirp);
2035 goto out_drop_write;
2036 }
2037
2038 /*
2039 * We do this buffering because we must not call back into the file
2040 * system's ->lookup() method from the filldir callback. That may well
2041 * deadlock a number of file systems.
2042 *
2043 * This is based heavily on the implementation of same in XFS.
2044 */
2045 struct buffered_dirent {
2046 u64 ino;
2047 loff_t offset;
2048 int namlen;
2049 unsigned int d_type;
2050 char name[];
2051 };
2052
2053 struct readdir_data {
2054 struct dir_context ctx;
2055 char *dirent;
2056 size_t used;
2057 int full;
2058 };
2059
2060 static bool nfsd_buffered_filldir(struct dir_context *ctx, const char *name,
2061 int namlen, loff_t offset, u64 ino,
2062 unsigned int d_type)
2063 {
2064 struct readdir_data *buf =
2065 container_of(ctx, struct readdir_data, ctx);
2066 struct buffered_dirent *de = (void *)(buf->dirent + buf->used);
2067 unsigned int reclen;
2068
2069 reclen = ALIGN(sizeof(struct buffered_dirent) + namlen, sizeof(u64));
2070 if (buf->used + reclen > PAGE_SIZE) {
2071 buf->full = 1;
2072 return false;
2073 }
2074
2075 de->namlen = namlen;
2076 de->offset = offset;
2077 de->ino = ino;
2078 de->d_type = d_type;
2079 memcpy(de->name, name, namlen);
2080 buf->used += reclen;
2081
2082 return true;
2083 }
2084
2085 static __be32 nfsd_buffered_readdir(struct file *file, struct svc_fh *fhp,
2086 nfsd_filldir_t func, struct readdir_cd *cdp,
2087 loff_t *offsetp)
2088 {
2089 struct buffered_dirent *de;
2090 int host_err;
2091 int size;
2092 loff_t offset;
2093 struct readdir_data buf = {
2094 .ctx.actor = nfsd_buffered_filldir,
2095 .dirent = (void *)__get_free_page(GFP_KERNEL)
2096 };
2097
2098 if (!buf.dirent)
2099 return nfserrno(-ENOMEM);
2100
2101 offset = *offsetp;
2102
2103 while (1) {
2104 unsigned int reclen;
2105
2106 cdp->err = nfserr_eof; /* will be cleared on successful read */
2107 buf.used = 0;
2108 buf.full = 0;
2109
2110 host_err = iterate_dir(file, &buf.ctx);
2111 if (buf.full)
2112 host_err = 0;
2113
2114 if (host_err < 0)
2115 break;
2116
2117 size = buf.used;
2118
2119 if (!size)
2120 break;
2121
2122 de = (struct buffered_dirent *)buf.dirent;
2123 while (size > 0) {
2124 offset = de->offset;
2125
2126 if (func(cdp, de->name, de->namlen, de->offset,
2127 de->ino, de->d_type))
2128 break;
2129
2130 if (cdp->err != nfs_ok)
2131 break;
2132
2133 trace_nfsd_dirent(fhp, de->ino, de->name, de->namlen);
2134
2135 reclen = ALIGN(sizeof(*de) + de->namlen,
2136 sizeof(u64));
2137 size -= reclen;
2138 de = (struct buffered_dirent *)((char *)de + reclen);
2139 }
2140 if (size > 0) /* We bailed out early */
2141 break;
2142
2143 offset = vfs_llseek(file, 0, SEEK_CUR);
2144 }
2145
2146 free_page((unsigned long)(buf.dirent));
2147
2148 if (host_err)
2149 return nfserrno(host_err);
2150
2151 *offsetp = offset;
2152 return cdp->err;
2153 }
2154
2155 /**
2156 * nfsd_readdir - Read entries from a directory
2157 * @rqstp: RPC transaction context
2158 * @fhp: NFS file handle of directory to be read
2159 * @offsetp: OUT: seek offset of final entry that was read
2160 * @cdp: OUT: an eof error value
2161 * @func: entry filler actor
2162 *
2163 * This implementation ignores the NFSv3/4 verifier cookie.
2164 *
2165 * NB: normal system calls hold file->f_pos_lock when calling
2166 * ->iterate_shared and ->llseek, but nfsd_readdir() does not.
2167 * Because the struct file acquired here is not visible to other
2168 * threads, it's internal state does not need mutex protection.
2169 *
2170 * Returns nfs_ok on success, otherwise an nfsstat code is
2171 * returned.
2172 */
2173 __be32
2174 nfsd_readdir(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t *offsetp,
2175 struct readdir_cd *cdp, nfsd_filldir_t func)
2176 {
2177 __be32 err;
2178 struct file *file;
2179 loff_t offset = *offsetp;
2180 int may_flags = NFSD_MAY_READ;
2181
2182 /* NFSv2 only supports 32 bit cookies */
2183 if (rqstp->rq_vers > 2)
2184 may_flags |= NFSD_MAY_64BIT_COOKIE;
2185
2186 err = nfsd_open(rqstp, fhp, S_IFDIR, may_flags, &file);
2187 if (err)
2188 goto out;
2189
2190 offset = vfs_llseek(file, offset, SEEK_SET);
2191 if (offset < 0) {
2192 err = nfserrno((int)offset);
2193 goto out_close;
2194 }
2195
2196 err = nfsd_buffered_readdir(file, fhp, func, cdp, offsetp);
2197
2198 if (err == nfserr_eof || err == nfserr_toosmall)
2199 err = nfs_ok; /* can still be found in ->err */
2200 out_close:
2201 nfsd_filp_close(file);
2202 out:
2203 return err;
2204 }
2205
2206 /**
2207 * nfsd_filp_close: close a file synchronously
2208 * @fp: the file to close
2209 *
2210 * nfsd_filp_close() is similar in behaviour to filp_close().
2211 * The difference is that if this is the final close on the
2212 * file, the that finalisation happens immediately, rather then
2213 * being handed over to a work_queue, as it the case for
2214 * filp_close().
2215 * When a user-space process closes a file (even when using
2216 * filp_close() the finalisation happens before returning to
2217 * userspace, so it is effectively synchronous. When a kernel thread
2218 * uses file_close(), on the other hand, the handling is completely
2219 * asynchronous. This means that any cost imposed by that finalisation
2220 * is not imposed on the nfsd thread, and nfsd could potentually
2221 * close files more quickly than the work queue finalises the close,
2222 * which would lead to unbounded growth in the queue.
2223 *
2224 * In some contexts is it not safe to synchronously wait for
2225 * close finalisation (see comment for __fput_sync()), but nfsd
2226 * does not match those contexts. In partcilarly it does not, at the
2227 * time that this function is called, hold and locks and no finalisation
2228 * of any file, socket, or device driver would have any cause to wait
2229 * for nfsd to make progress.
2230 */
2231 void nfsd_filp_close(struct file *fp)
2232 {
2233 get_file(fp);
2234 filp_close(fp, NULL);
2235 __fput_sync(fp);
2236 }
2237
2238 /*
2239 * Get file system stats
2240 * N.B. After this call fhp needs an fh_put
2241 */
2242 __be32
2243 nfsd_statfs(struct svc_rqst *rqstp, struct svc_fh *fhp, struct kstatfs *stat, int access)
2244 {
2245 __be32 err;
2246
2247 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP | access);
2248 if (!err) {
2249 struct path path = {
2250 .mnt = fhp->fh_export->ex_path.mnt,
2251 .dentry = fhp->fh_dentry,
2252 };
2253 if (vfs_statfs(&path, stat))
2254 err = nfserr_io;
2255 }
2256 return err;
2257 }
2258
2259 static int exp_rdonly(struct svc_rqst *rqstp, struct svc_export *exp)
2260 {
2261 return nfsexp_flags(rqstp, exp) & NFSEXP_READONLY;
2262 }
2263
2264 #ifdef CONFIG_NFSD_V4
2265 /*
2266 * Helper function to translate error numbers. In the case of xattr operations,
2267 * some error codes need to be translated outside of the standard translations.
2268 *
2269 * ENODATA needs to be translated to nfserr_noxattr.
2270 * E2BIG to nfserr_xattr2big.
2271 *
2272 * Additionally, vfs_listxattr can return -ERANGE. This means that the
2273 * file has too many extended attributes to retrieve inside an
2274 * XATTR_LIST_MAX sized buffer. This is a bug in the xattr implementation:
2275 * filesystems will allow the adding of extended attributes until they hit
2276 * their own internal limit. This limit may be larger than XATTR_LIST_MAX.
2277 * So, at that point, the attributes are present and valid, but can't
2278 * be retrieved using listxattr, since the upper level xattr code enforces
2279 * the XATTR_LIST_MAX limit.
2280 *
2281 * This bug means that we need to deal with listxattr returning -ERANGE. The
2282 * best mapping is to return TOOSMALL.
2283 */
2284 static __be32
2285 nfsd_xattr_errno(int err)
2286 {
2287 switch (err) {
2288 case -ENODATA:
2289 return nfserr_noxattr;
2290 case -E2BIG:
2291 return nfserr_xattr2big;
2292 case -ERANGE:
2293 return nfserr_toosmall;
2294 }
2295 return nfserrno(err);
2296 }
2297
2298 /*
2299 * Retrieve the specified user extended attribute. To avoid always
2300 * having to allocate the maximum size (since we are not getting
2301 * a maximum size from the RPC), do a probe + alloc. Hold a reader
2302 * lock on i_rwsem to prevent the extended attribute from changing
2303 * size while we're doing this.
2304 */
2305 __be32
2306 nfsd_getxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name,
2307 void **bufp, int *lenp)
2308 {
2309 ssize_t len;
2310 __be32 err;
2311 char *buf;
2312 struct inode *inode;
2313 struct dentry *dentry;
2314
2315 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_READ);
2316 if (err)
2317 return err;
2318
2319 err = nfs_ok;
2320 dentry = fhp->fh_dentry;
2321 inode = d_inode(dentry);
2322
2323 inode_lock_shared(inode);
2324
2325 len = vfs_getxattr(&nop_mnt_idmap, dentry, name, NULL, 0);
2326
2327 /*
2328 * Zero-length attribute, just return.
2329 */
2330 if (len == 0) {
2331 *bufp = NULL;
2332 *lenp = 0;
2333 goto out;
2334 }
2335
2336 if (len < 0) {
2337 err = nfsd_xattr_errno(len);
2338 goto out;
2339 }
2340
2341 if (len > *lenp) {
2342 err = nfserr_toosmall;
2343 goto out;
2344 }
2345
2346 buf = kvmalloc(len, GFP_KERNEL);
2347 if (buf == NULL) {
2348 err = nfserr_jukebox;
2349 goto out;
2350 }
2351
2352 len = vfs_getxattr(&nop_mnt_idmap, dentry, name, buf, len);
2353 if (len <= 0) {
2354 kvfree(buf);
2355 buf = NULL;
2356 err = nfsd_xattr_errno(len);
2357 }
2358
2359 *lenp = len;
2360 *bufp = buf;
2361
2362 out:
2363 inode_unlock_shared(inode);
2364
2365 return err;
2366 }
2367
2368 /*
2369 * Retrieve the xattr names. Since we can't know how many are
2370 * user extended attributes, we must get all attributes here,
2371 * and have the XDR encode filter out the "user." ones.
2372 *
2373 * While this could always just allocate an XATTR_LIST_MAX
2374 * buffer, that's a waste, so do a probe + allocate. To
2375 * avoid any changes between the probe and allocate, wrap
2376 * this in inode_lock.
2377 */
2378 __be32
2379 nfsd_listxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char **bufp,
2380 int *lenp)
2381 {
2382 ssize_t len;
2383 __be32 err;
2384 char *buf;
2385 struct inode *inode;
2386 struct dentry *dentry;
2387
2388 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_READ);
2389 if (err)
2390 return err;
2391
2392 dentry = fhp->fh_dentry;
2393 inode = d_inode(dentry);
2394 *lenp = 0;
2395
2396 inode_lock_shared(inode);
2397
2398 len = vfs_listxattr(dentry, NULL, 0);
2399 if (len <= 0) {
2400 err = nfsd_xattr_errno(len);
2401 goto out;
2402 }
2403
2404 if (len > XATTR_LIST_MAX) {
2405 err = nfserr_xattr2big;
2406 goto out;
2407 }
2408
2409 buf = kvmalloc(len, GFP_KERNEL);
2410 if (buf == NULL) {
2411 err = nfserr_jukebox;
2412 goto out;
2413 }
2414
2415 len = vfs_listxattr(dentry, buf, len);
2416 if (len <= 0) {
2417 kvfree(buf);
2418 err = nfsd_xattr_errno(len);
2419 goto out;
2420 }
2421
2422 *lenp = len;
2423 *bufp = buf;
2424
2425 err = nfs_ok;
2426 out:
2427 inode_unlock_shared(inode);
2428
2429 return err;
2430 }
2431
2432 /**
2433 * nfsd_removexattr - Remove an extended attribute
2434 * @rqstp: RPC transaction being executed
2435 * @fhp: NFS filehandle of object with xattr to remove
2436 * @name: name of xattr to remove (NUL-terminate)
2437 *
2438 * Pass in a NULL pointer for delegated_inode, and let the client deal
2439 * with NFS4ERR_DELAY (same as with e.g. setattr and remove).
2440 *
2441 * Returns nfs_ok on success, or an nfsstat in network byte order.
2442 */
2443 __be32
2444 nfsd_removexattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name)
2445 {
2446 __be32 err;
2447 int ret;
2448
2449 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_WRITE);
2450 if (err)
2451 return err;
2452
2453 ret = fh_want_write(fhp);
2454 if (ret)
2455 return nfserrno(ret);
2456
2457 inode_lock(fhp->fh_dentry->d_inode);
2458 err = fh_fill_pre_attrs(fhp);
2459 if (err != nfs_ok)
2460 goto out_unlock;
2461 ret = __vfs_removexattr_locked(&nop_mnt_idmap, fhp->fh_dentry,
2462 name, NULL);
2463 err = nfsd_xattr_errno(ret);
2464 fh_fill_post_attrs(fhp);
2465 out_unlock:
2466 inode_unlock(fhp->fh_dentry->d_inode);
2467 fh_drop_write(fhp);
2468
2469 return err;
2470 }
2471
2472 __be32
2473 nfsd_setxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name,
2474 void *buf, u32 len, u32 flags)
2475 {
2476 __be32 err;
2477 int ret;
2478
2479 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_WRITE);
2480 if (err)
2481 return err;
2482
2483 ret = fh_want_write(fhp);
2484 if (ret)
2485 return nfserrno(ret);
2486 inode_lock(fhp->fh_dentry->d_inode);
2487 err = fh_fill_pre_attrs(fhp);
2488 if (err != nfs_ok)
2489 goto out_unlock;
2490 ret = __vfs_setxattr_locked(&nop_mnt_idmap, fhp->fh_dentry,
2491 name, buf, len, flags, NULL);
2492 fh_fill_post_attrs(fhp);
2493 err = nfsd_xattr_errno(ret);
2494 out_unlock:
2495 inode_unlock(fhp->fh_dentry->d_inode);
2496 fh_drop_write(fhp);
2497 return err;
2498 }
2499 #endif
2500
2501 /*
2502 * Check for a user's access permissions to this inode.
2503 */
2504 __be32
2505 nfsd_permission(struct svc_rqst *rqstp, struct svc_export *exp,
2506 struct dentry *dentry, int acc)
2507 {
2508 struct inode *inode = d_inode(dentry);
2509 int err;
2510
2511 if ((acc & NFSD_MAY_MASK) == NFSD_MAY_NOP)
2512 return 0;
2513 #if 0
2514 dprintk("nfsd: permission 0x%x%s%s%s%s%s%s%s mode 0%o%s%s%s\n",
2515 acc,
2516 (acc & NFSD_MAY_READ)? " read" : "",
2517 (acc & NFSD_MAY_WRITE)? " write" : "",
2518 (acc & NFSD_MAY_EXEC)? " exec" : "",
2519 (acc & NFSD_MAY_SATTR)? " sattr" : "",
2520 (acc & NFSD_MAY_TRUNC)? " trunc" : "",
2521 (acc & NFSD_MAY_LOCK)? " lock" : "",
2522 (acc & NFSD_MAY_OWNER_OVERRIDE)? " owneroverride" : "",
2523 inode->i_mode,
2524 IS_IMMUTABLE(inode)? " immut" : "",
2525 IS_APPEND(inode)? " append" : "",
2526 __mnt_is_readonly(exp->ex_path.mnt)? " ro" : "");
2527 dprintk(" owner %d/%d user %d/%d\n",
2528 inode->i_uid, inode->i_gid, current_fsuid(), current_fsgid());
2529 #endif
2530
2531 /* Normally we reject any write/sattr etc access on a read-only file
2532 * system. But if it is IRIX doing check on write-access for a
2533 * device special file, we ignore rofs.
2534 */
2535 if (!(acc & NFSD_MAY_LOCAL_ACCESS))
2536 if (acc & (NFSD_MAY_WRITE | NFSD_MAY_SATTR | NFSD_MAY_TRUNC)) {
2537 if (exp_rdonly(rqstp, exp) ||
2538 __mnt_is_readonly(exp->ex_path.mnt))
2539 return nfserr_rofs;
2540 if (/* (acc & NFSD_MAY_WRITE) && */ IS_IMMUTABLE(inode))
2541 return nfserr_perm;
2542 }
2543 if ((acc & NFSD_MAY_TRUNC) && IS_APPEND(inode))
2544 return nfserr_perm;
2545
2546 if (acc & NFSD_MAY_LOCK) {
2547 /* If we cannot rely on authentication in NLM requests,
2548 * just allow locks, otherwise require read permission, or
2549 * ownership
2550 */
2551 if (exp->ex_flags & NFSEXP_NOAUTHNLM)
2552 return 0;
2553 else
2554 acc = NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE;
2555 }
2556 /*
2557 * The file owner always gets access permission for accesses that
2558 * would normally be checked at open time. This is to make
2559 * file access work even when the client has done a fchmod(fd, 0).
2560 *
2561 * However, `cp foo bar' should fail nevertheless when bar is
2562 * readonly. A sensible way to do this might be to reject all
2563 * attempts to truncate a read-only file, because a creat() call
2564 * always implies file truncation.
2565 * ... but this isn't really fair. A process may reasonably call
2566 * ftruncate on an open file descriptor on a file with perm 000.
2567 * We must trust the client to do permission checking - using "ACCESS"
2568 * with NFSv3.
2569 */
2570 if ((acc & NFSD_MAY_OWNER_OVERRIDE) &&
2571 uid_eq(inode->i_uid, current_fsuid()))
2572 return 0;
2573
2574 /* This assumes NFSD_MAY_{READ,WRITE,EXEC} == MAY_{READ,WRITE,EXEC} */
2575 err = inode_permission(&nop_mnt_idmap, inode,
2576 acc & (MAY_READ | MAY_WRITE | MAY_EXEC));
2577
2578 /* Allow read access to binaries even when mode 111 */
2579 if (err == -EACCES && S_ISREG(inode->i_mode) &&
2580 (acc == (NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE) ||
2581 acc == (NFSD_MAY_READ | NFSD_MAY_READ_IF_EXEC)))
2582 err = inode_permission(&nop_mnt_idmap, inode, MAY_EXEC);
2583
2584 return err? nfserrno(err) : 0;
2585 }
2586
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