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QE/FHCI: fixed the CONTROL bug
[zen-stable.git] / fs / nfsd / vfs.c
blobfd0acca5370a5da699fe62a5d94d0b6e81f67b78
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 */
54 struct 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
64 struct 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)
72 static 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 */
80 int
81 nfsd_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);
125 out:
126 return err;
127 }
128
129 static 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
140 static 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 */
167 int 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
177 nfsd_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
226 out_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
244 nfsd_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;
267 out:
268 dput(dentry);
269 exp_put(exp);
270 return err;
271 }
272
273 static 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 */
283 static int
284 commit_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
302 nfsd_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);
435 out:
436 return err;
437
438 out_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)
446 static 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)
467 static int
468 set_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);
488 out:
489 kfree(buf);
490 return error;
491 }
492
493 __be32
494 nfsd4_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
527 out_release:
528 posix_acl_release(pacl);
529 posix_acl_release(dpacl);
530 out_nfserr:
531 if (host_error == -EOPNOTSUPP)
532 return nfserr_attrnotsupp;
533 else
534 return nfserrno(host_error);
535 }
536
537 static 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
555 int
556 nfsd4_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 */
601 struct accessmap {
602 u32 access;
603 int how;
604 };
605 static 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
614 static 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
624 static 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
641 nfsd_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
699 static 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
715 nfsd_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);
771 out_nfserr:
772 err = nfserrno(host_err);
773 out:
774 validate_process_creds();
775 return err;
776 }
777
778 /*
779 * Close a file.
780 */
781 void
782 nfsd_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
792 static inline struct raparms *
793 nfsd_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;
822 found:
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 */
839 static int
840 nfsd_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
870 static 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
876 static __be32
877 nfsd_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
913 static 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 */
937 static 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
960 static __be32
961 nfsd_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
1018 out_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
1070 nfsd_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);
1084 out:
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
1094 nfsd_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 }
1117 out:
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
1132 nfsd_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);
1161 out:
1162 return err;
1163 }
1164 #endif /* CONFIG_NFSD_V3 */
1165
1166 static __be32
1167 nfsd_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 * */
1194 static void
1195 nfsd_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
1210 nfsd_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);
1330 out:
1331 if (dchild && !IS_ERR(dchild))
1332 dput(dchild);
1333 return err;
1334
1335 out_nfserr:
1336 err = nfserrno(host_err);
1337 goto out;
1338 }
1339
1340 #ifdef CONFIG_NFSD_V3
1341
1342 static 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
1352 do_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
1513 nfsd_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;
1545 out:
1546 return err;
1547
1548 out_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
1558 nfsd_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;
1611 out:
1612 return err;
1613
1614 out_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
1624 nfsd_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 }
1681 out_drop_write:
1682 mnt_drop_write(tfhp->fh_export->ex_path.mnt);
1683 out_dput:
1684 dput(dnew);
1685 out_unlock:
1686 fh_unlock(ffhp);
1687 out:
1688 return err;
1689
1690 out_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
1700 nfsd_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 }
1777 out_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
1795 out:
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
1804 nfsd_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);
1850 out_drop_write:
1851 mnt_drop_write(fhp->fh_export->ex_path.mnt);
1852 out_put:
1853 dput(rdentry);
1854
1855 out_nfserr:
1856 err = nfserrno(host_err);
1857 out:
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 */
1868 struct buffered_dirent {
1869 u64 ino;
1870 loff_t offset;
1871 int namlen;
1872 unsigned int d_type;
1873 char name[];
1874 };
1875
1876 struct readdir_data {
1877 char *dirent;
1878 size_t used;
1879 int full;
1880 };
1881
1882 static 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
1905 static __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
1986 nfsd_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 */
2007 out_close:
2008 nfsd_close(file);
2009 out:
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
2018 nfsd_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
2034 static 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
2043 nfsd_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
2123 void
2124 nfsd_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 */
2144 int
2145 nfsd_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
2178 out_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)
2185 struct posix_acl *
2186 nfsd_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
2217 int
2218 nfsd_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
2268 getout:
2269 kfree(value);
2270 return error;
2271 }
2272 #endif /* defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) */