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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/fcntl.h>
20#include <linux/namei.h>
21#include <linux/delay.h>
22#include <linux/fsnotify.h>
23#include <linux/posix_acl_xattr.h>
24#include <linux/xattr.h>
25#include <linux/jhash.h>
26#include <linux/ima.h>
27#include <linux/slab.h>
28#include <asm/uaccess.h>
29#include <linux/exportfs.h>
30#include <linux/writeback.h>
31
32#ifdef CONFIG_NFSD_V3
33#include "xdr3.h"
34#endif /* CONFIG_NFSD_V3 */
35
36#ifdef CONFIG_NFSD_V4
37#include "acl.h"
38#include "idmap.h"
39#endif /* CONFIG_NFSD_V4 */
40
41#include "nfsd.h"
42#include "vfs.h"
43
44#define NFSDDBG_FACILITY NFSDDBG_FILEOP
45
46
47/*
48 * This is a cache of readahead params that help us choose the proper
49 * readahead strategy. Initially, we set all readahead parameters to 0
50 * and let the VFS handle things.
51 * If you increase the number of cached files very much, you'll need to
52 * add a hash table here.
53 */
54struct raparms {
55 struct raparms *p_next;
56 unsigned int p_count;
57 ino_t p_ino;
58 dev_t p_dev;
59 int p_set;
60 struct file_ra_state p_ra;
61 unsigned int p_hindex;
62};
63
64struct raparm_hbucket {
65 struct raparms *pb_head;
66 spinlock_t pb_lock;
67} ____cacheline_aligned_in_smp;
68
69#define RAPARM_HASH_BITS 4
70#define RAPARM_HASH_SIZE (1<<RAPARM_HASH_BITS)
71#define RAPARM_HASH_MASK (RAPARM_HASH_SIZE-1)
72static struct raparm_hbucket raparm_hash[RAPARM_HASH_SIZE];
73
74/*
75 * Called from nfsd_lookup and encode_dirent. Check if we have crossed
76 * a mount point.
77 * Returns -EAGAIN or -ETIMEDOUT leaving *dpp and *expp unchanged,
78 * or nfs_ok having possibly changed *dpp and *expp
79 */
80int
81nfsd_cross_mnt(struct svc_rqst *rqstp, struct dentry **dpp,
82 struct svc_export **expp)
83{
84 struct svc_export *exp = *expp, *exp2 = NULL;
85 struct dentry *dentry = *dpp;
86 struct path path = {.mnt = mntget(exp->ex_path.mnt),
87 .dentry = dget(dentry)};
88 int err = 0;
89
90 err = follow_down(&path);
91 if (err < 0)
92 goto out;
93
94 exp2 = rqst_exp_get_by_name(rqstp, &path);
95 if (IS_ERR(exp2)) {
96 err = PTR_ERR(exp2);
97 /*
98 * We normally allow NFS clients to continue
99 * "underneath" a mountpoint that is not exported.
100 * The exception is V4ROOT, where no traversal is ever
101 * allowed without an explicit export of the new
102 * directory.
103 */
104 if (err == -ENOENT && !(exp->ex_flags & NFSEXP_V4ROOT))
105 err = 0;
106 path_put(&path);
107 goto out;
108 }
109 if (nfsd_v4client(rqstp) ||
110 (exp->ex_flags & NFSEXP_CROSSMOUNT) || EX_NOHIDE(exp2)) {
111 /* successfully crossed mount point */
112 /*
113 * This is subtle: path.dentry is *not* on path.mnt
114 * at this point. The only reason we are safe is that
115 * original mnt is pinned down by exp, so we should
116 * put path *before* putting exp
117 */
118 *dpp = path.dentry;
119 path.dentry = dentry;
120 *expp = exp2;
121 exp2 = exp;
122 }
123 path_put(&path);
124 exp_put(exp2);
125out:
126 return err;
127}
128
129static void follow_to_parent(struct path *path)
130{
131 struct dentry *dp;
132
133 while (path->dentry == path->mnt->mnt_root && follow_up(path))
134 ;
135 dp = dget_parent(path->dentry);
136 dput(path->dentry);
137 path->dentry = dp;
138}
139
140static int nfsd_lookup_parent(struct svc_rqst *rqstp, struct dentry *dparent, struct svc_export **exp, struct dentry **dentryp)
141{
142 struct svc_export *exp2;
143 struct path path = {.mnt = mntget((*exp)->ex_path.mnt),
144 .dentry = dget(dparent)};
145
146 follow_to_parent(&path);
147
148 exp2 = rqst_exp_parent(rqstp, &path);
149 if (PTR_ERR(exp2) == -ENOENT) {
150 *dentryp = dget(dparent);
151 } else if (IS_ERR(exp2)) {
152 path_put(&path);
153 return PTR_ERR(exp2);
154 } else {
155 *dentryp = dget(path.dentry);
156 exp_put(*exp);
157 *exp = exp2;
158 }
159 path_put(&path);
160 return 0;
161}
162
163/*
164 * For nfsd purposes, we treat V4ROOT exports as though there was an
165 * export at *every* directory.
166 */
167int nfsd_mountpoint(struct dentry *dentry, struct svc_export *exp)
168{
169 if (d_mountpoint(dentry))
170 return 1;
171 if (!(exp->ex_flags & NFSEXP_V4ROOT))
172 return 0;
173 return dentry->d_inode != NULL;
174}
175
176__be32
177nfsd_lookup_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp,
178 const char *name, unsigned int len,
179 struct svc_export **exp_ret, struct dentry **dentry_ret)
180{
181 struct svc_export *exp;
182 struct dentry *dparent;
183 struct dentry *dentry;
184 int host_err;
185
186 dprintk("nfsd: nfsd_lookup(fh %s, %.*s)\n", SVCFH_fmt(fhp), len,name);
187
188 dparent = fhp->fh_dentry;
189 exp = fhp->fh_export;
190 exp_get(exp);
191
192 /* Lookup the name, but don't follow links */
193 if (isdotent(name, len)) {
194 if (len==1)
195 dentry = dget(dparent);
196 else if (dparent != exp->ex_path.dentry)
197 dentry = dget_parent(dparent);
198 else if (!EX_NOHIDE(exp) && !nfsd_v4client(rqstp))
199 dentry = dget(dparent); /* .. == . just like at / */
200 else {
201 /* checking mountpoint crossing is very different when stepping up */
202 host_err = nfsd_lookup_parent(rqstp, dparent, &exp, &dentry);
203 if (host_err)
204 goto out_nfserr;
205 }
206 } else {
207 fh_lock(fhp);
208 dentry = lookup_one_len(name, dparent, len);
209 host_err = PTR_ERR(dentry);
210 if (IS_ERR(dentry))
211 goto out_nfserr;
212 /*
213 * check if we have crossed a mount point ...
214 */
215 if (nfsd_mountpoint(dentry, exp)) {
216 if ((host_err = nfsd_cross_mnt(rqstp, &dentry, &exp))) {
217 dput(dentry);
218 goto out_nfserr;
219 }
220 }
221 }
222 *dentry_ret = dentry;
223 *exp_ret = exp;
224 return 0;
225
226out_nfserr:
227 exp_put(exp);
228 return nfserrno(host_err);
229}
230
231/*
232 * Look up one component of a pathname.
233 * N.B. After this call _both_ fhp and resfh need an fh_put
234 *
235 * If the lookup would cross a mountpoint, and the mounted filesystem
236 * is exported to the client with NFSEXP_NOHIDE, then the lookup is
237 * accepted as it stands and the mounted directory is
238 * returned. Otherwise the covered directory is returned.
239 * NOTE: this mountpoint crossing is not supported properly by all
240 * clients and is explicitly disallowed for NFSv3
241 * NeilBrown <neilb@cse.unsw.edu.au>
242 */
243__be32
244nfsd_lookup(struct svc_rqst *rqstp, struct svc_fh *fhp, const char *name,
245 unsigned int len, struct svc_fh *resfh)
246{
247 struct svc_export *exp;
248 struct dentry *dentry;
249 __be32 err;
250
251 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC);
252 if (err)
253 return err;
254 err = nfsd_lookup_dentry(rqstp, fhp, name, len, &exp, &dentry);
255 if (err)
256 return err;
257 err = check_nfsd_access(exp, rqstp);
258 if (err)
259 goto out;
260 /*
261 * Note: we compose the file handle now, but as the
262 * dentry may be negative, it may need to be updated.
263 */
264 err = fh_compose(resfh, exp, dentry, fhp);
265 if (!err && !dentry->d_inode)
266 err = nfserr_noent;
267out:
268 dput(dentry);
269 exp_put(exp);
270 return err;
271}
272
273static int nfsd_break_lease(struct inode *inode)
274{
275 if (!S_ISREG(inode->i_mode))
276 return 0;
277 return break_lease(inode, O_WRONLY | O_NONBLOCK);
278}
279
280/*
281 * Commit metadata changes to stable storage.
282 */
283static int
284commit_metadata(struct svc_fh *fhp)
285{
286 struct inode *inode = fhp->fh_dentry->d_inode;
287 const struct export_operations *export_ops = inode->i_sb->s_export_op;
288
289 if (!EX_ISSYNC(fhp->fh_export))
290 return 0;
291
292 if (export_ops->commit_metadata)
293 return export_ops->commit_metadata(inode);
294 return sync_inode_metadata(inode, 1);
295}
296
297/*
298 * Set various file attributes.
299 * N.B. After this call fhp needs an fh_put
300 */
301__be32
302nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
303 int check_guard, time_t guardtime)
304{
305 struct dentry *dentry;
306 struct inode *inode;
307 int accmode = NFSD_MAY_SATTR;
308 int ftype = 0;
309 __be32 err;
310 int host_err;
311 int size_change = 0;
312
313 if (iap->ia_valid & (ATTR_ATIME | ATTR_MTIME | ATTR_SIZE))
314 accmode |= NFSD_MAY_WRITE|NFSD_MAY_OWNER_OVERRIDE;
315 if (iap->ia_valid & ATTR_SIZE)
316 ftype = S_IFREG;
317
318 /* Get inode */
319 err = fh_verify(rqstp, fhp, ftype, accmode);
320 if (err)
321 goto out;
322
323 dentry = fhp->fh_dentry;
324 inode = dentry->d_inode;
325
326 /* Ignore any mode updates on symlinks */
327 if (S_ISLNK(inode->i_mode))
328 iap->ia_valid &= ~ATTR_MODE;
329
330 if (!iap->ia_valid)
331 goto out;
332
333 /*
334 * NFSv2 does not differentiate between "set-[ac]time-to-now"
335 * which only requires access, and "set-[ac]time-to-X" which
336 * requires ownership.
337 * So if it looks like it might be "set both to the same time which
338 * is close to now", and if inode_change_ok fails, then we
339 * convert to "set to now" instead of "set to explicit time"
340 *
341 * We only call inode_change_ok as the last test as technically
342 * it is not an interface that we should be using. It is only
343 * valid if the filesystem does not define it's own i_op->setattr.
344 */
345#define BOTH_TIME_SET (ATTR_ATIME_SET | ATTR_MTIME_SET)
346#define MAX_TOUCH_TIME_ERROR (30*60)
347 if ((iap->ia_valid & BOTH_TIME_SET) == BOTH_TIME_SET &&
348 iap->ia_mtime.tv_sec == iap->ia_atime.tv_sec) {
349 /*
350 * Looks probable.
351 *
352 * Now just make sure time is in the right ballpark.
353 * Solaris, at least, doesn't seem to care what the time
354 * request is. We require it be within 30 minutes of now.
355 */
356 time_t delta = iap->ia_atime.tv_sec - get_seconds();
357 if (delta < 0)
358 delta = -delta;
359 if (delta < MAX_TOUCH_TIME_ERROR &&
360 inode_change_ok(inode, iap) != 0) {
361 /*
362 * Turn off ATTR_[AM]TIME_SET but leave ATTR_[AM]TIME.
363 * This will cause notify_change to set these times
364 * to "now"
365 */
366 iap->ia_valid &= ~BOTH_TIME_SET;
367 }
368 }
369
370 /*
371 * The size case is special.
372 * It changes the file as well as the attributes.
373 */
374 if (iap->ia_valid & ATTR_SIZE) {
375 if (iap->ia_size < inode->i_size) {
376 err = nfsd_permission(rqstp, fhp->fh_export, dentry,
377 NFSD_MAY_TRUNC|NFSD_MAY_OWNER_OVERRIDE);
378 if (err)
379 goto out;
380 }
381
382 host_err = get_write_access(inode);
383 if (host_err)
384 goto out_nfserr;
385
386 size_change = 1;
387 host_err = locks_verify_truncate(inode, NULL, iap->ia_size);
388 if (host_err) {
389 put_write_access(inode);
390 goto out_nfserr;
391 }
392 }
393
394 /* sanitize the mode change */
395 if (iap->ia_valid & ATTR_MODE) {
396 iap->ia_mode &= S_IALLUGO;
397 iap->ia_mode |= (inode->i_mode & ~S_IALLUGO);
398 }
399
400 /* Revoke setuid/setgid on chown */
401 if (!S_ISDIR(inode->i_mode) &&
402 (((iap->ia_valid & ATTR_UID) && iap->ia_uid != inode->i_uid) ||
403 ((iap->ia_valid & ATTR_GID) && iap->ia_gid != inode->i_gid))) {
404 iap->ia_valid |= ATTR_KILL_PRIV;
405 if (iap->ia_valid & ATTR_MODE) {
406 /* we're setting mode too, just clear the s*id bits */
407 iap->ia_mode &= ~S_ISUID;
408 if (iap->ia_mode & S_IXGRP)
409 iap->ia_mode &= ~S_ISGID;
410 } else {
411 /* set ATTR_KILL_* bits and let VFS handle it */
412 iap->ia_valid |= (ATTR_KILL_SUID | ATTR_KILL_SGID);
413 }
414 }
415
416 /* Change the attributes. */
417
418 iap->ia_valid |= ATTR_CTIME;
419
420 err = nfserr_notsync;
421 if (!check_guard || guardtime == inode->i_ctime.tv_sec) {
422 host_err = nfsd_break_lease(inode);
423 if (host_err)
424 goto out_nfserr;
425 fh_lock(fhp);
426
427 host_err = notify_change(dentry, iap);
428 err = nfserrno(host_err);
429 fh_unlock(fhp);
430 }
431 if (size_change)
432 put_write_access(inode);
433 if (!err)
434 commit_metadata(fhp);
435out:
436 return err;
437
438out_nfserr:
439 err = nfserrno(host_err);
440 goto out;
441}
442
443#if defined(CONFIG_NFSD_V2_ACL) || \
444 defined(CONFIG_NFSD_V3_ACL) || \
445 defined(CONFIG_NFSD_V4)
446static ssize_t nfsd_getxattr(struct dentry *dentry, char *key, void **buf)
447{
448 ssize_t buflen;
449 ssize_t ret;
450
451 buflen = vfs_getxattr(dentry, key, NULL, 0);
452 if (buflen <= 0)
453 return buflen;
454
455 *buf = kmalloc(buflen, GFP_KERNEL);
456 if (!*buf)
457 return -ENOMEM;
458
459 ret = vfs_getxattr(dentry, key, *buf, buflen);
460 if (ret < 0)
461 kfree(*buf);
462 return ret;
463}
464#endif
465
466#if defined(CONFIG_NFSD_V4)
467static int
468set_nfsv4_acl_one(struct dentry *dentry, struct posix_acl *pacl, char *key)
469{
470 int len;
471 size_t buflen;
472 char *buf = NULL;
473 int error = 0;
474
475 buflen = posix_acl_xattr_size(pacl->a_count);
476 buf = kmalloc(buflen, GFP_KERNEL);
477 error = -ENOMEM;
478 if (buf == NULL)
479 goto out;
480
481 len = posix_acl_to_xattr(pacl, buf, buflen);
482 if (len < 0) {
483 error = len;
484 goto out;
485 }
486
487 error = vfs_setxattr(dentry, key, buf, len, 0);
488out:
489 kfree(buf);
490 return error;
491}
492
493__be32
494nfsd4_set_nfs4_acl(struct svc_rqst *rqstp, struct svc_fh *fhp,
495 struct nfs4_acl *acl)
496{
497 __be32 error;
498 int host_error;
499 struct dentry *dentry;
500 struct inode *inode;
501 struct posix_acl *pacl = NULL, *dpacl = NULL;
502 unsigned int flags = 0;
503
504 /* Get inode */
505 error = fh_verify(rqstp, fhp, 0 /* S_IFREG */, NFSD_MAY_SATTR);
506 if (error)
507 return error;
508
509 dentry = fhp->fh_dentry;
510 inode = dentry->d_inode;
511 if (S_ISDIR(inode->i_mode))
512 flags = NFS4_ACL_DIR;
513
514 host_error = nfs4_acl_nfsv4_to_posix(acl, &pacl, &dpacl, flags);
515 if (host_error == -EINVAL) {
516 return nfserr_attrnotsupp;
517 } else if (host_error < 0)
518 goto out_nfserr;
519
520 host_error = set_nfsv4_acl_one(dentry, pacl, POSIX_ACL_XATTR_ACCESS);
521 if (host_error < 0)
522 goto out_release;
523
524 if (S_ISDIR(inode->i_mode))
525 host_error = set_nfsv4_acl_one(dentry, dpacl, POSIX_ACL_XATTR_DEFAULT);
526
527out_release:
528 posix_acl_release(pacl);
529 posix_acl_release(dpacl);
530out_nfserr:
531 if (host_error == -EOPNOTSUPP)
532 return nfserr_attrnotsupp;
533 else
534 return nfserrno(host_error);
535}
536
537static struct posix_acl *
538_get_posix_acl(struct dentry *dentry, char *key)
539{
540 void *buf = NULL;
541 struct posix_acl *pacl = NULL;
542 int buflen;
543
544 buflen = nfsd_getxattr(dentry, key, &buf);
545 if (!buflen)
546 buflen = -ENODATA;
547 if (buflen <= 0)
548 return ERR_PTR(buflen);
549
550 pacl = posix_acl_from_xattr(buf, buflen);
551 kfree(buf);
552 return pacl;
553}
554
555int
556nfsd4_get_nfs4_acl(struct svc_rqst *rqstp, struct dentry *dentry, struct nfs4_acl **acl)
557{
558 struct inode *inode = dentry->d_inode;
559 int error = 0;
560 struct posix_acl *pacl = NULL, *dpacl = NULL;
561 unsigned int flags = 0;
562
563 pacl = _get_posix_acl(dentry, POSIX_ACL_XATTR_ACCESS);
564 if (IS_ERR(pacl) && PTR_ERR(pacl) == -ENODATA)
565 pacl = posix_acl_from_mode(inode->i_mode, GFP_KERNEL);
566 if (IS_ERR(pacl)) {
567 error = PTR_ERR(pacl);
568 pacl = NULL;
569 goto out;
570 }
571
572 if (S_ISDIR(inode->i_mode)) {
573 dpacl = _get_posix_acl(dentry, POSIX_ACL_XATTR_DEFAULT);
574 if (IS_ERR(dpacl) && PTR_ERR(dpacl) == -ENODATA)
575 dpacl = NULL;
576 else if (IS_ERR(dpacl)) {
577 error = PTR_ERR(dpacl);
578 dpacl = NULL;
579 goto out;
580 }
581 flags = NFS4_ACL_DIR;
582 }
583
584 *acl = nfs4_acl_posix_to_nfsv4(pacl, dpacl, flags);
585 if (IS_ERR(*acl)) {
586 error = PTR_ERR(*acl);
587 *acl = NULL;
588 }
589 out:
590 posix_acl_release(pacl);
591 posix_acl_release(dpacl);
592 return error;
593}
594
595#endif /* defined(CONFIG_NFSD_V4) */
596
597#ifdef CONFIG_NFSD_V3
598/*
599 * Check server access rights to a file system object
600 */
601struct accessmap {
602 u32 access;
603 int how;
604};
605static struct accessmap nfs3_regaccess[] = {
606 { NFS3_ACCESS_READ, NFSD_MAY_READ },
607 { NFS3_ACCESS_EXECUTE, NFSD_MAY_EXEC },
608 { NFS3_ACCESS_MODIFY, NFSD_MAY_WRITE|NFSD_MAY_TRUNC },
609 { NFS3_ACCESS_EXTEND, NFSD_MAY_WRITE },
610
611 { 0, 0 }
612};
613
614static struct accessmap nfs3_diraccess[] = {
615 { NFS3_ACCESS_READ, NFSD_MAY_READ },
616 { NFS3_ACCESS_LOOKUP, NFSD_MAY_EXEC },
617 { NFS3_ACCESS_MODIFY, NFSD_MAY_EXEC|NFSD_MAY_WRITE|NFSD_MAY_TRUNC},
618 { NFS3_ACCESS_EXTEND, NFSD_MAY_EXEC|NFSD_MAY_WRITE },
619 { NFS3_ACCESS_DELETE, NFSD_MAY_REMOVE },
620
621 { 0, 0 }
622};
623
624static struct accessmap nfs3_anyaccess[] = {
625 /* Some clients - Solaris 2.6 at least, make an access call
626 * to the server to check for access for things like /dev/null
627 * (which really, the server doesn't care about). So
628 * We provide simple access checking for them, looking
629 * mainly at mode bits, and we make sure to ignore read-only
630 * filesystem checks
631 */
632 { NFS3_ACCESS_READ, NFSD_MAY_READ },
633 { NFS3_ACCESS_EXECUTE, NFSD_MAY_EXEC },
634 { NFS3_ACCESS_MODIFY, NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS },
635 { NFS3_ACCESS_EXTEND, NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS },
636
637 { 0, 0 }
638};
639
640__be32
641nfsd_access(struct svc_rqst *rqstp, struct svc_fh *fhp, u32 *access, u32 *supported)
642{
643 struct accessmap *map;
644 struct svc_export *export;
645 struct dentry *dentry;
646 u32 query, result = 0, sresult = 0;
647 __be32 error;
648
649 error = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP);
650 if (error)
651 goto out;
652
653 export = fhp->fh_export;
654 dentry = fhp->fh_dentry;
655
656 if (S_ISREG(dentry->d_inode->i_mode))
657 map = nfs3_regaccess;
658 else if (S_ISDIR(dentry->d_inode->i_mode))
659 map = nfs3_diraccess;
660 else
661 map = nfs3_anyaccess;
662
663
664 query = *access;
665 for (; map->access; map++) {
666 if (map->access & query) {
667 __be32 err2;
668
669 sresult |= map->access;
670
671 err2 = nfsd_permission(rqstp, export, dentry, map->how);
672 switch (err2) {
673 case nfs_ok:
674 result |= map->access;
675 break;
676
677 /* the following error codes just mean the access was not allowed,
678 * rather than an error occurred */
679 case nfserr_rofs:
680 case nfserr_acces:
681 case nfserr_perm:
682 /* simply don't "or" in the access bit. */
683 break;
684 default:
685 error = err2;
686 goto out;
687 }
688 }
689 }
690 *access = result;
691 if (supported)
692 *supported = sresult;
693
694 out:
695 return error;
696}
697#endif /* CONFIG_NFSD_V3 */
698
699static int nfsd_open_break_lease(struct inode *inode, int access)
700{
701 unsigned int mode;
702
703 if (access & NFSD_MAY_NOT_BREAK_LEASE)
704 return 0;
705 mode = (access & NFSD_MAY_WRITE) ? O_WRONLY : O_RDONLY;
706 return break_lease(inode, mode | O_NONBLOCK);
707}
708
709/*
710 * Open an existing file or directory.
711 * The access argument indicates the type of open (read/write/lock)
712 * N.B. After this call fhp needs an fh_put
713 */
714__be32
715nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
716 int access, struct file **filp)
717{
718 struct dentry *dentry;
719 struct inode *inode;
720 int flags = O_RDONLY|O_LARGEFILE;
721 __be32 err;
722 int host_err = 0;
723
724 validate_process_creds();
725
726 /*
727 * If we get here, then the client has already done an "open",
728 * and (hopefully) checked permission - so allow OWNER_OVERRIDE
729 * in case a chmod has now revoked permission.
730 */
731 err = fh_verify(rqstp, fhp, type, access | NFSD_MAY_OWNER_OVERRIDE);
732 if (err)
733 goto out;
734
735 dentry = fhp->fh_dentry;
736 inode = dentry->d_inode;
737
738 /* Disallow write access to files with the append-only bit set
739 * or any access when mandatory locking enabled
740 */
741 err = nfserr_perm;
742 if (IS_APPEND(inode) && (access & NFSD_MAY_WRITE))
743 goto out;
744 /*
745 * We must ignore files (but only files) which might have mandatory
746 * locks on them because there is no way to know if the accesser has
747 * the lock.
748 */
749 if (S_ISREG((inode)->i_mode) && mandatory_lock(inode))
750 goto out;
751
752 if (!inode->i_fop)
753 goto out;
754
755 host_err = nfsd_open_break_lease(inode, access);
756 if (host_err) /* NOMEM or WOULDBLOCK */
757 goto out_nfserr;
758
759 if (access & NFSD_MAY_WRITE) {
760 if (access & NFSD_MAY_READ)
761 flags = O_RDWR|O_LARGEFILE;
762 else
763 flags = O_WRONLY|O_LARGEFILE;
764 }
765 *filp = dentry_open(dget(dentry), mntget(fhp->fh_export->ex_path.mnt),
766 flags, current_cred());
767 if (IS_ERR(*filp))
768 host_err = PTR_ERR(*filp);
769 else
770 host_err = ima_file_check(*filp, access);
771out_nfserr:
772 err = nfserrno(host_err);
773out:
774 validate_process_creds();
775 return err;
776}
777
778/*
779 * Close a file.
780 */
781void
782nfsd_close(struct file *filp)
783{
784 fput(filp);
785}
786
787/*
788 * Obtain the readahead parameters for the file
789 * specified by (dev, ino).
790 */
791
792static inline struct raparms *
793nfsd_get_raparms(dev_t dev, ino_t ino)
794{
795 struct raparms *ra, **rap, **frap = NULL;
796 int depth = 0;
797 unsigned int hash;
798 struct raparm_hbucket *rab;
799
800 hash = jhash_2words(dev, ino, 0xfeedbeef) & RAPARM_HASH_MASK;
801 rab = &raparm_hash[hash];
802
803 spin_lock(&rab->pb_lock);
804 for (rap = &rab->pb_head; (ra = *rap); rap = &ra->p_next) {
805 if (ra->p_ino == ino && ra->p_dev == dev)
806 goto found;
807 depth++;
808 if (ra->p_count == 0)
809 frap = rap;
810 }
811 depth = nfsdstats.ra_size;
812 if (!frap) {
813 spin_unlock(&rab->pb_lock);
814 return NULL;
815 }
816 rap = frap;
817 ra = *frap;
818 ra->p_dev = dev;
819 ra->p_ino = ino;
820 ra->p_set = 0;
821 ra->p_hindex = hash;
822found:
823 if (rap != &rab->pb_head) {
824 *rap = ra->p_next;
825 ra->p_next = rab->pb_head;
826 rab->pb_head = ra;
827 }
828 ra->p_count++;
829 nfsdstats.ra_depth[depth*10/nfsdstats.ra_size]++;
830 spin_unlock(&rab->pb_lock);
831 return ra;
832}
833
834/*
835 * Grab and keep cached pages associated with a file in the svc_rqst
836 * so that they can be passed to the network sendmsg/sendpage routines
837 * directly. They will be released after the sending has completed.
838 */
839static int
840nfsd_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
841 struct splice_desc *sd)
842{
843 struct svc_rqst *rqstp = sd->u.data;
844 struct page **pp = rqstp->rq_respages + rqstp->rq_resused;
845 struct page *page = buf->page;
846 size_t size;
847
848 size = sd->len;
849
850 if (rqstp->rq_res.page_len == 0) {
851 get_page(page);
852 put_page(*pp);
853 *pp = page;
854 rqstp->rq_resused++;
855 rqstp->rq_res.page_base = buf->offset;
856 rqstp->rq_res.page_len = size;
857 } else if (page != pp[-1]) {
858 get_page(page);
859 if (*pp)
860 put_page(*pp);
861 *pp = page;
862 rqstp->rq_resused++;
863 rqstp->rq_res.page_len += size;
864 } else
865 rqstp->rq_res.page_len += size;
866
867 return size;
868}
869
870static int nfsd_direct_splice_actor(struct pipe_inode_info *pipe,
871 struct splice_desc *sd)
872{
873 return __splice_from_pipe(pipe, sd, nfsd_splice_actor);
874}
875
876static __be32
877nfsd_vfs_read(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
878 loff_t offset, struct kvec *vec, int vlen, unsigned long *count)
879{
880 mm_segment_t oldfs;
881 __be32 err;
882 int host_err;
883
884 err = nfserr_perm;
885
886 if (file->f_op->splice_read && rqstp->rq_splice_ok) {
887 struct splice_desc sd = {
888 .len = 0,
889 .total_len = *count,
890 .pos = offset,
891 .u.data = rqstp,
892 };
893
894 rqstp->rq_resused = 1;
895 host_err = splice_direct_to_actor(file, &sd, nfsd_direct_splice_actor);
896 } else {
897 oldfs = get_fs();
898 set_fs(KERNEL_DS);
899 host_err = vfs_readv(file, (struct iovec __user *)vec, vlen, &offset);
900 set_fs(oldfs);
901 }
902
903 if (host_err >= 0) {
904 nfsdstats.io_read += host_err;
905 *count = host_err;
906 err = 0;
907 fsnotify_access(file);
908 } else
909 err = nfserrno(host_err);
910 return err;
911}
912
913static void kill_suid(struct dentry *dentry)
914{
915 struct iattr ia;
916 ia.ia_valid = ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_KILL_PRIV;
917
918 mutex_lock(&dentry->d_inode->i_mutex);
919 notify_change(dentry, &ia);
920 mutex_unlock(&dentry->d_inode->i_mutex);
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 */
937static int wait_for_concurrent_writes(struct file *file)
938{
939 struct inode *inode = file->f_path.dentry->d_inode;
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
960static __be32
961nfsd_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 *stablep)
964{
965 struct svc_export *exp;
966 struct dentry *dentry;
967 struct inode *inode;
968 mm_segment_t oldfs;
969 __be32 err = 0;
970 int host_err;
971 int stable = *stablep;
972 int use_wgather;
973
974 dentry = file->f_path.dentry;
975 inode = dentry->d_inode;
976 exp = fhp->fh_export;
977
978 /*
979 * Request sync writes if
980 * - the sync export option has been set, or
981 * - the client requested O_SYNC behavior (NFSv3 feature).
982 * - The file system doesn't support fsync().
983 * When NFSv2 gathered writes have been configured for this volume,
984 * flushing the data to disk is handled separately below.
985 */
986 use_wgather = (rqstp->rq_vers == 2) && EX_WGATHER(exp);
987
988 if (!file->f_op->fsync) {/* COMMIT3 cannot work */
989 stable = 2;
990 *stablep = 2; /* FILE_SYNC */
991 }
992
993 if (!EX_ISSYNC(exp))
994 stable = 0;
995 if (stable && !use_wgather) {
996 spin_lock(&file->f_lock);
997 file->f_flags |= O_SYNC;
998 spin_unlock(&file->f_lock);
999 }
1000
1001 /* Write the data. */
1002 oldfs = get_fs(); set_fs(KERNEL_DS);
1003 host_err = vfs_writev(file, (struct iovec __user *)vec, vlen, &offset);
1004 set_fs(oldfs);
1005 if (host_err < 0)
1006 goto out_nfserr;
1007 *cnt = host_err;
1008 nfsdstats.io_write += host_err;
1009 fsnotify_modify(file);
1010
1011 /* clear setuid/setgid flag after write */
1012 if (inode->i_mode & (S_ISUID | S_ISGID))
1013 kill_suid(dentry);
1014
1015 if (stable && use_wgather)
1016 host_err = wait_for_concurrent_writes(file);
1017
1018out_nfserr:
1019 dprintk("nfsd: write complete host_err=%d\n", host_err);
1020 if (host_err >= 0)
1021 err = 0;
1022 else
1023 err = nfserrno(host_err);
1024 return err;
1025}
1026
1027/*
1028 * Read data from a file. count must contain the requested read count
1029 * on entry. On return, *count contains the number of bytes actually read.
1030 * N.B. After this call fhp needs an fh_put
1031 */
1032__be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
1033 loff_t offset, struct kvec *vec, int vlen, unsigned long *count)
1034{
1035 struct file *file;
1036 struct inode *inode;
1037 struct raparms *ra;
1038 __be32 err;
1039
1040 err = nfsd_open(rqstp, fhp, S_IFREG, NFSD_MAY_READ, &file);
1041 if (err)
1042 return err;
1043
1044 inode = file->f_path.dentry->d_inode;
1045
1046 /* Get readahead parameters */
1047 ra = nfsd_get_raparms(inode->i_sb->s_dev, inode->i_ino);
1048
1049 if (ra && ra->p_set)
1050 file->f_ra = ra->p_ra;
1051
1052 err = nfsd_vfs_read(rqstp, fhp, file, offset, vec, vlen, count);
1053
1054 /* Write back readahead params */
1055 if (ra) {
1056 struct raparm_hbucket *rab = &raparm_hash[ra->p_hindex];
1057 spin_lock(&rab->pb_lock);
1058 ra->p_ra = file->f_ra;
1059 ra->p_set = 1;
1060 ra->p_count--;
1061 spin_unlock(&rab->pb_lock);
1062 }
1063
1064 nfsd_close(file);
1065 return err;
1066}
1067
1068/* As above, but use the provided file descriptor. */
1069__be32
1070nfsd_read_file(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
1071 loff_t offset, struct kvec *vec, int vlen,
1072 unsigned long *count)
1073{
1074 __be32 err;
1075
1076 if (file) {
1077 err = nfsd_permission(rqstp, fhp->fh_export, fhp->fh_dentry,
1078 NFSD_MAY_READ|NFSD_MAY_OWNER_OVERRIDE);
1079 if (err)
1080 goto out;
1081 err = nfsd_vfs_read(rqstp, fhp, file, offset, vec, vlen, count);
1082 } else /* Note file may still be NULL in NFSv4 special stateid case: */
1083 err = nfsd_read(rqstp, fhp, offset, vec, vlen, count);
1084out:
1085 return err;
1086}
1087
1088/*
1089 * Write data to a file.
1090 * The stable flag requests synchronous writes.
1091 * N.B. After this call fhp needs an fh_put
1092 */
1093__be32
1094nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
1095 loff_t offset, struct kvec *vec, int vlen, unsigned long *cnt,
1096 int *stablep)
1097{
1098 __be32 err = 0;
1099
1100 if (file) {
1101 err = nfsd_permission(rqstp, fhp->fh_export, fhp->fh_dentry,
1102 NFSD_MAY_WRITE|NFSD_MAY_OWNER_OVERRIDE);
1103 if (err)
1104 goto out;
1105 err = nfsd_vfs_write(rqstp, fhp, file, offset, vec, vlen, cnt,
1106 stablep);
1107 } else {
1108 err = nfsd_open(rqstp, fhp, S_IFREG, NFSD_MAY_WRITE, &file);
1109 if (err)
1110 goto out;
1111
1112 if (cnt)
1113 err = nfsd_vfs_write(rqstp, fhp, file, offset, vec, vlen,
1114 cnt, stablep);
1115 nfsd_close(file);
1116 }
1117out:
1118 return err;
1119}
1120
1121#ifdef CONFIG_NFSD_V3
1122/*
1123 * Commit all pending writes to stable storage.
1124 *
1125 * Note: we only guarantee that data that lies within the range specified
1126 * by the 'offset' and 'count' parameters will be synced.
1127 *
1128 * Unfortunately we cannot lock the file to make sure we return full WCC
1129 * data to the client, as locking happens lower down in the filesystem.
1130 */
1131__be32
1132nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp,
1133 loff_t offset, unsigned long count)
1134{
1135 struct file *file;
1136 loff_t end = LLONG_MAX;
1137 __be32 err = nfserr_inval;
1138
1139 if (offset < 0)
1140 goto out;
1141 if (count != 0) {
1142 end = offset + (loff_t)count - 1;
1143 if (end < offset)
1144 goto out;
1145 }
1146
1147 err = nfsd_open(rqstp, fhp, S_IFREG,
1148 NFSD_MAY_WRITE|NFSD_MAY_NOT_BREAK_LEASE, &file);
1149 if (err)
1150 goto out;
1151 if (EX_ISSYNC(fhp->fh_export)) {
1152 int err2 = vfs_fsync_range(file, offset, end, 0);
1153
1154 if (err2 != -EINVAL)
1155 err = nfserrno(err2);
1156 else
1157 err = nfserr_notsupp;
1158 }
1159
1160 nfsd_close(file);
1161out:
1162 return err;
1163}
1164#endif /* CONFIG_NFSD_V3 */
1165
1166static __be32
1167nfsd_create_setattr(struct svc_rqst *rqstp, struct svc_fh *resfhp,
1168 struct iattr *iap)
1169{
1170 /*
1171 * Mode has already been set earlier in create:
1172 */
1173 iap->ia_valid &= ~ATTR_MODE;
1174 /*
1175 * Setting uid/gid works only for root. Irix appears to
1176 * send along the gid on create when it tries to implement
1177 * setgid directories via NFS:
1178 */
1179 if (current_fsuid() != 0)
1180 iap->ia_valid &= ~(ATTR_UID|ATTR_GID);
1181 if (iap->ia_valid)
1182 return nfsd_setattr(rqstp, resfhp, iap, 0, (time_t)0);
1183 return 0;
1184}
1185
1186/* HPUX client sometimes creates a file in mode 000, and sets size to 0.
1187 * setting size to 0 may fail for some specific file systems by the permission
1188 * checking which requires WRITE permission but the mode is 000.
1189 * we ignore the resizing(to 0) on the just new created file, since the size is
1190 * 0 after file created.
1191 *
1192 * call this only after vfs_create() is called.
1193 * */
1194static void
1195nfsd_check_ignore_resizing(struct iattr *iap)
1196{
1197 if ((iap->ia_valid & ATTR_SIZE) && (iap->ia_size == 0))
1198 iap->ia_valid &= ~ATTR_SIZE;
1199}
1200
1201/*
1202 * Create a file (regular, directory, device, fifo); UNIX sockets
1203 * not yet implemented.
1204 * If the response fh has been verified, the parent directory should
1205 * already be locked. Note that the parent directory is left locked.
1206 *
1207 * N.B. Every call to nfsd_create needs an fh_put for _both_ fhp and resfhp
1208 */
1209__be32
1210nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
1211 char *fname, int flen, struct iattr *iap,
1212 int type, dev_t rdev, struct svc_fh *resfhp)
1213{
1214 struct dentry *dentry, *dchild = NULL;
1215 struct inode *dirp;
1216 __be32 err;
1217 __be32 err2;
1218 int host_err;
1219
1220 err = nfserr_perm;
1221 if (!flen)
1222 goto out;
1223 err = nfserr_exist;
1224 if (isdotent(fname, flen))
1225 goto out;
1226
1227 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
1228 if (err)
1229 goto out;
1230
1231 dentry = fhp->fh_dentry;
1232 dirp = dentry->d_inode;
1233
1234 err = nfserr_notdir;
1235 if (!dirp->i_op->lookup)
1236 goto out;
1237 /*
1238 * Check whether the response file handle has been verified yet.
1239 * If it has, the parent directory should already be locked.
1240 */
1241 if (!resfhp->fh_dentry) {
1242 /* called from nfsd_proc_mkdir, or possibly nfsd3_proc_create */
1243 fh_lock_nested(fhp, I_MUTEX_PARENT);
1244 dchild = lookup_one_len(fname, dentry, flen);
1245 host_err = PTR_ERR(dchild);
1246 if (IS_ERR(dchild))
1247 goto out_nfserr;
1248 err = fh_compose(resfhp, fhp->fh_export, dchild, fhp);
1249 if (err)
1250 goto out;
1251 } else {
1252 /* called from nfsd_proc_create */
1253 dchild = dget(resfhp->fh_dentry);
1254 if (!fhp->fh_locked) {
1255 /* not actually possible */
1256 printk(KERN_ERR
1257 "nfsd_create: parent %s/%s not locked!\n",
1258 dentry->d_parent->d_name.name,
1259 dentry->d_name.name);
1260 err = nfserr_io;
1261 goto out;
1262 }
1263 }
1264 /*
1265 * Make sure the child dentry is still negative ...
1266 */
1267 err = nfserr_exist;
1268 if (dchild->d_inode) {
1269 dprintk("nfsd_create: dentry %s/%s not negative!\n",
1270 dentry->d_name.name, dchild->d_name.name);
1271 goto out;
1272 }
1273
1274 if (!(iap->ia_valid & ATTR_MODE))
1275 iap->ia_mode = 0;
1276 iap->ia_mode = (iap->ia_mode & S_IALLUGO) | type;
1277
1278 err = nfserr_inval;
1279 if (!S_ISREG(type) && !S_ISDIR(type) && !special_file(type)) {
1280 printk(KERN_WARNING "nfsd: bad file type %o in nfsd_create\n",
1281 type);
1282 goto out;
1283 }
1284
1285 host_err = mnt_want_write(fhp->fh_export->ex_path.mnt);
1286 if (host_err)
1287 goto out_nfserr;
1288
1289 /*
1290 * Get the dir op function pointer.
1291 */
1292 err = 0;
1293 switch (type) {
1294 case S_IFREG:
1295 host_err = vfs_create(dirp, dchild, iap->ia_mode, NULL);
1296 if (!host_err)
1297 nfsd_check_ignore_resizing(iap);
1298 break;
1299 case S_IFDIR:
1300 host_err = vfs_mkdir(dirp, dchild, iap->ia_mode);
1301 break;
1302 case S_IFCHR:
1303 case S_IFBLK:
1304 case S_IFIFO:
1305 case S_IFSOCK:
1306 host_err = vfs_mknod(dirp, dchild, iap->ia_mode, rdev);
1307 break;
1308 }
1309 if (host_err < 0) {
1310 mnt_drop_write(fhp->fh_export->ex_path.mnt);
1311 goto out_nfserr;
1312 }
1313
1314 err = nfsd_create_setattr(rqstp, resfhp, iap);
1315
1316 /*
1317 * nfsd_setattr already committed the child. Transactional filesystems
1318 * had a chance to commit changes for both parent and child
1319 * simultaneously making the following commit_metadata a noop.
1320 */
1321 err2 = nfserrno(commit_metadata(fhp));
1322 if (err2)
1323 err = err2;
1324 mnt_drop_write(fhp->fh_export->ex_path.mnt);
1325 /*
1326 * Update the file handle to get the new inode info.
1327 */
1328 if (!err)
1329 err = fh_update(resfhp);
1330out:
1331 if (dchild && !IS_ERR(dchild))
1332 dput(dchild);
1333 return err;
1334
1335out_nfserr:
1336 err = nfserrno(host_err);
1337 goto out;
1338}
1339
1340#ifdef CONFIG_NFSD_V3
1341
1342static inline int nfsd_create_is_exclusive(int createmode)
1343{
1344 return createmode == NFS3_CREATE_EXCLUSIVE
1345 || createmode == NFS4_CREATE_EXCLUSIVE4_1;
1346}
1347
1348/*
1349 * NFSv3 and NFSv4 version of nfsd_create
1350 */
1351__be32
1352do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
1353 char *fname, int flen, struct iattr *iap,
1354 struct svc_fh *resfhp, int createmode, u32 *verifier,
1355 int *truncp, int *created)
1356{
1357 struct dentry *dentry, *dchild = NULL;
1358 struct inode *dirp;
1359 __be32 err;
1360 int host_err;
1361 __u32 v_mtime=0, v_atime=0;
1362
1363 err = nfserr_perm;
1364 if (!flen)
1365 goto out;
1366 err = nfserr_exist;
1367 if (isdotent(fname, flen))
1368 goto out;
1369 if (!(iap->ia_valid & ATTR_MODE))
1370 iap->ia_mode = 0;
1371 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC);
1372 if (err)
1373 goto out;
1374
1375 dentry = fhp->fh_dentry;
1376 dirp = dentry->d_inode;
1377
1378 /* Get all the sanity checks out of the way before
1379 * we lock the parent. */
1380 err = nfserr_notdir;
1381 if (!dirp->i_op->lookup)
1382 goto out;
1383 fh_lock_nested(fhp, I_MUTEX_PARENT);
1384
1385 /*
1386 * Compose the response file handle.
1387 */
1388 dchild = lookup_one_len(fname, dentry, flen);
1389 host_err = PTR_ERR(dchild);
1390 if (IS_ERR(dchild))
1391 goto out_nfserr;
1392
1393 /* If file doesn't exist, check for permissions to create one */
1394 if (!dchild->d_inode) {
1395 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
1396 if (err)
1397 goto out;
1398 }
1399
1400 err = fh_compose(resfhp, fhp->fh_export, dchild, fhp);
1401 if (err)
1402 goto out;
1403
1404 if (nfsd_create_is_exclusive(createmode)) {
1405 /* solaris7 gets confused (bugid 4218508) if these have
1406 * the high bit set, so just clear the high bits. If this is
1407 * ever changed to use different attrs for storing the
1408 * verifier, then do_open_lookup() will also need to be fixed
1409 * accordingly.
1410 */
1411 v_mtime = verifier[0]&0x7fffffff;
1412 v_atime = verifier[1]&0x7fffffff;
1413 }
1414
1415 host_err = mnt_want_write(fhp->fh_export->ex_path.mnt);
1416 if (host_err)
1417 goto out_nfserr;
1418 if (dchild->d_inode) {
1419 err = 0;
1420
1421 switch (createmode) {
1422 case NFS3_CREATE_UNCHECKED:
1423 if (! S_ISREG(dchild->d_inode->i_mode))
1424 err = nfserr_exist;
1425 else if (truncp) {
1426 /* in nfsv4, we need to treat this case a little
1427 * differently. we don't want to truncate the
1428 * file now; this would be wrong if the OPEN
1429 * fails for some other reason. furthermore,
1430 * if the size is nonzero, we should ignore it
1431 * according to spec!
1432 */
1433 *truncp = (iap->ia_valid & ATTR_SIZE) && !iap->ia_size;
1434 }
1435 else {
1436 iap->ia_valid &= ATTR_SIZE;
1437 goto set_attr;
1438 }
1439 break;
1440 case NFS3_CREATE_EXCLUSIVE:
1441 if ( dchild->d_inode->i_mtime.tv_sec == v_mtime
1442 && dchild->d_inode->i_atime.tv_sec == v_atime
1443 && dchild->d_inode->i_size == 0 )
1444 break;
1445 case NFS4_CREATE_EXCLUSIVE4_1:
1446 if ( dchild->d_inode->i_mtime.tv_sec == v_mtime
1447 && dchild->d_inode->i_atime.tv_sec == v_atime
1448 && dchild->d_inode->i_size == 0 )
1449 goto set_attr;
1450 /* fallthru */
1451 case NFS3_CREATE_GUARDED:
1452 err = nfserr_exist;
1453 }
1454 mnt_drop_write(fhp->fh_export->ex_path.mnt);
1455 goto out;
1456 }
1457
1458 host_err = vfs_create(dirp, dchild, iap->ia_mode, NULL);
1459 if (host_err < 0) {
1460 mnt_drop_write(fhp->fh_export->ex_path.mnt);
1461 goto out_nfserr;
1462 }
1463 if (created)
1464 *created = 1;
1465
1466 nfsd_check_ignore_resizing(iap);
1467
1468 if (nfsd_create_is_exclusive(createmode)) {
1469 /* Cram the verifier into atime/mtime */
1470 iap->ia_valid = ATTR_MTIME|ATTR_ATIME
1471 | ATTR_MTIME_SET|ATTR_ATIME_SET;
1472 /* XXX someone who knows this better please fix it for nsec */
1473 iap->ia_mtime.tv_sec = v_mtime;
1474 iap->ia_atime.tv_sec = v_atime;
1475 iap->ia_mtime.tv_nsec = 0;
1476 iap->ia_atime.tv_nsec = 0;
1477 }
1478
1479 set_attr:
1480 err = nfsd_create_setattr(rqstp, resfhp, iap);
1481
1482 /*
1483 * nfsd_setattr already committed the child (and possibly also the parent).
1484 */
1485 if (!err)
1486 err = nfserrno(commit_metadata(fhp));
1487
1488 mnt_drop_write(fhp->fh_export->ex_path.mnt);
1489 /*
1490 * Update the filehandle to get the new inode info.
1491 */
1492 if (!err)
1493 err = fh_update(resfhp);
1494
1495 out:
1496 fh_unlock(fhp);
1497 if (dchild && !IS_ERR(dchild))
1498 dput(dchild);
1499 return err;
1500
1501 out_nfserr:
1502 err = nfserrno(host_err);
1503 goto out;
1504}
1505#endif /* CONFIG_NFSD_V3 */
1506
1507/*
1508 * Read a symlink. On entry, *lenp must contain the maximum path length that
1509 * fits into the buffer. On return, it contains the true length.
1510 * N.B. After this call fhp needs an fh_put
1511 */
1512__be32
1513nfsd_readlink(struct svc_rqst *rqstp, struct svc_fh *fhp, char *buf, int *lenp)
1514{
1515 struct dentry *dentry;
1516 struct inode *inode;
1517 mm_segment_t oldfs;
1518 __be32 err;
1519 int host_err;
1520
1521 err = fh_verify(rqstp, fhp, S_IFLNK, NFSD_MAY_NOP);
1522 if (err)
1523 goto out;
1524
1525 dentry = fhp->fh_dentry;
1526 inode = dentry->d_inode;
1527
1528 err = nfserr_inval;
1529 if (!inode->i_op->readlink)
1530 goto out;
1531
1532 touch_atime(fhp->fh_export->ex_path.mnt, dentry);
1533 /* N.B. Why does this call need a get_fs()??
1534 * Remove the set_fs and watch the fireworks:-) --okir
1535 */
1536
1537 oldfs = get_fs(); set_fs(KERNEL_DS);
1538 host_err = inode->i_op->readlink(dentry, buf, *lenp);
1539 set_fs(oldfs);
1540
1541 if (host_err < 0)
1542 goto out_nfserr;
1543 *lenp = host_err;
1544 err = 0;
1545out:
1546 return err;
1547
1548out_nfserr:
1549 err = nfserrno(host_err);
1550 goto out;
1551}
1552
1553/*
1554 * Create a symlink and look up its inode
1555 * N.B. After this call _both_ fhp and resfhp need an fh_put
1556 */
1557__be32
1558nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp,
1559 char *fname, int flen,
1560 char *path, int plen,
1561 struct svc_fh *resfhp,
1562 struct iattr *iap)
1563{
1564 struct dentry *dentry, *dnew;
1565 __be32 err, cerr;
1566 int host_err;
1567
1568 err = nfserr_noent;
1569 if (!flen || !plen)
1570 goto out;
1571 err = nfserr_exist;
1572 if (isdotent(fname, flen))
1573 goto out;
1574
1575 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
1576 if (err)
1577 goto out;
1578 fh_lock(fhp);
1579 dentry = fhp->fh_dentry;
1580 dnew = lookup_one_len(fname, dentry, flen);
1581 host_err = PTR_ERR(dnew);
1582 if (IS_ERR(dnew))
1583 goto out_nfserr;
1584
1585 host_err = mnt_want_write(fhp->fh_export->ex_path.mnt);
1586 if (host_err)
1587 goto out_nfserr;
1588
1589 if (unlikely(path[plen] != 0)) {
1590 char *path_alloced = kmalloc(plen+1, GFP_KERNEL);
1591 if (path_alloced == NULL)
1592 host_err = -ENOMEM;
1593 else {
1594 strncpy(path_alloced, path, plen);
1595 path_alloced[plen] = 0;
1596 host_err = vfs_symlink(dentry->d_inode, dnew, path_alloced);
1597 kfree(path_alloced);
1598 }
1599 } else
1600 host_err = vfs_symlink(dentry->d_inode, dnew, path);
1601 err = nfserrno(host_err);
1602 if (!err)
1603 err = nfserrno(commit_metadata(fhp));
1604 fh_unlock(fhp);
1605
1606 mnt_drop_write(fhp->fh_export->ex_path.mnt);
1607
1608 cerr = fh_compose(resfhp, fhp->fh_export, dnew, fhp);
1609 dput(dnew);
1610 if (err==0) err = cerr;
1611out:
1612 return err;
1613
1614out_nfserr:
1615 err = nfserrno(host_err);
1616 goto out;
1617}
1618
1619/*
1620 * Create a hardlink
1621 * N.B. After this call _both_ ffhp and tfhp need an fh_put
1622 */
1623__be32
1624nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp,
1625 char *name, int len, struct svc_fh *tfhp)
1626{
1627 struct dentry *ddir, *dnew, *dold;
1628 struct inode *dirp;
1629 __be32 err;
1630 int host_err;
1631
1632 err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_CREATE);
1633 if (err)
1634 goto out;
1635 err = fh_verify(rqstp, tfhp, -S_IFDIR, NFSD_MAY_NOP);
1636 if (err)
1637 goto out;
1638
1639 err = nfserr_perm;
1640 if (!len)
1641 goto out;
1642 err = nfserr_exist;
1643 if (isdotent(name, len))
1644 goto out;
1645
1646 fh_lock_nested(ffhp, I_MUTEX_PARENT);
1647 ddir = ffhp->fh_dentry;
1648 dirp = ddir->d_inode;
1649
1650 dnew = lookup_one_len(name, ddir, len);
1651 host_err = PTR_ERR(dnew);
1652 if (IS_ERR(dnew))
1653 goto out_nfserr;
1654
1655 dold = tfhp->fh_dentry;
1656
1657 host_err = mnt_want_write(tfhp->fh_export->ex_path.mnt);
1658 if (host_err) {
1659 err = nfserrno(host_err);
1660 goto out_dput;
1661 }
1662 err = nfserr_noent;
1663 if (!dold->d_inode)
1664 goto out_drop_write;
1665 host_err = nfsd_break_lease(dold->d_inode);
1666 if (host_err) {
1667 err = nfserrno(host_err);
1668 goto out_drop_write;
1669 }
1670 host_err = vfs_link(dold, dirp, dnew);
1671 if (!host_err) {
1672 err = nfserrno(commit_metadata(ffhp));
1673 if (!err)
1674 err = nfserrno(commit_metadata(tfhp));
1675 } else {
1676 if (host_err == -EXDEV && rqstp->rq_vers == 2)
1677 err = nfserr_acces;
1678 else
1679 err = nfserrno(host_err);
1680 }
1681out_drop_write:
1682 mnt_drop_write(tfhp->fh_export->ex_path.mnt);
1683out_dput:
1684 dput(dnew);
1685out_unlock:
1686 fh_unlock(ffhp);
1687out:
1688 return err;
1689
1690out_nfserr:
1691 err = nfserrno(host_err);
1692 goto out_unlock;
1693}
1694
1695/*
1696 * Rename a file
1697 * N.B. After this call _both_ ffhp and tfhp need an fh_put
1698 */
1699__be32
1700nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
1701 struct svc_fh *tfhp, char *tname, int tlen)
1702{
1703 struct dentry *fdentry, *tdentry, *odentry, *ndentry, *trap;
1704 struct inode *fdir, *tdir;
1705 __be32 err;
1706 int host_err;
1707
1708 err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_REMOVE);
1709 if (err)
1710 goto out;
1711 err = fh_verify(rqstp, tfhp, S_IFDIR, NFSD_MAY_CREATE);
1712 if (err)
1713 goto out;
1714
1715 fdentry = ffhp->fh_dentry;
1716 fdir = fdentry->d_inode;
1717
1718 tdentry = tfhp->fh_dentry;
1719 tdir = tdentry->d_inode;
1720
1721 err = (rqstp->rq_vers == 2) ? nfserr_acces : nfserr_xdev;
1722 if (ffhp->fh_export != tfhp->fh_export)
1723 goto out;
1724
1725 err = nfserr_perm;
1726 if (!flen || isdotent(fname, flen) || !tlen || isdotent(tname, tlen))
1727 goto out;
1728
1729 /* cannot use fh_lock as we need deadlock protective ordering
1730 * so do it by hand */
1731 trap = lock_rename(tdentry, fdentry);
1732 ffhp->fh_locked = tfhp->fh_locked = 1;
1733 fill_pre_wcc(ffhp);
1734 fill_pre_wcc(tfhp);
1735
1736 odentry = lookup_one_len(fname, fdentry, flen);
1737 host_err = PTR_ERR(odentry);
1738 if (IS_ERR(odentry))
1739 goto out_nfserr;
1740
1741 host_err = -ENOENT;
1742 if (!odentry->d_inode)
1743 goto out_dput_old;
1744 host_err = -EINVAL;
1745 if (odentry == trap)
1746 goto out_dput_old;
1747
1748 ndentry = lookup_one_len(tname, tdentry, tlen);
1749 host_err = PTR_ERR(ndentry);
1750 if (IS_ERR(ndentry))
1751 goto out_dput_old;
1752 host_err = -ENOTEMPTY;
1753 if (ndentry == trap)
1754 goto out_dput_new;
1755
1756 host_err = -EXDEV;
1757 if (ffhp->fh_export->ex_path.mnt != tfhp->fh_export->ex_path.mnt)
1758 goto out_dput_new;
1759 host_err = mnt_want_write(ffhp->fh_export->ex_path.mnt);
1760 if (host_err)
1761 goto out_dput_new;
1762
1763 host_err = nfsd_break_lease(odentry->d_inode);
1764 if (host_err)
1765 goto out_drop_write;
1766 if (ndentry->d_inode) {
1767 host_err = nfsd_break_lease(ndentry->d_inode);
1768 if (host_err)
1769 goto out_drop_write;
1770 }
1771 host_err = vfs_rename(fdir, odentry, tdir, ndentry);
1772 if (!host_err) {
1773 host_err = commit_metadata(tfhp);
1774 if (!host_err)
1775 host_err = commit_metadata(ffhp);
1776 }
1777out_drop_write:
1778 mnt_drop_write(ffhp->fh_export->ex_path.mnt);
1779 out_dput_new:
1780 dput(ndentry);
1781 out_dput_old:
1782 dput(odentry);
1783 out_nfserr:
1784 err = nfserrno(host_err);
1785
1786 /* we cannot reply on fh_unlock on the two filehandles,
1787 * as that would do the wrong thing if the two directories
1788 * were the same, so again we do it by hand
1789 */
1790 fill_post_wcc(ffhp);
1791 fill_post_wcc(tfhp);
1792 unlock_rename(tdentry, fdentry);
1793 ffhp->fh_locked = tfhp->fh_locked = 0;
1794
1795out:
1796 return err;
1797}
1798
1799/*
1800 * Unlink a file or directory
1801 * N.B. After this call fhp needs an fh_put
1802 */
1803__be32
1804nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
1805 char *fname, int flen)
1806{
1807 struct dentry *dentry, *rdentry;
1808 struct inode *dirp;
1809 __be32 err;
1810 int host_err;
1811
1812 err = nfserr_acces;
1813 if (!flen || isdotent(fname, flen))
1814 goto out;
1815 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_REMOVE);
1816 if (err)
1817 goto out;
1818
1819 fh_lock_nested(fhp, I_MUTEX_PARENT);
1820 dentry = fhp->fh_dentry;
1821 dirp = dentry->d_inode;
1822
1823 rdentry = lookup_one_len(fname, dentry, flen);
1824 host_err = PTR_ERR(rdentry);
1825 if (IS_ERR(rdentry))
1826 goto out_nfserr;
1827
1828 if (!rdentry->d_inode) {
1829 dput(rdentry);
1830 err = nfserr_noent;
1831 goto out;
1832 }
1833
1834 if (!type)
1835 type = rdentry->d_inode->i_mode & S_IFMT;
1836
1837 host_err = mnt_want_write(fhp->fh_export->ex_path.mnt);
1838 if (host_err)
1839 goto out_put;
1840
1841 host_err = nfsd_break_lease(rdentry->d_inode);
1842 if (host_err)
1843 goto out_drop_write;
1844 if (type != S_IFDIR)
1845 host_err = vfs_unlink(dirp, rdentry);
1846 else
1847 host_err = vfs_rmdir(dirp, rdentry);
1848 if (!host_err)
1849 host_err = commit_metadata(fhp);
1850out_drop_write:
1851 mnt_drop_write(fhp->fh_export->ex_path.mnt);
1852out_put:
1853 dput(rdentry);
1854
1855out_nfserr:
1856 err = nfserrno(host_err);
1857out:
1858 return err;
1859}
1860
1861/*
1862 * We do this buffering because we must not call back into the file
1863 * system's ->lookup() method from the filldir callback. That may well
1864 * deadlock a number of file systems.
1865 *
1866 * This is based heavily on the implementation of same in XFS.
1867 */
1868struct buffered_dirent {
1869 u64 ino;
1870 loff_t offset;
1871 int namlen;
1872 unsigned int d_type;
1873 char name[];
1874};
1875
1876struct readdir_data {
1877 char *dirent;
1878 size_t used;
1879 int full;
1880};
1881
1882static int nfsd_buffered_filldir(void *__buf, const char *name, int namlen,
1883 loff_t offset, u64 ino, unsigned int d_type)
1884{
1885 struct readdir_data *buf = __buf;
1886 struct buffered_dirent *de = (void *)(buf->dirent + buf->used);
1887 unsigned int reclen;
1888
1889 reclen = ALIGN(sizeof(struct buffered_dirent) + namlen, sizeof(u64));
1890 if (buf->used + reclen > PAGE_SIZE) {
1891 buf->full = 1;
1892 return -EINVAL;
1893 }
1894
1895 de->namlen = namlen;
1896 de->offset = offset;
1897 de->ino = ino;
1898 de->d_type = d_type;
1899 memcpy(de->name, name, namlen);
1900 buf->used += reclen;
1901
1902 return 0;
1903}
1904
1905static __be32 nfsd_buffered_readdir(struct file *file, filldir_t func,
1906 struct readdir_cd *cdp, loff_t *offsetp)
1907{
1908 struct readdir_data buf;
1909 struct buffered_dirent *de;
1910 int host_err;
1911 int size;
1912 loff_t offset;
1913
1914 buf.dirent = (void *)__get_free_page(GFP_KERNEL);
1915 if (!buf.dirent)
1916 return nfserrno(-ENOMEM);
1917
1918 offset = *offsetp;
1919
1920 while (1) {
1921 struct inode *dir_inode = file->f_path.dentry->d_inode;
1922 unsigned int reclen;
1923
1924 cdp->err = nfserr_eof; /* will be cleared on successful read */
1925 buf.used = 0;
1926 buf.full = 0;
1927
1928 host_err = vfs_readdir(file, nfsd_buffered_filldir, &buf);
1929 if (buf.full)
1930 host_err = 0;
1931
1932 if (host_err < 0)
1933 break;
1934
1935 size = buf.used;
1936
1937 if (!size)
1938 break;
1939
1940 /*
1941 * Various filldir functions may end up calling back into
1942 * lookup_one_len() and the file system's ->lookup() method.
1943 * These expect i_mutex to be held, as it would within readdir.
1944 */
1945 host_err = mutex_lock_killable(&dir_inode->i_mutex);
1946 if (host_err)
1947 break;
1948
1949 de = (struct buffered_dirent *)buf.dirent;
1950 while (size > 0) {
1951 offset = de->offset;
1952
1953 if (func(cdp, de->name, de->namlen, de->offset,
1954 de->ino, de->d_type))
1955 break;
1956
1957 if (cdp->err != nfs_ok)
1958 break;
1959
1960 reclen = ALIGN(sizeof(*de) + de->namlen,
1961 sizeof(u64));
1962 size -= reclen;
1963 de = (struct buffered_dirent *)((char *)de + reclen);
1964 }
1965 mutex_unlock(&dir_inode->i_mutex);
1966 if (size > 0) /* We bailed out early */
1967 break;
1968
1969 offset = vfs_llseek(file, 0, SEEK_CUR);
1970 }
1971
1972 free_page((unsigned long)(buf.dirent));
1973
1974 if (host_err)
1975 return nfserrno(host_err);
1976
1977 *offsetp = offset;
1978 return cdp->err;
1979}
1980
1981/*
1982 * Read entries from a directory.
1983 * The NFSv3/4 verifier we ignore for now.
1984 */
1985__be32
1986nfsd_readdir(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t *offsetp,
1987 struct readdir_cd *cdp, filldir_t func)
1988{
1989 __be32 err;
1990 struct file *file;
1991 loff_t offset = *offsetp;
1992
1993 err = nfsd_open(rqstp, fhp, S_IFDIR, NFSD_MAY_READ, &file);
1994 if (err)
1995 goto out;
1996
1997 offset = vfs_llseek(file, offset, 0);
1998 if (offset < 0) {
1999 err = nfserrno((int)offset);
2000 goto out_close;
2001 }
2002
2003 err = nfsd_buffered_readdir(file, func, cdp, offsetp);
2004
2005 if (err == nfserr_eof || err == nfserr_toosmall)
2006 err = nfs_ok; /* can still be found in ->err */
2007out_close:
2008 nfsd_close(file);
2009out:
2010 return err;
2011}
2012
2013/*
2014 * Get file system stats
2015 * N.B. After this call fhp needs an fh_put
2016 */
2017__be32
2018nfsd_statfs(struct svc_rqst *rqstp, struct svc_fh *fhp, struct kstatfs *stat, int access)
2019{
2020 __be32 err;
2021
2022 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP | access);
2023 if (!err) {
2024 struct path path = {
2025 .mnt = fhp->fh_export->ex_path.mnt,
2026 .dentry = fhp->fh_dentry,
2027 };
2028 if (vfs_statfs(&path, stat))
2029 err = nfserr_io;
2030 }
2031 return err;
2032}
2033
2034static int exp_rdonly(struct svc_rqst *rqstp, struct svc_export *exp)
2035{
2036 return nfsexp_flags(rqstp, exp) & NFSEXP_READONLY;
2037}
2038
2039/*
2040 * Check for a user's access permissions to this inode.
2041 */
2042__be32
2043nfsd_permission(struct svc_rqst *rqstp, struct svc_export *exp,
2044 struct dentry *dentry, int acc)
2045{
2046 struct inode *inode = dentry->d_inode;
2047 int err;
2048
2049 if ((acc & NFSD_MAY_MASK) == NFSD_MAY_NOP)
2050 return 0;
2051#if 0
2052 dprintk("nfsd: permission 0x%x%s%s%s%s%s%s%s mode 0%o%s%s%s\n",
2053 acc,
2054 (acc & NFSD_MAY_READ)? " read" : "",
2055 (acc & NFSD_MAY_WRITE)? " write" : "",
2056 (acc & NFSD_MAY_EXEC)? " exec" : "",
2057 (acc & NFSD_MAY_SATTR)? " sattr" : "",
2058 (acc & NFSD_MAY_TRUNC)? " trunc" : "",
2059 (acc & NFSD_MAY_LOCK)? " lock" : "",
2060 (acc & NFSD_MAY_OWNER_OVERRIDE)? " owneroverride" : "",
2061 inode->i_mode,
2062 IS_IMMUTABLE(inode)? " immut" : "",
2063 IS_APPEND(inode)? " append" : "",
2064 __mnt_is_readonly(exp->ex_path.mnt)? " ro" : "");
2065 dprintk(" owner %d/%d user %d/%d\n",
2066 inode->i_uid, inode->i_gid, current_fsuid(), current_fsgid());
2067#endif
2068
2069 /* Normally we reject any write/sattr etc access on a read-only file
2070 * system. But if it is IRIX doing check on write-access for a
2071 * device special file, we ignore rofs.
2072 */
2073 if (!(acc & NFSD_MAY_LOCAL_ACCESS))
2074 if (acc & (NFSD_MAY_WRITE | NFSD_MAY_SATTR | NFSD_MAY_TRUNC)) {
2075 if (exp_rdonly(rqstp, exp) ||
2076 __mnt_is_readonly(exp->ex_path.mnt))
2077 return nfserr_rofs;
2078 if (/* (acc & NFSD_MAY_WRITE) && */ IS_IMMUTABLE(inode))
2079 return nfserr_perm;
2080 }
2081 if ((acc & NFSD_MAY_TRUNC) && IS_APPEND(inode))
2082 return nfserr_perm;
2083
2084 if (acc & NFSD_MAY_LOCK) {
2085 /* If we cannot rely on authentication in NLM requests,
2086 * just allow locks, otherwise require read permission, or
2087 * ownership
2088 */
2089 if (exp->ex_flags & NFSEXP_NOAUTHNLM)
2090 return 0;
2091 else
2092 acc = NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE;
2093 }
2094 /*
2095 * The file owner always gets access permission for accesses that
2096 * would normally be checked at open time. This is to make
2097 * file access work even when the client has done a fchmod(fd, 0).
2098 *
2099 * However, `cp foo bar' should fail nevertheless when bar is
2100 * readonly. A sensible way to do this might be to reject all
2101 * attempts to truncate a read-only file, because a creat() call
2102 * always implies file truncation.
2103 * ... but this isn't really fair. A process may reasonably call
2104 * ftruncate on an open file descriptor on a file with perm 000.
2105 * We must trust the client to do permission checking - using "ACCESS"
2106 * with NFSv3.
2107 */
2108 if ((acc & NFSD_MAY_OWNER_OVERRIDE) &&
2109 inode->i_uid == current_fsuid())
2110 return 0;
2111
2112 /* This assumes NFSD_MAY_{READ,WRITE,EXEC} == MAY_{READ,WRITE,EXEC} */
2113 err = inode_permission(inode, acc & (MAY_READ|MAY_WRITE|MAY_EXEC));
2114
2115 /* Allow read access to binaries even when mode 111 */
2116 if (err == -EACCES && S_ISREG(inode->i_mode) &&
2117 acc == (NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE))
2118 err = inode_permission(inode, MAY_EXEC);
2119
2120 return err? nfserrno(err) : 0;
2121}
2122
2123void
2124nfsd_racache_shutdown(void)
2125{
2126 struct raparms *raparm, *last_raparm;
2127 unsigned int i;
2128
2129 dprintk("nfsd: freeing readahead buffers.\n");
2130
2131 for (i = 0; i < RAPARM_HASH_SIZE; i++) {
2132 raparm = raparm_hash[i].pb_head;
2133 while(raparm) {
2134 last_raparm = raparm;
2135 raparm = raparm->p_next;
2136 kfree(last_raparm);
2137 }
2138 raparm_hash[i].pb_head = NULL;
2139 }
2140}
2141/*
2142 * Initialize readahead param cache
2143 */
2144int
2145nfsd_racache_init(int cache_size)
2146{
2147 int i;
2148 int j = 0;
2149 int nperbucket;
2150 struct raparms **raparm = NULL;
2151
2152
2153 if (raparm_hash[0].pb_head)
2154 return 0;
2155 nperbucket = DIV_ROUND_UP(cache_size, RAPARM_HASH_SIZE);
2156 if (nperbucket < 2)
2157 nperbucket = 2;
2158 cache_size = nperbucket * RAPARM_HASH_SIZE;
2159
2160 dprintk("nfsd: allocating %d readahead buffers.\n", cache_size);
2161
2162 for (i = 0; i < RAPARM_HASH_SIZE; i++) {
2163 spin_lock_init(&raparm_hash[i].pb_lock);
2164
2165 raparm = &raparm_hash[i].pb_head;
2166 for (j = 0; j < nperbucket; j++) {
2167 *raparm = kzalloc(sizeof(struct raparms), GFP_KERNEL);
2168 if (!*raparm)
2169 goto out_nomem;
2170 raparm = &(*raparm)->p_next;
2171 }
2172 *raparm = NULL;
2173 }
2174
2175 nfsdstats.ra_size = cache_size;
2176 return 0;
2177
2178out_nomem:
2179 dprintk("nfsd: kmalloc failed, freeing readahead buffers\n");
2180 nfsd_racache_shutdown();
2181 return -ENOMEM;
2182}
2183
2184#if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
2185struct posix_acl *
2186nfsd_get_posix_acl(struct svc_fh *fhp, int type)
2187{
2188 struct inode *inode = fhp->fh_dentry->d_inode;
2189 char *name;
2190 void *value = NULL;
2191 ssize_t size;
2192 struct posix_acl *acl;
2193
2194 if (!IS_POSIXACL(inode))
2195 return ERR_PTR(-EOPNOTSUPP);
2196
2197 switch (type) {
2198 case ACL_TYPE_ACCESS:
2199 name = POSIX_ACL_XATTR_ACCESS;
2200 break;
2201 case ACL_TYPE_DEFAULT:
2202 name = POSIX_ACL_XATTR_DEFAULT;
2203 break;
2204 default:
2205 return ERR_PTR(-EOPNOTSUPP);
2206 }
2207
2208 size = nfsd_getxattr(fhp->fh_dentry, name, &value);
2209 if (size < 0)
2210 return ERR_PTR(size);
2211
2212 acl = posix_acl_from_xattr(value, size);
2213 kfree(value);
2214 return acl;
2215}
2216
2217int
2218nfsd_set_posix_acl(struct svc_fh *fhp, int type, struct posix_acl *acl)
2219{
2220 struct inode *inode = fhp->fh_dentry->d_inode;
2221 char *name;
2222 void *value = NULL;
2223 size_t size;
2224 int error;
2225
2226 if (!IS_POSIXACL(inode) ||
2227 !inode->i_op->setxattr || !inode->i_op->removexattr)
2228 return -EOPNOTSUPP;
2229 switch(type) {
2230 case ACL_TYPE_ACCESS:
2231 name = POSIX_ACL_XATTR_ACCESS;
2232 break;
2233 case ACL_TYPE_DEFAULT:
2234 name = POSIX_ACL_XATTR_DEFAULT;
2235 break;
2236 default:
2237 return -EOPNOTSUPP;
2238 }
2239
2240 if (acl && acl->a_count) {
2241 size = posix_acl_xattr_size(acl->a_count);
2242 value = kmalloc(size, GFP_KERNEL);
2243 if (!value)
2244 return -ENOMEM;
2245 error = posix_acl_to_xattr(acl, value, size);
2246 if (error < 0)
2247 goto getout;
2248 size = error;
2249 } else
2250 size = 0;
2251
2252 error = mnt_want_write(fhp->fh_export->ex_path.mnt);
2253 if (error)
2254 goto getout;
2255 if (size)
2256 error = vfs_setxattr(fhp->fh_dentry, name, value, size, 0);
2257 else {
2258 if (!S_ISDIR(inode->i_mode) && type == ACL_TYPE_DEFAULT)
2259 error = 0;
2260 else {
2261 error = vfs_removexattr(fhp->fh_dentry, name);
2262 if (error == -ENODATA)
2263 error = 0;
2264 }
2265 }
2266 mnt_drop_write(fhp->fh_export->ex_path.mnt);
2267
2268getout:
2269 kfree(value);
2270 return error;
2271}
2272#endif /* defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) */
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * File operations used by nfsd. Some of these have been ripped from
4 * other parts of the kernel because they weren't exported, others
5 * are partial duplicates with added or changed functionality.
6 *
7 * Note that several functions dget() the dentry upon which they want
8 * to act, most notably those that create directory entries. Response
9 * dentry's are dput()'d if necessary in the release callback.
10 * So if you notice code paths that apparently fail to dput() the
11 * dentry, don't worry--they have been taken care of.
12 *
13 * Copyright (C) 1995-1999 Olaf Kirch <okir@monad.swb.de>
14 * Zerocpy NFS support (C) 2002 Hirokazu Takahashi <taka@valinux.co.jp>
15 */
16
17#include <linux/fs.h>
18#include <linux/file.h>
19#include <linux/splice.h>
20#include <linux/falloc.h>
21#include <linux/fcntl.h>
22#include <linux/namei.h>
23#include <linux/delay.h>
24#include <linux/fsnotify.h>
25#include <linux/posix_acl_xattr.h>
26#include <linux/xattr.h>
27#include <linux/jhash.h>
28#include <linux/ima.h>
29#include <linux/pagemap.h>
30#include <linux/slab.h>
31#include <linux/uaccess.h>
32#include <linux/exportfs.h>
33#include <linux/writeback.h>
34#include <linux/security.h>
35
36#include "xdr3.h"
37
38#ifdef CONFIG_NFSD_V4
39#include "../internal.h"
40#include "acl.h"
41#include "idmap.h"
42#include "xdr4.h"
43#endif /* CONFIG_NFSD_V4 */
44
45#include "nfsd.h"
46#include "vfs.h"
47#include "filecache.h"
48#include "trace.h"
49
50#define NFSDDBG_FACILITY NFSDDBG_FILEOP
51
52/**
53 * nfserrno - Map Linux errnos to NFS errnos
54 * @errno: POSIX(-ish) error code to be mapped
55 *
56 * Returns the appropriate (net-endian) nfserr_* (or nfs_ok if errno is 0). If
57 * it's an error we don't expect, log it once and return nfserr_io.
58 */
59__be32
60nfserrno (int errno)
61{
62 static struct {
63 __be32 nfserr;
64 int syserr;
65 } nfs_errtbl[] = {
66 { nfs_ok, 0 },
67 { nfserr_perm, -EPERM },
68 { nfserr_noent, -ENOENT },
69 { nfserr_io, -EIO },
70 { nfserr_nxio, -ENXIO },
71 { nfserr_fbig, -E2BIG },
72 { nfserr_stale, -EBADF },
73 { nfserr_acces, -EACCES },
74 { nfserr_exist, -EEXIST },
75 { nfserr_xdev, -EXDEV },
76 { nfserr_mlink, -EMLINK },
77 { nfserr_nodev, -ENODEV },
78 { nfserr_notdir, -ENOTDIR },
79 { nfserr_isdir, -EISDIR },
80 { nfserr_inval, -EINVAL },
81 { nfserr_fbig, -EFBIG },
82 { nfserr_nospc, -ENOSPC },
83 { nfserr_rofs, -EROFS },
84 { nfserr_mlink, -EMLINK },
85 { nfserr_nametoolong, -ENAMETOOLONG },
86 { nfserr_notempty, -ENOTEMPTY },
87 { nfserr_dquot, -EDQUOT },
88 { nfserr_stale, -ESTALE },
89 { nfserr_jukebox, -ETIMEDOUT },
90 { nfserr_jukebox, -ERESTARTSYS },
91 { nfserr_jukebox, -EAGAIN },
92 { nfserr_jukebox, -EWOULDBLOCK },
93 { nfserr_jukebox, -ENOMEM },
94 { nfserr_io, -ETXTBSY },
95 { nfserr_notsupp, -EOPNOTSUPP },
96 { nfserr_toosmall, -ETOOSMALL },
97 { nfserr_serverfault, -ESERVERFAULT },
98 { nfserr_serverfault, -ENFILE },
99 { nfserr_io, -EREMOTEIO },
100 { nfserr_stale, -EOPENSTALE },
101 { nfserr_io, -EUCLEAN },
102 { nfserr_perm, -ENOKEY },
103 { nfserr_no_grace, -ENOGRACE},
104 };
105 int i;
106
107 for (i = 0; i < ARRAY_SIZE(nfs_errtbl); i++) {
108 if (nfs_errtbl[i].syserr == errno)
109 return nfs_errtbl[i].nfserr;
110 }
111 WARN_ONCE(1, "nfsd: non-standard errno: %d\n", errno);
112 return nfserr_io;
113}
114
115/*
116 * Called from nfsd_lookup and encode_dirent. Check if we have crossed
117 * a mount point.
118 * Returns -EAGAIN or -ETIMEDOUT leaving *dpp and *expp unchanged,
119 * or nfs_ok having possibly changed *dpp and *expp
120 */
121int
122nfsd_cross_mnt(struct svc_rqst *rqstp, struct dentry **dpp,
123 struct svc_export **expp)
124{
125 struct svc_export *exp = *expp, *exp2 = NULL;
126 struct dentry *dentry = *dpp;
127 struct path path = {.mnt = mntget(exp->ex_path.mnt),
128 .dentry = dget(dentry)};
129 unsigned int follow_flags = 0;
130 int err = 0;
131
132 if (exp->ex_flags & NFSEXP_CROSSMOUNT)
133 follow_flags = LOOKUP_AUTOMOUNT;
134
135 err = follow_down(&path, follow_flags);
136 if (err < 0)
137 goto out;
138 if (path.mnt == exp->ex_path.mnt && path.dentry == dentry &&
139 nfsd_mountpoint(dentry, exp) == 2) {
140 /* This is only a mountpoint in some other namespace */
141 path_put(&path);
142 goto out;
143 }
144
145 exp2 = rqst_exp_get_by_name(rqstp, &path);
146 if (IS_ERR(exp2)) {
147 err = PTR_ERR(exp2);
148 /*
149 * We normally allow NFS clients to continue
150 * "underneath" a mountpoint that is not exported.
151 * The exception is V4ROOT, where no traversal is ever
152 * allowed without an explicit export of the new
153 * directory.
154 */
155 if (err == -ENOENT && !(exp->ex_flags & NFSEXP_V4ROOT))
156 err = 0;
157 path_put(&path);
158 goto out;
159 }
160 if (nfsd_v4client(rqstp) ||
161 (exp->ex_flags & NFSEXP_CROSSMOUNT) || EX_NOHIDE(exp2)) {
162 /* successfully crossed mount point */
163 /*
164 * This is subtle: path.dentry is *not* on path.mnt
165 * at this point. The only reason we are safe is that
166 * original mnt is pinned down by exp, so we should
167 * put path *before* putting exp
168 */
169 *dpp = path.dentry;
170 path.dentry = dentry;
171 *expp = exp2;
172 exp2 = exp;
173 }
174 path_put(&path);
175 exp_put(exp2);
176out:
177 return err;
178}
179
180static void follow_to_parent(struct path *path)
181{
182 struct dentry *dp;
183
184 while (path->dentry == path->mnt->mnt_root && follow_up(path))
185 ;
186 dp = dget_parent(path->dentry);
187 dput(path->dentry);
188 path->dentry = dp;
189}
190
191static int nfsd_lookup_parent(struct svc_rqst *rqstp, struct dentry *dparent, struct svc_export **exp, struct dentry **dentryp)
192{
193 struct svc_export *exp2;
194 struct path path = {.mnt = mntget((*exp)->ex_path.mnt),
195 .dentry = dget(dparent)};
196
197 follow_to_parent(&path);
198
199 exp2 = rqst_exp_parent(rqstp, &path);
200 if (PTR_ERR(exp2) == -ENOENT) {
201 *dentryp = dget(dparent);
202 } else if (IS_ERR(exp2)) {
203 path_put(&path);
204 return PTR_ERR(exp2);
205 } else {
206 *dentryp = dget(path.dentry);
207 exp_put(*exp);
208 *exp = exp2;
209 }
210 path_put(&path);
211 return 0;
212}
213
214/*
215 * For nfsd purposes, we treat V4ROOT exports as though there was an
216 * export at *every* directory.
217 * We return:
218 * '1' if this dentry *must* be an export point,
219 * '2' if it might be, if there is really a mount here, and
220 * '0' if there is no chance of an export point here.
221 */
222int nfsd_mountpoint(struct dentry *dentry, struct svc_export *exp)
223{
224 if (!d_inode(dentry))
225 return 0;
226 if (exp->ex_flags & NFSEXP_V4ROOT)
227 return 1;
228 if (nfsd4_is_junction(dentry))
229 return 1;
230 if (d_managed(dentry))
231 /*
232 * Might only be a mountpoint in a different namespace,
233 * but we need to check.
234 */
235 return 2;
236 return 0;
237}
238
239__be32
240nfsd_lookup_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp,
241 const char *name, unsigned int len,
242 struct svc_export **exp_ret, struct dentry **dentry_ret)
243{
244 struct svc_export *exp;
245 struct dentry *dparent;
246 struct dentry *dentry;
247 int host_err;
248
249 dprintk("nfsd: nfsd_lookup(fh %s, %.*s)\n", SVCFH_fmt(fhp), len,name);
250
251 dparent = fhp->fh_dentry;
252 exp = exp_get(fhp->fh_export);
253
254 /* Lookup the name, but don't follow links */
255 if (isdotent(name, len)) {
256 if (len==1)
257 dentry = dget(dparent);
258 else if (dparent != exp->ex_path.dentry)
259 dentry = dget_parent(dparent);
260 else if (!EX_NOHIDE(exp) && !nfsd_v4client(rqstp))
261 dentry = dget(dparent); /* .. == . just like at / */
262 else {
263 /* checking mountpoint crossing is very different when stepping up */
264 host_err = nfsd_lookup_parent(rqstp, dparent, &exp, &dentry);
265 if (host_err)
266 goto out_nfserr;
267 }
268 } else {
269 dentry = lookup_one_len_unlocked(name, dparent, len);
270 host_err = PTR_ERR(dentry);
271 if (IS_ERR(dentry))
272 goto out_nfserr;
273 if (nfsd_mountpoint(dentry, exp)) {
274 host_err = nfsd_cross_mnt(rqstp, &dentry, &exp);
275 if (host_err) {
276 dput(dentry);
277 goto out_nfserr;
278 }
279 }
280 }
281 *dentry_ret = dentry;
282 *exp_ret = exp;
283 return 0;
284
285out_nfserr:
286 exp_put(exp);
287 return nfserrno(host_err);
288}
289
290/**
291 * nfsd_lookup - look up a single path component for nfsd
292 *
293 * @rqstp: the request context
294 * @fhp: the file handle of the directory
295 * @name: the component name, or %NULL to look up parent
296 * @len: length of name to examine
297 * @resfh: pointer to pre-initialised filehandle to hold result.
298 *
299 * Look up one component of a pathname.
300 * N.B. After this call _both_ fhp and resfh need an fh_put
301 *
302 * If the lookup would cross a mountpoint, and the mounted filesystem
303 * is exported to the client with NFSEXP_NOHIDE, then the lookup is
304 * accepted as it stands and the mounted directory is
305 * returned. Otherwise the covered directory is returned.
306 * NOTE: this mountpoint crossing is not supported properly by all
307 * clients and is explicitly disallowed for NFSv3
308 *
309 */
310__be32
311nfsd_lookup(struct svc_rqst *rqstp, struct svc_fh *fhp, const char *name,
312 unsigned int len, struct svc_fh *resfh)
313{
314 struct svc_export *exp;
315 struct dentry *dentry;
316 __be32 err;
317
318 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC);
319 if (err)
320 return err;
321 err = nfsd_lookup_dentry(rqstp, fhp, name, len, &exp, &dentry);
322 if (err)
323 return err;
324 err = check_nfsd_access(exp, rqstp);
325 if (err)
326 goto out;
327 /*
328 * Note: we compose the file handle now, but as the
329 * dentry may be negative, it may need to be updated.
330 */
331 err = fh_compose(resfh, exp, dentry, fhp);
332 if (!err && d_really_is_negative(dentry))
333 err = nfserr_noent;
334out:
335 dput(dentry);
336 exp_put(exp);
337 return err;
338}
339
340static void
341commit_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 */
361static int
362commit_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
371static int
372commit_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 */
385static void
386nfsd_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
416static __be32
417nfsd_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
433static 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 * @check_guard: set to 1 if guardtime is a valid timestamp
480 * @guardtime: do not act if ctime.tv_sec does not match this timestamp
481 *
482 * This call may adjust the contents of @attr (in particular, this
483 * call may change the bits in the na_iattr.ia_valid field).
484 *
485 * Returns nfs_ok on success, otherwise an NFS status code is
486 * returned. Caller must release @fhp by calling fh_put in either
487 * case.
488 */
489__be32
490nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp,
491 struct nfsd_attrs *attr,
492 int check_guard, time64_t guardtime)
493{
494 struct dentry *dentry;
495 struct inode *inode;
496 struct iattr *iap = attr->na_iattr;
497 int accmode = NFSD_MAY_SATTR;
498 umode_t ftype = 0;
499 __be32 err;
500 int host_err;
501 bool get_write_count;
502 bool size_change = (iap->ia_valid & ATTR_SIZE);
503 int retries;
504
505 if (iap->ia_valid & ATTR_SIZE) {
506 accmode |= NFSD_MAY_WRITE|NFSD_MAY_OWNER_OVERRIDE;
507 ftype = S_IFREG;
508 }
509
510 /*
511 * If utimes(2) and friends are called with times not NULL, we should
512 * not set NFSD_MAY_WRITE bit. Otherwise fh_verify->nfsd_permission
513 * will return EACCES, when the caller's effective UID does not match
514 * the owner of the file, and the caller is not privileged. In this
515 * situation, we should return EPERM(notify_change will return this).
516 */
517 if (iap->ia_valid & (ATTR_ATIME | ATTR_MTIME)) {
518 accmode |= NFSD_MAY_OWNER_OVERRIDE;
519 if (!(iap->ia_valid & (ATTR_ATIME_SET | ATTR_MTIME_SET)))
520 accmode |= NFSD_MAY_WRITE;
521 }
522
523 /* Callers that do fh_verify should do the fh_want_write: */
524 get_write_count = !fhp->fh_dentry;
525
526 /* Get inode */
527 err = fh_verify(rqstp, fhp, ftype, accmode);
528 if (err)
529 return err;
530 if (get_write_count) {
531 host_err = fh_want_write(fhp);
532 if (host_err)
533 goto out;
534 }
535
536 dentry = fhp->fh_dentry;
537 inode = d_inode(dentry);
538
539 nfsd_sanitize_attrs(inode, iap);
540
541 if (check_guard && guardtime != inode_get_ctime_sec(inode))
542 return nfserr_notsync;
543
544 /*
545 * The size case is special, it changes the file in addition to the
546 * attributes, and file systems don't expect it to be mixed with
547 * "random" attribute changes. We thus split out the size change
548 * into a separate call to ->setattr, and do the rest as a separate
549 * setattr call.
550 */
551 if (size_change) {
552 err = nfsd_get_write_access(rqstp, fhp, iap);
553 if (err)
554 return err;
555 }
556
557 inode_lock(inode);
558 for (retries = 1;;) {
559 struct iattr attrs;
560
561 /*
562 * notify_change() can alter its iattr argument, making
563 * @iap unsuitable for submission multiple times. Make a
564 * copy for every loop iteration.
565 */
566 attrs = *iap;
567 host_err = __nfsd_setattr(dentry, &attrs);
568 if (host_err != -EAGAIN || !retries--)
569 break;
570 if (!nfsd_wait_for_delegreturn(rqstp, inode))
571 break;
572 }
573 if (attr->na_seclabel && attr->na_seclabel->len)
574 attr->na_labelerr = security_inode_setsecctx(dentry,
575 attr->na_seclabel->data, attr->na_seclabel->len);
576 if (IS_ENABLED(CONFIG_FS_POSIX_ACL) && attr->na_pacl)
577 attr->na_aclerr = set_posix_acl(&nop_mnt_idmap,
578 dentry, ACL_TYPE_ACCESS,
579 attr->na_pacl);
580 if (IS_ENABLED(CONFIG_FS_POSIX_ACL) &&
581 !attr->na_aclerr && attr->na_dpacl && S_ISDIR(inode->i_mode))
582 attr->na_aclerr = set_posix_acl(&nop_mnt_idmap,
583 dentry, ACL_TYPE_DEFAULT,
584 attr->na_dpacl);
585 inode_unlock(inode);
586 if (size_change)
587 put_write_access(inode);
588out:
589 if (!host_err)
590 host_err = commit_metadata(fhp);
591 return nfserrno(host_err);
592}
593
594#if defined(CONFIG_NFSD_V4)
595/*
596 * NFS junction information is stored in an extended attribute.
597 */
598#define NFSD_JUNCTION_XATTR_NAME XATTR_TRUSTED_PREFIX "junction.nfs"
599
600/**
601 * nfsd4_is_junction - Test if an object could be an NFS junction
602 *
603 * @dentry: object to test
604 *
605 * Returns 1 if "dentry" appears to contain NFS junction information.
606 * Otherwise 0 is returned.
607 */
608int nfsd4_is_junction(struct dentry *dentry)
609{
610 struct inode *inode = d_inode(dentry);
611
612 if (inode == NULL)
613 return 0;
614 if (inode->i_mode & S_IXUGO)
615 return 0;
616 if (!(inode->i_mode & S_ISVTX))
617 return 0;
618 if (vfs_getxattr(&nop_mnt_idmap, dentry, NFSD_JUNCTION_XATTR_NAME,
619 NULL, 0) <= 0)
620 return 0;
621 return 1;
622}
623
624static struct nfsd4_compound_state *nfsd4_get_cstate(struct svc_rqst *rqstp)
625{
626 return &((struct nfsd4_compoundres *)rqstp->rq_resp)->cstate;
627}
628
629__be32 nfsd4_clone_file_range(struct svc_rqst *rqstp,
630 struct nfsd_file *nf_src, u64 src_pos,
631 struct nfsd_file *nf_dst, u64 dst_pos,
632 u64 count, bool sync)
633{
634 struct file *src = nf_src->nf_file;
635 struct file *dst = nf_dst->nf_file;
636 errseq_t since;
637 loff_t cloned;
638 __be32 ret = 0;
639
640 since = READ_ONCE(dst->f_wb_err);
641 cloned = vfs_clone_file_range(src, src_pos, dst, dst_pos, count, 0);
642 if (cloned < 0) {
643 ret = nfserrno(cloned);
644 goto out_err;
645 }
646 if (count && cloned != count) {
647 ret = nfserrno(-EINVAL);
648 goto out_err;
649 }
650 if (sync) {
651 loff_t dst_end = count ? dst_pos + count - 1 : LLONG_MAX;
652 int status = vfs_fsync_range(dst, dst_pos, dst_end, 0);
653
654 if (!status)
655 status = filemap_check_wb_err(dst->f_mapping, since);
656 if (!status)
657 status = commit_inode_metadata(file_inode(src));
658 if (status < 0) {
659 struct nfsd_net *nn = net_generic(nf_dst->nf_net,
660 nfsd_net_id);
661
662 trace_nfsd_clone_file_range_err(rqstp,
663 &nfsd4_get_cstate(rqstp)->save_fh,
664 src_pos,
665 &nfsd4_get_cstate(rqstp)->current_fh,
666 dst_pos,
667 count, status);
668 commit_reset_write_verifier(nn, rqstp, status);
669 ret = nfserrno(status);
670 }
671 }
672out_err:
673 return ret;
674}
675
676ssize_t nfsd_copy_file_range(struct file *src, u64 src_pos, struct file *dst,
677 u64 dst_pos, u64 count)
678{
679 ssize_t ret;
680
681 /*
682 * Limit copy to 4MB to prevent indefinitely blocking an nfsd
683 * thread and client rpc slot. The choice of 4MB is somewhat
684 * arbitrary. We might instead base this on r/wsize, or make it
685 * tunable, or use a time instead of a byte limit, or implement
686 * asynchronous copy. In theory a client could also recognize a
687 * limit like this and pipeline multiple COPY requests.
688 */
689 count = min_t(u64, count, 1 << 22);
690 ret = vfs_copy_file_range(src, src_pos, dst, dst_pos, count, 0);
691
692 if (ret == -EOPNOTSUPP || ret == -EXDEV)
693 ret = vfs_copy_file_range(src, src_pos, dst, dst_pos, count,
694 COPY_FILE_SPLICE);
695 return ret;
696}
697
698__be32 nfsd4_vfs_fallocate(struct svc_rqst *rqstp, struct svc_fh *fhp,
699 struct file *file, loff_t offset, loff_t len,
700 int flags)
701{
702 int error;
703
704 if (!S_ISREG(file_inode(file)->i_mode))
705 return nfserr_inval;
706
707 error = vfs_fallocate(file, flags, offset, len);
708 if (!error)
709 error = commit_metadata(fhp);
710
711 return nfserrno(error);
712}
713#endif /* defined(CONFIG_NFSD_V4) */
714
715/*
716 * Check server access rights to a file system object
717 */
718struct accessmap {
719 u32 access;
720 int how;
721};
722static struct accessmap nfs3_regaccess[] = {
723 { NFS3_ACCESS_READ, NFSD_MAY_READ },
724 { NFS3_ACCESS_EXECUTE, NFSD_MAY_EXEC },
725 { NFS3_ACCESS_MODIFY, NFSD_MAY_WRITE|NFSD_MAY_TRUNC },
726 { NFS3_ACCESS_EXTEND, NFSD_MAY_WRITE },
727
728#ifdef CONFIG_NFSD_V4
729 { NFS4_ACCESS_XAREAD, NFSD_MAY_READ },
730 { NFS4_ACCESS_XAWRITE, NFSD_MAY_WRITE },
731 { NFS4_ACCESS_XALIST, NFSD_MAY_READ },
732#endif
733
734 { 0, 0 }
735};
736
737static struct accessmap nfs3_diraccess[] = {
738 { NFS3_ACCESS_READ, NFSD_MAY_READ },
739 { NFS3_ACCESS_LOOKUP, NFSD_MAY_EXEC },
740 { NFS3_ACCESS_MODIFY, NFSD_MAY_EXEC|NFSD_MAY_WRITE|NFSD_MAY_TRUNC},
741 { NFS3_ACCESS_EXTEND, NFSD_MAY_EXEC|NFSD_MAY_WRITE },
742 { NFS3_ACCESS_DELETE, NFSD_MAY_REMOVE },
743
744#ifdef CONFIG_NFSD_V4
745 { NFS4_ACCESS_XAREAD, NFSD_MAY_READ },
746 { NFS4_ACCESS_XAWRITE, NFSD_MAY_WRITE },
747 { NFS4_ACCESS_XALIST, NFSD_MAY_READ },
748#endif
749
750 { 0, 0 }
751};
752
753static struct accessmap nfs3_anyaccess[] = {
754 /* Some clients - Solaris 2.6 at least, make an access call
755 * to the server to check for access for things like /dev/null
756 * (which really, the server doesn't care about). So
757 * We provide simple access checking for them, looking
758 * mainly at mode bits, and we make sure to ignore read-only
759 * filesystem checks
760 */
761 { NFS3_ACCESS_READ, NFSD_MAY_READ },
762 { NFS3_ACCESS_EXECUTE, NFSD_MAY_EXEC },
763 { NFS3_ACCESS_MODIFY, NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS },
764 { NFS3_ACCESS_EXTEND, NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS },
765
766 { 0, 0 }
767};
768
769__be32
770nfsd_access(struct svc_rqst *rqstp, struct svc_fh *fhp, u32 *access, u32 *supported)
771{
772 struct accessmap *map;
773 struct svc_export *export;
774 struct dentry *dentry;
775 u32 query, result = 0, sresult = 0;
776 __be32 error;
777
778 error = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP);
779 if (error)
780 goto out;
781
782 export = fhp->fh_export;
783 dentry = fhp->fh_dentry;
784
785 if (d_is_reg(dentry))
786 map = nfs3_regaccess;
787 else if (d_is_dir(dentry))
788 map = nfs3_diraccess;
789 else
790 map = nfs3_anyaccess;
791
792
793 query = *access;
794 for (; map->access; map++) {
795 if (map->access & query) {
796 __be32 err2;
797
798 sresult |= map->access;
799
800 err2 = nfsd_permission(rqstp, export, dentry, map->how);
801 switch (err2) {
802 case nfs_ok:
803 result |= map->access;
804 break;
805
806 /* the following error codes just mean the access was not allowed,
807 * rather than an error occurred */
808 case nfserr_rofs:
809 case nfserr_acces:
810 case nfserr_perm:
811 /* simply don't "or" in the access bit. */
812 break;
813 default:
814 error = err2;
815 goto out;
816 }
817 }
818 }
819 *access = result;
820 if (supported)
821 *supported = sresult;
822
823 out:
824 return error;
825}
826
827int nfsd_open_break_lease(struct inode *inode, int access)
828{
829 unsigned int mode;
830
831 if (access & NFSD_MAY_NOT_BREAK_LEASE)
832 return 0;
833 mode = (access & NFSD_MAY_WRITE) ? O_WRONLY : O_RDONLY;
834 return break_lease(inode, mode | O_NONBLOCK);
835}
836
837/*
838 * Open an existing file or directory.
839 * The may_flags argument indicates the type of open (read/write/lock)
840 * and additional flags.
841 * N.B. After this call fhp needs an fh_put
842 */
843static int
844__nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type,
845 int may_flags, struct file **filp)
846{
847 struct path path;
848 struct inode *inode;
849 struct file *file;
850 int flags = O_RDONLY|O_LARGEFILE;
851 int host_err = -EPERM;
852
853 path.mnt = fhp->fh_export->ex_path.mnt;
854 path.dentry = fhp->fh_dentry;
855 inode = d_inode(path.dentry);
856
857 if (IS_APPEND(inode) && (may_flags & NFSD_MAY_WRITE))
858 goto out;
859
860 if (!inode->i_fop)
861 goto out;
862
863 host_err = nfsd_open_break_lease(inode, may_flags);
864 if (host_err) /* NOMEM or WOULDBLOCK */
865 goto out;
866
867 if (may_flags & NFSD_MAY_WRITE) {
868 if (may_flags & NFSD_MAY_READ)
869 flags = O_RDWR|O_LARGEFILE;
870 else
871 flags = O_WRONLY|O_LARGEFILE;
872 }
873
874 file = dentry_open(&path, flags, current_cred());
875 if (IS_ERR(file)) {
876 host_err = PTR_ERR(file);
877 goto out;
878 }
879
880 host_err = ima_file_check(file, may_flags);
881 if (host_err) {
882 fput(file);
883 goto out;
884 }
885
886 if (may_flags & NFSD_MAY_64BIT_COOKIE)
887 file->f_mode |= FMODE_64BITHASH;
888 else
889 file->f_mode |= FMODE_32BITHASH;
890
891 *filp = file;
892out:
893 return host_err;
894}
895
896__be32
897nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type,
898 int may_flags, struct file **filp)
899{
900 __be32 err;
901 int host_err;
902 bool retried = false;
903
904 /*
905 * If we get here, then the client has already done an "open",
906 * and (hopefully) checked permission - so allow OWNER_OVERRIDE
907 * in case a chmod has now revoked permission.
908 *
909 * Arguably we should also allow the owner override for
910 * directories, but we never have and it doesn't seem to have
911 * caused anyone a problem. If we were to change this, note
912 * also that our filldir callbacks would need a variant of
913 * lookup_one_len that doesn't check permissions.
914 */
915 if (type == S_IFREG)
916 may_flags |= NFSD_MAY_OWNER_OVERRIDE;
917retry:
918 err = fh_verify(rqstp, fhp, type, may_flags);
919 if (!err) {
920 host_err = __nfsd_open(rqstp, fhp, type, may_flags, filp);
921 if (host_err == -EOPENSTALE && !retried) {
922 retried = true;
923 fh_put(fhp);
924 goto retry;
925 }
926 err = nfserrno(host_err);
927 }
928 return err;
929}
930
931/**
932 * nfsd_open_verified - Open a regular file for the filecache
933 * @rqstp: RPC request
934 * @fhp: NFS filehandle of the file to open
935 * @may_flags: internal permission flags
936 * @filp: OUT: open "struct file *"
937 *
938 * Returns zero on success, or a negative errno value.
939 */
940int
941nfsd_open_verified(struct svc_rqst *rqstp, struct svc_fh *fhp, int may_flags,
942 struct file **filp)
943{
944 return __nfsd_open(rqstp, fhp, S_IFREG, may_flags, filp);
945}
946
947/*
948 * Grab and keep cached pages associated with a file in the svc_rqst
949 * so that they can be passed to the network sendmsg routines
950 * directly. They will be released after the sending has completed.
951 *
952 * Return values: Number of bytes consumed, or -EIO if there are no
953 * remaining pages in rqstp->rq_pages.
954 */
955static int
956nfsd_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
957 struct splice_desc *sd)
958{
959 struct svc_rqst *rqstp = sd->u.data;
960 struct page *page = buf->page; // may be a compound one
961 unsigned offset = buf->offset;
962 struct page *last_page;
963
964 last_page = page + (offset + sd->len - 1) / PAGE_SIZE;
965 for (page += offset / PAGE_SIZE; page <= last_page; page++) {
966 /*
967 * Skip page replacement when extending the contents of the
968 * current page. But note that we may get two zero_pages in a
969 * row from shmem.
970 */
971 if (page == *(rqstp->rq_next_page - 1) &&
972 offset_in_page(rqstp->rq_res.page_base +
973 rqstp->rq_res.page_len))
974 continue;
975 if (unlikely(!svc_rqst_replace_page(rqstp, page)))
976 return -EIO;
977 }
978 if (rqstp->rq_res.page_len == 0) // first call
979 rqstp->rq_res.page_base = offset % PAGE_SIZE;
980 rqstp->rq_res.page_len += sd->len;
981 return sd->len;
982}
983
984static int nfsd_direct_splice_actor(struct pipe_inode_info *pipe,
985 struct splice_desc *sd)
986{
987 return __splice_from_pipe(pipe, sd, nfsd_splice_actor);
988}
989
990static u32 nfsd_eof_on_read(struct file *file, loff_t offset, ssize_t len,
991 size_t expected)
992{
993 if (expected != 0 && len == 0)
994 return 1;
995 if (offset+len >= i_size_read(file_inode(file)))
996 return 1;
997 return 0;
998}
999
1000static __be32 nfsd_finish_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
1001 struct file *file, loff_t offset,
1002 unsigned long *count, u32 *eof, ssize_t host_err)
1003{
1004 if (host_err >= 0) {
1005 nfsd_stats_io_read_add(fhp->fh_export, host_err);
1006 *eof = nfsd_eof_on_read(file, offset, host_err, *count);
1007 *count = host_err;
1008 fsnotify_access(file);
1009 trace_nfsd_read_io_done(rqstp, fhp, offset, *count);
1010 return 0;
1011 } else {
1012 trace_nfsd_read_err(rqstp, fhp, offset, host_err);
1013 return nfserrno(host_err);
1014 }
1015}
1016
1017/**
1018 * nfsd_splice_read - Perform a VFS read using a splice pipe
1019 * @rqstp: RPC transaction context
1020 * @fhp: file handle of file to be read
1021 * @file: opened struct file of file to be read
1022 * @offset: starting byte offset
1023 * @count: IN: requested number of bytes; OUT: number of bytes read
1024 * @eof: OUT: set non-zero if operation reached the end of the file
1025 *
1026 * Returns nfs_ok on success, otherwise an nfserr stat value is
1027 * returned.
1028 */
1029__be32 nfsd_splice_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
1030 struct file *file, loff_t offset, unsigned long *count,
1031 u32 *eof)
1032{
1033 struct splice_desc sd = {
1034 .len = 0,
1035 .total_len = *count,
1036 .pos = offset,
1037 .u.data = rqstp,
1038 };
1039 ssize_t host_err;
1040
1041 trace_nfsd_read_splice(rqstp, fhp, offset, *count);
1042 host_err = rw_verify_area(READ, file, &offset, *count);
1043 if (!host_err)
1044 host_err = splice_direct_to_actor(file, &sd,
1045 nfsd_direct_splice_actor);
1046 return nfsd_finish_read(rqstp, fhp, file, offset, count, eof, host_err);
1047}
1048
1049/**
1050 * nfsd_iter_read - Perform a VFS read using an iterator
1051 * @rqstp: RPC transaction context
1052 * @fhp: file handle of file to be read
1053 * @file: opened struct file of file to be read
1054 * @offset: starting byte offset
1055 * @count: IN: requested number of bytes; OUT: number of bytes read
1056 * @base: offset in first page of read buffer
1057 * @eof: OUT: set non-zero if operation reached the end of the file
1058 *
1059 * Some filesystems or situations cannot use nfsd_splice_read. This
1060 * function is the slightly less-performant fallback for those cases.
1061 *
1062 * Returns nfs_ok on success, otherwise an nfserr stat value is
1063 * returned.
1064 */
1065__be32 nfsd_iter_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
1066 struct file *file, loff_t offset, unsigned long *count,
1067 unsigned int base, u32 *eof)
1068{
1069 unsigned long v, total;
1070 struct iov_iter iter;
1071 loff_t ppos = offset;
1072 struct page *page;
1073 ssize_t host_err;
1074
1075 v = 0;
1076 total = *count;
1077 while (total) {
1078 page = *(rqstp->rq_next_page++);
1079 rqstp->rq_vec[v].iov_base = page_address(page) + base;
1080 rqstp->rq_vec[v].iov_len = min_t(size_t, total, PAGE_SIZE - base);
1081 total -= rqstp->rq_vec[v].iov_len;
1082 ++v;
1083 base = 0;
1084 }
1085 WARN_ON_ONCE(v > ARRAY_SIZE(rqstp->rq_vec));
1086
1087 trace_nfsd_read_vector(rqstp, fhp, offset, *count);
1088 iov_iter_kvec(&iter, ITER_DEST, rqstp->rq_vec, v, *count);
1089 host_err = vfs_iter_read(file, &iter, &ppos, 0);
1090 return nfsd_finish_read(rqstp, fhp, file, offset, count, eof, host_err);
1091}
1092
1093/*
1094 * Gathered writes: If another process is currently writing to the file,
1095 * there's a high chance this is another nfsd (triggered by a bulk write
1096 * from a client's biod). Rather than syncing the file with each write
1097 * request, we sleep for 10 msec.
1098 *
1099 * I don't know if this roughly approximates C. Juszak's idea of
1100 * gathered writes, but it's a nice and simple solution (IMHO), and it
1101 * seems to work:-)
1102 *
1103 * Note: we do this only in the NFSv2 case, since v3 and higher have a
1104 * better tool (separate unstable writes and commits) for solving this
1105 * problem.
1106 */
1107static int wait_for_concurrent_writes(struct file *file)
1108{
1109 struct inode *inode = file_inode(file);
1110 static ino_t last_ino;
1111 static dev_t last_dev;
1112 int err = 0;
1113
1114 if (atomic_read(&inode->i_writecount) > 1
1115 || (last_ino == inode->i_ino && last_dev == inode->i_sb->s_dev)) {
1116 dprintk("nfsd: write defer %d\n", task_pid_nr(current));
1117 msleep(10);
1118 dprintk("nfsd: write resume %d\n", task_pid_nr(current));
1119 }
1120
1121 if (inode->i_state & I_DIRTY) {
1122 dprintk("nfsd: write sync %d\n", task_pid_nr(current));
1123 err = vfs_fsync(file, 0);
1124 }
1125 last_ino = inode->i_ino;
1126 last_dev = inode->i_sb->s_dev;
1127 return err;
1128}
1129
1130__be32
1131nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf,
1132 loff_t offset, struct kvec *vec, int vlen,
1133 unsigned long *cnt, int stable,
1134 __be32 *verf)
1135{
1136 struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
1137 struct file *file = nf->nf_file;
1138 struct super_block *sb = file_inode(file)->i_sb;
1139 struct svc_export *exp;
1140 struct iov_iter iter;
1141 errseq_t since;
1142 __be32 nfserr;
1143 int host_err;
1144 int use_wgather;
1145 loff_t pos = offset;
1146 unsigned long exp_op_flags = 0;
1147 unsigned int pflags = current->flags;
1148 rwf_t flags = 0;
1149 bool restore_flags = false;
1150
1151 trace_nfsd_write_opened(rqstp, fhp, offset, *cnt);
1152
1153 if (sb->s_export_op)
1154 exp_op_flags = sb->s_export_op->flags;
1155
1156 if (test_bit(RQ_LOCAL, &rqstp->rq_flags) &&
1157 !(exp_op_flags & EXPORT_OP_REMOTE_FS)) {
1158 /*
1159 * We want throttling in balance_dirty_pages()
1160 * and shrink_inactive_list() to only consider
1161 * the backingdev we are writing to, so that nfs to
1162 * localhost doesn't cause nfsd to lock up due to all
1163 * the client's dirty pages or its congested queue.
1164 */
1165 current->flags |= PF_LOCAL_THROTTLE;
1166 restore_flags = true;
1167 }
1168
1169 exp = fhp->fh_export;
1170 use_wgather = (rqstp->rq_vers == 2) && EX_WGATHER(exp);
1171
1172 if (!EX_ISSYNC(exp))
1173 stable = NFS_UNSTABLE;
1174
1175 if (stable && !use_wgather)
1176 flags |= RWF_SYNC;
1177
1178 iov_iter_kvec(&iter, ITER_SOURCE, vec, vlen, *cnt);
1179 since = READ_ONCE(file->f_wb_err);
1180 if (verf)
1181 nfsd_copy_write_verifier(verf, nn);
1182 host_err = vfs_iter_write(file, &iter, &pos, flags);
1183 if (host_err < 0) {
1184 commit_reset_write_verifier(nn, rqstp, host_err);
1185 goto out_nfserr;
1186 }
1187 *cnt = host_err;
1188 nfsd_stats_io_write_add(exp, *cnt);
1189 fsnotify_modify(file);
1190 host_err = filemap_check_wb_err(file->f_mapping, since);
1191 if (host_err < 0)
1192 goto out_nfserr;
1193
1194 if (stable && use_wgather) {
1195 host_err = wait_for_concurrent_writes(file);
1196 if (host_err < 0)
1197 commit_reset_write_verifier(nn, rqstp, host_err);
1198 }
1199
1200out_nfserr:
1201 if (host_err >= 0) {
1202 trace_nfsd_write_io_done(rqstp, fhp, offset, *cnt);
1203 nfserr = nfs_ok;
1204 } else {
1205 trace_nfsd_write_err(rqstp, fhp, offset, host_err);
1206 nfserr = nfserrno(host_err);
1207 }
1208 if (restore_flags)
1209 current_restore_flags(pflags, PF_LOCAL_THROTTLE);
1210 return nfserr;
1211}
1212
1213/**
1214 * nfsd_read_splice_ok - check if spliced reading is supported
1215 * @rqstp: RPC transaction context
1216 *
1217 * Return values:
1218 * %true: nfsd_splice_read() may be used
1219 * %false: nfsd_splice_read() must not be used
1220 *
1221 * NFS READ normally uses splice to send data in-place. However the
1222 * data in cache can change after the reply's MIC is computed but
1223 * before the RPC reply is sent. To prevent the client from
1224 * rejecting the server-computed MIC in this somewhat rare case, do
1225 * not use splice with the GSS integrity and privacy services.
1226 */
1227bool nfsd_read_splice_ok(struct svc_rqst *rqstp)
1228{
1229 switch (svc_auth_flavor(rqstp)) {
1230 case RPC_AUTH_GSS_KRB5I:
1231 case RPC_AUTH_GSS_KRB5P:
1232 return false;
1233 }
1234 return true;
1235}
1236
1237/**
1238 * nfsd_read - Read data from a file
1239 * @rqstp: RPC transaction context
1240 * @fhp: file handle of file to be read
1241 * @offset: starting byte offset
1242 * @count: IN: requested number of bytes; OUT: number of bytes read
1243 * @eof: OUT: set non-zero if operation reached the end of the file
1244 *
1245 * The caller must verify that there is enough space in @rqstp.rq_res
1246 * to perform this operation.
1247 *
1248 * N.B. After this call fhp needs an fh_put
1249 *
1250 * Returns nfs_ok on success, otherwise an nfserr stat value is
1251 * returned.
1252 */
1253__be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
1254 loff_t offset, unsigned long *count, u32 *eof)
1255{
1256 struct nfsd_file *nf;
1257 struct file *file;
1258 __be32 err;
1259
1260 trace_nfsd_read_start(rqstp, fhp, offset, *count);
1261 err = nfsd_file_acquire_gc(rqstp, fhp, NFSD_MAY_READ, &nf);
1262 if (err)
1263 return err;
1264
1265 file = nf->nf_file;
1266 if (file->f_op->splice_read && nfsd_read_splice_ok(rqstp))
1267 err = nfsd_splice_read(rqstp, fhp, file, offset, count, eof);
1268 else
1269 err = nfsd_iter_read(rqstp, fhp, file, offset, count, 0, eof);
1270
1271 nfsd_file_put(nf);
1272 trace_nfsd_read_done(rqstp, fhp, offset, *count);
1273 return err;
1274}
1275
1276/*
1277 * Write data to a file.
1278 * The stable flag requests synchronous writes.
1279 * N.B. After this call fhp needs an fh_put
1280 */
1281__be32
1282nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t offset,
1283 struct kvec *vec, int vlen, unsigned long *cnt, int stable,
1284 __be32 *verf)
1285{
1286 struct nfsd_file *nf;
1287 __be32 err;
1288
1289 trace_nfsd_write_start(rqstp, fhp, offset, *cnt);
1290
1291 err = nfsd_file_acquire_gc(rqstp, fhp, NFSD_MAY_WRITE, &nf);
1292 if (err)
1293 goto out;
1294
1295 err = nfsd_vfs_write(rqstp, fhp, nf, offset, vec,
1296 vlen, cnt, stable, verf);
1297 nfsd_file_put(nf);
1298out:
1299 trace_nfsd_write_done(rqstp, fhp, offset, *cnt);
1300 return err;
1301}
1302
1303/**
1304 * nfsd_commit - Commit pending writes to stable storage
1305 * @rqstp: RPC request being processed
1306 * @fhp: NFS filehandle
1307 * @nf: target file
1308 * @offset: raw offset from beginning of file
1309 * @count: raw count of bytes to sync
1310 * @verf: filled in with the server's current write verifier
1311 *
1312 * Note: we guarantee that data that lies within the range specified
1313 * by the 'offset' and 'count' parameters will be synced. The server
1314 * is permitted to sync data that lies outside this range at the
1315 * same time.
1316 *
1317 * Unfortunately we cannot lock the file to make sure we return full WCC
1318 * data to the client, as locking happens lower down in the filesystem.
1319 *
1320 * Return values:
1321 * An nfsstat value in network byte order.
1322 */
1323__be32
1324nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf,
1325 u64 offset, u32 count, __be32 *verf)
1326{
1327 __be32 err = nfs_ok;
1328 u64 maxbytes;
1329 loff_t start, end;
1330 struct nfsd_net *nn;
1331
1332 /*
1333 * Convert the client-provided (offset, count) range to a
1334 * (start, end) range. If the client-provided range falls
1335 * outside the maximum file size of the underlying FS,
1336 * clamp the sync range appropriately.
1337 */
1338 start = 0;
1339 end = LLONG_MAX;
1340 maxbytes = (u64)fhp->fh_dentry->d_sb->s_maxbytes;
1341 if (offset < maxbytes) {
1342 start = offset;
1343 if (count && (offset + count - 1 < maxbytes))
1344 end = offset + count - 1;
1345 }
1346
1347 nn = net_generic(nf->nf_net, nfsd_net_id);
1348 if (EX_ISSYNC(fhp->fh_export)) {
1349 errseq_t since = READ_ONCE(nf->nf_file->f_wb_err);
1350 int err2;
1351
1352 err2 = vfs_fsync_range(nf->nf_file, start, end, 0);
1353 switch (err2) {
1354 case 0:
1355 nfsd_copy_write_verifier(verf, nn);
1356 err2 = filemap_check_wb_err(nf->nf_file->f_mapping,
1357 since);
1358 err = nfserrno(err2);
1359 break;
1360 case -EINVAL:
1361 err = nfserr_notsupp;
1362 break;
1363 default:
1364 commit_reset_write_verifier(nn, rqstp, err2);
1365 err = nfserrno(err2);
1366 }
1367 } else
1368 nfsd_copy_write_verifier(verf, nn);
1369
1370 return err;
1371}
1372
1373/**
1374 * nfsd_create_setattr - Set a created file's attributes
1375 * @rqstp: RPC transaction being executed
1376 * @fhp: NFS filehandle of parent directory
1377 * @resfhp: NFS filehandle of new object
1378 * @attrs: requested attributes of new object
1379 *
1380 * Returns nfs_ok on success, or an nfsstat in network byte order.
1381 */
1382__be32
1383nfsd_create_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp,
1384 struct svc_fh *resfhp, struct nfsd_attrs *attrs)
1385{
1386 struct iattr *iap = attrs->na_iattr;
1387 __be32 status;
1388
1389 /*
1390 * Mode has already been set by file creation.
1391 */
1392 iap->ia_valid &= ~ATTR_MODE;
1393
1394 /*
1395 * Setting uid/gid works only for root. Irix appears to
1396 * send along the gid on create when it tries to implement
1397 * setgid directories via NFS:
1398 */
1399 if (!uid_eq(current_fsuid(), GLOBAL_ROOT_UID))
1400 iap->ia_valid &= ~(ATTR_UID|ATTR_GID);
1401
1402 /*
1403 * Callers expect new file metadata to be committed even
1404 * if the attributes have not changed.
1405 */
1406 if (iap->ia_valid)
1407 status = nfsd_setattr(rqstp, resfhp, attrs, 0, (time64_t)0);
1408 else
1409 status = nfserrno(commit_metadata(resfhp));
1410
1411 /*
1412 * Transactional filesystems had a chance to commit changes
1413 * for both parent and child simultaneously making the
1414 * following commit_metadata a noop in many cases.
1415 */
1416 if (!status)
1417 status = nfserrno(commit_metadata(fhp));
1418
1419 /*
1420 * Update the new filehandle to pick up the new attributes.
1421 */
1422 if (!status)
1423 status = fh_update(resfhp);
1424
1425 return status;
1426}
1427
1428/* HPUX client sometimes creates a file in mode 000, and sets size to 0.
1429 * setting size to 0 may fail for some specific file systems by the permission
1430 * checking which requires WRITE permission but the mode is 000.
1431 * we ignore the resizing(to 0) on the just new created file, since the size is
1432 * 0 after file created.
1433 *
1434 * call this only after vfs_create() is called.
1435 * */
1436static void
1437nfsd_check_ignore_resizing(struct iattr *iap)
1438{
1439 if ((iap->ia_valid & ATTR_SIZE) && (iap->ia_size == 0))
1440 iap->ia_valid &= ~ATTR_SIZE;
1441}
1442
1443/* The parent directory should already be locked: */
1444__be32
1445nfsd_create_locked(struct svc_rqst *rqstp, struct svc_fh *fhp,
1446 struct nfsd_attrs *attrs,
1447 int type, dev_t rdev, struct svc_fh *resfhp)
1448{
1449 struct dentry *dentry, *dchild;
1450 struct inode *dirp;
1451 struct iattr *iap = attrs->na_iattr;
1452 __be32 err;
1453 int host_err;
1454
1455 dentry = fhp->fh_dentry;
1456 dirp = d_inode(dentry);
1457
1458 dchild = dget(resfhp->fh_dentry);
1459 err = nfsd_permission(rqstp, fhp->fh_export, dentry, NFSD_MAY_CREATE);
1460 if (err)
1461 goto out;
1462
1463 if (!(iap->ia_valid & ATTR_MODE))
1464 iap->ia_mode = 0;
1465 iap->ia_mode = (iap->ia_mode & S_IALLUGO) | type;
1466
1467 if (!IS_POSIXACL(dirp))
1468 iap->ia_mode &= ~current_umask();
1469
1470 err = 0;
1471 switch (type) {
1472 case S_IFREG:
1473 host_err = vfs_create(&nop_mnt_idmap, dirp, dchild,
1474 iap->ia_mode, true);
1475 if (!host_err)
1476 nfsd_check_ignore_resizing(iap);
1477 break;
1478 case S_IFDIR:
1479 host_err = vfs_mkdir(&nop_mnt_idmap, dirp, dchild, iap->ia_mode);
1480 if (!host_err && unlikely(d_unhashed(dchild))) {
1481 struct dentry *d;
1482 d = lookup_one_len(dchild->d_name.name,
1483 dchild->d_parent,
1484 dchild->d_name.len);
1485 if (IS_ERR(d)) {
1486 host_err = PTR_ERR(d);
1487 break;
1488 }
1489 if (unlikely(d_is_negative(d))) {
1490 dput(d);
1491 err = nfserr_serverfault;
1492 goto out;
1493 }
1494 dput(resfhp->fh_dentry);
1495 resfhp->fh_dentry = dget(d);
1496 err = fh_update(resfhp);
1497 dput(dchild);
1498 dchild = d;
1499 if (err)
1500 goto out;
1501 }
1502 break;
1503 case S_IFCHR:
1504 case S_IFBLK:
1505 case S_IFIFO:
1506 case S_IFSOCK:
1507 host_err = vfs_mknod(&nop_mnt_idmap, dirp, dchild,
1508 iap->ia_mode, rdev);
1509 break;
1510 default:
1511 printk(KERN_WARNING "nfsd: bad file type %o in nfsd_create\n",
1512 type);
1513 host_err = -EINVAL;
1514 }
1515 if (host_err < 0)
1516 goto out_nfserr;
1517
1518 err = nfsd_create_setattr(rqstp, fhp, resfhp, attrs);
1519
1520out:
1521 dput(dchild);
1522 return err;
1523
1524out_nfserr:
1525 err = nfserrno(host_err);
1526 goto out;
1527}
1528
1529/*
1530 * Create a filesystem object (regular, directory, special).
1531 * Note that the parent directory is left locked.
1532 *
1533 * N.B. Every call to nfsd_create needs an fh_put for _both_ fhp and resfhp
1534 */
1535__be32
1536nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
1537 char *fname, int flen, struct nfsd_attrs *attrs,
1538 int type, dev_t rdev, struct svc_fh *resfhp)
1539{
1540 struct dentry *dentry, *dchild = NULL;
1541 __be32 err;
1542 int host_err;
1543
1544 if (isdotent(fname, flen))
1545 return nfserr_exist;
1546
1547 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_NOP);
1548 if (err)
1549 return err;
1550
1551 dentry = fhp->fh_dentry;
1552
1553 host_err = fh_want_write(fhp);
1554 if (host_err)
1555 return nfserrno(host_err);
1556
1557 inode_lock_nested(dentry->d_inode, I_MUTEX_PARENT);
1558 dchild = lookup_one_len(fname, dentry, flen);
1559 host_err = PTR_ERR(dchild);
1560 if (IS_ERR(dchild)) {
1561 err = nfserrno(host_err);
1562 goto out_unlock;
1563 }
1564 err = fh_compose(resfhp, fhp->fh_export, dchild, fhp);
1565 /*
1566 * We unconditionally drop our ref to dchild as fh_compose will have
1567 * already grabbed its own ref for it.
1568 */
1569 dput(dchild);
1570 if (err)
1571 goto out_unlock;
1572 err = fh_fill_pre_attrs(fhp);
1573 if (err != nfs_ok)
1574 goto out_unlock;
1575 err = nfsd_create_locked(rqstp, fhp, attrs, type, rdev, resfhp);
1576 fh_fill_post_attrs(fhp);
1577out_unlock:
1578 inode_unlock(dentry->d_inode);
1579 return err;
1580}
1581
1582/*
1583 * Read a symlink. On entry, *lenp must contain the maximum path length that
1584 * fits into the buffer. On return, it contains the true length.
1585 * N.B. After this call fhp needs an fh_put
1586 */
1587__be32
1588nfsd_readlink(struct svc_rqst *rqstp, struct svc_fh *fhp, char *buf, int *lenp)
1589{
1590 __be32 err;
1591 const char *link;
1592 struct path path;
1593 DEFINE_DELAYED_CALL(done);
1594 int len;
1595
1596 err = fh_verify(rqstp, fhp, S_IFLNK, NFSD_MAY_NOP);
1597 if (unlikely(err))
1598 return err;
1599
1600 path.mnt = fhp->fh_export->ex_path.mnt;
1601 path.dentry = fhp->fh_dentry;
1602
1603 if (unlikely(!d_is_symlink(path.dentry)))
1604 return nfserr_inval;
1605
1606 touch_atime(&path);
1607
1608 link = vfs_get_link(path.dentry, &done);
1609 if (IS_ERR(link))
1610 return nfserrno(PTR_ERR(link));
1611
1612 len = strlen(link);
1613 if (len < *lenp)
1614 *lenp = len;
1615 memcpy(buf, link, *lenp);
1616 do_delayed_call(&done);
1617 return 0;
1618}
1619
1620/**
1621 * nfsd_symlink - Create a symlink and look up its inode
1622 * @rqstp: RPC transaction being executed
1623 * @fhp: NFS filehandle of parent directory
1624 * @fname: filename of the new symlink
1625 * @flen: length of @fname
1626 * @path: content of the new symlink (NUL-terminated)
1627 * @attrs: requested attributes of new object
1628 * @resfhp: NFS filehandle of new object
1629 *
1630 * N.B. After this call _both_ fhp and resfhp need an fh_put
1631 *
1632 * Returns nfs_ok on success, or an nfsstat in network byte order.
1633 */
1634__be32
1635nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp,
1636 char *fname, int flen,
1637 char *path, struct nfsd_attrs *attrs,
1638 struct svc_fh *resfhp)
1639{
1640 struct dentry *dentry, *dnew;
1641 __be32 err, cerr;
1642 int host_err;
1643
1644 err = nfserr_noent;
1645 if (!flen || path[0] == '\0')
1646 goto out;
1647 err = nfserr_exist;
1648 if (isdotent(fname, flen))
1649 goto out;
1650
1651 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
1652 if (err)
1653 goto out;
1654
1655 host_err = fh_want_write(fhp);
1656 if (host_err) {
1657 err = nfserrno(host_err);
1658 goto out;
1659 }
1660
1661 dentry = fhp->fh_dentry;
1662 inode_lock_nested(dentry->d_inode, I_MUTEX_PARENT);
1663 dnew = lookup_one_len(fname, dentry, flen);
1664 if (IS_ERR(dnew)) {
1665 err = nfserrno(PTR_ERR(dnew));
1666 inode_unlock(dentry->d_inode);
1667 goto out_drop_write;
1668 }
1669 err = fh_fill_pre_attrs(fhp);
1670 if (err != nfs_ok)
1671 goto out_unlock;
1672 host_err = vfs_symlink(&nop_mnt_idmap, d_inode(dentry), dnew, path);
1673 err = nfserrno(host_err);
1674 cerr = fh_compose(resfhp, fhp->fh_export, dnew, fhp);
1675 if (!err)
1676 nfsd_create_setattr(rqstp, fhp, resfhp, attrs);
1677 fh_fill_post_attrs(fhp);
1678out_unlock:
1679 inode_unlock(dentry->d_inode);
1680 if (!err)
1681 err = nfserrno(commit_metadata(fhp));
1682 dput(dnew);
1683 if (err==0) err = cerr;
1684out_drop_write:
1685 fh_drop_write(fhp);
1686out:
1687 return err;
1688}
1689
1690/*
1691 * Create a hardlink
1692 * N.B. After this call _both_ ffhp and tfhp need an fh_put
1693 */
1694__be32
1695nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp,
1696 char *name, int len, struct svc_fh *tfhp)
1697{
1698 struct dentry *ddir, *dnew, *dold;
1699 struct inode *dirp;
1700 __be32 err;
1701 int host_err;
1702
1703 err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_CREATE);
1704 if (err)
1705 goto out;
1706 err = fh_verify(rqstp, tfhp, 0, NFSD_MAY_NOP);
1707 if (err)
1708 goto out;
1709 err = nfserr_isdir;
1710 if (d_is_dir(tfhp->fh_dentry))
1711 goto out;
1712 err = nfserr_perm;
1713 if (!len)
1714 goto out;
1715 err = nfserr_exist;
1716 if (isdotent(name, len))
1717 goto out;
1718
1719 host_err = fh_want_write(tfhp);
1720 if (host_err) {
1721 err = nfserrno(host_err);
1722 goto out;
1723 }
1724
1725 ddir = ffhp->fh_dentry;
1726 dirp = d_inode(ddir);
1727 inode_lock_nested(dirp, I_MUTEX_PARENT);
1728
1729 dnew = lookup_one_len(name, ddir, len);
1730 if (IS_ERR(dnew)) {
1731 err = nfserrno(PTR_ERR(dnew));
1732 goto out_unlock;
1733 }
1734
1735 dold = tfhp->fh_dentry;
1736
1737 err = nfserr_noent;
1738 if (d_really_is_negative(dold))
1739 goto out_dput;
1740 err = fh_fill_pre_attrs(ffhp);
1741 if (err != nfs_ok)
1742 goto out_dput;
1743 host_err = vfs_link(dold, &nop_mnt_idmap, dirp, dnew, NULL);
1744 fh_fill_post_attrs(ffhp);
1745 inode_unlock(dirp);
1746 if (!host_err) {
1747 err = nfserrno(commit_metadata(ffhp));
1748 if (!err)
1749 err = nfserrno(commit_metadata(tfhp));
1750 } else {
1751 if (host_err == -EXDEV && rqstp->rq_vers == 2)
1752 err = nfserr_acces;
1753 else
1754 err = nfserrno(host_err);
1755 }
1756 dput(dnew);
1757out_drop_write:
1758 fh_drop_write(tfhp);
1759out:
1760 return err;
1761
1762out_dput:
1763 dput(dnew);
1764out_unlock:
1765 inode_unlock(dirp);
1766 goto out_drop_write;
1767}
1768
1769static void
1770nfsd_close_cached_files(struct dentry *dentry)
1771{
1772 struct inode *inode = d_inode(dentry);
1773
1774 if (inode && S_ISREG(inode->i_mode))
1775 nfsd_file_close_inode_sync(inode);
1776}
1777
1778static bool
1779nfsd_has_cached_files(struct dentry *dentry)
1780{
1781 bool ret = false;
1782 struct inode *inode = d_inode(dentry);
1783
1784 if (inode && S_ISREG(inode->i_mode))
1785 ret = nfsd_file_is_cached(inode);
1786 return ret;
1787}
1788
1789/*
1790 * Rename a file
1791 * N.B. After this call _both_ ffhp and tfhp need an fh_put
1792 */
1793__be32
1794nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
1795 struct svc_fh *tfhp, char *tname, int tlen)
1796{
1797 struct dentry *fdentry, *tdentry, *odentry, *ndentry, *trap;
1798 struct inode *fdir, *tdir;
1799 __be32 err;
1800 int host_err;
1801 bool close_cached = false;
1802
1803 err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_REMOVE);
1804 if (err)
1805 goto out;
1806 err = fh_verify(rqstp, tfhp, S_IFDIR, NFSD_MAY_CREATE);
1807 if (err)
1808 goto out;
1809
1810 fdentry = ffhp->fh_dentry;
1811 fdir = d_inode(fdentry);
1812
1813 tdentry = tfhp->fh_dentry;
1814 tdir = d_inode(tdentry);
1815
1816 err = nfserr_perm;
1817 if (!flen || isdotent(fname, flen) || !tlen || isdotent(tname, tlen))
1818 goto out;
1819
1820 err = (rqstp->rq_vers == 2) ? nfserr_acces : nfserr_xdev;
1821 if (ffhp->fh_export->ex_path.mnt != tfhp->fh_export->ex_path.mnt)
1822 goto out;
1823 if (ffhp->fh_export->ex_path.dentry != tfhp->fh_export->ex_path.dentry)
1824 goto out;
1825
1826retry:
1827 host_err = fh_want_write(ffhp);
1828 if (host_err) {
1829 err = nfserrno(host_err);
1830 goto out;
1831 }
1832
1833 trap = lock_rename(tdentry, fdentry);
1834 if (IS_ERR(trap)) {
1835 err = (rqstp->rq_vers == 2) ? nfserr_acces : nfserr_xdev;
1836 goto out;
1837 }
1838 err = fh_fill_pre_attrs(ffhp);
1839 if (err != nfs_ok)
1840 goto out_unlock;
1841 err = fh_fill_pre_attrs(tfhp);
1842 if (err != nfs_ok)
1843 goto out_unlock;
1844
1845 odentry = lookup_one_len(fname, fdentry, flen);
1846 host_err = PTR_ERR(odentry);
1847 if (IS_ERR(odentry))
1848 goto out_nfserr;
1849
1850 host_err = -ENOENT;
1851 if (d_really_is_negative(odentry))
1852 goto out_dput_old;
1853 host_err = -EINVAL;
1854 if (odentry == trap)
1855 goto out_dput_old;
1856
1857 ndentry = lookup_one_len(tname, tdentry, tlen);
1858 host_err = PTR_ERR(ndentry);
1859 if (IS_ERR(ndentry))
1860 goto out_dput_old;
1861 host_err = -ENOTEMPTY;
1862 if (ndentry == trap)
1863 goto out_dput_new;
1864
1865 if ((ndentry->d_sb->s_export_op->flags & EXPORT_OP_CLOSE_BEFORE_UNLINK) &&
1866 nfsd_has_cached_files(ndentry)) {
1867 close_cached = true;
1868 goto out_dput_old;
1869 } else {
1870 struct renamedata rd = {
1871 .old_mnt_idmap = &nop_mnt_idmap,
1872 .old_dir = fdir,
1873 .old_dentry = odentry,
1874 .new_mnt_idmap = &nop_mnt_idmap,
1875 .new_dir = tdir,
1876 .new_dentry = ndentry,
1877 };
1878 int retries;
1879
1880 for (retries = 1;;) {
1881 host_err = vfs_rename(&rd);
1882 if (host_err != -EAGAIN || !retries--)
1883 break;
1884 if (!nfsd_wait_for_delegreturn(rqstp, d_inode(odentry)))
1885 break;
1886 }
1887 if (!host_err) {
1888 host_err = commit_metadata(tfhp);
1889 if (!host_err)
1890 host_err = commit_metadata(ffhp);
1891 }
1892 }
1893 out_dput_new:
1894 dput(ndentry);
1895 out_dput_old:
1896 dput(odentry);
1897 out_nfserr:
1898 err = nfserrno(host_err);
1899
1900 if (!close_cached) {
1901 fh_fill_post_attrs(ffhp);
1902 fh_fill_post_attrs(tfhp);
1903 }
1904out_unlock:
1905 unlock_rename(tdentry, fdentry);
1906 fh_drop_write(ffhp);
1907
1908 /*
1909 * If the target dentry has cached open files, then we need to try to
1910 * close them prior to doing the rename. Flushing delayed fput
1911 * shouldn't be done with locks held however, so we delay it until this
1912 * point and then reattempt the whole shebang.
1913 */
1914 if (close_cached) {
1915 close_cached = false;
1916 nfsd_close_cached_files(ndentry);
1917 dput(ndentry);
1918 goto retry;
1919 }
1920out:
1921 return err;
1922}
1923
1924/*
1925 * Unlink a file or directory
1926 * N.B. After this call fhp needs an fh_put
1927 */
1928__be32
1929nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
1930 char *fname, int flen)
1931{
1932 struct dentry *dentry, *rdentry;
1933 struct inode *dirp;
1934 struct inode *rinode;
1935 __be32 err;
1936 int host_err;
1937
1938 err = nfserr_acces;
1939 if (!flen || isdotent(fname, flen))
1940 goto out;
1941 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_REMOVE);
1942 if (err)
1943 goto out;
1944
1945 host_err = fh_want_write(fhp);
1946 if (host_err)
1947 goto out_nfserr;
1948
1949 dentry = fhp->fh_dentry;
1950 dirp = d_inode(dentry);
1951 inode_lock_nested(dirp, I_MUTEX_PARENT);
1952
1953 rdentry = lookup_one_len(fname, dentry, flen);
1954 host_err = PTR_ERR(rdentry);
1955 if (IS_ERR(rdentry))
1956 goto out_unlock;
1957
1958 if (d_really_is_negative(rdentry)) {
1959 dput(rdentry);
1960 host_err = -ENOENT;
1961 goto out_unlock;
1962 }
1963 rinode = d_inode(rdentry);
1964 err = fh_fill_pre_attrs(fhp);
1965 if (err != nfs_ok)
1966 goto out_unlock;
1967
1968 ihold(rinode);
1969 if (!type)
1970 type = d_inode(rdentry)->i_mode & S_IFMT;
1971
1972 if (type != S_IFDIR) {
1973 int retries;
1974
1975 if (rdentry->d_sb->s_export_op->flags & EXPORT_OP_CLOSE_BEFORE_UNLINK)
1976 nfsd_close_cached_files(rdentry);
1977
1978 for (retries = 1;;) {
1979 host_err = vfs_unlink(&nop_mnt_idmap, dirp, rdentry, NULL);
1980 if (host_err != -EAGAIN || !retries--)
1981 break;
1982 if (!nfsd_wait_for_delegreturn(rqstp, rinode))
1983 break;
1984 }
1985 } else {
1986 host_err = vfs_rmdir(&nop_mnt_idmap, dirp, rdentry);
1987 }
1988 fh_fill_post_attrs(fhp);
1989
1990 inode_unlock(dirp);
1991 if (!host_err)
1992 host_err = commit_metadata(fhp);
1993 dput(rdentry);
1994 iput(rinode); /* truncate the inode here */
1995
1996out_drop_write:
1997 fh_drop_write(fhp);
1998out_nfserr:
1999 if (host_err == -EBUSY) {
2000 /* name is mounted-on. There is no perfect
2001 * error status.
2002 */
2003 if (nfsd_v4client(rqstp))
2004 err = nfserr_file_open;
2005 else
2006 err = nfserr_acces;
2007 } else {
2008 err = nfserrno(host_err);
2009 }
2010out:
2011 return err;
2012out_unlock:
2013 inode_unlock(dirp);
2014 goto out_drop_write;
2015}
2016
2017/*
2018 * We do this buffering because we must not call back into the file
2019 * system's ->lookup() method from the filldir callback. That may well
2020 * deadlock a number of file systems.
2021 *
2022 * This is based heavily on the implementation of same in XFS.
2023 */
2024struct buffered_dirent {
2025 u64 ino;
2026 loff_t offset;
2027 int namlen;
2028 unsigned int d_type;
2029 char name[];
2030};
2031
2032struct readdir_data {
2033 struct dir_context ctx;
2034 char *dirent;
2035 size_t used;
2036 int full;
2037};
2038
2039static bool nfsd_buffered_filldir(struct dir_context *ctx, const char *name,
2040 int namlen, loff_t offset, u64 ino,
2041 unsigned int d_type)
2042{
2043 struct readdir_data *buf =
2044 container_of(ctx, struct readdir_data, ctx);
2045 struct buffered_dirent *de = (void *)(buf->dirent + buf->used);
2046 unsigned int reclen;
2047
2048 reclen = ALIGN(sizeof(struct buffered_dirent) + namlen, sizeof(u64));
2049 if (buf->used + reclen > PAGE_SIZE) {
2050 buf->full = 1;
2051 return false;
2052 }
2053
2054 de->namlen = namlen;
2055 de->offset = offset;
2056 de->ino = ino;
2057 de->d_type = d_type;
2058 memcpy(de->name, name, namlen);
2059 buf->used += reclen;
2060
2061 return true;
2062}
2063
2064static __be32 nfsd_buffered_readdir(struct file *file, struct svc_fh *fhp,
2065 nfsd_filldir_t func, struct readdir_cd *cdp,
2066 loff_t *offsetp)
2067{
2068 struct buffered_dirent *de;
2069 int host_err;
2070 int size;
2071 loff_t offset;
2072 struct readdir_data buf = {
2073 .ctx.actor = nfsd_buffered_filldir,
2074 .dirent = (void *)__get_free_page(GFP_KERNEL)
2075 };
2076
2077 if (!buf.dirent)
2078 return nfserrno(-ENOMEM);
2079
2080 offset = *offsetp;
2081
2082 while (1) {
2083 unsigned int reclen;
2084
2085 cdp->err = nfserr_eof; /* will be cleared on successful read */
2086 buf.used = 0;
2087 buf.full = 0;
2088
2089 host_err = iterate_dir(file, &buf.ctx);
2090 if (buf.full)
2091 host_err = 0;
2092
2093 if (host_err < 0)
2094 break;
2095
2096 size = buf.used;
2097
2098 if (!size)
2099 break;
2100
2101 de = (struct buffered_dirent *)buf.dirent;
2102 while (size > 0) {
2103 offset = de->offset;
2104
2105 if (func(cdp, de->name, de->namlen, de->offset,
2106 de->ino, de->d_type))
2107 break;
2108
2109 if (cdp->err != nfs_ok)
2110 break;
2111
2112 trace_nfsd_dirent(fhp, de->ino, de->name, de->namlen);
2113
2114 reclen = ALIGN(sizeof(*de) + de->namlen,
2115 sizeof(u64));
2116 size -= reclen;
2117 de = (struct buffered_dirent *)((char *)de + reclen);
2118 }
2119 if (size > 0) /* We bailed out early */
2120 break;
2121
2122 offset = vfs_llseek(file, 0, SEEK_CUR);
2123 }
2124
2125 free_page((unsigned long)(buf.dirent));
2126
2127 if (host_err)
2128 return nfserrno(host_err);
2129
2130 *offsetp = offset;
2131 return cdp->err;
2132}
2133
2134/**
2135 * nfsd_readdir - Read entries from a directory
2136 * @rqstp: RPC transaction context
2137 * @fhp: NFS file handle of directory to be read
2138 * @offsetp: OUT: seek offset of final entry that was read
2139 * @cdp: OUT: an eof error value
2140 * @func: entry filler actor
2141 *
2142 * This implementation ignores the NFSv3/4 verifier cookie.
2143 *
2144 * NB: normal system calls hold file->f_pos_lock when calling
2145 * ->iterate_shared and ->llseek, but nfsd_readdir() does not.
2146 * Because the struct file acquired here is not visible to other
2147 * threads, it's internal state does not need mutex protection.
2148 *
2149 * Returns nfs_ok on success, otherwise an nfsstat code is
2150 * returned.
2151 */
2152__be32
2153nfsd_readdir(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t *offsetp,
2154 struct readdir_cd *cdp, nfsd_filldir_t func)
2155{
2156 __be32 err;
2157 struct file *file;
2158 loff_t offset = *offsetp;
2159 int may_flags = NFSD_MAY_READ;
2160
2161 /* NFSv2 only supports 32 bit cookies */
2162 if (rqstp->rq_vers > 2)
2163 may_flags |= NFSD_MAY_64BIT_COOKIE;
2164
2165 err = nfsd_open(rqstp, fhp, S_IFDIR, may_flags, &file);
2166 if (err)
2167 goto out;
2168
2169 offset = vfs_llseek(file, offset, SEEK_SET);
2170 if (offset < 0) {
2171 err = nfserrno((int)offset);
2172 goto out_close;
2173 }
2174
2175 err = nfsd_buffered_readdir(file, fhp, func, cdp, offsetp);
2176
2177 if (err == nfserr_eof || err == nfserr_toosmall)
2178 err = nfs_ok; /* can still be found in ->err */
2179out_close:
2180 fput(file);
2181out:
2182 return err;
2183}
2184
2185/*
2186 * Get file system stats
2187 * N.B. After this call fhp needs an fh_put
2188 */
2189__be32
2190nfsd_statfs(struct svc_rqst *rqstp, struct svc_fh *fhp, struct kstatfs *stat, int access)
2191{
2192 __be32 err;
2193
2194 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP | access);
2195 if (!err) {
2196 struct path path = {
2197 .mnt = fhp->fh_export->ex_path.mnt,
2198 .dentry = fhp->fh_dentry,
2199 };
2200 if (vfs_statfs(&path, stat))
2201 err = nfserr_io;
2202 }
2203 return err;
2204}
2205
2206static int exp_rdonly(struct svc_rqst *rqstp, struct svc_export *exp)
2207{
2208 return nfsexp_flags(rqstp, exp) & NFSEXP_READONLY;
2209}
2210
2211#ifdef CONFIG_NFSD_V4
2212/*
2213 * Helper function to translate error numbers. In the case of xattr operations,
2214 * some error codes need to be translated outside of the standard translations.
2215 *
2216 * ENODATA needs to be translated to nfserr_noxattr.
2217 * E2BIG to nfserr_xattr2big.
2218 *
2219 * Additionally, vfs_listxattr can return -ERANGE. This means that the
2220 * file has too many extended attributes to retrieve inside an
2221 * XATTR_LIST_MAX sized buffer. This is a bug in the xattr implementation:
2222 * filesystems will allow the adding of extended attributes until they hit
2223 * their own internal limit. This limit may be larger than XATTR_LIST_MAX.
2224 * So, at that point, the attributes are present and valid, but can't
2225 * be retrieved using listxattr, since the upper level xattr code enforces
2226 * the XATTR_LIST_MAX limit.
2227 *
2228 * This bug means that we need to deal with listxattr returning -ERANGE. The
2229 * best mapping is to return TOOSMALL.
2230 */
2231static __be32
2232nfsd_xattr_errno(int err)
2233{
2234 switch (err) {
2235 case -ENODATA:
2236 return nfserr_noxattr;
2237 case -E2BIG:
2238 return nfserr_xattr2big;
2239 case -ERANGE:
2240 return nfserr_toosmall;
2241 }
2242 return nfserrno(err);
2243}
2244
2245/*
2246 * Retrieve the specified user extended attribute. To avoid always
2247 * having to allocate the maximum size (since we are not getting
2248 * a maximum size from the RPC), do a probe + alloc. Hold a reader
2249 * lock on i_rwsem to prevent the extended attribute from changing
2250 * size while we're doing this.
2251 */
2252__be32
2253nfsd_getxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name,
2254 void **bufp, int *lenp)
2255{
2256 ssize_t len;
2257 __be32 err;
2258 char *buf;
2259 struct inode *inode;
2260 struct dentry *dentry;
2261
2262 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_READ);
2263 if (err)
2264 return err;
2265
2266 err = nfs_ok;
2267 dentry = fhp->fh_dentry;
2268 inode = d_inode(dentry);
2269
2270 inode_lock_shared(inode);
2271
2272 len = vfs_getxattr(&nop_mnt_idmap, dentry, name, NULL, 0);
2273
2274 /*
2275 * Zero-length attribute, just return.
2276 */
2277 if (len == 0) {
2278 *bufp = NULL;
2279 *lenp = 0;
2280 goto out;
2281 }
2282
2283 if (len < 0) {
2284 err = nfsd_xattr_errno(len);
2285 goto out;
2286 }
2287
2288 if (len > *lenp) {
2289 err = nfserr_toosmall;
2290 goto out;
2291 }
2292
2293 buf = kvmalloc(len, GFP_KERNEL);
2294 if (buf == NULL) {
2295 err = nfserr_jukebox;
2296 goto out;
2297 }
2298
2299 len = vfs_getxattr(&nop_mnt_idmap, dentry, name, buf, len);
2300 if (len <= 0) {
2301 kvfree(buf);
2302 buf = NULL;
2303 err = nfsd_xattr_errno(len);
2304 }
2305
2306 *lenp = len;
2307 *bufp = buf;
2308
2309out:
2310 inode_unlock_shared(inode);
2311
2312 return err;
2313}
2314
2315/*
2316 * Retrieve the xattr names. Since we can't know how many are
2317 * user extended attributes, we must get all attributes here,
2318 * and have the XDR encode filter out the "user." ones.
2319 *
2320 * While this could always just allocate an XATTR_LIST_MAX
2321 * buffer, that's a waste, so do a probe + allocate. To
2322 * avoid any changes between the probe and allocate, wrap
2323 * this in inode_lock.
2324 */
2325__be32
2326nfsd_listxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char **bufp,
2327 int *lenp)
2328{
2329 ssize_t len;
2330 __be32 err;
2331 char *buf;
2332 struct inode *inode;
2333 struct dentry *dentry;
2334
2335 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_READ);
2336 if (err)
2337 return err;
2338
2339 dentry = fhp->fh_dentry;
2340 inode = d_inode(dentry);
2341 *lenp = 0;
2342
2343 inode_lock_shared(inode);
2344
2345 len = vfs_listxattr(dentry, NULL, 0);
2346 if (len <= 0) {
2347 err = nfsd_xattr_errno(len);
2348 goto out;
2349 }
2350
2351 if (len > XATTR_LIST_MAX) {
2352 err = nfserr_xattr2big;
2353 goto out;
2354 }
2355
2356 buf = kvmalloc(len, GFP_KERNEL);
2357 if (buf == NULL) {
2358 err = nfserr_jukebox;
2359 goto out;
2360 }
2361
2362 len = vfs_listxattr(dentry, buf, len);
2363 if (len <= 0) {
2364 kvfree(buf);
2365 err = nfsd_xattr_errno(len);
2366 goto out;
2367 }
2368
2369 *lenp = len;
2370 *bufp = buf;
2371
2372 err = nfs_ok;
2373out:
2374 inode_unlock_shared(inode);
2375
2376 return err;
2377}
2378
2379/**
2380 * nfsd_removexattr - Remove an extended attribute
2381 * @rqstp: RPC transaction being executed
2382 * @fhp: NFS filehandle of object with xattr to remove
2383 * @name: name of xattr to remove (NUL-terminate)
2384 *
2385 * Pass in a NULL pointer for delegated_inode, and let the client deal
2386 * with NFS4ERR_DELAY (same as with e.g. setattr and remove).
2387 *
2388 * Returns nfs_ok on success, or an nfsstat in network byte order.
2389 */
2390__be32
2391nfsd_removexattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name)
2392{
2393 __be32 err;
2394 int ret;
2395
2396 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_WRITE);
2397 if (err)
2398 return err;
2399
2400 ret = fh_want_write(fhp);
2401 if (ret)
2402 return nfserrno(ret);
2403
2404 inode_lock(fhp->fh_dentry->d_inode);
2405 err = fh_fill_pre_attrs(fhp);
2406 if (err != nfs_ok)
2407 goto out_unlock;
2408 ret = __vfs_removexattr_locked(&nop_mnt_idmap, fhp->fh_dentry,
2409 name, NULL);
2410 err = nfsd_xattr_errno(ret);
2411 fh_fill_post_attrs(fhp);
2412out_unlock:
2413 inode_unlock(fhp->fh_dentry->d_inode);
2414 fh_drop_write(fhp);
2415
2416 return err;
2417}
2418
2419__be32
2420nfsd_setxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name,
2421 void *buf, u32 len, u32 flags)
2422{
2423 __be32 err;
2424 int ret;
2425
2426 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_WRITE);
2427 if (err)
2428 return err;
2429
2430 ret = fh_want_write(fhp);
2431 if (ret)
2432 return nfserrno(ret);
2433 inode_lock(fhp->fh_dentry->d_inode);
2434 err = fh_fill_pre_attrs(fhp);
2435 if (err != nfs_ok)
2436 goto out_unlock;
2437 ret = __vfs_setxattr_locked(&nop_mnt_idmap, fhp->fh_dentry,
2438 name, buf, len, flags, NULL);
2439 fh_fill_post_attrs(fhp);
2440 err = nfsd_xattr_errno(ret);
2441out_unlock:
2442 inode_unlock(fhp->fh_dentry->d_inode);
2443 fh_drop_write(fhp);
2444 return err;
2445}
2446#endif
2447
2448/*
2449 * Check for a user's access permissions to this inode.
2450 */
2451__be32
2452nfsd_permission(struct svc_rqst *rqstp, struct svc_export *exp,
2453 struct dentry *dentry, int acc)
2454{
2455 struct inode *inode = d_inode(dentry);
2456 int err;
2457
2458 if ((acc & NFSD_MAY_MASK) == NFSD_MAY_NOP)
2459 return 0;
2460#if 0
2461 dprintk("nfsd: permission 0x%x%s%s%s%s%s%s%s mode 0%o%s%s%s\n",
2462 acc,
2463 (acc & NFSD_MAY_READ)? " read" : "",
2464 (acc & NFSD_MAY_WRITE)? " write" : "",
2465 (acc & NFSD_MAY_EXEC)? " exec" : "",
2466 (acc & NFSD_MAY_SATTR)? " sattr" : "",
2467 (acc & NFSD_MAY_TRUNC)? " trunc" : "",
2468 (acc & NFSD_MAY_LOCK)? " lock" : "",
2469 (acc & NFSD_MAY_OWNER_OVERRIDE)? " owneroverride" : "",
2470 inode->i_mode,
2471 IS_IMMUTABLE(inode)? " immut" : "",
2472 IS_APPEND(inode)? " append" : "",
2473 __mnt_is_readonly(exp->ex_path.mnt)? " ro" : "");
2474 dprintk(" owner %d/%d user %d/%d\n",
2475 inode->i_uid, inode->i_gid, current_fsuid(), current_fsgid());
2476#endif
2477
2478 /* Normally we reject any write/sattr etc access on a read-only file
2479 * system. But if it is IRIX doing check on write-access for a
2480 * device special file, we ignore rofs.
2481 */
2482 if (!(acc & NFSD_MAY_LOCAL_ACCESS))
2483 if (acc & (NFSD_MAY_WRITE | NFSD_MAY_SATTR | NFSD_MAY_TRUNC)) {
2484 if (exp_rdonly(rqstp, exp) ||
2485 __mnt_is_readonly(exp->ex_path.mnt))
2486 return nfserr_rofs;
2487 if (/* (acc & NFSD_MAY_WRITE) && */ IS_IMMUTABLE(inode))
2488 return nfserr_perm;
2489 }
2490 if ((acc & NFSD_MAY_TRUNC) && IS_APPEND(inode))
2491 return nfserr_perm;
2492
2493 if (acc & NFSD_MAY_LOCK) {
2494 /* If we cannot rely on authentication in NLM requests,
2495 * just allow locks, otherwise require read permission, or
2496 * ownership
2497 */
2498 if (exp->ex_flags & NFSEXP_NOAUTHNLM)
2499 return 0;
2500 else
2501 acc = NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE;
2502 }
2503 /*
2504 * The file owner always gets access permission for accesses that
2505 * would normally be checked at open time. This is to make
2506 * file access work even when the client has done a fchmod(fd, 0).
2507 *
2508 * However, `cp foo bar' should fail nevertheless when bar is
2509 * readonly. A sensible way to do this might be to reject all
2510 * attempts to truncate a read-only file, because a creat() call
2511 * always implies file truncation.
2512 * ... but this isn't really fair. A process may reasonably call
2513 * ftruncate on an open file descriptor on a file with perm 000.
2514 * We must trust the client to do permission checking - using "ACCESS"
2515 * with NFSv3.
2516 */
2517 if ((acc & NFSD_MAY_OWNER_OVERRIDE) &&
2518 uid_eq(inode->i_uid, current_fsuid()))
2519 return 0;
2520
2521 /* This assumes NFSD_MAY_{READ,WRITE,EXEC} == MAY_{READ,WRITE,EXEC} */
2522 err = inode_permission(&nop_mnt_idmap, inode,
2523 acc & (MAY_READ | MAY_WRITE | MAY_EXEC));
2524
2525 /* Allow read access to binaries even when mode 111 */
2526 if (err == -EACCES && S_ISREG(inode->i_mode) &&
2527 (acc == (NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE) ||
2528 acc == (NFSD_MAY_READ | NFSD_MAY_READ_IF_EXEC)))
2529 err = inode_permission(&nop_mnt_idmap, inode, MAY_EXEC);
2530
2531 return err? nfserrno(err) : 0;
2532}