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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(&init_user_ns, 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(&init_user_ns, 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(&init_user_ns, dentry, NFSD_JUNCTION_XATTR_NAME,
503 NULL, 0) <= 0)
504 return 0;
505 return 1;
506}
507#ifdef CONFIG_NFSD_V4_SECURITY_LABEL
508__be32 nfsd4_set_nfs4_label(struct svc_rqst *rqstp, struct svc_fh *fhp,
509 struct xdr_netobj *label)
510{
511 __be32 error;
512 int host_error;
513 struct dentry *dentry;
514
515 error = fh_verify(rqstp, fhp, 0 /* S_IFREG */, NFSD_MAY_SATTR);
516 if (error)
517 return error;
518
519 dentry = fhp->fh_dentry;
520
521 inode_lock(d_inode(dentry));
522 host_error = security_inode_setsecctx(dentry, label->data, label->len);
523 inode_unlock(d_inode(dentry));
524 return nfserrno(host_error);
525}
526#else
527__be32 nfsd4_set_nfs4_label(struct svc_rqst *rqstp, struct svc_fh *fhp,
528 struct xdr_netobj *label)
529{
530 return nfserr_notsupp;
531}
532#endif
533
534__be32 nfsd4_clone_file_range(struct nfsd_file *nf_src, u64 src_pos,
535 struct nfsd_file *nf_dst, u64 dst_pos, u64 count, bool sync)
536{
537 struct file *src = nf_src->nf_file;
538 struct file *dst = nf_dst->nf_file;
539 loff_t cloned;
540 __be32 ret = 0;
541
542 down_write(&nf_dst->nf_rwsem);
543 cloned = vfs_clone_file_range(src, src_pos, dst, dst_pos, count, 0);
544 if (cloned < 0) {
545 ret = nfserrno(cloned);
546 goto out_err;
547 }
548 if (count && cloned != count) {
549 ret = nfserrno(-EINVAL);
550 goto out_err;
551 }
552 if (sync) {
553 loff_t dst_end = count ? dst_pos + count - 1 : LLONG_MAX;
554 int status = vfs_fsync_range(dst, dst_pos, dst_end, 0);
555
556 if (!status)
557 status = commit_inode_metadata(file_inode(src));
558 if (status < 0) {
559 nfsd_reset_boot_verifier(net_generic(nf_dst->nf_net,
560 nfsd_net_id));
561 ret = nfserrno(status);
562 }
563 }
564out_err:
565 up_write(&nf_dst->nf_rwsem);
566 return ret;
567}
568
569ssize_t nfsd_copy_file_range(struct file *src, u64 src_pos, struct file *dst,
570 u64 dst_pos, u64 count)
571{
572
573 /*
574 * Limit copy to 4MB to prevent indefinitely blocking an nfsd
575 * thread and client rpc slot. The choice of 4MB is somewhat
576 * arbitrary. We might instead base this on r/wsize, or make it
577 * tunable, or use a time instead of a byte limit, or implement
578 * asynchronous copy. In theory a client could also recognize a
579 * limit like this and pipeline multiple COPY requests.
580 */
581 count = min_t(u64, count, 1 << 22);
582 return vfs_copy_file_range(src, src_pos, dst, dst_pos, count, 0);
583}
584
585__be32 nfsd4_vfs_fallocate(struct svc_rqst *rqstp, struct svc_fh *fhp,
586 struct file *file, loff_t offset, loff_t len,
587 int flags)
588{
589 int error;
590
591 if (!S_ISREG(file_inode(file)->i_mode))
592 return nfserr_inval;
593
594 error = vfs_fallocate(file, flags, offset, len);
595 if (!error)
596 error = commit_metadata(fhp);
597
598 return nfserrno(error);
599}
600#endif /* defined(CONFIG_NFSD_V4) */
601
602#ifdef CONFIG_NFSD_V3
603/*
604 * Check server access rights to a file system object
605 */
606struct accessmap {
607 u32 access;
608 int how;
609};
610static struct accessmap nfs3_regaccess[] = {
611 { NFS3_ACCESS_READ, NFSD_MAY_READ },
612 { NFS3_ACCESS_EXECUTE, NFSD_MAY_EXEC },
613 { NFS3_ACCESS_MODIFY, NFSD_MAY_WRITE|NFSD_MAY_TRUNC },
614 { NFS3_ACCESS_EXTEND, NFSD_MAY_WRITE },
615
616#ifdef CONFIG_NFSD_V4
617 { NFS4_ACCESS_XAREAD, NFSD_MAY_READ },
618 { NFS4_ACCESS_XAWRITE, NFSD_MAY_WRITE },
619 { NFS4_ACCESS_XALIST, NFSD_MAY_READ },
620#endif
621
622 { 0, 0 }
623};
624
625static struct accessmap nfs3_diraccess[] = {
626 { NFS3_ACCESS_READ, NFSD_MAY_READ },
627 { NFS3_ACCESS_LOOKUP, NFSD_MAY_EXEC },
628 { NFS3_ACCESS_MODIFY, NFSD_MAY_EXEC|NFSD_MAY_WRITE|NFSD_MAY_TRUNC},
629 { NFS3_ACCESS_EXTEND, NFSD_MAY_EXEC|NFSD_MAY_WRITE },
630 { NFS3_ACCESS_DELETE, NFSD_MAY_REMOVE },
631
632#ifdef CONFIG_NFSD_V4
633 { NFS4_ACCESS_XAREAD, NFSD_MAY_READ },
634 { NFS4_ACCESS_XAWRITE, NFSD_MAY_WRITE },
635 { NFS4_ACCESS_XALIST, NFSD_MAY_READ },
636#endif
637
638 { 0, 0 }
639};
640
641static struct accessmap nfs3_anyaccess[] = {
642 /* Some clients - Solaris 2.6 at least, make an access call
643 * to the server to check for access for things like /dev/null
644 * (which really, the server doesn't care about). So
645 * We provide simple access checking for them, looking
646 * mainly at mode bits, and we make sure to ignore read-only
647 * filesystem checks
648 */
649 { NFS3_ACCESS_READ, NFSD_MAY_READ },
650 { NFS3_ACCESS_EXECUTE, NFSD_MAY_EXEC },
651 { NFS3_ACCESS_MODIFY, NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS },
652 { NFS3_ACCESS_EXTEND, NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS },
653
654 { 0, 0 }
655};
656
657__be32
658nfsd_access(struct svc_rqst *rqstp, struct svc_fh *fhp, u32 *access, u32 *supported)
659{
660 struct accessmap *map;
661 struct svc_export *export;
662 struct dentry *dentry;
663 u32 query, result = 0, sresult = 0;
664 __be32 error;
665
666 error = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP);
667 if (error)
668 goto out;
669
670 export = fhp->fh_export;
671 dentry = fhp->fh_dentry;
672
673 if (d_is_reg(dentry))
674 map = nfs3_regaccess;
675 else if (d_is_dir(dentry))
676 map = nfs3_diraccess;
677 else
678 map = nfs3_anyaccess;
679
680
681 query = *access;
682 for (; map->access; map++) {
683 if (map->access & query) {
684 __be32 err2;
685
686 sresult |= map->access;
687
688 err2 = nfsd_permission(rqstp, export, dentry, map->how);
689 switch (err2) {
690 case nfs_ok:
691 result |= map->access;
692 break;
693
694 /* the following error codes just mean the access was not allowed,
695 * rather than an error occurred */
696 case nfserr_rofs:
697 case nfserr_acces:
698 case nfserr_perm:
699 /* simply don't "or" in the access bit. */
700 break;
701 default:
702 error = err2;
703 goto out;
704 }
705 }
706 }
707 *access = result;
708 if (supported)
709 *supported = sresult;
710
711 out:
712 return error;
713}
714#endif /* CONFIG_NFSD_V3 */
715
716int nfsd_open_break_lease(struct inode *inode, int access)
717{
718 unsigned int mode;
719
720 if (access & NFSD_MAY_NOT_BREAK_LEASE)
721 return 0;
722 mode = (access & NFSD_MAY_WRITE) ? O_WRONLY : O_RDONLY;
723 return break_lease(inode, mode | O_NONBLOCK);
724}
725
726/*
727 * Open an existing file or directory.
728 * The may_flags argument indicates the type of open (read/write/lock)
729 * and additional flags.
730 * N.B. After this call fhp needs an fh_put
731 */
732static __be32
733__nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type,
734 int may_flags, struct file **filp)
735{
736 struct path path;
737 struct inode *inode;
738 struct file *file;
739 int flags = O_RDONLY|O_LARGEFILE;
740 __be32 err;
741 int host_err = 0;
742
743 path.mnt = fhp->fh_export->ex_path.mnt;
744 path.dentry = fhp->fh_dentry;
745 inode = d_inode(path.dentry);
746
747 /* Disallow write access to files with the append-only bit set
748 * or any access when mandatory locking enabled
749 */
750 err = nfserr_perm;
751 if (IS_APPEND(inode) && (may_flags & NFSD_MAY_WRITE))
752 goto out;
753 /*
754 * We must ignore files (but only files) which might have mandatory
755 * locks on them because there is no way to know if the accesser has
756 * the lock.
757 */
758 if (S_ISREG((inode)->i_mode) && mandatory_lock(inode))
759 goto out;
760
761 if (!inode->i_fop)
762 goto out;
763
764 host_err = nfsd_open_break_lease(inode, may_flags);
765 if (host_err) /* NOMEM or WOULDBLOCK */
766 goto out_nfserr;
767
768 if (may_flags & NFSD_MAY_WRITE) {
769 if (may_flags & NFSD_MAY_READ)
770 flags = O_RDWR|O_LARGEFILE;
771 else
772 flags = O_WRONLY|O_LARGEFILE;
773 }
774
775 file = dentry_open(&path, flags, current_cred());
776 if (IS_ERR(file)) {
777 host_err = PTR_ERR(file);
778 goto out_nfserr;
779 }
780
781 host_err = ima_file_check(file, may_flags);
782 if (host_err) {
783 fput(file);
784 goto out_nfserr;
785 }
786
787 if (may_flags & NFSD_MAY_64BIT_COOKIE)
788 file->f_mode |= FMODE_64BITHASH;
789 else
790 file->f_mode |= FMODE_32BITHASH;
791
792 *filp = file;
793out_nfserr:
794 err = nfserrno(host_err);
795out:
796 return err;
797}
798
799__be32
800nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type,
801 int may_flags, struct file **filp)
802{
803 __be32 err;
804
805 validate_process_creds();
806 /*
807 * If we get here, then the client has already done an "open",
808 * and (hopefully) checked permission - so allow OWNER_OVERRIDE
809 * in case a chmod has now revoked permission.
810 *
811 * Arguably we should also allow the owner override for
812 * directories, but we never have and it doesn't seem to have
813 * caused anyone a problem. If we were to change this, note
814 * also that our filldir callbacks would need a variant of
815 * lookup_one_len that doesn't check permissions.
816 */
817 if (type == S_IFREG)
818 may_flags |= NFSD_MAY_OWNER_OVERRIDE;
819 err = fh_verify(rqstp, fhp, type, may_flags);
820 if (!err)
821 err = __nfsd_open(rqstp, fhp, type, may_flags, filp);
822 validate_process_creds();
823 return err;
824}
825
826__be32
827nfsd_open_verified(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type,
828 int may_flags, struct file **filp)
829{
830 __be32 err;
831
832 validate_process_creds();
833 err = __nfsd_open(rqstp, fhp, type, may_flags, filp);
834 validate_process_creds();
835 return err;
836}
837
838/*
839 * Grab and keep cached pages associated with a file in the svc_rqst
840 * so that they can be passed to the network sendmsg/sendpage routines
841 * directly. They will be released after the sending has completed.
842 */
843static int
844nfsd_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
845 struct splice_desc *sd)
846{
847 struct svc_rqst *rqstp = sd->u.data;
848 struct page **pp = rqstp->rq_next_page;
849 struct page *page = buf->page;
850 size_t size;
851
852 size = sd->len;
853
854 if (rqstp->rq_res.page_len == 0) {
855 get_page(page);
856 put_page(*rqstp->rq_next_page);
857 *(rqstp->rq_next_page++) = page;
858 rqstp->rq_res.page_base = buf->offset;
859 rqstp->rq_res.page_len = size;
860 } else if (page != pp[-1]) {
861 get_page(page);
862 if (*rqstp->rq_next_page)
863 put_page(*rqstp->rq_next_page);
864 *(rqstp->rq_next_page++) = page;
865 rqstp->rq_res.page_len += size;
866 } else
867 rqstp->rq_res.page_len += size;
868
869 return size;
870}
871
872static int nfsd_direct_splice_actor(struct pipe_inode_info *pipe,
873 struct splice_desc *sd)
874{
875 return __splice_from_pipe(pipe, sd, nfsd_splice_actor);
876}
877
878static u32 nfsd_eof_on_read(struct file *file, loff_t offset, ssize_t len,
879 size_t expected)
880{
881 if (expected != 0 && len == 0)
882 return 1;
883 if (offset+len >= i_size_read(file_inode(file)))
884 return 1;
885 return 0;
886}
887
888static __be32 nfsd_finish_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
889 struct file *file, loff_t offset,
890 unsigned long *count, u32 *eof, ssize_t host_err)
891{
892 if (host_err >= 0) {
893 nfsd_stats_io_read_add(fhp->fh_export, host_err);
894 *eof = nfsd_eof_on_read(file, offset, host_err, *count);
895 *count = host_err;
896 fsnotify_access(file);
897 trace_nfsd_read_io_done(rqstp, fhp, offset, *count);
898 return 0;
899 } else {
900 trace_nfsd_read_err(rqstp, fhp, offset, host_err);
901 return nfserrno(host_err);
902 }
903}
904
905__be32 nfsd_splice_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
906 struct file *file, loff_t offset, unsigned long *count,
907 u32 *eof)
908{
909 struct splice_desc sd = {
910 .len = 0,
911 .total_len = *count,
912 .pos = offset,
913 .u.data = rqstp,
914 };
915 ssize_t host_err;
916
917 trace_nfsd_read_splice(rqstp, fhp, offset, *count);
918 rqstp->rq_next_page = rqstp->rq_respages + 1;
919 host_err = splice_direct_to_actor(file, &sd, nfsd_direct_splice_actor);
920 return nfsd_finish_read(rqstp, fhp, file, offset, count, eof, host_err);
921}
922
923__be32 nfsd_readv(struct svc_rqst *rqstp, struct svc_fh *fhp,
924 struct file *file, loff_t offset,
925 struct kvec *vec, int vlen, unsigned long *count,
926 u32 *eof)
927{
928 struct iov_iter iter;
929 loff_t ppos = offset;
930 ssize_t host_err;
931
932 trace_nfsd_read_vector(rqstp, fhp, offset, *count);
933 iov_iter_kvec(&iter, READ, vec, vlen, *count);
934 host_err = vfs_iter_read(file, &iter, &ppos, 0);
935 return nfsd_finish_read(rqstp, fhp, file, offset, count, eof, host_err);
936}
937
938/*
939 * Gathered writes: If another process is currently writing to the file,
940 * there's a high chance this is another nfsd (triggered by a bulk write
941 * from a client's biod). Rather than syncing the file with each write
942 * request, we sleep for 10 msec.
943 *
944 * I don't know if this roughly approximates C. Juszak's idea of
945 * gathered writes, but it's a nice and simple solution (IMHO), and it
946 * seems to work:-)
947 *
948 * Note: we do this only in the NFSv2 case, since v3 and higher have a
949 * better tool (separate unstable writes and commits) for solving this
950 * problem.
951 */
952static int wait_for_concurrent_writes(struct file *file)
953{
954 struct inode *inode = file_inode(file);
955 static ino_t last_ino;
956 static dev_t last_dev;
957 int err = 0;
958
959 if (atomic_read(&inode->i_writecount) > 1
960 || (last_ino == inode->i_ino && last_dev == inode->i_sb->s_dev)) {
961 dprintk("nfsd: write defer %d\n", task_pid_nr(current));
962 msleep(10);
963 dprintk("nfsd: write resume %d\n", task_pid_nr(current));
964 }
965
966 if (inode->i_state & I_DIRTY) {
967 dprintk("nfsd: write sync %d\n", task_pid_nr(current));
968 err = vfs_fsync(file, 0);
969 }
970 last_ino = inode->i_ino;
971 last_dev = inode->i_sb->s_dev;
972 return err;
973}
974
975__be32
976nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf,
977 loff_t offset, struct kvec *vec, int vlen,
978 unsigned long *cnt, int stable,
979 __be32 *verf)
980{
981 struct file *file = nf->nf_file;
982 struct super_block *sb = file_inode(file)->i_sb;
983 struct svc_export *exp;
984 struct iov_iter iter;
985 __be32 nfserr;
986 int host_err;
987 int use_wgather;
988 loff_t pos = offset;
989 unsigned long exp_op_flags = 0;
990 unsigned int pflags = current->flags;
991 rwf_t flags = 0;
992 bool restore_flags = false;
993
994 trace_nfsd_write_opened(rqstp, fhp, offset, *cnt);
995
996 if (sb->s_export_op)
997 exp_op_flags = sb->s_export_op->flags;
998
999 if (test_bit(RQ_LOCAL, &rqstp->rq_flags) &&
1000 !(exp_op_flags & EXPORT_OP_REMOTE_FS)) {
1001 /*
1002 * We want throttling in balance_dirty_pages()
1003 * and shrink_inactive_list() to only consider
1004 * the backingdev we are writing to, so that nfs to
1005 * localhost doesn't cause nfsd to lock up due to all
1006 * the client's dirty pages or its congested queue.
1007 */
1008 current->flags |= PF_LOCAL_THROTTLE;
1009 restore_flags = true;
1010 }
1011
1012 exp = fhp->fh_export;
1013 use_wgather = (rqstp->rq_vers == 2) && EX_WGATHER(exp);
1014
1015 if (!EX_ISSYNC(exp))
1016 stable = NFS_UNSTABLE;
1017
1018 if (stable && !use_wgather)
1019 flags |= RWF_SYNC;
1020
1021 iov_iter_kvec(&iter, WRITE, vec, vlen, *cnt);
1022 if (flags & RWF_SYNC) {
1023 down_write(&nf->nf_rwsem);
1024 host_err = vfs_iter_write(file, &iter, &pos, flags);
1025 if (host_err < 0)
1026 nfsd_reset_boot_verifier(net_generic(SVC_NET(rqstp),
1027 nfsd_net_id));
1028 up_write(&nf->nf_rwsem);
1029 } else {
1030 down_read(&nf->nf_rwsem);
1031 if (verf)
1032 nfsd_copy_boot_verifier(verf,
1033 net_generic(SVC_NET(rqstp),
1034 nfsd_net_id));
1035 host_err = vfs_iter_write(file, &iter, &pos, flags);
1036 up_read(&nf->nf_rwsem);
1037 }
1038 if (host_err < 0) {
1039 nfsd_reset_boot_verifier(net_generic(SVC_NET(rqstp),
1040 nfsd_net_id));
1041 goto out_nfserr;
1042 }
1043 *cnt = host_err;
1044 nfsd_stats_io_write_add(exp, *cnt);
1045 fsnotify_modify(file);
1046
1047 if (stable && use_wgather) {
1048 host_err = wait_for_concurrent_writes(file);
1049 if (host_err < 0)
1050 nfsd_reset_boot_verifier(net_generic(SVC_NET(rqstp),
1051 nfsd_net_id));
1052 }
1053
1054out_nfserr:
1055 if (host_err >= 0) {
1056 trace_nfsd_write_io_done(rqstp, fhp, offset, *cnt);
1057 nfserr = nfs_ok;
1058 } else {
1059 trace_nfsd_write_err(rqstp, fhp, offset, host_err);
1060 nfserr = nfserrno(host_err);
1061 }
1062 if (restore_flags)
1063 current_restore_flags(pflags, PF_LOCAL_THROTTLE);
1064 return nfserr;
1065}
1066
1067/*
1068 * Read data from a file. count must contain the requested read count
1069 * on entry. On return, *count contains the number of bytes actually read.
1070 * N.B. After this call fhp needs an fh_put
1071 */
1072__be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
1073 loff_t offset, struct kvec *vec, int vlen, unsigned long *count,
1074 u32 *eof)
1075{
1076 struct nfsd_file *nf;
1077 struct file *file;
1078 __be32 err;
1079
1080 trace_nfsd_read_start(rqstp, fhp, offset, *count);
1081 err = nfsd_file_acquire(rqstp, fhp, NFSD_MAY_READ, &nf);
1082 if (err)
1083 return err;
1084
1085 file = nf->nf_file;
1086 if (file->f_op->splice_read && test_bit(RQ_SPLICE_OK, &rqstp->rq_flags))
1087 err = nfsd_splice_read(rqstp, fhp, file, offset, count, eof);
1088 else
1089 err = nfsd_readv(rqstp, fhp, file, offset, vec, vlen, count, eof);
1090
1091 nfsd_file_put(nf);
1092
1093 trace_nfsd_read_done(rqstp, fhp, offset, *count);
1094
1095 return err;
1096}
1097
1098/*
1099 * Write data to a file.
1100 * The stable flag requests synchronous writes.
1101 * N.B. After this call fhp needs an fh_put
1102 */
1103__be32
1104nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t offset,
1105 struct kvec *vec, int vlen, unsigned long *cnt, int stable,
1106 __be32 *verf)
1107{
1108 struct nfsd_file *nf;
1109 __be32 err;
1110
1111 trace_nfsd_write_start(rqstp, fhp, offset, *cnt);
1112
1113 err = nfsd_file_acquire(rqstp, fhp, NFSD_MAY_WRITE, &nf);
1114 if (err)
1115 goto out;
1116
1117 err = nfsd_vfs_write(rqstp, fhp, nf, offset, vec,
1118 vlen, cnt, stable, verf);
1119 nfsd_file_put(nf);
1120out:
1121 trace_nfsd_write_done(rqstp, fhp, offset, *cnt);
1122 return err;
1123}
1124
1125#ifdef CONFIG_NFSD_V3
1126static int
1127nfsd_filemap_write_and_wait_range(struct nfsd_file *nf, loff_t offset,
1128 loff_t end)
1129{
1130 struct address_space *mapping = nf->nf_file->f_mapping;
1131 int ret = filemap_fdatawrite_range(mapping, offset, end);
1132
1133 if (ret)
1134 return ret;
1135 filemap_fdatawait_range_keep_errors(mapping, offset, end);
1136 return 0;
1137}
1138
1139/*
1140 * Commit all pending writes to stable storage.
1141 *
1142 * Note: we only guarantee that data that lies within the range specified
1143 * by the 'offset' and 'count' parameters will be synced.
1144 *
1145 * Unfortunately we cannot lock the file to make sure we return full WCC
1146 * data to the client, as locking happens lower down in the filesystem.
1147 */
1148__be32
1149nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp,
1150 loff_t offset, unsigned long count, __be32 *verf)
1151{
1152 struct nfsd_file *nf;
1153 loff_t end = LLONG_MAX;
1154 __be32 err = nfserr_inval;
1155
1156 if (offset < 0)
1157 goto out;
1158 if (count != 0) {
1159 end = offset + (loff_t)count - 1;
1160 if (end < offset)
1161 goto out;
1162 }
1163
1164 err = nfsd_file_acquire(rqstp, fhp,
1165 NFSD_MAY_WRITE|NFSD_MAY_NOT_BREAK_LEASE, &nf);
1166 if (err)
1167 goto out;
1168 if (EX_ISSYNC(fhp->fh_export)) {
1169 int err2 = nfsd_filemap_write_and_wait_range(nf, offset, end);
1170
1171 down_write(&nf->nf_rwsem);
1172 if (!err2)
1173 err2 = vfs_fsync_range(nf->nf_file, offset, end, 0);
1174 switch (err2) {
1175 case 0:
1176 nfsd_copy_boot_verifier(verf, net_generic(nf->nf_net,
1177 nfsd_net_id));
1178 break;
1179 case -EINVAL:
1180 err = nfserr_notsupp;
1181 break;
1182 default:
1183 err = nfserrno(err2);
1184 nfsd_reset_boot_verifier(net_generic(nf->nf_net,
1185 nfsd_net_id));
1186 }
1187 up_write(&nf->nf_rwsem);
1188 } else
1189 nfsd_copy_boot_verifier(verf, net_generic(nf->nf_net,
1190 nfsd_net_id));
1191
1192 nfsd_file_put(nf);
1193out:
1194 return err;
1195}
1196#endif /* CONFIG_NFSD_V3 */
1197
1198static __be32
1199nfsd_create_setattr(struct svc_rqst *rqstp, struct svc_fh *resfhp,
1200 struct iattr *iap)
1201{
1202 /*
1203 * Mode has already been set earlier in create:
1204 */
1205 iap->ia_valid &= ~ATTR_MODE;
1206 /*
1207 * Setting uid/gid works only for root. Irix appears to
1208 * send along the gid on create when it tries to implement
1209 * setgid directories via NFS:
1210 */
1211 if (!uid_eq(current_fsuid(), GLOBAL_ROOT_UID))
1212 iap->ia_valid &= ~(ATTR_UID|ATTR_GID);
1213 if (iap->ia_valid)
1214 return nfsd_setattr(rqstp, resfhp, iap, 0, (time64_t)0);
1215 /* Callers expect file metadata to be committed here */
1216 return nfserrno(commit_metadata(resfhp));
1217}
1218
1219/* HPUX client sometimes creates a file in mode 000, and sets size to 0.
1220 * setting size to 0 may fail for some specific file systems by the permission
1221 * checking which requires WRITE permission but the mode is 000.
1222 * we ignore the resizing(to 0) on the just new created file, since the size is
1223 * 0 after file created.
1224 *
1225 * call this only after vfs_create() is called.
1226 * */
1227static void
1228nfsd_check_ignore_resizing(struct iattr *iap)
1229{
1230 if ((iap->ia_valid & ATTR_SIZE) && (iap->ia_size == 0))
1231 iap->ia_valid &= ~ATTR_SIZE;
1232}
1233
1234/* The parent directory should already be locked: */
1235__be32
1236nfsd_create_locked(struct svc_rqst *rqstp, struct svc_fh *fhp,
1237 char *fname, int flen, struct iattr *iap,
1238 int type, dev_t rdev, struct svc_fh *resfhp)
1239{
1240 struct dentry *dentry, *dchild;
1241 struct inode *dirp;
1242 __be32 err;
1243 __be32 err2;
1244 int host_err;
1245
1246 dentry = fhp->fh_dentry;
1247 dirp = d_inode(dentry);
1248
1249 dchild = dget(resfhp->fh_dentry);
1250 if (!fhp->fh_locked) {
1251 WARN_ONCE(1, "nfsd_create: parent %pd2 not locked!\n",
1252 dentry);
1253 err = nfserr_io;
1254 goto out;
1255 }
1256
1257 err = nfsd_permission(rqstp, fhp->fh_export, dentry, NFSD_MAY_CREATE);
1258 if (err)
1259 goto out;
1260
1261 if (!(iap->ia_valid & ATTR_MODE))
1262 iap->ia_mode = 0;
1263 iap->ia_mode = (iap->ia_mode & S_IALLUGO) | type;
1264
1265 if (!IS_POSIXACL(dirp))
1266 iap->ia_mode &= ~current_umask();
1267
1268 err = 0;
1269 host_err = 0;
1270 switch (type) {
1271 case S_IFREG:
1272 host_err = vfs_create(&init_user_ns, dirp, dchild, iap->ia_mode, true);
1273 if (!host_err)
1274 nfsd_check_ignore_resizing(iap);
1275 break;
1276 case S_IFDIR:
1277 host_err = vfs_mkdir(&init_user_ns, dirp, dchild, iap->ia_mode);
1278 if (!host_err && unlikely(d_unhashed(dchild))) {
1279 struct dentry *d;
1280 d = lookup_one_len(dchild->d_name.name,
1281 dchild->d_parent,
1282 dchild->d_name.len);
1283 if (IS_ERR(d)) {
1284 host_err = PTR_ERR(d);
1285 break;
1286 }
1287 if (unlikely(d_is_negative(d))) {
1288 dput(d);
1289 err = nfserr_serverfault;
1290 goto out;
1291 }
1292 dput(resfhp->fh_dentry);
1293 resfhp->fh_dentry = dget(d);
1294 err = fh_update(resfhp);
1295 dput(dchild);
1296 dchild = d;
1297 if (err)
1298 goto out;
1299 }
1300 break;
1301 case S_IFCHR:
1302 case S_IFBLK:
1303 case S_IFIFO:
1304 case S_IFSOCK:
1305 host_err = vfs_mknod(&init_user_ns, dirp, dchild,
1306 iap->ia_mode, rdev);
1307 break;
1308 default:
1309 printk(KERN_WARNING "nfsd: bad file type %o in nfsd_create\n",
1310 type);
1311 host_err = -EINVAL;
1312 }
1313 if (host_err < 0)
1314 goto out_nfserr;
1315
1316 err = nfsd_create_setattr(rqstp, resfhp, iap);
1317
1318 /*
1319 * nfsd_create_setattr already committed the child. Transactional
1320 * filesystems had a chance to commit changes for both parent and
1321 * child simultaneously making the following commit_metadata a
1322 * noop.
1323 */
1324 err2 = nfserrno(commit_metadata(fhp));
1325 if (err2)
1326 err = err2;
1327 /*
1328 * Update the file handle to get the new inode info.
1329 */
1330 if (!err)
1331 err = fh_update(resfhp);
1332out:
1333 dput(dchild);
1334 return err;
1335
1336out_nfserr:
1337 err = nfserrno(host_err);
1338 goto out;
1339}
1340
1341/*
1342 * Create a filesystem object (regular, directory, special).
1343 * Note that the parent directory is left locked.
1344 *
1345 * N.B. Every call to nfsd_create needs an fh_put for _both_ fhp and resfhp
1346 */
1347__be32
1348nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
1349 char *fname, int flen, struct iattr *iap,
1350 int type, dev_t rdev, struct svc_fh *resfhp)
1351{
1352 struct dentry *dentry, *dchild = NULL;
1353 __be32 err;
1354 int host_err;
1355
1356 if (isdotent(fname, flen))
1357 return nfserr_exist;
1358
1359 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_NOP);
1360 if (err)
1361 return err;
1362
1363 dentry = fhp->fh_dentry;
1364
1365 host_err = fh_want_write(fhp);
1366 if (host_err)
1367 return nfserrno(host_err);
1368
1369 fh_lock_nested(fhp, I_MUTEX_PARENT);
1370 dchild = lookup_one_len(fname, dentry, flen);
1371 host_err = PTR_ERR(dchild);
1372 if (IS_ERR(dchild))
1373 return nfserrno(host_err);
1374 err = fh_compose(resfhp, fhp->fh_export, dchild, fhp);
1375 /*
1376 * We unconditionally drop our ref to dchild as fh_compose will have
1377 * already grabbed its own ref for it.
1378 */
1379 dput(dchild);
1380 if (err)
1381 return err;
1382 return nfsd_create_locked(rqstp, fhp, fname, flen, iap, type,
1383 rdev, resfhp);
1384}
1385
1386#ifdef CONFIG_NFSD_V3
1387
1388/*
1389 * NFSv3 and NFSv4 version of nfsd_create
1390 */
1391__be32
1392do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
1393 char *fname, int flen, struct iattr *iap,
1394 struct svc_fh *resfhp, int createmode, u32 *verifier,
1395 bool *truncp, bool *created)
1396{
1397 struct dentry *dentry, *dchild = NULL;
1398 struct inode *dirp;
1399 __be32 err;
1400 int host_err;
1401 __u32 v_mtime=0, v_atime=0;
1402
1403 err = nfserr_perm;
1404 if (!flen)
1405 goto out;
1406 err = nfserr_exist;
1407 if (isdotent(fname, flen))
1408 goto out;
1409 if (!(iap->ia_valid & ATTR_MODE))
1410 iap->ia_mode = 0;
1411 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC);
1412 if (err)
1413 goto out;
1414
1415 dentry = fhp->fh_dentry;
1416 dirp = d_inode(dentry);
1417
1418 host_err = fh_want_write(fhp);
1419 if (host_err)
1420 goto out_nfserr;
1421
1422 fh_lock_nested(fhp, I_MUTEX_PARENT);
1423
1424 /*
1425 * Compose the response file handle.
1426 */
1427 dchild = lookup_one_len(fname, dentry, flen);
1428 host_err = PTR_ERR(dchild);
1429 if (IS_ERR(dchild))
1430 goto out_nfserr;
1431
1432 /* If file doesn't exist, check for permissions to create one */
1433 if (d_really_is_negative(dchild)) {
1434 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
1435 if (err)
1436 goto out;
1437 }
1438
1439 err = fh_compose(resfhp, fhp->fh_export, dchild, fhp);
1440 if (err)
1441 goto out;
1442
1443 if (nfsd_create_is_exclusive(createmode)) {
1444 /* solaris7 gets confused (bugid 4218508) if these have
1445 * the high bit set, so just clear the high bits. If this is
1446 * ever changed to use different attrs for storing the
1447 * verifier, then do_open_lookup() will also need to be fixed
1448 * accordingly.
1449 */
1450 v_mtime = verifier[0]&0x7fffffff;
1451 v_atime = verifier[1]&0x7fffffff;
1452 }
1453
1454 if (d_really_is_positive(dchild)) {
1455 err = 0;
1456
1457 switch (createmode) {
1458 case NFS3_CREATE_UNCHECKED:
1459 if (! d_is_reg(dchild))
1460 goto out;
1461 else if (truncp) {
1462 /* in nfsv4, we need to treat this case a little
1463 * differently. we don't want to truncate the
1464 * file now; this would be wrong if the OPEN
1465 * fails for some other reason. furthermore,
1466 * if the size is nonzero, we should ignore it
1467 * according to spec!
1468 */
1469 *truncp = (iap->ia_valid & ATTR_SIZE) && !iap->ia_size;
1470 }
1471 else {
1472 iap->ia_valid &= ATTR_SIZE;
1473 goto set_attr;
1474 }
1475 break;
1476 case NFS3_CREATE_EXCLUSIVE:
1477 if ( d_inode(dchild)->i_mtime.tv_sec == v_mtime
1478 && d_inode(dchild)->i_atime.tv_sec == v_atime
1479 && d_inode(dchild)->i_size == 0 ) {
1480 if (created)
1481 *created = true;
1482 break;
1483 }
1484 fallthrough;
1485 case NFS4_CREATE_EXCLUSIVE4_1:
1486 if ( d_inode(dchild)->i_mtime.tv_sec == v_mtime
1487 && d_inode(dchild)->i_atime.tv_sec == v_atime
1488 && d_inode(dchild)->i_size == 0 ) {
1489 if (created)
1490 *created = true;
1491 goto set_attr;
1492 }
1493 fallthrough;
1494 case NFS3_CREATE_GUARDED:
1495 err = nfserr_exist;
1496 }
1497 fh_drop_write(fhp);
1498 goto out;
1499 }
1500
1501 if (!IS_POSIXACL(dirp))
1502 iap->ia_mode &= ~current_umask();
1503
1504 host_err = vfs_create(&init_user_ns, dirp, dchild, iap->ia_mode, true);
1505 if (host_err < 0) {
1506 fh_drop_write(fhp);
1507 goto out_nfserr;
1508 }
1509 if (created)
1510 *created = true;
1511
1512 nfsd_check_ignore_resizing(iap);
1513
1514 if (nfsd_create_is_exclusive(createmode)) {
1515 /* Cram the verifier into atime/mtime */
1516 iap->ia_valid = ATTR_MTIME|ATTR_ATIME
1517 | ATTR_MTIME_SET|ATTR_ATIME_SET;
1518 /* XXX someone who knows this better please fix it for nsec */
1519 iap->ia_mtime.tv_sec = v_mtime;
1520 iap->ia_atime.tv_sec = v_atime;
1521 iap->ia_mtime.tv_nsec = 0;
1522 iap->ia_atime.tv_nsec = 0;
1523 }
1524
1525 set_attr:
1526 err = nfsd_create_setattr(rqstp, resfhp, iap);
1527
1528 /*
1529 * nfsd_create_setattr already committed the child
1530 * (and possibly also the parent).
1531 */
1532 if (!err)
1533 err = nfserrno(commit_metadata(fhp));
1534
1535 /*
1536 * Update the filehandle to get the new inode info.
1537 */
1538 if (!err)
1539 err = fh_update(resfhp);
1540
1541 out:
1542 fh_unlock(fhp);
1543 if (dchild && !IS_ERR(dchild))
1544 dput(dchild);
1545 fh_drop_write(fhp);
1546 return err;
1547
1548 out_nfserr:
1549 err = nfserrno(host_err);
1550 goto out;
1551}
1552#endif /* CONFIG_NFSD_V3 */
1553
1554/*
1555 * Read a symlink. On entry, *lenp must contain the maximum path length that
1556 * fits into the buffer. On return, it contains the true length.
1557 * N.B. After this call fhp needs an fh_put
1558 */
1559__be32
1560nfsd_readlink(struct svc_rqst *rqstp, struct svc_fh *fhp, char *buf, int *lenp)
1561{
1562 __be32 err;
1563 const char *link;
1564 struct path path;
1565 DEFINE_DELAYED_CALL(done);
1566 int len;
1567
1568 err = fh_verify(rqstp, fhp, S_IFLNK, NFSD_MAY_NOP);
1569 if (unlikely(err))
1570 return err;
1571
1572 path.mnt = fhp->fh_export->ex_path.mnt;
1573 path.dentry = fhp->fh_dentry;
1574
1575 if (unlikely(!d_is_symlink(path.dentry)))
1576 return nfserr_inval;
1577
1578 touch_atime(&path);
1579
1580 link = vfs_get_link(path.dentry, &done);
1581 if (IS_ERR(link))
1582 return nfserrno(PTR_ERR(link));
1583
1584 len = strlen(link);
1585 if (len < *lenp)
1586 *lenp = len;
1587 memcpy(buf, link, *lenp);
1588 do_delayed_call(&done);
1589 return 0;
1590}
1591
1592/*
1593 * Create a symlink and look up its inode
1594 * N.B. After this call _both_ fhp and resfhp need an fh_put
1595 */
1596__be32
1597nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp,
1598 char *fname, int flen,
1599 char *path,
1600 struct svc_fh *resfhp)
1601{
1602 struct dentry *dentry, *dnew;
1603 __be32 err, cerr;
1604 int host_err;
1605
1606 err = nfserr_noent;
1607 if (!flen || path[0] == '\0')
1608 goto out;
1609 err = nfserr_exist;
1610 if (isdotent(fname, flen))
1611 goto out;
1612
1613 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
1614 if (err)
1615 goto out;
1616
1617 host_err = fh_want_write(fhp);
1618 if (host_err)
1619 goto out_nfserr;
1620
1621 fh_lock(fhp);
1622 dentry = fhp->fh_dentry;
1623 dnew = lookup_one_len(fname, dentry, flen);
1624 host_err = PTR_ERR(dnew);
1625 if (IS_ERR(dnew))
1626 goto out_nfserr;
1627
1628 host_err = vfs_symlink(&init_user_ns, d_inode(dentry), dnew, path);
1629 err = nfserrno(host_err);
1630 fh_unlock(fhp);
1631 if (!err)
1632 err = nfserrno(commit_metadata(fhp));
1633
1634 fh_drop_write(fhp);
1635
1636 cerr = fh_compose(resfhp, fhp->fh_export, dnew, fhp);
1637 dput(dnew);
1638 if (err==0) err = cerr;
1639out:
1640 return err;
1641
1642out_nfserr:
1643 err = nfserrno(host_err);
1644 goto out;
1645}
1646
1647/*
1648 * Create a hardlink
1649 * N.B. After this call _both_ ffhp and tfhp need an fh_put
1650 */
1651__be32
1652nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp,
1653 char *name, int len, struct svc_fh *tfhp)
1654{
1655 struct dentry *ddir, *dnew, *dold;
1656 struct inode *dirp;
1657 __be32 err;
1658 int host_err;
1659
1660 err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_CREATE);
1661 if (err)
1662 goto out;
1663 err = fh_verify(rqstp, tfhp, 0, NFSD_MAY_NOP);
1664 if (err)
1665 goto out;
1666 err = nfserr_isdir;
1667 if (d_is_dir(tfhp->fh_dentry))
1668 goto out;
1669 err = nfserr_perm;
1670 if (!len)
1671 goto out;
1672 err = nfserr_exist;
1673 if (isdotent(name, len))
1674 goto out;
1675
1676 host_err = fh_want_write(tfhp);
1677 if (host_err) {
1678 err = nfserrno(host_err);
1679 goto out;
1680 }
1681
1682 fh_lock_nested(ffhp, I_MUTEX_PARENT);
1683 ddir = ffhp->fh_dentry;
1684 dirp = d_inode(ddir);
1685
1686 dnew = lookup_one_len(name, ddir, len);
1687 host_err = PTR_ERR(dnew);
1688 if (IS_ERR(dnew))
1689 goto out_nfserr;
1690
1691 dold = tfhp->fh_dentry;
1692
1693 err = nfserr_noent;
1694 if (d_really_is_negative(dold))
1695 goto out_dput;
1696 host_err = vfs_link(dold, &init_user_ns, dirp, dnew, NULL);
1697 fh_unlock(ffhp);
1698 if (!host_err) {
1699 err = nfserrno(commit_metadata(ffhp));
1700 if (!err)
1701 err = nfserrno(commit_metadata(tfhp));
1702 } else {
1703 if (host_err == -EXDEV && rqstp->rq_vers == 2)
1704 err = nfserr_acces;
1705 else
1706 err = nfserrno(host_err);
1707 }
1708out_dput:
1709 dput(dnew);
1710out_unlock:
1711 fh_unlock(ffhp);
1712 fh_drop_write(tfhp);
1713out:
1714 return err;
1715
1716out_nfserr:
1717 err = nfserrno(host_err);
1718 goto out_unlock;
1719}
1720
1721static void
1722nfsd_close_cached_files(struct dentry *dentry)
1723{
1724 struct inode *inode = d_inode(dentry);
1725
1726 if (inode && S_ISREG(inode->i_mode))
1727 nfsd_file_close_inode_sync(inode);
1728}
1729
1730static bool
1731nfsd_has_cached_files(struct dentry *dentry)
1732{
1733 bool ret = false;
1734 struct inode *inode = d_inode(dentry);
1735
1736 if (inode && S_ISREG(inode->i_mode))
1737 ret = nfsd_file_is_cached(inode);
1738 return ret;
1739}
1740
1741/*
1742 * Rename a file
1743 * N.B. After this call _both_ ffhp and tfhp need an fh_put
1744 */
1745__be32
1746nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
1747 struct svc_fh *tfhp, char *tname, int tlen)
1748{
1749 struct dentry *fdentry, *tdentry, *odentry, *ndentry, *trap;
1750 struct inode *fdir, *tdir;
1751 __be32 err;
1752 int host_err;
1753 bool close_cached = false;
1754
1755 err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_REMOVE);
1756 if (err)
1757 goto out;
1758 err = fh_verify(rqstp, tfhp, S_IFDIR, NFSD_MAY_CREATE);
1759 if (err)
1760 goto out;
1761
1762 fdentry = ffhp->fh_dentry;
1763 fdir = d_inode(fdentry);
1764
1765 tdentry = tfhp->fh_dentry;
1766 tdir = d_inode(tdentry);
1767
1768 err = nfserr_perm;
1769 if (!flen || isdotent(fname, flen) || !tlen || isdotent(tname, tlen))
1770 goto out;
1771
1772retry:
1773 host_err = fh_want_write(ffhp);
1774 if (host_err) {
1775 err = nfserrno(host_err);
1776 goto out;
1777 }
1778
1779 /* cannot use fh_lock as we need deadlock protective ordering
1780 * so do it by hand */
1781 trap = lock_rename(tdentry, fdentry);
1782 ffhp->fh_locked = tfhp->fh_locked = true;
1783 fill_pre_wcc(ffhp);
1784 fill_pre_wcc(tfhp);
1785
1786 odentry = lookup_one_len(fname, fdentry, flen);
1787 host_err = PTR_ERR(odentry);
1788 if (IS_ERR(odentry))
1789 goto out_nfserr;
1790
1791 host_err = -ENOENT;
1792 if (d_really_is_negative(odentry))
1793 goto out_dput_old;
1794 host_err = -EINVAL;
1795 if (odentry == trap)
1796 goto out_dput_old;
1797
1798 ndentry = lookup_one_len(tname, tdentry, tlen);
1799 host_err = PTR_ERR(ndentry);
1800 if (IS_ERR(ndentry))
1801 goto out_dput_old;
1802 host_err = -ENOTEMPTY;
1803 if (ndentry == trap)
1804 goto out_dput_new;
1805
1806 host_err = -EXDEV;
1807 if (ffhp->fh_export->ex_path.mnt != tfhp->fh_export->ex_path.mnt)
1808 goto out_dput_new;
1809 if (ffhp->fh_export->ex_path.dentry != tfhp->fh_export->ex_path.dentry)
1810 goto out_dput_new;
1811
1812 if ((ndentry->d_sb->s_export_op->flags & EXPORT_OP_CLOSE_BEFORE_UNLINK) &&
1813 nfsd_has_cached_files(ndentry)) {
1814 close_cached = true;
1815 goto out_dput_old;
1816 } else {
1817 struct renamedata rd = {
1818 .old_mnt_userns = &init_user_ns,
1819 .old_dir = fdir,
1820 .old_dentry = odentry,
1821 .new_mnt_userns = &init_user_ns,
1822 .new_dir = tdir,
1823 .new_dentry = ndentry,
1824 };
1825 host_err = vfs_rename(&rd);
1826 if (!host_err) {
1827 host_err = commit_metadata(tfhp);
1828 if (!host_err)
1829 host_err = commit_metadata(ffhp);
1830 }
1831 }
1832 out_dput_new:
1833 dput(ndentry);
1834 out_dput_old:
1835 dput(odentry);
1836 out_nfserr:
1837 err = nfserrno(host_err);
1838 /*
1839 * We cannot rely on fh_unlock on the two filehandles,
1840 * as that would do the wrong thing if the two directories
1841 * were the same, so again we do it by hand.
1842 */
1843 if (!close_cached) {
1844 fill_post_wcc(ffhp);
1845 fill_post_wcc(tfhp);
1846 }
1847 unlock_rename(tdentry, fdentry);
1848 ffhp->fh_locked = tfhp->fh_locked = false;
1849 fh_drop_write(ffhp);
1850
1851 /*
1852 * If the target dentry has cached open files, then we need to try to
1853 * close them prior to doing the rename. Flushing delayed fput
1854 * shouldn't be done with locks held however, so we delay it until this
1855 * point and then reattempt the whole shebang.
1856 */
1857 if (close_cached) {
1858 close_cached = false;
1859 nfsd_close_cached_files(ndentry);
1860 dput(ndentry);
1861 goto retry;
1862 }
1863out:
1864 return err;
1865}
1866
1867/*
1868 * Unlink a file or directory
1869 * N.B. After this call fhp needs an fh_put
1870 */
1871__be32
1872nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
1873 char *fname, int flen)
1874{
1875 struct dentry *dentry, *rdentry;
1876 struct inode *dirp;
1877 struct inode *rinode;
1878 __be32 err;
1879 int host_err;
1880
1881 err = nfserr_acces;
1882 if (!flen || isdotent(fname, flen))
1883 goto out;
1884 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_REMOVE);
1885 if (err)
1886 goto out;
1887
1888 host_err = fh_want_write(fhp);
1889 if (host_err)
1890 goto out_nfserr;
1891
1892 fh_lock_nested(fhp, I_MUTEX_PARENT);
1893 dentry = fhp->fh_dentry;
1894 dirp = d_inode(dentry);
1895
1896 rdentry = lookup_one_len(fname, dentry, flen);
1897 host_err = PTR_ERR(rdentry);
1898 if (IS_ERR(rdentry))
1899 goto out_drop_write;
1900
1901 if (d_really_is_negative(rdentry)) {
1902 dput(rdentry);
1903 host_err = -ENOENT;
1904 goto out_drop_write;
1905 }
1906 rinode = d_inode(rdentry);
1907 ihold(rinode);
1908
1909 if (!type)
1910 type = d_inode(rdentry)->i_mode & S_IFMT;
1911
1912 if (type != S_IFDIR) {
1913 if (rdentry->d_sb->s_export_op->flags & EXPORT_OP_CLOSE_BEFORE_UNLINK)
1914 nfsd_close_cached_files(rdentry);
1915 host_err = vfs_unlink(&init_user_ns, dirp, rdentry, NULL);
1916 } else {
1917 host_err = vfs_rmdir(&init_user_ns, dirp, rdentry);
1918 }
1919
1920 fh_unlock(fhp);
1921 if (!host_err)
1922 host_err = commit_metadata(fhp);
1923 dput(rdentry);
1924 iput(rinode); /* truncate the inode here */
1925
1926out_drop_write:
1927 fh_drop_write(fhp);
1928out_nfserr:
1929 if (host_err == -EBUSY) {
1930 /* name is mounted-on. There is no perfect
1931 * error status.
1932 */
1933 if (nfsd_v4client(rqstp))
1934 err = nfserr_file_open;
1935 else
1936 err = nfserr_acces;
1937 } else {
1938 err = nfserrno(host_err);
1939 }
1940out:
1941 return err;
1942}
1943
1944/*
1945 * We do this buffering because we must not call back into the file
1946 * system's ->lookup() method from the filldir callback. That may well
1947 * deadlock a number of file systems.
1948 *
1949 * This is based heavily on the implementation of same in XFS.
1950 */
1951struct buffered_dirent {
1952 u64 ino;
1953 loff_t offset;
1954 int namlen;
1955 unsigned int d_type;
1956 char name[];
1957};
1958
1959struct readdir_data {
1960 struct dir_context ctx;
1961 char *dirent;
1962 size_t used;
1963 int full;
1964};
1965
1966static int nfsd_buffered_filldir(struct dir_context *ctx, const char *name,
1967 int namlen, loff_t offset, u64 ino,
1968 unsigned int d_type)
1969{
1970 struct readdir_data *buf =
1971 container_of(ctx, struct readdir_data, ctx);
1972 struct buffered_dirent *de = (void *)(buf->dirent + buf->used);
1973 unsigned int reclen;
1974
1975 reclen = ALIGN(sizeof(struct buffered_dirent) + namlen, sizeof(u64));
1976 if (buf->used + reclen > PAGE_SIZE) {
1977 buf->full = 1;
1978 return -EINVAL;
1979 }
1980
1981 de->namlen = namlen;
1982 de->offset = offset;
1983 de->ino = ino;
1984 de->d_type = d_type;
1985 memcpy(de->name, name, namlen);
1986 buf->used += reclen;
1987
1988 return 0;
1989}
1990
1991static __be32 nfsd_buffered_readdir(struct file *file, struct svc_fh *fhp,
1992 nfsd_filldir_t func, struct readdir_cd *cdp,
1993 loff_t *offsetp)
1994{
1995 struct buffered_dirent *de;
1996 int host_err;
1997 int size;
1998 loff_t offset;
1999 struct readdir_data buf = {
2000 .ctx.actor = nfsd_buffered_filldir,
2001 .dirent = (void *)__get_free_page(GFP_KERNEL)
2002 };
2003
2004 if (!buf.dirent)
2005 return nfserrno(-ENOMEM);
2006
2007 offset = *offsetp;
2008
2009 while (1) {
2010 unsigned int reclen;
2011
2012 cdp->err = nfserr_eof; /* will be cleared on successful read */
2013 buf.used = 0;
2014 buf.full = 0;
2015
2016 host_err = iterate_dir(file, &buf.ctx);
2017 if (buf.full)
2018 host_err = 0;
2019
2020 if (host_err < 0)
2021 break;
2022
2023 size = buf.used;
2024
2025 if (!size)
2026 break;
2027
2028 de = (struct buffered_dirent *)buf.dirent;
2029 while (size > 0) {
2030 offset = de->offset;
2031
2032 if (func(cdp, de->name, de->namlen, de->offset,
2033 de->ino, de->d_type))
2034 break;
2035
2036 if (cdp->err != nfs_ok)
2037 break;
2038
2039 trace_nfsd_dirent(fhp, de->ino, de->name, de->namlen);
2040
2041 reclen = ALIGN(sizeof(*de) + de->namlen,
2042 sizeof(u64));
2043 size -= reclen;
2044 de = (struct buffered_dirent *)((char *)de + reclen);
2045 }
2046 if (size > 0) /* We bailed out early */
2047 break;
2048
2049 offset = vfs_llseek(file, 0, SEEK_CUR);
2050 }
2051
2052 free_page((unsigned long)(buf.dirent));
2053
2054 if (host_err)
2055 return nfserrno(host_err);
2056
2057 *offsetp = offset;
2058 return cdp->err;
2059}
2060
2061/*
2062 * Read entries from a directory.
2063 * The NFSv3/4 verifier we ignore for now.
2064 */
2065__be32
2066nfsd_readdir(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t *offsetp,
2067 struct readdir_cd *cdp, nfsd_filldir_t func)
2068{
2069 __be32 err;
2070 struct file *file;
2071 loff_t offset = *offsetp;
2072 int may_flags = NFSD_MAY_READ;
2073
2074 /* NFSv2 only supports 32 bit cookies */
2075 if (rqstp->rq_vers > 2)
2076 may_flags |= NFSD_MAY_64BIT_COOKIE;
2077
2078 err = nfsd_open(rqstp, fhp, S_IFDIR, may_flags, &file);
2079 if (err)
2080 goto out;
2081
2082 offset = vfs_llseek(file, offset, SEEK_SET);
2083 if (offset < 0) {
2084 err = nfserrno((int)offset);
2085 goto out_close;
2086 }
2087
2088 err = nfsd_buffered_readdir(file, fhp, func, cdp, offsetp);
2089
2090 if (err == nfserr_eof || err == nfserr_toosmall)
2091 err = nfs_ok; /* can still be found in ->err */
2092out_close:
2093 fput(file);
2094out:
2095 return err;
2096}
2097
2098/*
2099 * Get file system stats
2100 * N.B. After this call fhp needs an fh_put
2101 */
2102__be32
2103nfsd_statfs(struct svc_rqst *rqstp, struct svc_fh *fhp, struct kstatfs *stat, int access)
2104{
2105 __be32 err;
2106
2107 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP | access);
2108 if (!err) {
2109 struct path path = {
2110 .mnt = fhp->fh_export->ex_path.mnt,
2111 .dentry = fhp->fh_dentry,
2112 };
2113 if (vfs_statfs(&path, stat))
2114 err = nfserr_io;
2115 }
2116 return err;
2117}
2118
2119static int exp_rdonly(struct svc_rqst *rqstp, struct svc_export *exp)
2120{
2121 return nfsexp_flags(rqstp, exp) & NFSEXP_READONLY;
2122}
2123
2124#ifdef CONFIG_NFSD_V4
2125/*
2126 * Helper function to translate error numbers. In the case of xattr operations,
2127 * some error codes need to be translated outside of the standard translations.
2128 *
2129 * ENODATA needs to be translated to nfserr_noxattr.
2130 * E2BIG to nfserr_xattr2big.
2131 *
2132 * Additionally, vfs_listxattr can return -ERANGE. This means that the
2133 * file has too many extended attributes to retrieve inside an
2134 * XATTR_LIST_MAX sized buffer. This is a bug in the xattr implementation:
2135 * filesystems will allow the adding of extended attributes until they hit
2136 * their own internal limit. This limit may be larger than XATTR_LIST_MAX.
2137 * So, at that point, the attributes are present and valid, but can't
2138 * be retrieved using listxattr, since the upper level xattr code enforces
2139 * the XATTR_LIST_MAX limit.
2140 *
2141 * This bug means that we need to deal with listxattr returning -ERANGE. The
2142 * best mapping is to return TOOSMALL.
2143 */
2144static __be32
2145nfsd_xattr_errno(int err)
2146{
2147 switch (err) {
2148 case -ENODATA:
2149 return nfserr_noxattr;
2150 case -E2BIG:
2151 return nfserr_xattr2big;
2152 case -ERANGE:
2153 return nfserr_toosmall;
2154 }
2155 return nfserrno(err);
2156}
2157
2158/*
2159 * Retrieve the specified user extended attribute. To avoid always
2160 * having to allocate the maximum size (since we are not getting
2161 * a maximum size from the RPC), do a probe + alloc. Hold a reader
2162 * lock on i_rwsem to prevent the extended attribute from changing
2163 * size while we're doing this.
2164 */
2165__be32
2166nfsd_getxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name,
2167 void **bufp, int *lenp)
2168{
2169 ssize_t len;
2170 __be32 err;
2171 char *buf;
2172 struct inode *inode;
2173 struct dentry *dentry;
2174
2175 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_READ);
2176 if (err)
2177 return err;
2178
2179 err = nfs_ok;
2180 dentry = fhp->fh_dentry;
2181 inode = d_inode(dentry);
2182
2183 inode_lock_shared(inode);
2184
2185 len = vfs_getxattr(&init_user_ns, dentry, name, NULL, 0);
2186
2187 /*
2188 * Zero-length attribute, just return.
2189 */
2190 if (len == 0) {
2191 *bufp = NULL;
2192 *lenp = 0;
2193 goto out;
2194 }
2195
2196 if (len < 0) {
2197 err = nfsd_xattr_errno(len);
2198 goto out;
2199 }
2200
2201 if (len > *lenp) {
2202 err = nfserr_toosmall;
2203 goto out;
2204 }
2205
2206 buf = kvmalloc(len, GFP_KERNEL | GFP_NOFS);
2207 if (buf == NULL) {
2208 err = nfserr_jukebox;
2209 goto out;
2210 }
2211
2212 len = vfs_getxattr(&init_user_ns, dentry, name, buf, len);
2213 if (len <= 0) {
2214 kvfree(buf);
2215 buf = NULL;
2216 err = nfsd_xattr_errno(len);
2217 }
2218
2219 *lenp = len;
2220 *bufp = buf;
2221
2222out:
2223 inode_unlock_shared(inode);
2224
2225 return err;
2226}
2227
2228/*
2229 * Retrieve the xattr names. Since we can't know how many are
2230 * user extended attributes, we must get all attributes here,
2231 * and have the XDR encode filter out the "user." ones.
2232 *
2233 * While this could always just allocate an XATTR_LIST_MAX
2234 * buffer, that's a waste, so do a probe + allocate. To
2235 * avoid any changes between the probe and allocate, wrap
2236 * this in inode_lock.
2237 */
2238__be32
2239nfsd_listxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char **bufp,
2240 int *lenp)
2241{
2242 ssize_t len;
2243 __be32 err;
2244 char *buf;
2245 struct inode *inode;
2246 struct dentry *dentry;
2247
2248 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_READ);
2249 if (err)
2250 return err;
2251
2252 dentry = fhp->fh_dentry;
2253 inode = d_inode(dentry);
2254 *lenp = 0;
2255
2256 inode_lock_shared(inode);
2257
2258 len = vfs_listxattr(dentry, NULL, 0);
2259 if (len <= 0) {
2260 err = nfsd_xattr_errno(len);
2261 goto out;
2262 }
2263
2264 if (len > XATTR_LIST_MAX) {
2265 err = nfserr_xattr2big;
2266 goto out;
2267 }
2268
2269 /*
2270 * We're holding i_rwsem - use GFP_NOFS.
2271 */
2272 buf = kvmalloc(len, GFP_KERNEL | GFP_NOFS);
2273 if (buf == NULL) {
2274 err = nfserr_jukebox;
2275 goto out;
2276 }
2277
2278 len = vfs_listxattr(dentry, buf, len);
2279 if (len <= 0) {
2280 kvfree(buf);
2281 err = nfsd_xattr_errno(len);
2282 goto out;
2283 }
2284
2285 *lenp = len;
2286 *bufp = buf;
2287
2288 err = nfs_ok;
2289out:
2290 inode_unlock_shared(inode);
2291
2292 return err;
2293}
2294
2295/*
2296 * Removexattr and setxattr need to call fh_lock to both lock the inode
2297 * and set the change attribute. Since the top-level vfs_removexattr
2298 * and vfs_setxattr calls already do their own inode_lock calls, call
2299 * the _locked variant. Pass in a NULL pointer for delegated_inode,
2300 * and let the client deal with NFS4ERR_DELAY (same as with e.g.
2301 * setattr and remove).
2302 */
2303__be32
2304nfsd_removexattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name)
2305{
2306 __be32 err;
2307 int ret;
2308
2309 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_WRITE);
2310 if (err)
2311 return err;
2312
2313 ret = fh_want_write(fhp);
2314 if (ret)
2315 return nfserrno(ret);
2316
2317 fh_lock(fhp);
2318
2319 ret = __vfs_removexattr_locked(&init_user_ns, fhp->fh_dentry,
2320 name, NULL);
2321
2322 fh_unlock(fhp);
2323 fh_drop_write(fhp);
2324
2325 return nfsd_xattr_errno(ret);
2326}
2327
2328__be32
2329nfsd_setxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name,
2330 void *buf, u32 len, u32 flags)
2331{
2332 __be32 err;
2333 int ret;
2334
2335 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_WRITE);
2336 if (err)
2337 return err;
2338
2339 ret = fh_want_write(fhp);
2340 if (ret)
2341 return nfserrno(ret);
2342 fh_lock(fhp);
2343
2344 ret = __vfs_setxattr_locked(&init_user_ns, fhp->fh_dentry, name, buf,
2345 len, flags, NULL);
2346
2347 fh_unlock(fhp);
2348 fh_drop_write(fhp);
2349
2350 return nfsd_xattr_errno(ret);
2351}
2352#endif
2353
2354/*
2355 * Check for a user's access permissions to this inode.
2356 */
2357__be32
2358nfsd_permission(struct svc_rqst *rqstp, struct svc_export *exp,
2359 struct dentry *dentry, int acc)
2360{
2361 struct inode *inode = d_inode(dentry);
2362 int err;
2363
2364 if ((acc & NFSD_MAY_MASK) == NFSD_MAY_NOP)
2365 return 0;
2366#if 0
2367 dprintk("nfsd: permission 0x%x%s%s%s%s%s%s%s mode 0%o%s%s%s\n",
2368 acc,
2369 (acc & NFSD_MAY_READ)? " read" : "",
2370 (acc & NFSD_MAY_WRITE)? " write" : "",
2371 (acc & NFSD_MAY_EXEC)? " exec" : "",
2372 (acc & NFSD_MAY_SATTR)? " sattr" : "",
2373 (acc & NFSD_MAY_TRUNC)? " trunc" : "",
2374 (acc & NFSD_MAY_LOCK)? " lock" : "",
2375 (acc & NFSD_MAY_OWNER_OVERRIDE)? " owneroverride" : "",
2376 inode->i_mode,
2377 IS_IMMUTABLE(inode)? " immut" : "",
2378 IS_APPEND(inode)? " append" : "",
2379 __mnt_is_readonly(exp->ex_path.mnt)? " ro" : "");
2380 dprintk(" owner %d/%d user %d/%d\n",
2381 inode->i_uid, inode->i_gid, current_fsuid(), current_fsgid());
2382#endif
2383
2384 /* Normally we reject any write/sattr etc access on a read-only file
2385 * system. But if it is IRIX doing check on write-access for a
2386 * device special file, we ignore rofs.
2387 */
2388 if (!(acc & NFSD_MAY_LOCAL_ACCESS))
2389 if (acc & (NFSD_MAY_WRITE | NFSD_MAY_SATTR | NFSD_MAY_TRUNC)) {
2390 if (exp_rdonly(rqstp, exp) ||
2391 __mnt_is_readonly(exp->ex_path.mnt))
2392 return nfserr_rofs;
2393 if (/* (acc & NFSD_MAY_WRITE) && */ IS_IMMUTABLE(inode))
2394 return nfserr_perm;
2395 }
2396 if ((acc & NFSD_MAY_TRUNC) && IS_APPEND(inode))
2397 return nfserr_perm;
2398
2399 if (acc & NFSD_MAY_LOCK) {
2400 /* If we cannot rely on authentication in NLM requests,
2401 * just allow locks, otherwise require read permission, or
2402 * ownership
2403 */
2404 if (exp->ex_flags & NFSEXP_NOAUTHNLM)
2405 return 0;
2406 else
2407 acc = NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE;
2408 }
2409 /*
2410 * The file owner always gets access permission for accesses that
2411 * would normally be checked at open time. This is to make
2412 * file access work even when the client has done a fchmod(fd, 0).
2413 *
2414 * However, `cp foo bar' should fail nevertheless when bar is
2415 * readonly. A sensible way to do this might be to reject all
2416 * attempts to truncate a read-only file, because a creat() call
2417 * always implies file truncation.
2418 * ... but this isn't really fair. A process may reasonably call
2419 * ftruncate on an open file descriptor on a file with perm 000.
2420 * We must trust the client to do permission checking - using "ACCESS"
2421 * with NFSv3.
2422 */
2423 if ((acc & NFSD_MAY_OWNER_OVERRIDE) &&
2424 uid_eq(inode->i_uid, current_fsuid()))
2425 return 0;
2426
2427 /* This assumes NFSD_MAY_{READ,WRITE,EXEC} == MAY_{READ,WRITE,EXEC} */
2428 err = inode_permission(&init_user_ns, inode,
2429 acc & (MAY_READ | MAY_WRITE | MAY_EXEC));
2430
2431 /* Allow read access to binaries even when mode 111 */
2432 if (err == -EACCES && S_ISREG(inode->i_mode) &&
2433 (acc == (NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE) ||
2434 acc == (NFSD_MAY_READ | NFSD_MAY_READ_IF_EXEC)))
2435 err = inode_permission(&init_user_ns, inode, MAY_EXEC);
2436
2437 return err? nfserrno(err) : 0;
2438}