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TOMOYO Linux Cross Reference
Linux/fs/nfsd/vfs.c

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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  */
 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               acc == (NFSD_MAY_READ | NFSD_MAY_READ_IF_EXEC)))
2119                 err = inode_permission(inode, MAY_EXEC);
2120 
2121         return err? nfserrno(err) : 0;
2122 }
2123 
2124 void
2125 nfsd_racache_shutdown(void)
2126 {
2127         struct raparms *raparm, *last_raparm;
2128         unsigned int i;
2129 
2130         dprintk("nfsd: freeing readahead buffers.\n");
2131 
2132         for (i = 0; i < RAPARM_HASH_SIZE; i++) {
2133                 raparm = raparm_hash[i].pb_head;
2134                 while(raparm) {
2135                         last_raparm = raparm;
2136                         raparm = raparm->p_next;
2137                         kfree(last_raparm);
2138                 }
2139                 raparm_hash[i].pb_head = NULL;
2140         }
2141 }
2142 /*
2143  * Initialize readahead param cache
2144  */
2145 int
2146 nfsd_racache_init(int cache_size)
2147 {
2148         int     i;
2149         int     j = 0;
2150         int     nperbucket;
2151         struct raparms **raparm = NULL;
2152 
2153 
2154         if (raparm_hash[0].pb_head)
2155                 return 0;
2156         nperbucket = DIV_ROUND_UP(cache_size, RAPARM_HASH_SIZE);
2157         if (nperbucket < 2)
2158                 nperbucket = 2;
2159         cache_size = nperbucket * RAPARM_HASH_SIZE;
2160 
2161         dprintk("nfsd: allocating %d readahead buffers.\n", cache_size);
2162 
2163         for (i = 0; i < RAPARM_HASH_SIZE; i++) {
2164                 spin_lock_init(&raparm_hash[i].pb_lock);
2165 
2166                 raparm = &raparm_hash[i].pb_head;
2167                 for (j = 0; j < nperbucket; j++) {
2168                         *raparm = kzalloc(sizeof(struct raparms), GFP_KERNEL);
2169                         if (!*raparm)
2170                                 goto out_nomem;
2171                         raparm = &(*raparm)->p_next;
2172                 }
2173                 *raparm = NULL;
2174         }
2175 
2176         nfsdstats.ra_size = cache_size;
2177         return 0;
2178 
2179 out_nomem:
2180         dprintk("nfsd: kmalloc failed, freeing readahead buffers\n");
2181         nfsd_racache_shutdown();
2182         return -ENOMEM;
2183 }
2184 
2185 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
2186 struct posix_acl *
2187 nfsd_get_posix_acl(struct svc_fh *fhp, int type)
2188 {
2189         struct inode *inode = fhp->fh_dentry->d_inode;
2190         char *name;
2191         void *value = NULL;
2192         ssize_t size;
2193         struct posix_acl *acl;
2194 
2195         if (!IS_POSIXACL(inode))
2196                 return ERR_PTR(-EOPNOTSUPP);
2197 
2198         switch (type) {
2199         case ACL_TYPE_ACCESS:
2200                 name = POSIX_ACL_XATTR_ACCESS;
2201                 break;
2202         case ACL_TYPE_DEFAULT:
2203                 name = POSIX_ACL_XATTR_DEFAULT;
2204                 break;
2205         default:
2206                 return ERR_PTR(-EOPNOTSUPP);
2207         }
2208 
2209         size = nfsd_getxattr(fhp->fh_dentry, name, &value);
2210         if (size < 0)
2211                 return ERR_PTR(size);
2212 
2213         acl = posix_acl_from_xattr(value, size);
2214         kfree(value);
2215         return acl;
2216 }
2217 
2218 int
2219 nfsd_set_posix_acl(struct svc_fh *fhp, int type, struct posix_acl *acl)
2220 {
2221         struct inode *inode = fhp->fh_dentry->d_inode;
2222         char *name;
2223         void *value = NULL;
2224         size_t size;
2225         int error;
2226 
2227         if (!IS_POSIXACL(inode) ||
2228             !inode->i_op->setxattr || !inode->i_op->removexattr)
2229                 return -EOPNOTSUPP;
2230         switch(type) {
2231                 case ACL_TYPE_ACCESS:
2232                         name = POSIX_ACL_XATTR_ACCESS;
2233                         break;
2234                 case ACL_TYPE_DEFAULT:
2235                         name = POSIX_ACL_XATTR_DEFAULT;
2236                         break;
2237                 default:
2238                         return -EOPNOTSUPP;
2239         }
2240 
2241         if (acl && acl->a_count) {
2242                 size = posix_acl_xattr_size(acl->a_count);
2243                 value = kmalloc(size, GFP_KERNEL);
2244                 if (!value)
2245                         return -ENOMEM;
2246                 error = posix_acl_to_xattr(acl, value, size);
2247                 if (error < 0)
2248                         goto getout;
2249                 size = error;
2250         } else
2251                 size = 0;
2252 
2253         error = mnt_want_write(fhp->fh_export->ex_path.mnt);
2254         if (error)
2255                 goto getout;
2256         if (size)
2257                 error = vfs_setxattr(fhp->fh_dentry, name, value, size, 0);
2258         else {
2259                 if (!S_ISDIR(inode->i_mode) && type == ACL_TYPE_DEFAULT)
2260                         error = 0;
2261                 else {
2262                         error = vfs_removexattr(fhp->fh_dentry, name);
2263                         if (error == -ENODATA)
2264                                 error = 0;
2265                 }
2266         }
2267         mnt_drop_write(fhp->fh_export->ex_path.mnt);
2268 
2269 getout:
2270         kfree(value);
2271         return error;
2272 }
2273 #endif  /* defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) */
2274 

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