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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/slab.h>
30#include <linux/uaccess.h>
31#include <linux/exportfs.h>
32#include <linux/writeback.h>
33#include <linux/security.h>
34
35#ifdef CONFIG_NFSD_V3
36#include "xdr3.h"
37#endif /* CONFIG_NFSD_V3 */
38
39#ifdef CONFIG_NFSD_V4
40#include "../internal.h"
41#include "acl.h"
42#include "idmap.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 * Called from nfsd_lookup and encode_dirent. Check if we have crossed
54 * a mount point.
55 * Returns -EAGAIN or -ETIMEDOUT leaving *dpp and *expp unchanged,
56 * or nfs_ok having possibly changed *dpp and *expp
57 */
58int
59nfsd_cross_mnt(struct svc_rqst *rqstp, struct dentry **dpp,
60 struct svc_export **expp)
61{
62 struct svc_export *exp = *expp, *exp2 = NULL;
63 struct dentry *dentry = *dpp;
64 struct path path = {.mnt = mntget(exp->ex_path.mnt),
65 .dentry = dget(dentry)};
66 int err = 0;
67
68 err = follow_down(&path);
69 if (err < 0)
70 goto out;
71 if (path.mnt == exp->ex_path.mnt && path.dentry == dentry &&
72 nfsd_mountpoint(dentry, exp) == 2) {
73 /* This is only a mountpoint in some other namespace */
74 path_put(&path);
75 goto out;
76 }
77
78 exp2 = rqst_exp_get_by_name(rqstp, &path);
79 if (IS_ERR(exp2)) {
80 err = PTR_ERR(exp2);
81 /*
82 * We normally allow NFS clients to continue
83 * "underneath" a mountpoint that is not exported.
84 * The exception is V4ROOT, where no traversal is ever
85 * allowed without an explicit export of the new
86 * directory.
87 */
88 if (err == -ENOENT && !(exp->ex_flags & NFSEXP_V4ROOT))
89 err = 0;
90 path_put(&path);
91 goto out;
92 }
93 if (nfsd_v4client(rqstp) ||
94 (exp->ex_flags & NFSEXP_CROSSMOUNT) || EX_NOHIDE(exp2)) {
95 /* successfully crossed mount point */
96 /*
97 * This is subtle: path.dentry is *not* on path.mnt
98 * at this point. The only reason we are safe is that
99 * original mnt is pinned down by exp, so we should
100 * put path *before* putting exp
101 */
102 *dpp = path.dentry;
103 path.dentry = dentry;
104 *expp = exp2;
105 exp2 = exp;
106 }
107 path_put(&path);
108 exp_put(exp2);
109out:
110 return err;
111}
112
113static void follow_to_parent(struct path *path)
114{
115 struct dentry *dp;
116
117 while (path->dentry == path->mnt->mnt_root && follow_up(path))
118 ;
119 dp = dget_parent(path->dentry);
120 dput(path->dentry);
121 path->dentry = dp;
122}
123
124static int nfsd_lookup_parent(struct svc_rqst *rqstp, struct dentry *dparent, struct svc_export **exp, struct dentry **dentryp)
125{
126 struct svc_export *exp2;
127 struct path path = {.mnt = mntget((*exp)->ex_path.mnt),
128 .dentry = dget(dparent)};
129
130 follow_to_parent(&path);
131
132 exp2 = rqst_exp_parent(rqstp, &path);
133 if (PTR_ERR(exp2) == -ENOENT) {
134 *dentryp = dget(dparent);
135 } else if (IS_ERR(exp2)) {
136 path_put(&path);
137 return PTR_ERR(exp2);
138 } else {
139 *dentryp = dget(path.dentry);
140 exp_put(*exp);
141 *exp = exp2;
142 }
143 path_put(&path);
144 return 0;
145}
146
147/*
148 * For nfsd purposes, we treat V4ROOT exports as though there was an
149 * export at *every* directory.
150 * We return:
151 * '1' if this dentry *must* be an export point,
152 * '2' if it might be, if there is really a mount here, and
153 * '0' if there is no chance of an export point here.
154 */
155int nfsd_mountpoint(struct dentry *dentry, struct svc_export *exp)
156{
157 if (!d_inode(dentry))
158 return 0;
159 if (exp->ex_flags & NFSEXP_V4ROOT)
160 return 1;
161 if (nfsd4_is_junction(dentry))
162 return 1;
163 if (d_mountpoint(dentry))
164 /*
165 * Might only be a mountpoint in a different namespace,
166 * but we need to check.
167 */
168 return 2;
169 return 0;
170}
171
172__be32
173nfsd_lookup_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp,
174 const char *name, unsigned int len,
175 struct svc_export **exp_ret, struct dentry **dentry_ret)
176{
177 struct svc_export *exp;
178 struct dentry *dparent;
179 struct dentry *dentry;
180 int host_err;
181
182 dprintk("nfsd: nfsd_lookup(fh %s, %.*s)\n", SVCFH_fmt(fhp), len,name);
183
184 dparent = fhp->fh_dentry;
185 exp = exp_get(fhp->fh_export);
186
187 /* Lookup the name, but don't follow links */
188 if (isdotent(name, len)) {
189 if (len==1)
190 dentry = dget(dparent);
191 else if (dparent != exp->ex_path.dentry)
192 dentry = dget_parent(dparent);
193 else if (!EX_NOHIDE(exp) && !nfsd_v4client(rqstp))
194 dentry = dget(dparent); /* .. == . just like at / */
195 else {
196 /* checking mountpoint crossing is very different when stepping up */
197 host_err = nfsd_lookup_parent(rqstp, dparent, &exp, &dentry);
198 if (host_err)
199 goto out_nfserr;
200 }
201 } else {
202 /*
203 * In the nfsd4_open() case, this may be held across
204 * subsequent open and delegation acquisition which may
205 * need to take the child's i_mutex:
206 */
207 fh_lock_nested(fhp, I_MUTEX_PARENT);
208 dentry = lookup_one_len(name, dparent, len);
209 host_err = PTR_ERR(dentry);
210 if (IS_ERR(dentry))
211 goto out_nfserr;
212 if (nfsd_mountpoint(dentry, exp)) {
213 /*
214 * We don't need the i_mutex after all. It's
215 * still possible we could open this (regular
216 * files can be mountpoints too), but the
217 * i_mutex is just there to prevent renames of
218 * something that we might be about to delegate,
219 * and a mountpoint won't be renamed:
220 */
221 fh_unlock(fhp);
222 if ((host_err = nfsd_cross_mnt(rqstp, &dentry, &exp))) {
223 dput(dentry);
224 goto out_nfserr;
225 }
226 }
227 }
228 *dentry_ret = dentry;
229 *exp_ret = exp;
230 return 0;
231
232out_nfserr:
233 exp_put(exp);
234 return nfserrno(host_err);
235}
236
237/*
238 * Look up one component of a pathname.
239 * N.B. After this call _both_ fhp and resfh need an fh_put
240 *
241 * If the lookup would cross a mountpoint, and the mounted filesystem
242 * is exported to the client with NFSEXP_NOHIDE, then the lookup is
243 * accepted as it stands and the mounted directory is
244 * returned. Otherwise the covered directory is returned.
245 * NOTE: this mountpoint crossing is not supported properly by all
246 * clients and is explicitly disallowed for NFSv3
247 * NeilBrown <neilb@cse.unsw.edu.au>
248 */
249__be32
250nfsd_lookup(struct svc_rqst *rqstp, struct svc_fh *fhp, const char *name,
251 unsigned int len, struct svc_fh *resfh)
252{
253 struct svc_export *exp;
254 struct dentry *dentry;
255 __be32 err;
256
257 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC);
258 if (err)
259 return err;
260 err = nfsd_lookup_dentry(rqstp, fhp, name, len, &exp, &dentry);
261 if (err)
262 return err;
263 err = check_nfsd_access(exp, rqstp);
264 if (err)
265 goto out;
266 /*
267 * Note: we compose the file handle now, but as the
268 * dentry may be negative, it may need to be updated.
269 */
270 err = fh_compose(resfh, exp, dentry, fhp);
271 if (!err && d_really_is_negative(dentry))
272 err = nfserr_noent;
273out:
274 dput(dentry);
275 exp_put(exp);
276 return err;
277}
278
279/*
280 * Commit metadata changes to stable storage.
281 */
282static int
283commit_inode_metadata(struct inode *inode)
284{
285 const struct export_operations *export_ops = inode->i_sb->s_export_op;
286
287 if (export_ops->commit_metadata)
288 return export_ops->commit_metadata(inode);
289 return sync_inode_metadata(inode, 1);
290}
291
292static int
293commit_metadata(struct svc_fh *fhp)
294{
295 struct inode *inode = d_inode(fhp->fh_dentry);
296
297 if (!EX_ISSYNC(fhp->fh_export))
298 return 0;
299 return commit_inode_metadata(inode);
300}
301
302/*
303 * Go over the attributes and take care of the small differences between
304 * NFS semantics and what Linux expects.
305 */
306static void
307nfsd_sanitize_attrs(struct inode *inode, struct iattr *iap)
308{
309 /* sanitize the mode change */
310 if (iap->ia_valid & ATTR_MODE) {
311 iap->ia_mode &= S_IALLUGO;
312 iap->ia_mode |= (inode->i_mode & ~S_IALLUGO);
313 }
314
315 /* Revoke setuid/setgid on chown */
316 if (!S_ISDIR(inode->i_mode) &&
317 ((iap->ia_valid & ATTR_UID) || (iap->ia_valid & ATTR_GID))) {
318 iap->ia_valid |= ATTR_KILL_PRIV;
319 if (iap->ia_valid & ATTR_MODE) {
320 /* we're setting mode too, just clear the s*id bits */
321 iap->ia_mode &= ~S_ISUID;
322 if (iap->ia_mode & S_IXGRP)
323 iap->ia_mode &= ~S_ISGID;
324 } else {
325 /* set ATTR_KILL_* bits and let VFS handle it */
326 iap->ia_valid |= (ATTR_KILL_SUID | ATTR_KILL_SGID);
327 }
328 }
329}
330
331static __be32
332nfsd_get_write_access(struct svc_rqst *rqstp, struct svc_fh *fhp,
333 struct iattr *iap)
334{
335 struct inode *inode = d_inode(fhp->fh_dentry);
336 int host_err;
337
338 if (iap->ia_size < inode->i_size) {
339 __be32 err;
340
341 err = nfsd_permission(rqstp, fhp->fh_export, fhp->fh_dentry,
342 NFSD_MAY_TRUNC | NFSD_MAY_OWNER_OVERRIDE);
343 if (err)
344 return err;
345 }
346
347 host_err = get_write_access(inode);
348 if (host_err)
349 goto out_nfserrno;
350
351 host_err = locks_verify_truncate(inode, NULL, iap->ia_size);
352 if (host_err)
353 goto out_put_write_access;
354 return 0;
355
356out_put_write_access:
357 put_write_access(inode);
358out_nfserrno:
359 return nfserrno(host_err);
360}
361
362/*
363 * Set various file attributes. After this call fhp needs an fh_put.
364 */
365__be32
366nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
367 int check_guard, time64_t guardtime)
368{
369 struct dentry *dentry;
370 struct inode *inode;
371 int accmode = NFSD_MAY_SATTR;
372 umode_t ftype = 0;
373 __be32 err;
374 int host_err;
375 bool get_write_count;
376 bool size_change = (iap->ia_valid & ATTR_SIZE);
377
378 if (iap->ia_valid & ATTR_SIZE) {
379 accmode |= NFSD_MAY_WRITE|NFSD_MAY_OWNER_OVERRIDE;
380 ftype = S_IFREG;
381 }
382
383 /*
384 * If utimes(2) and friends are called with times not NULL, we should
385 * not set NFSD_MAY_WRITE bit. Otherwise fh_verify->nfsd_permission
386 * will return EACCES, when the caller's effective UID does not match
387 * the owner of the file, and the caller is not privileged. In this
388 * situation, we should return EPERM(notify_change will return this).
389 */
390 if (iap->ia_valid & (ATTR_ATIME | ATTR_MTIME)) {
391 accmode |= NFSD_MAY_OWNER_OVERRIDE;
392 if (!(iap->ia_valid & (ATTR_ATIME_SET | ATTR_MTIME_SET)))
393 accmode |= NFSD_MAY_WRITE;
394 }
395
396 /* Callers that do fh_verify should do the fh_want_write: */
397 get_write_count = !fhp->fh_dentry;
398
399 /* Get inode */
400 err = fh_verify(rqstp, fhp, ftype, accmode);
401 if (err)
402 return err;
403 if (get_write_count) {
404 host_err = fh_want_write(fhp);
405 if (host_err)
406 goto out;
407 }
408
409 dentry = fhp->fh_dentry;
410 inode = d_inode(dentry);
411
412 /* Ignore any mode updates on symlinks */
413 if (S_ISLNK(inode->i_mode))
414 iap->ia_valid &= ~ATTR_MODE;
415
416 if (!iap->ia_valid)
417 return 0;
418
419 nfsd_sanitize_attrs(inode, iap);
420
421 if (check_guard && guardtime != inode->i_ctime.tv_sec)
422 return nfserr_notsync;
423
424 /*
425 * The size case is special, it changes the file in addition to the
426 * attributes, and file systems don't expect it to be mixed with
427 * "random" attribute changes. We thus split out the size change
428 * into a separate call to ->setattr, and do the rest as a separate
429 * setattr call.
430 */
431 if (size_change) {
432 err = nfsd_get_write_access(rqstp, fhp, iap);
433 if (err)
434 return err;
435 }
436
437 fh_lock(fhp);
438 if (size_change) {
439 /*
440 * RFC5661, Section 18.30.4:
441 * Changing the size of a file with SETATTR indirectly
442 * changes the time_modify and change attributes.
443 *
444 * (and similar for the older RFCs)
445 */
446 struct iattr size_attr = {
447 .ia_valid = ATTR_SIZE | ATTR_CTIME | ATTR_MTIME,
448 .ia_size = iap->ia_size,
449 };
450
451 host_err = notify_change(dentry, &size_attr, NULL);
452 if (host_err)
453 goto out_unlock;
454 iap->ia_valid &= ~ATTR_SIZE;
455
456 /*
457 * Avoid the additional setattr call below if the only other
458 * attribute that the client sends is the mtime, as we update
459 * it as part of the size change above.
460 */
461 if ((iap->ia_valid & ~ATTR_MTIME) == 0)
462 goto out_unlock;
463 }
464
465 iap->ia_valid |= ATTR_CTIME;
466 host_err = notify_change(dentry, iap, NULL);
467
468out_unlock:
469 fh_unlock(fhp);
470 if (size_change)
471 put_write_access(inode);
472out:
473 if (!host_err)
474 host_err = commit_metadata(fhp);
475 return nfserrno(host_err);
476}
477
478#if defined(CONFIG_NFSD_V4)
479/*
480 * NFS junction information is stored in an extended attribute.
481 */
482#define NFSD_JUNCTION_XATTR_NAME XATTR_TRUSTED_PREFIX "junction.nfs"
483
484/**
485 * nfsd4_is_junction - Test if an object could be an NFS junction
486 *
487 * @dentry: object to test
488 *
489 * Returns 1 if "dentry" appears to contain NFS junction information.
490 * Otherwise 0 is returned.
491 */
492int nfsd4_is_junction(struct dentry *dentry)
493{
494 struct inode *inode = d_inode(dentry);
495
496 if (inode == NULL)
497 return 0;
498 if (inode->i_mode & S_IXUGO)
499 return 0;
500 if (!(inode->i_mode & S_ISVTX))
501 return 0;
502 if (vfs_getxattr(dentry, NFSD_JUNCTION_XATTR_NAME, NULL, 0) <= 0)
503 return 0;
504 return 1;
505}
506#ifdef CONFIG_NFSD_V4_SECURITY_LABEL
507__be32 nfsd4_set_nfs4_label(struct svc_rqst *rqstp, struct svc_fh *fhp,
508 struct xdr_netobj *label)
509{
510 __be32 error;
511 int host_error;
512 struct dentry *dentry;
513
514 error = fh_verify(rqstp, fhp, 0 /* S_IFREG */, NFSD_MAY_SATTR);
515 if (error)
516 return error;
517
518 dentry = fhp->fh_dentry;
519
520 inode_lock(d_inode(dentry));
521 host_error = security_inode_setsecctx(dentry, label->data, label->len);
522 inode_unlock(d_inode(dentry));
523 return nfserrno(host_error);
524}
525#else
526__be32 nfsd4_set_nfs4_label(struct svc_rqst *rqstp, struct svc_fh *fhp,
527 struct xdr_netobj *label)
528{
529 return nfserr_notsupp;
530}
531#endif
532
533__be32 nfsd4_clone_file_range(struct nfsd_file *nf_src, u64 src_pos,
534 struct nfsd_file *nf_dst, u64 dst_pos, u64 count, bool sync)
535{
536 struct file *src = nf_src->nf_file;
537 struct file *dst = nf_dst->nf_file;
538 loff_t cloned;
539 __be32 ret = 0;
540
541 down_write(&nf_dst->nf_rwsem);
542 cloned = vfs_clone_file_range(src, src_pos, dst, dst_pos, count, 0);
543 if (cloned < 0) {
544 ret = nfserrno(cloned);
545 goto out_err;
546 }
547 if (count && cloned != count) {
548 ret = nfserrno(-EINVAL);
549 goto out_err;
550 }
551 if (sync) {
552 loff_t dst_end = count ? dst_pos + count - 1 : LLONG_MAX;
553 int status = vfs_fsync_range(dst, dst_pos, dst_end, 0);
554
555 if (!status)
556 status = commit_inode_metadata(file_inode(src));
557 if (status < 0) {
558 nfsd_reset_boot_verifier(net_generic(nf_dst->nf_net,
559 nfsd_net_id));
560 ret = nfserrno(status);
561 }
562 }
563out_err:
564 up_write(&nf_dst->nf_rwsem);
565 return ret;
566}
567
568ssize_t nfsd_copy_file_range(struct file *src, u64 src_pos, struct file *dst,
569 u64 dst_pos, u64 count)
570{
571
572 /*
573 * Limit copy to 4MB to prevent indefinitely blocking an nfsd
574 * thread and client rpc slot. The choice of 4MB is somewhat
575 * arbitrary. We might instead base this on r/wsize, or make it
576 * tunable, or use a time instead of a byte limit, or implement
577 * asynchronous copy. In theory a client could also recognize a
578 * limit like this and pipeline multiple COPY requests.
579 */
580 count = min_t(u64, count, 1 << 22);
581 return vfs_copy_file_range(src, src_pos, dst, dst_pos, count, 0);
582}
583
584__be32 nfsd4_vfs_fallocate(struct svc_rqst *rqstp, struct svc_fh *fhp,
585 struct file *file, loff_t offset, loff_t len,
586 int flags)
587{
588 int error;
589
590 if (!S_ISREG(file_inode(file)->i_mode))
591 return nfserr_inval;
592
593 error = vfs_fallocate(file, flags, offset, len);
594 if (!error)
595 error = commit_metadata(fhp);
596
597 return nfserrno(error);
598}
599#endif /* defined(CONFIG_NFSD_V4) */
600
601#ifdef CONFIG_NFSD_V3
602/*
603 * Check server access rights to a file system object
604 */
605struct accessmap {
606 u32 access;
607 int how;
608};
609static struct accessmap nfs3_regaccess[] = {
610 { NFS3_ACCESS_READ, NFSD_MAY_READ },
611 { NFS3_ACCESS_EXECUTE, NFSD_MAY_EXEC },
612 { NFS3_ACCESS_MODIFY, NFSD_MAY_WRITE|NFSD_MAY_TRUNC },
613 { NFS3_ACCESS_EXTEND, NFSD_MAY_WRITE },
614
615#ifdef CONFIG_NFSD_V4
616 { NFS4_ACCESS_XAREAD, NFSD_MAY_READ },
617 { NFS4_ACCESS_XAWRITE, NFSD_MAY_WRITE },
618 { NFS4_ACCESS_XALIST, NFSD_MAY_READ },
619#endif
620
621 { 0, 0 }
622};
623
624static struct accessmap nfs3_diraccess[] = {
625 { NFS3_ACCESS_READ, NFSD_MAY_READ },
626 { NFS3_ACCESS_LOOKUP, NFSD_MAY_EXEC },
627 { NFS3_ACCESS_MODIFY, NFSD_MAY_EXEC|NFSD_MAY_WRITE|NFSD_MAY_TRUNC},
628 { NFS3_ACCESS_EXTEND, NFSD_MAY_EXEC|NFSD_MAY_WRITE },
629 { NFS3_ACCESS_DELETE, NFSD_MAY_REMOVE },
630
631#ifdef CONFIG_NFSD_V4
632 { NFS4_ACCESS_XAREAD, NFSD_MAY_READ },
633 { NFS4_ACCESS_XAWRITE, NFSD_MAY_WRITE },
634 { NFS4_ACCESS_XALIST, NFSD_MAY_READ },
635#endif
636
637 { 0, 0 }
638};
639
640static struct accessmap nfs3_anyaccess[] = {
641 /* Some clients - Solaris 2.6 at least, make an access call
642 * to the server to check for access for things like /dev/null
643 * (which really, the server doesn't care about). So
644 * We provide simple access checking for them, looking
645 * mainly at mode bits, and we make sure to ignore read-only
646 * filesystem checks
647 */
648 { NFS3_ACCESS_READ, NFSD_MAY_READ },
649 { NFS3_ACCESS_EXECUTE, NFSD_MAY_EXEC },
650 { NFS3_ACCESS_MODIFY, NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS },
651 { NFS3_ACCESS_EXTEND, NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS },
652
653 { 0, 0 }
654};
655
656__be32
657nfsd_access(struct svc_rqst *rqstp, struct svc_fh *fhp, u32 *access, u32 *supported)
658{
659 struct accessmap *map;
660 struct svc_export *export;
661 struct dentry *dentry;
662 u32 query, result = 0, sresult = 0;
663 __be32 error;
664
665 error = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP);
666 if (error)
667 goto out;
668
669 export = fhp->fh_export;
670 dentry = fhp->fh_dentry;
671
672 if (d_is_reg(dentry))
673 map = nfs3_regaccess;
674 else if (d_is_dir(dentry))
675 map = nfs3_diraccess;
676 else
677 map = nfs3_anyaccess;
678
679
680 query = *access;
681 for (; map->access; map++) {
682 if (map->access & query) {
683 __be32 err2;
684
685 sresult |= map->access;
686
687 err2 = nfsd_permission(rqstp, export, dentry, map->how);
688 switch (err2) {
689 case nfs_ok:
690 result |= map->access;
691 break;
692
693 /* the following error codes just mean the access was not allowed,
694 * rather than an error occurred */
695 case nfserr_rofs:
696 case nfserr_acces:
697 case nfserr_perm:
698 /* simply don't "or" in the access bit. */
699 break;
700 default:
701 error = err2;
702 goto out;
703 }
704 }
705 }
706 *access = result;
707 if (supported)
708 *supported = sresult;
709
710 out:
711 return error;
712}
713#endif /* CONFIG_NFSD_V3 */
714
715int nfsd_open_break_lease(struct inode *inode, int access)
716{
717 unsigned int mode;
718
719 if (access & NFSD_MAY_NOT_BREAK_LEASE)
720 return 0;
721 mode = (access & NFSD_MAY_WRITE) ? O_WRONLY : O_RDONLY;
722 return break_lease(inode, mode | O_NONBLOCK);
723}
724
725/*
726 * Open an existing file or directory.
727 * The may_flags argument indicates the type of open (read/write/lock)
728 * and additional flags.
729 * N.B. After this call fhp needs an fh_put
730 */
731static __be32
732__nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type,
733 int may_flags, struct file **filp)
734{
735 struct path path;
736 struct inode *inode;
737 struct file *file;
738 int flags = O_RDONLY|O_LARGEFILE;
739 __be32 err;
740 int host_err = 0;
741
742 path.mnt = fhp->fh_export->ex_path.mnt;
743 path.dentry = fhp->fh_dentry;
744 inode = d_inode(path.dentry);
745
746 /* Disallow write access to files with the append-only bit set
747 * or any access when mandatory locking enabled
748 */
749 err = nfserr_perm;
750 if (IS_APPEND(inode) && (may_flags & NFSD_MAY_WRITE))
751 goto out;
752 /*
753 * We must ignore files (but only files) which might have mandatory
754 * locks on them because there is no way to know if the accesser has
755 * the lock.
756 */
757 if (S_ISREG((inode)->i_mode) && mandatory_lock(inode))
758 goto out;
759
760 if (!inode->i_fop)
761 goto out;
762
763 host_err = nfsd_open_break_lease(inode, may_flags);
764 if (host_err) /* NOMEM or WOULDBLOCK */
765 goto out_nfserr;
766
767 if (may_flags & NFSD_MAY_WRITE) {
768 if (may_flags & NFSD_MAY_READ)
769 flags = O_RDWR|O_LARGEFILE;
770 else
771 flags = O_WRONLY|O_LARGEFILE;
772 }
773
774 file = dentry_open(&path, flags, current_cred());
775 if (IS_ERR(file)) {
776 host_err = PTR_ERR(file);
777 goto out_nfserr;
778 }
779
780 host_err = ima_file_check(file, may_flags);
781 if (host_err) {
782 fput(file);
783 goto out_nfserr;
784 }
785
786 if (may_flags & NFSD_MAY_64BIT_COOKIE)
787 file->f_mode |= FMODE_64BITHASH;
788 else
789 file->f_mode |= FMODE_32BITHASH;
790
791 *filp = file;
792out_nfserr:
793 err = nfserrno(host_err);
794out:
795 return err;
796}
797
798__be32
799nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type,
800 int may_flags, struct file **filp)
801{
802 __be32 err;
803
804 validate_process_creds();
805 /*
806 * If we get here, then the client has already done an "open",
807 * and (hopefully) checked permission - so allow OWNER_OVERRIDE
808 * in case a chmod has now revoked permission.
809 *
810 * Arguably we should also allow the owner override for
811 * directories, but we never have and it doesn't seem to have
812 * caused anyone a problem. If we were to change this, note
813 * also that our filldir callbacks would need a variant of
814 * lookup_one_len that doesn't check permissions.
815 */
816 if (type == S_IFREG)
817 may_flags |= NFSD_MAY_OWNER_OVERRIDE;
818 err = fh_verify(rqstp, fhp, type, may_flags);
819 if (!err)
820 err = __nfsd_open(rqstp, fhp, type, may_flags, filp);
821 validate_process_creds();
822 return err;
823}
824
825__be32
826nfsd_open_verified(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type,
827 int may_flags, struct file **filp)
828{
829 __be32 err;
830
831 validate_process_creds();
832 err = __nfsd_open(rqstp, fhp, type, may_flags, filp);
833 validate_process_creds();
834 return err;
835}
836
837/*
838 * Grab and keep cached pages associated with a file in the svc_rqst
839 * so that they can be passed to the network sendmsg/sendpage routines
840 * directly. They will be released after the sending has completed.
841 */
842static int
843nfsd_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
844 struct splice_desc *sd)
845{
846 struct svc_rqst *rqstp = sd->u.data;
847 struct page **pp = rqstp->rq_next_page;
848 struct page *page = buf->page;
849 size_t size;
850
851 size = sd->len;
852
853 if (rqstp->rq_res.page_len == 0) {
854 get_page(page);
855 put_page(*rqstp->rq_next_page);
856 *(rqstp->rq_next_page++) = page;
857 rqstp->rq_res.page_base = buf->offset;
858 rqstp->rq_res.page_len = size;
859 } else if (page != pp[-1]) {
860 get_page(page);
861 if (*rqstp->rq_next_page)
862 put_page(*rqstp->rq_next_page);
863 *(rqstp->rq_next_page++) = page;
864 rqstp->rq_res.page_len += size;
865 } else
866 rqstp->rq_res.page_len += size;
867
868 return size;
869}
870
871static int nfsd_direct_splice_actor(struct pipe_inode_info *pipe,
872 struct splice_desc *sd)
873{
874 return __splice_from_pipe(pipe, sd, nfsd_splice_actor);
875}
876
877static u32 nfsd_eof_on_read(struct file *file, loff_t offset, ssize_t len,
878 size_t expected)
879{
880 if (expected != 0 && len == 0)
881 return 1;
882 if (offset+len >= i_size_read(file_inode(file)))
883 return 1;
884 return 0;
885}
886
887static __be32 nfsd_finish_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
888 struct file *file, loff_t offset,
889 unsigned long *count, u32 *eof, ssize_t host_err)
890{
891 if (host_err >= 0) {
892 nfsdstats.io_read += host_err;
893 *eof = nfsd_eof_on_read(file, offset, host_err, *count);
894 *count = host_err;
895 fsnotify_access(file);
896 trace_nfsd_read_io_done(rqstp, fhp, offset, *count);
897 return 0;
898 } else {
899 trace_nfsd_read_err(rqstp, fhp, offset, host_err);
900 return nfserrno(host_err);
901 }
902}
903
904__be32 nfsd_splice_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
905 struct file *file, loff_t offset, unsigned long *count,
906 u32 *eof)
907{
908 struct splice_desc sd = {
909 .len = 0,
910 .total_len = *count,
911 .pos = offset,
912 .u.data = rqstp,
913 };
914 ssize_t host_err;
915
916 trace_nfsd_read_splice(rqstp, fhp, offset, *count);
917 rqstp->rq_next_page = rqstp->rq_respages + 1;
918 host_err = splice_direct_to_actor(file, &sd, nfsd_direct_splice_actor);
919 return nfsd_finish_read(rqstp, fhp, file, offset, count, eof, host_err);
920}
921
922__be32 nfsd_readv(struct svc_rqst *rqstp, struct svc_fh *fhp,
923 struct file *file, loff_t offset,
924 struct kvec *vec, int vlen, unsigned long *count,
925 u32 *eof)
926{
927 struct iov_iter iter;
928 loff_t ppos = offset;
929 ssize_t host_err;
930
931 trace_nfsd_read_vector(rqstp, fhp, offset, *count);
932 iov_iter_kvec(&iter, READ, vec, vlen, *count);
933 host_err = vfs_iter_read(file, &iter, &ppos, 0);
934 return nfsd_finish_read(rqstp, fhp, file, offset, count, eof, host_err);
935}
936
937/*
938 * Gathered writes: If another process is currently writing to the file,
939 * there's a high chance this is another nfsd (triggered by a bulk write
940 * from a client's biod). Rather than syncing the file with each write
941 * request, we sleep for 10 msec.
942 *
943 * I don't know if this roughly approximates C. Juszak's idea of
944 * gathered writes, but it's a nice and simple solution (IMHO), and it
945 * seems to work:-)
946 *
947 * Note: we do this only in the NFSv2 case, since v3 and higher have a
948 * better tool (separate unstable writes and commits) for solving this
949 * problem.
950 */
951static int wait_for_concurrent_writes(struct file *file)
952{
953 struct inode *inode = file_inode(file);
954 static ino_t last_ino;
955 static dev_t last_dev;
956 int err = 0;
957
958 if (atomic_read(&inode->i_writecount) > 1
959 || (last_ino == inode->i_ino && last_dev == inode->i_sb->s_dev)) {
960 dprintk("nfsd: write defer %d\n", task_pid_nr(current));
961 msleep(10);
962 dprintk("nfsd: write resume %d\n", task_pid_nr(current));
963 }
964
965 if (inode->i_state & I_DIRTY) {
966 dprintk("nfsd: write sync %d\n", task_pid_nr(current));
967 err = vfs_fsync(file, 0);
968 }
969 last_ino = inode->i_ino;
970 last_dev = inode->i_sb->s_dev;
971 return err;
972}
973
974__be32
975nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf,
976 loff_t offset, struct kvec *vec, int vlen,
977 unsigned long *cnt, int stable,
978 __be32 *verf)
979{
980 struct file *file = nf->nf_file;
981 struct svc_export *exp;
982 struct iov_iter iter;
983 __be32 nfserr;
984 int host_err;
985 int use_wgather;
986 loff_t pos = offset;
987 unsigned int pflags = current->flags;
988 rwf_t flags = 0;
989
990 trace_nfsd_write_opened(rqstp, fhp, offset, *cnt);
991
992 if (test_bit(RQ_LOCAL, &rqstp->rq_flags))
993 /*
994 * We want throttling in balance_dirty_pages()
995 * and shrink_inactive_list() to only consider
996 * the backingdev we are writing to, so that nfs to
997 * localhost doesn't cause nfsd to lock up due to all
998 * the client's dirty pages or its congested queue.
999 */
1000 current->flags |= PF_LOCAL_THROTTLE;
1001
1002 exp = fhp->fh_export;
1003 use_wgather = (rqstp->rq_vers == 2) && EX_WGATHER(exp);
1004
1005 if (!EX_ISSYNC(exp))
1006 stable = NFS_UNSTABLE;
1007
1008 if (stable && !use_wgather)
1009 flags |= RWF_SYNC;
1010
1011 iov_iter_kvec(&iter, WRITE, vec, vlen, *cnt);
1012 if (flags & RWF_SYNC) {
1013 down_write(&nf->nf_rwsem);
1014 host_err = vfs_iter_write(file, &iter, &pos, flags);
1015 if (host_err < 0)
1016 nfsd_reset_boot_verifier(net_generic(SVC_NET(rqstp),
1017 nfsd_net_id));
1018 up_write(&nf->nf_rwsem);
1019 } else {
1020 down_read(&nf->nf_rwsem);
1021 if (verf)
1022 nfsd_copy_boot_verifier(verf,
1023 net_generic(SVC_NET(rqstp),
1024 nfsd_net_id));
1025 host_err = vfs_iter_write(file, &iter, &pos, flags);
1026 up_read(&nf->nf_rwsem);
1027 }
1028 if (host_err < 0) {
1029 nfsd_reset_boot_verifier(net_generic(SVC_NET(rqstp),
1030 nfsd_net_id));
1031 goto out_nfserr;
1032 }
1033 *cnt = host_err;
1034 nfsdstats.io_write += *cnt;
1035 fsnotify_modify(file);
1036
1037 if (stable && use_wgather) {
1038 host_err = wait_for_concurrent_writes(file);
1039 if (host_err < 0)
1040 nfsd_reset_boot_verifier(net_generic(SVC_NET(rqstp),
1041 nfsd_net_id));
1042 }
1043
1044out_nfserr:
1045 if (host_err >= 0) {
1046 trace_nfsd_write_io_done(rqstp, fhp, offset, *cnt);
1047 nfserr = nfs_ok;
1048 } else {
1049 trace_nfsd_write_err(rqstp, fhp, offset, host_err);
1050 nfserr = nfserrno(host_err);
1051 }
1052 if (test_bit(RQ_LOCAL, &rqstp->rq_flags))
1053 current_restore_flags(pflags, PF_LOCAL_THROTTLE);
1054 return nfserr;
1055}
1056
1057/*
1058 * Read data from a file. count must contain the requested read count
1059 * on entry. On return, *count contains the number of bytes actually read.
1060 * N.B. After this call fhp needs an fh_put
1061 */
1062__be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
1063 loff_t offset, struct kvec *vec, int vlen, unsigned long *count,
1064 u32 *eof)
1065{
1066 struct nfsd_file *nf;
1067 struct file *file;
1068 __be32 err;
1069
1070 trace_nfsd_read_start(rqstp, fhp, offset, *count);
1071 err = nfsd_file_acquire(rqstp, fhp, NFSD_MAY_READ, &nf);
1072 if (err)
1073 return err;
1074
1075 file = nf->nf_file;
1076 if (file->f_op->splice_read && test_bit(RQ_SPLICE_OK, &rqstp->rq_flags))
1077 err = nfsd_splice_read(rqstp, fhp, file, offset, count, eof);
1078 else
1079 err = nfsd_readv(rqstp, fhp, file, offset, vec, vlen, count, eof);
1080
1081 nfsd_file_put(nf);
1082
1083 trace_nfsd_read_done(rqstp, fhp, offset, *count);
1084
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, loff_t offset,
1095 struct kvec *vec, int vlen, unsigned long *cnt, int stable,
1096 __be32 *verf)
1097{
1098 struct nfsd_file *nf;
1099 __be32 err;
1100
1101 trace_nfsd_write_start(rqstp, fhp, offset, *cnt);
1102
1103 err = nfsd_file_acquire(rqstp, fhp, NFSD_MAY_WRITE, &nf);
1104 if (err)
1105 goto out;
1106
1107 err = nfsd_vfs_write(rqstp, fhp, nf, offset, vec,
1108 vlen, cnt, stable, verf);
1109 nfsd_file_put(nf);
1110out:
1111 trace_nfsd_write_done(rqstp, fhp, offset, *cnt);
1112 return err;
1113}
1114
1115#ifdef CONFIG_NFSD_V3
1116/*
1117 * Commit all pending writes to stable storage.
1118 *
1119 * Note: we only guarantee that data that lies within the range specified
1120 * by the 'offset' and 'count' parameters will be synced.
1121 *
1122 * Unfortunately we cannot lock the file to make sure we return full WCC
1123 * data to the client, as locking happens lower down in the filesystem.
1124 */
1125__be32
1126nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp,
1127 loff_t offset, unsigned long count, __be32 *verf)
1128{
1129 struct nfsd_file *nf;
1130 loff_t end = LLONG_MAX;
1131 __be32 err = nfserr_inval;
1132
1133 if (offset < 0)
1134 goto out;
1135 if (count != 0) {
1136 end = offset + (loff_t)count - 1;
1137 if (end < offset)
1138 goto out;
1139 }
1140
1141 err = nfsd_file_acquire(rqstp, fhp,
1142 NFSD_MAY_WRITE|NFSD_MAY_NOT_BREAK_LEASE, &nf);
1143 if (err)
1144 goto out;
1145 if (EX_ISSYNC(fhp->fh_export)) {
1146 int err2;
1147
1148 down_write(&nf->nf_rwsem);
1149 err2 = vfs_fsync_range(nf->nf_file, offset, end, 0);
1150 switch (err2) {
1151 case 0:
1152 nfsd_copy_boot_verifier(verf, net_generic(nf->nf_net,
1153 nfsd_net_id));
1154 break;
1155 case -EINVAL:
1156 err = nfserr_notsupp;
1157 break;
1158 default:
1159 err = nfserrno(err2);
1160 nfsd_reset_boot_verifier(net_generic(nf->nf_net,
1161 nfsd_net_id));
1162 }
1163 up_write(&nf->nf_rwsem);
1164 } else
1165 nfsd_copy_boot_verifier(verf, net_generic(nf->nf_net,
1166 nfsd_net_id));
1167
1168 nfsd_file_put(nf);
1169out:
1170 return err;
1171}
1172#endif /* CONFIG_NFSD_V3 */
1173
1174static __be32
1175nfsd_create_setattr(struct svc_rqst *rqstp, struct svc_fh *resfhp,
1176 struct iattr *iap)
1177{
1178 /*
1179 * Mode has already been set earlier in create:
1180 */
1181 iap->ia_valid &= ~ATTR_MODE;
1182 /*
1183 * Setting uid/gid works only for root. Irix appears to
1184 * send along the gid on create when it tries to implement
1185 * setgid directories via NFS:
1186 */
1187 if (!uid_eq(current_fsuid(), GLOBAL_ROOT_UID))
1188 iap->ia_valid &= ~(ATTR_UID|ATTR_GID);
1189 if (iap->ia_valid)
1190 return nfsd_setattr(rqstp, resfhp, iap, 0, (time64_t)0);
1191 /* Callers expect file metadata to be committed here */
1192 return nfserrno(commit_metadata(resfhp));
1193}
1194
1195/* HPUX client sometimes creates a file in mode 000, and sets size to 0.
1196 * setting size to 0 may fail for some specific file systems by the permission
1197 * checking which requires WRITE permission but the mode is 000.
1198 * we ignore the resizing(to 0) on the just new created file, since the size is
1199 * 0 after file created.
1200 *
1201 * call this only after vfs_create() is called.
1202 * */
1203static void
1204nfsd_check_ignore_resizing(struct iattr *iap)
1205{
1206 if ((iap->ia_valid & ATTR_SIZE) && (iap->ia_size == 0))
1207 iap->ia_valid &= ~ATTR_SIZE;
1208}
1209
1210/* The parent directory should already be locked: */
1211__be32
1212nfsd_create_locked(struct svc_rqst *rqstp, struct svc_fh *fhp,
1213 char *fname, int flen, struct iattr *iap,
1214 int type, dev_t rdev, struct svc_fh *resfhp)
1215{
1216 struct dentry *dentry, *dchild;
1217 struct inode *dirp;
1218 __be32 err;
1219 __be32 err2;
1220 int host_err;
1221
1222 dentry = fhp->fh_dentry;
1223 dirp = d_inode(dentry);
1224
1225 dchild = dget(resfhp->fh_dentry);
1226 if (!fhp->fh_locked) {
1227 WARN_ONCE(1, "nfsd_create: parent %pd2 not locked!\n",
1228 dentry);
1229 err = nfserr_io;
1230 goto out;
1231 }
1232
1233 err = nfsd_permission(rqstp, fhp->fh_export, dentry, NFSD_MAY_CREATE);
1234 if (err)
1235 goto out;
1236
1237 if (!(iap->ia_valid & ATTR_MODE))
1238 iap->ia_mode = 0;
1239 iap->ia_mode = (iap->ia_mode & S_IALLUGO) | type;
1240
1241 if (!IS_POSIXACL(dirp))
1242 iap->ia_mode &= ~current_umask();
1243
1244 err = 0;
1245 host_err = 0;
1246 switch (type) {
1247 case S_IFREG:
1248 host_err = vfs_create(dirp, dchild, iap->ia_mode, true);
1249 if (!host_err)
1250 nfsd_check_ignore_resizing(iap);
1251 break;
1252 case S_IFDIR:
1253 host_err = vfs_mkdir(dirp, dchild, iap->ia_mode);
1254 if (!host_err && unlikely(d_unhashed(dchild))) {
1255 struct dentry *d;
1256 d = lookup_one_len(dchild->d_name.name,
1257 dchild->d_parent,
1258 dchild->d_name.len);
1259 if (IS_ERR(d)) {
1260 host_err = PTR_ERR(d);
1261 break;
1262 }
1263 if (unlikely(d_is_negative(d))) {
1264 dput(d);
1265 err = nfserr_serverfault;
1266 goto out;
1267 }
1268 dput(resfhp->fh_dentry);
1269 resfhp->fh_dentry = dget(d);
1270 err = fh_update(resfhp);
1271 dput(dchild);
1272 dchild = d;
1273 if (err)
1274 goto out;
1275 }
1276 break;
1277 case S_IFCHR:
1278 case S_IFBLK:
1279 case S_IFIFO:
1280 case S_IFSOCK:
1281 host_err = vfs_mknod(dirp, dchild, iap->ia_mode, rdev);
1282 break;
1283 default:
1284 printk(KERN_WARNING "nfsd: bad file type %o in nfsd_create\n",
1285 type);
1286 host_err = -EINVAL;
1287 }
1288 if (host_err < 0)
1289 goto out_nfserr;
1290
1291 err = nfsd_create_setattr(rqstp, resfhp, iap);
1292
1293 /*
1294 * nfsd_create_setattr already committed the child. Transactional
1295 * filesystems had a chance to commit changes for both parent and
1296 * child simultaneously making the following commit_metadata a
1297 * noop.
1298 */
1299 err2 = nfserrno(commit_metadata(fhp));
1300 if (err2)
1301 err = err2;
1302 /*
1303 * Update the file handle to get the new inode info.
1304 */
1305 if (!err)
1306 err = fh_update(resfhp);
1307out:
1308 dput(dchild);
1309 return err;
1310
1311out_nfserr:
1312 err = nfserrno(host_err);
1313 goto out;
1314}
1315
1316/*
1317 * Create a filesystem object (regular, directory, special).
1318 * Note that the parent directory is left locked.
1319 *
1320 * N.B. Every call to nfsd_create needs an fh_put for _both_ fhp and resfhp
1321 */
1322__be32
1323nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
1324 char *fname, int flen, struct iattr *iap,
1325 int type, dev_t rdev, struct svc_fh *resfhp)
1326{
1327 struct dentry *dentry, *dchild = NULL;
1328 __be32 err;
1329 int host_err;
1330
1331 if (isdotent(fname, flen))
1332 return nfserr_exist;
1333
1334 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_NOP);
1335 if (err)
1336 return err;
1337
1338 dentry = fhp->fh_dentry;
1339
1340 host_err = fh_want_write(fhp);
1341 if (host_err)
1342 return nfserrno(host_err);
1343
1344 fh_lock_nested(fhp, I_MUTEX_PARENT);
1345 dchild = lookup_one_len(fname, dentry, flen);
1346 host_err = PTR_ERR(dchild);
1347 if (IS_ERR(dchild))
1348 return nfserrno(host_err);
1349 err = fh_compose(resfhp, fhp->fh_export, dchild, fhp);
1350 /*
1351 * We unconditionally drop our ref to dchild as fh_compose will have
1352 * already grabbed its own ref for it.
1353 */
1354 dput(dchild);
1355 if (err)
1356 return err;
1357 return nfsd_create_locked(rqstp, fhp, fname, flen, iap, type,
1358 rdev, resfhp);
1359}
1360
1361#ifdef CONFIG_NFSD_V3
1362
1363/*
1364 * NFSv3 and NFSv4 version of nfsd_create
1365 */
1366__be32
1367do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
1368 char *fname, int flen, struct iattr *iap,
1369 struct svc_fh *resfhp, int createmode, u32 *verifier,
1370 bool *truncp, bool *created)
1371{
1372 struct dentry *dentry, *dchild = NULL;
1373 struct inode *dirp;
1374 __be32 err;
1375 int host_err;
1376 __u32 v_mtime=0, v_atime=0;
1377
1378 err = nfserr_perm;
1379 if (!flen)
1380 goto out;
1381 err = nfserr_exist;
1382 if (isdotent(fname, flen))
1383 goto out;
1384 if (!(iap->ia_valid & ATTR_MODE))
1385 iap->ia_mode = 0;
1386 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC);
1387 if (err)
1388 goto out;
1389
1390 dentry = fhp->fh_dentry;
1391 dirp = d_inode(dentry);
1392
1393 host_err = fh_want_write(fhp);
1394 if (host_err)
1395 goto out_nfserr;
1396
1397 fh_lock_nested(fhp, I_MUTEX_PARENT);
1398
1399 /*
1400 * Compose the response file handle.
1401 */
1402 dchild = lookup_one_len(fname, dentry, flen);
1403 host_err = PTR_ERR(dchild);
1404 if (IS_ERR(dchild))
1405 goto out_nfserr;
1406
1407 /* If file doesn't exist, check for permissions to create one */
1408 if (d_really_is_negative(dchild)) {
1409 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
1410 if (err)
1411 goto out;
1412 }
1413
1414 err = fh_compose(resfhp, fhp->fh_export, dchild, fhp);
1415 if (err)
1416 goto out;
1417
1418 if (nfsd_create_is_exclusive(createmode)) {
1419 /* solaris7 gets confused (bugid 4218508) if these have
1420 * the high bit set, so just clear the high bits. If this is
1421 * ever changed to use different attrs for storing the
1422 * verifier, then do_open_lookup() will also need to be fixed
1423 * accordingly.
1424 */
1425 v_mtime = verifier[0]&0x7fffffff;
1426 v_atime = verifier[1]&0x7fffffff;
1427 }
1428
1429 if (d_really_is_positive(dchild)) {
1430 err = 0;
1431
1432 switch (createmode) {
1433 case NFS3_CREATE_UNCHECKED:
1434 if (! d_is_reg(dchild))
1435 goto out;
1436 else if (truncp) {
1437 /* in nfsv4, we need to treat this case a little
1438 * differently. we don't want to truncate the
1439 * file now; this would be wrong if the OPEN
1440 * fails for some other reason. furthermore,
1441 * if the size is nonzero, we should ignore it
1442 * according to spec!
1443 */
1444 *truncp = (iap->ia_valid & ATTR_SIZE) && !iap->ia_size;
1445 }
1446 else {
1447 iap->ia_valid &= ATTR_SIZE;
1448 goto set_attr;
1449 }
1450 break;
1451 case NFS3_CREATE_EXCLUSIVE:
1452 if ( d_inode(dchild)->i_mtime.tv_sec == v_mtime
1453 && d_inode(dchild)->i_atime.tv_sec == v_atime
1454 && d_inode(dchild)->i_size == 0 ) {
1455 if (created)
1456 *created = true;
1457 break;
1458 }
1459 fallthrough;
1460 case NFS4_CREATE_EXCLUSIVE4_1:
1461 if ( d_inode(dchild)->i_mtime.tv_sec == v_mtime
1462 && d_inode(dchild)->i_atime.tv_sec == v_atime
1463 && d_inode(dchild)->i_size == 0 ) {
1464 if (created)
1465 *created = true;
1466 goto set_attr;
1467 }
1468 fallthrough;
1469 case NFS3_CREATE_GUARDED:
1470 err = nfserr_exist;
1471 }
1472 fh_drop_write(fhp);
1473 goto out;
1474 }
1475
1476 if (!IS_POSIXACL(dirp))
1477 iap->ia_mode &= ~current_umask();
1478
1479 host_err = vfs_create(dirp, dchild, iap->ia_mode, true);
1480 if (host_err < 0) {
1481 fh_drop_write(fhp);
1482 goto out_nfserr;
1483 }
1484 if (created)
1485 *created = true;
1486
1487 nfsd_check_ignore_resizing(iap);
1488
1489 if (nfsd_create_is_exclusive(createmode)) {
1490 /* Cram the verifier into atime/mtime */
1491 iap->ia_valid = ATTR_MTIME|ATTR_ATIME
1492 | ATTR_MTIME_SET|ATTR_ATIME_SET;
1493 /* XXX someone who knows this better please fix it for nsec */
1494 iap->ia_mtime.tv_sec = v_mtime;
1495 iap->ia_atime.tv_sec = v_atime;
1496 iap->ia_mtime.tv_nsec = 0;
1497 iap->ia_atime.tv_nsec = 0;
1498 }
1499
1500 set_attr:
1501 err = nfsd_create_setattr(rqstp, resfhp, iap);
1502
1503 /*
1504 * nfsd_create_setattr already committed the child
1505 * (and possibly also the parent).
1506 */
1507 if (!err)
1508 err = nfserrno(commit_metadata(fhp));
1509
1510 /*
1511 * Update the filehandle to get the new inode info.
1512 */
1513 if (!err)
1514 err = fh_update(resfhp);
1515
1516 out:
1517 fh_unlock(fhp);
1518 if (dchild && !IS_ERR(dchild))
1519 dput(dchild);
1520 fh_drop_write(fhp);
1521 return err;
1522
1523 out_nfserr:
1524 err = nfserrno(host_err);
1525 goto out;
1526}
1527#endif /* CONFIG_NFSD_V3 */
1528
1529/*
1530 * Read a symlink. On entry, *lenp must contain the maximum path length that
1531 * fits into the buffer. On return, it contains the true length.
1532 * N.B. After this call fhp needs an fh_put
1533 */
1534__be32
1535nfsd_readlink(struct svc_rqst *rqstp, struct svc_fh *fhp, char *buf, int *lenp)
1536{
1537 __be32 err;
1538 const char *link;
1539 struct path path;
1540 DEFINE_DELAYED_CALL(done);
1541 int len;
1542
1543 err = fh_verify(rqstp, fhp, S_IFLNK, NFSD_MAY_NOP);
1544 if (unlikely(err))
1545 return err;
1546
1547 path.mnt = fhp->fh_export->ex_path.mnt;
1548 path.dentry = fhp->fh_dentry;
1549
1550 if (unlikely(!d_is_symlink(path.dentry)))
1551 return nfserr_inval;
1552
1553 touch_atime(&path);
1554
1555 link = vfs_get_link(path.dentry, &done);
1556 if (IS_ERR(link))
1557 return nfserrno(PTR_ERR(link));
1558
1559 len = strlen(link);
1560 if (len < *lenp)
1561 *lenp = len;
1562 memcpy(buf, link, *lenp);
1563 do_delayed_call(&done);
1564 return 0;
1565}
1566
1567/*
1568 * Create a symlink and look up its inode
1569 * N.B. After this call _both_ fhp and resfhp need an fh_put
1570 */
1571__be32
1572nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp,
1573 char *fname, int flen,
1574 char *path,
1575 struct svc_fh *resfhp)
1576{
1577 struct dentry *dentry, *dnew;
1578 __be32 err, cerr;
1579 int host_err;
1580
1581 err = nfserr_noent;
1582 if (!flen || path[0] == '\0')
1583 goto out;
1584 err = nfserr_exist;
1585 if (isdotent(fname, flen))
1586 goto out;
1587
1588 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
1589 if (err)
1590 goto out;
1591
1592 host_err = fh_want_write(fhp);
1593 if (host_err)
1594 goto out_nfserr;
1595
1596 fh_lock(fhp);
1597 dentry = fhp->fh_dentry;
1598 dnew = lookup_one_len(fname, dentry, flen);
1599 host_err = PTR_ERR(dnew);
1600 if (IS_ERR(dnew))
1601 goto out_nfserr;
1602
1603 host_err = vfs_symlink(d_inode(dentry), dnew, path);
1604 err = nfserrno(host_err);
1605 if (!err)
1606 err = nfserrno(commit_metadata(fhp));
1607 fh_unlock(fhp);
1608
1609 fh_drop_write(fhp);
1610
1611 cerr = fh_compose(resfhp, fhp->fh_export, dnew, fhp);
1612 dput(dnew);
1613 if (err==0) err = cerr;
1614out:
1615 return err;
1616
1617out_nfserr:
1618 err = nfserrno(host_err);
1619 goto out;
1620}
1621
1622/*
1623 * Create a hardlink
1624 * N.B. After this call _both_ ffhp and tfhp need an fh_put
1625 */
1626__be32
1627nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp,
1628 char *name, int len, struct svc_fh *tfhp)
1629{
1630 struct dentry *ddir, *dnew, *dold;
1631 struct inode *dirp;
1632 __be32 err;
1633 int host_err;
1634
1635 err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_CREATE);
1636 if (err)
1637 goto out;
1638 err = fh_verify(rqstp, tfhp, 0, NFSD_MAY_NOP);
1639 if (err)
1640 goto out;
1641 err = nfserr_isdir;
1642 if (d_is_dir(tfhp->fh_dentry))
1643 goto out;
1644 err = nfserr_perm;
1645 if (!len)
1646 goto out;
1647 err = nfserr_exist;
1648 if (isdotent(name, len))
1649 goto out;
1650
1651 host_err = fh_want_write(tfhp);
1652 if (host_err) {
1653 err = nfserrno(host_err);
1654 goto out;
1655 }
1656
1657 fh_lock_nested(ffhp, I_MUTEX_PARENT);
1658 ddir = ffhp->fh_dentry;
1659 dirp = d_inode(ddir);
1660
1661 dnew = lookup_one_len(name, ddir, len);
1662 host_err = PTR_ERR(dnew);
1663 if (IS_ERR(dnew))
1664 goto out_nfserr;
1665
1666 dold = tfhp->fh_dentry;
1667
1668 err = nfserr_noent;
1669 if (d_really_is_negative(dold))
1670 goto out_dput;
1671 host_err = vfs_link(dold, dirp, dnew, NULL);
1672 if (!host_err) {
1673 err = nfserrno(commit_metadata(ffhp));
1674 if (!err)
1675 err = nfserrno(commit_metadata(tfhp));
1676 } else {
1677 if (host_err == -EXDEV && rqstp->rq_vers == 2)
1678 err = nfserr_acces;
1679 else
1680 err = nfserrno(host_err);
1681 }
1682out_dput:
1683 dput(dnew);
1684out_unlock:
1685 fh_unlock(ffhp);
1686 fh_drop_write(tfhp);
1687out:
1688 return err;
1689
1690out_nfserr:
1691 err = nfserrno(host_err);
1692 goto out_unlock;
1693}
1694
1695static void
1696nfsd_close_cached_files(struct dentry *dentry)
1697{
1698 struct inode *inode = d_inode(dentry);
1699
1700 if (inode && S_ISREG(inode->i_mode))
1701 nfsd_file_close_inode_sync(inode);
1702}
1703
1704static bool
1705nfsd_has_cached_files(struct dentry *dentry)
1706{
1707 bool ret = false;
1708 struct inode *inode = d_inode(dentry);
1709
1710 if (inode && S_ISREG(inode->i_mode))
1711 ret = nfsd_file_is_cached(inode);
1712 return ret;
1713}
1714
1715/*
1716 * Rename a file
1717 * N.B. After this call _both_ ffhp and tfhp need an fh_put
1718 */
1719__be32
1720nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
1721 struct svc_fh *tfhp, char *tname, int tlen)
1722{
1723 struct dentry *fdentry, *tdentry, *odentry, *ndentry, *trap;
1724 struct inode *fdir, *tdir;
1725 __be32 err;
1726 int host_err;
1727 bool has_cached = false;
1728
1729 err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_REMOVE);
1730 if (err)
1731 goto out;
1732 err = fh_verify(rqstp, tfhp, S_IFDIR, NFSD_MAY_CREATE);
1733 if (err)
1734 goto out;
1735
1736 fdentry = ffhp->fh_dentry;
1737 fdir = d_inode(fdentry);
1738
1739 tdentry = tfhp->fh_dentry;
1740 tdir = d_inode(tdentry);
1741
1742 err = nfserr_perm;
1743 if (!flen || isdotent(fname, flen) || !tlen || isdotent(tname, tlen))
1744 goto out;
1745
1746retry:
1747 host_err = fh_want_write(ffhp);
1748 if (host_err) {
1749 err = nfserrno(host_err);
1750 goto out;
1751 }
1752
1753 /* cannot use fh_lock as we need deadlock protective ordering
1754 * so do it by hand */
1755 trap = lock_rename(tdentry, fdentry);
1756 ffhp->fh_locked = tfhp->fh_locked = true;
1757 fill_pre_wcc(ffhp);
1758 fill_pre_wcc(tfhp);
1759
1760 odentry = lookup_one_len(fname, fdentry, flen);
1761 host_err = PTR_ERR(odentry);
1762 if (IS_ERR(odentry))
1763 goto out_nfserr;
1764
1765 host_err = -ENOENT;
1766 if (d_really_is_negative(odentry))
1767 goto out_dput_old;
1768 host_err = -EINVAL;
1769 if (odentry == trap)
1770 goto out_dput_old;
1771
1772 ndentry = lookup_one_len(tname, tdentry, tlen);
1773 host_err = PTR_ERR(ndentry);
1774 if (IS_ERR(ndentry))
1775 goto out_dput_old;
1776 host_err = -ENOTEMPTY;
1777 if (ndentry == trap)
1778 goto out_dput_new;
1779
1780 host_err = -EXDEV;
1781 if (ffhp->fh_export->ex_path.mnt != tfhp->fh_export->ex_path.mnt)
1782 goto out_dput_new;
1783 if (ffhp->fh_export->ex_path.dentry != tfhp->fh_export->ex_path.dentry)
1784 goto out_dput_new;
1785
1786 if (nfsd_has_cached_files(ndentry)) {
1787 has_cached = true;
1788 goto out_dput_old;
1789 } else {
1790 host_err = vfs_rename(fdir, odentry, tdir, ndentry, NULL, 0);
1791 if (!host_err) {
1792 host_err = commit_metadata(tfhp);
1793 if (!host_err)
1794 host_err = commit_metadata(ffhp);
1795 }
1796 }
1797 out_dput_new:
1798 dput(ndentry);
1799 out_dput_old:
1800 dput(odentry);
1801 out_nfserr:
1802 err = nfserrno(host_err);
1803 /*
1804 * We cannot rely on fh_unlock on the two filehandles,
1805 * as that would do the wrong thing if the two directories
1806 * were the same, so again we do it by hand.
1807 */
1808 if (!has_cached) {
1809 fill_post_wcc(ffhp);
1810 fill_post_wcc(tfhp);
1811 }
1812 unlock_rename(tdentry, fdentry);
1813 ffhp->fh_locked = tfhp->fh_locked = false;
1814 fh_drop_write(ffhp);
1815
1816 /*
1817 * If the target dentry has cached open files, then we need to try to
1818 * close them prior to doing the rename. Flushing delayed fput
1819 * shouldn't be done with locks held however, so we delay it until this
1820 * point and then reattempt the whole shebang.
1821 */
1822 if (has_cached) {
1823 has_cached = false;
1824 nfsd_close_cached_files(ndentry);
1825 dput(ndentry);
1826 goto retry;
1827 }
1828out:
1829 return err;
1830}
1831
1832/*
1833 * Unlink a file or directory
1834 * N.B. After this call fhp needs an fh_put
1835 */
1836__be32
1837nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
1838 char *fname, int flen)
1839{
1840 struct dentry *dentry, *rdentry;
1841 struct inode *dirp;
1842 __be32 err;
1843 int host_err;
1844
1845 err = nfserr_acces;
1846 if (!flen || isdotent(fname, flen))
1847 goto out;
1848 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_REMOVE);
1849 if (err)
1850 goto out;
1851
1852 host_err = fh_want_write(fhp);
1853 if (host_err)
1854 goto out_nfserr;
1855
1856 fh_lock_nested(fhp, I_MUTEX_PARENT);
1857 dentry = fhp->fh_dentry;
1858 dirp = d_inode(dentry);
1859
1860 rdentry = lookup_one_len(fname, dentry, flen);
1861 host_err = PTR_ERR(rdentry);
1862 if (IS_ERR(rdentry))
1863 goto out_drop_write;
1864
1865 if (d_really_is_negative(rdentry)) {
1866 dput(rdentry);
1867 host_err = -ENOENT;
1868 goto out_drop_write;
1869 }
1870
1871 if (!type)
1872 type = d_inode(rdentry)->i_mode & S_IFMT;
1873
1874 if (type != S_IFDIR) {
1875 nfsd_close_cached_files(rdentry);
1876 host_err = vfs_unlink(dirp, rdentry, NULL);
1877 } else {
1878 host_err = vfs_rmdir(dirp, rdentry);
1879 }
1880
1881 if (!host_err)
1882 host_err = commit_metadata(fhp);
1883 dput(rdentry);
1884
1885out_drop_write:
1886 fh_drop_write(fhp);
1887out_nfserr:
1888 if (host_err == -EBUSY) {
1889 /* name is mounted-on. There is no perfect
1890 * error status.
1891 */
1892 if (nfsd_v4client(rqstp))
1893 err = nfserr_file_open;
1894 else
1895 err = nfserr_acces;
1896 } else {
1897 err = nfserrno(host_err);
1898 }
1899out:
1900 return err;
1901}
1902
1903/*
1904 * We do this buffering because we must not call back into the file
1905 * system's ->lookup() method from the filldir callback. That may well
1906 * deadlock a number of file systems.
1907 *
1908 * This is based heavily on the implementation of same in XFS.
1909 */
1910struct buffered_dirent {
1911 u64 ino;
1912 loff_t offset;
1913 int namlen;
1914 unsigned int d_type;
1915 char name[];
1916};
1917
1918struct readdir_data {
1919 struct dir_context ctx;
1920 char *dirent;
1921 size_t used;
1922 int full;
1923};
1924
1925static int nfsd_buffered_filldir(struct dir_context *ctx, const char *name,
1926 int namlen, loff_t offset, u64 ino,
1927 unsigned int d_type)
1928{
1929 struct readdir_data *buf =
1930 container_of(ctx, struct readdir_data, ctx);
1931 struct buffered_dirent *de = (void *)(buf->dirent + buf->used);
1932 unsigned int reclen;
1933
1934 reclen = ALIGN(sizeof(struct buffered_dirent) + namlen, sizeof(u64));
1935 if (buf->used + reclen > PAGE_SIZE) {
1936 buf->full = 1;
1937 return -EINVAL;
1938 }
1939
1940 de->namlen = namlen;
1941 de->offset = offset;
1942 de->ino = ino;
1943 de->d_type = d_type;
1944 memcpy(de->name, name, namlen);
1945 buf->used += reclen;
1946
1947 return 0;
1948}
1949
1950static __be32 nfsd_buffered_readdir(struct file *file, nfsd_filldir_t func,
1951 struct readdir_cd *cdp, loff_t *offsetp)
1952{
1953 struct buffered_dirent *de;
1954 int host_err;
1955 int size;
1956 loff_t offset;
1957 struct readdir_data buf = {
1958 .ctx.actor = nfsd_buffered_filldir,
1959 .dirent = (void *)__get_free_page(GFP_KERNEL)
1960 };
1961
1962 if (!buf.dirent)
1963 return nfserrno(-ENOMEM);
1964
1965 offset = *offsetp;
1966
1967 while (1) {
1968 unsigned int reclen;
1969
1970 cdp->err = nfserr_eof; /* will be cleared on successful read */
1971 buf.used = 0;
1972 buf.full = 0;
1973
1974 host_err = iterate_dir(file, &buf.ctx);
1975 if (buf.full)
1976 host_err = 0;
1977
1978 if (host_err < 0)
1979 break;
1980
1981 size = buf.used;
1982
1983 if (!size)
1984 break;
1985
1986 de = (struct buffered_dirent *)buf.dirent;
1987 while (size > 0) {
1988 offset = de->offset;
1989
1990 if (func(cdp, de->name, de->namlen, de->offset,
1991 de->ino, de->d_type))
1992 break;
1993
1994 if (cdp->err != nfs_ok)
1995 break;
1996
1997 reclen = ALIGN(sizeof(*de) + de->namlen,
1998 sizeof(u64));
1999 size -= reclen;
2000 de = (struct buffered_dirent *)((char *)de + reclen);
2001 }
2002 if (size > 0) /* We bailed out early */
2003 break;
2004
2005 offset = vfs_llseek(file, 0, SEEK_CUR);
2006 }
2007
2008 free_page((unsigned long)(buf.dirent));
2009
2010 if (host_err)
2011 return nfserrno(host_err);
2012
2013 *offsetp = offset;
2014 return cdp->err;
2015}
2016
2017/*
2018 * Read entries from a directory.
2019 * The NFSv3/4 verifier we ignore for now.
2020 */
2021__be32
2022nfsd_readdir(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t *offsetp,
2023 struct readdir_cd *cdp, nfsd_filldir_t func)
2024{
2025 __be32 err;
2026 struct file *file;
2027 loff_t offset = *offsetp;
2028 int may_flags = NFSD_MAY_READ;
2029
2030 /* NFSv2 only supports 32 bit cookies */
2031 if (rqstp->rq_vers > 2)
2032 may_flags |= NFSD_MAY_64BIT_COOKIE;
2033
2034 err = nfsd_open(rqstp, fhp, S_IFDIR, may_flags, &file);
2035 if (err)
2036 goto out;
2037
2038 offset = vfs_llseek(file, offset, SEEK_SET);
2039 if (offset < 0) {
2040 err = nfserrno((int)offset);
2041 goto out_close;
2042 }
2043
2044 err = nfsd_buffered_readdir(file, func, cdp, offsetp);
2045
2046 if (err == nfserr_eof || err == nfserr_toosmall)
2047 err = nfs_ok; /* can still be found in ->err */
2048out_close:
2049 fput(file);
2050out:
2051 return err;
2052}
2053
2054/*
2055 * Get file system stats
2056 * N.B. After this call fhp needs an fh_put
2057 */
2058__be32
2059nfsd_statfs(struct svc_rqst *rqstp, struct svc_fh *fhp, struct kstatfs *stat, int access)
2060{
2061 __be32 err;
2062
2063 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP | access);
2064 if (!err) {
2065 struct path path = {
2066 .mnt = fhp->fh_export->ex_path.mnt,
2067 .dentry = fhp->fh_dentry,
2068 };
2069 if (vfs_statfs(&path, stat))
2070 err = nfserr_io;
2071 }
2072 return err;
2073}
2074
2075static int exp_rdonly(struct svc_rqst *rqstp, struct svc_export *exp)
2076{
2077 return nfsexp_flags(rqstp, exp) & NFSEXP_READONLY;
2078}
2079
2080#ifdef CONFIG_NFSD_V4
2081/*
2082 * Helper function to translate error numbers. In the case of xattr operations,
2083 * some error codes need to be translated outside of the standard translations.
2084 *
2085 * ENODATA needs to be translated to nfserr_noxattr.
2086 * E2BIG to nfserr_xattr2big.
2087 *
2088 * Additionally, vfs_listxattr can return -ERANGE. This means that the
2089 * file has too many extended attributes to retrieve inside an
2090 * XATTR_LIST_MAX sized buffer. This is a bug in the xattr implementation:
2091 * filesystems will allow the adding of extended attributes until they hit
2092 * their own internal limit. This limit may be larger than XATTR_LIST_MAX.
2093 * So, at that point, the attributes are present and valid, but can't
2094 * be retrieved using listxattr, since the upper level xattr code enforces
2095 * the XATTR_LIST_MAX limit.
2096 *
2097 * This bug means that we need to deal with listxattr returning -ERANGE. The
2098 * best mapping is to return TOOSMALL.
2099 */
2100static __be32
2101nfsd_xattr_errno(int err)
2102{
2103 switch (err) {
2104 case -ENODATA:
2105 return nfserr_noxattr;
2106 case -E2BIG:
2107 return nfserr_xattr2big;
2108 case -ERANGE:
2109 return nfserr_toosmall;
2110 }
2111 return nfserrno(err);
2112}
2113
2114/*
2115 * Retrieve the specified user extended attribute. To avoid always
2116 * having to allocate the maximum size (since we are not getting
2117 * a maximum size from the RPC), do a probe + alloc. Hold a reader
2118 * lock on i_rwsem to prevent the extended attribute from changing
2119 * size while we're doing this.
2120 */
2121__be32
2122nfsd_getxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name,
2123 void **bufp, int *lenp)
2124{
2125 ssize_t len;
2126 __be32 err;
2127 char *buf;
2128 struct inode *inode;
2129 struct dentry *dentry;
2130
2131 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_READ);
2132 if (err)
2133 return err;
2134
2135 err = nfs_ok;
2136 dentry = fhp->fh_dentry;
2137 inode = d_inode(dentry);
2138
2139 inode_lock_shared(inode);
2140
2141 len = vfs_getxattr(dentry, name, NULL, 0);
2142
2143 /*
2144 * Zero-length attribute, just return.
2145 */
2146 if (len == 0) {
2147 *bufp = NULL;
2148 *lenp = 0;
2149 goto out;
2150 }
2151
2152 if (len < 0) {
2153 err = nfsd_xattr_errno(len);
2154 goto out;
2155 }
2156
2157 if (len > *lenp) {
2158 err = nfserr_toosmall;
2159 goto out;
2160 }
2161
2162 buf = kvmalloc(len, GFP_KERNEL | GFP_NOFS);
2163 if (buf == NULL) {
2164 err = nfserr_jukebox;
2165 goto out;
2166 }
2167
2168 len = vfs_getxattr(dentry, name, buf, len);
2169 if (len <= 0) {
2170 kvfree(buf);
2171 buf = NULL;
2172 err = nfsd_xattr_errno(len);
2173 }
2174
2175 *lenp = len;
2176 *bufp = buf;
2177
2178out:
2179 inode_unlock_shared(inode);
2180
2181 return err;
2182}
2183
2184/*
2185 * Retrieve the xattr names. Since we can't know how many are
2186 * user extended attributes, we must get all attributes here,
2187 * and have the XDR encode filter out the "user." ones.
2188 *
2189 * While this could always just allocate an XATTR_LIST_MAX
2190 * buffer, that's a waste, so do a probe + allocate. To
2191 * avoid any changes between the probe and allocate, wrap
2192 * this in inode_lock.
2193 */
2194__be32
2195nfsd_listxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char **bufp,
2196 int *lenp)
2197{
2198 ssize_t len;
2199 __be32 err;
2200 char *buf;
2201 struct inode *inode;
2202 struct dentry *dentry;
2203
2204 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_READ);
2205 if (err)
2206 return err;
2207
2208 dentry = fhp->fh_dentry;
2209 inode = d_inode(dentry);
2210 *lenp = 0;
2211
2212 inode_lock_shared(inode);
2213
2214 len = vfs_listxattr(dentry, NULL, 0);
2215 if (len <= 0) {
2216 err = nfsd_xattr_errno(len);
2217 goto out;
2218 }
2219
2220 if (len > XATTR_LIST_MAX) {
2221 err = nfserr_xattr2big;
2222 goto out;
2223 }
2224
2225 /*
2226 * We're holding i_rwsem - use GFP_NOFS.
2227 */
2228 buf = kvmalloc(len, GFP_KERNEL | GFP_NOFS);
2229 if (buf == NULL) {
2230 err = nfserr_jukebox;
2231 goto out;
2232 }
2233
2234 len = vfs_listxattr(dentry, buf, len);
2235 if (len <= 0) {
2236 kvfree(buf);
2237 err = nfsd_xattr_errno(len);
2238 goto out;
2239 }
2240
2241 *lenp = len;
2242 *bufp = buf;
2243
2244 err = nfs_ok;
2245out:
2246 inode_unlock_shared(inode);
2247
2248 return err;
2249}
2250
2251/*
2252 * Removexattr and setxattr need to call fh_lock to both lock the inode
2253 * and set the change attribute. Since the top-level vfs_removexattr
2254 * and vfs_setxattr calls already do their own inode_lock calls, call
2255 * the _locked variant. Pass in a NULL pointer for delegated_inode,
2256 * and let the client deal with NFS4ERR_DELAY (same as with e.g.
2257 * setattr and remove).
2258 */
2259__be32
2260nfsd_removexattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name)
2261{
2262 int err, ret;
2263
2264 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_WRITE);
2265 if (err)
2266 return err;
2267
2268 ret = fh_want_write(fhp);
2269 if (ret)
2270 return nfserrno(ret);
2271
2272 fh_lock(fhp);
2273
2274 ret = __vfs_removexattr_locked(fhp->fh_dentry, name, NULL);
2275
2276 fh_unlock(fhp);
2277 fh_drop_write(fhp);
2278
2279 return nfsd_xattr_errno(ret);
2280}
2281
2282__be32
2283nfsd_setxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name,
2284 void *buf, u32 len, u32 flags)
2285{
2286 int err, ret;
2287
2288 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_WRITE);
2289 if (err)
2290 return err;
2291
2292 ret = fh_want_write(fhp);
2293 if (ret)
2294 return nfserrno(ret);
2295 fh_lock(fhp);
2296
2297 ret = __vfs_setxattr_locked(fhp->fh_dentry, name, buf, len, flags,
2298 NULL);
2299
2300 fh_unlock(fhp);
2301 fh_drop_write(fhp);
2302
2303 return nfsd_xattr_errno(ret);
2304}
2305#endif
2306
2307/*
2308 * Check for a user's access permissions to this inode.
2309 */
2310__be32
2311nfsd_permission(struct svc_rqst *rqstp, struct svc_export *exp,
2312 struct dentry *dentry, int acc)
2313{
2314 struct inode *inode = d_inode(dentry);
2315 int err;
2316
2317 if ((acc & NFSD_MAY_MASK) == NFSD_MAY_NOP)
2318 return 0;
2319#if 0
2320 dprintk("nfsd: permission 0x%x%s%s%s%s%s%s%s mode 0%o%s%s%s\n",
2321 acc,
2322 (acc & NFSD_MAY_READ)? " read" : "",
2323 (acc & NFSD_MAY_WRITE)? " write" : "",
2324 (acc & NFSD_MAY_EXEC)? " exec" : "",
2325 (acc & NFSD_MAY_SATTR)? " sattr" : "",
2326 (acc & NFSD_MAY_TRUNC)? " trunc" : "",
2327 (acc & NFSD_MAY_LOCK)? " lock" : "",
2328 (acc & NFSD_MAY_OWNER_OVERRIDE)? " owneroverride" : "",
2329 inode->i_mode,
2330 IS_IMMUTABLE(inode)? " immut" : "",
2331 IS_APPEND(inode)? " append" : "",
2332 __mnt_is_readonly(exp->ex_path.mnt)? " ro" : "");
2333 dprintk(" owner %d/%d user %d/%d\n",
2334 inode->i_uid, inode->i_gid, current_fsuid(), current_fsgid());
2335#endif
2336
2337 /* Normally we reject any write/sattr etc access on a read-only file
2338 * system. But if it is IRIX doing check on write-access for a
2339 * device special file, we ignore rofs.
2340 */
2341 if (!(acc & NFSD_MAY_LOCAL_ACCESS))
2342 if (acc & (NFSD_MAY_WRITE | NFSD_MAY_SATTR | NFSD_MAY_TRUNC)) {
2343 if (exp_rdonly(rqstp, exp) ||
2344 __mnt_is_readonly(exp->ex_path.mnt))
2345 return nfserr_rofs;
2346 if (/* (acc & NFSD_MAY_WRITE) && */ IS_IMMUTABLE(inode))
2347 return nfserr_perm;
2348 }
2349 if ((acc & NFSD_MAY_TRUNC) && IS_APPEND(inode))
2350 return nfserr_perm;
2351
2352 if (acc & NFSD_MAY_LOCK) {
2353 /* If we cannot rely on authentication in NLM requests,
2354 * just allow locks, otherwise require read permission, or
2355 * ownership
2356 */
2357 if (exp->ex_flags & NFSEXP_NOAUTHNLM)
2358 return 0;
2359 else
2360 acc = NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE;
2361 }
2362 /*
2363 * The file owner always gets access permission for accesses that
2364 * would normally be checked at open time. This is to make
2365 * file access work even when the client has done a fchmod(fd, 0).
2366 *
2367 * However, `cp foo bar' should fail nevertheless when bar is
2368 * readonly. A sensible way to do this might be to reject all
2369 * attempts to truncate a read-only file, because a creat() call
2370 * always implies file truncation.
2371 * ... but this isn't really fair. A process may reasonably call
2372 * ftruncate on an open file descriptor on a file with perm 000.
2373 * We must trust the client to do permission checking - using "ACCESS"
2374 * with NFSv3.
2375 */
2376 if ((acc & NFSD_MAY_OWNER_OVERRIDE) &&
2377 uid_eq(inode->i_uid, current_fsuid()))
2378 return 0;
2379
2380 /* This assumes NFSD_MAY_{READ,WRITE,EXEC} == MAY_{READ,WRITE,EXEC} */
2381 err = inode_permission(inode, acc & (MAY_READ|MAY_WRITE|MAY_EXEC));
2382
2383 /* Allow read access to binaries even when mode 111 */
2384 if (err == -EACCES && S_ISREG(inode->i_mode) &&
2385 (acc == (NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE) ||
2386 acc == (NFSD_MAY_READ | NFSD_MAY_READ_IF_EXEC)))
2387 err = inode_permission(inode, MAY_EXEC);
2388
2389 return err? nfserrno(err) : 0;
2390}