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