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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/falloc.h>
 20 #include <linux/fcntl.h>
 21 #include <linux/namei.h>
 22 #include <linux/delay.h>
 23 #include <linux/fsnotify.h>
 24 #include <linux/posix_acl_xattr.h>
 25 #include <linux/xattr.h>
 26 #include <linux/jhash.h>
 27 #include <linux/ima.h>
 28 #include <linux/slab.h>
 29 #include <asm/uaccess.h>
 30 #include <linux/exportfs.h>
 31 #include <linux/writeback.h>
 32 #include <linux/security.h>
 33 
 34 #ifdef CONFIG_NFSD_V3
 35 #include "xdr3.h"
 36 #endif /* CONFIG_NFSD_V3 */
 37 
 38 #ifdef CONFIG_NFSD_V4
 39 #include "acl.h"
 40 #include "idmap.h"
 41 #endif /* CONFIG_NFSD_V4 */
 42 
 43 #include "nfsd.h"
 44 #include "vfs.h"
 45 
 46 #define NFSDDBG_FACILITY                NFSDDBG_FILEOP
 47 
 48 
 49 /*
 50  * This is a cache of readahead params that help us choose the proper
 51  * readahead strategy. Initially, we set all readahead parameters to 0
 52  * and let the VFS handle things.
 53  * If you increase the number of cached files very much, you'll need to
 54  * add a hash table here.
 55  */
 56 struct raparms {
 57         struct raparms          *p_next;
 58         unsigned int            p_count;
 59         ino_t                   p_ino;
 60         dev_t                   p_dev;
 61         int                     p_set;
 62         struct file_ra_state    p_ra;
 63         unsigned int            p_hindex;
 64 };
 65 
 66 struct raparm_hbucket {
 67         struct raparms          *pb_head;
 68         spinlock_t              pb_lock;
 69 } ____cacheline_aligned_in_smp;
 70 
 71 #define RAPARM_HASH_BITS        4
 72 #define RAPARM_HASH_SIZE        (1<<RAPARM_HASH_BITS)
 73 #define RAPARM_HASH_MASK        (RAPARM_HASH_SIZE-1)
 74 static struct raparm_hbucket    raparm_hash[RAPARM_HASH_SIZE];
 75 
 76 /* 
 77  * Called from nfsd_lookup and encode_dirent. Check if we have crossed 
 78  * a mount point.
 79  * Returns -EAGAIN or -ETIMEDOUT leaving *dpp and *expp unchanged,
 80  *  or nfs_ok having possibly changed *dpp and *expp
 81  */
 82 int
 83 nfsd_cross_mnt(struct svc_rqst *rqstp, struct dentry **dpp, 
 84                         struct svc_export **expp)
 85 {
 86         struct svc_export *exp = *expp, *exp2 = NULL;
 87         struct dentry *dentry = *dpp;
 88         struct path path = {.mnt = mntget(exp->ex_path.mnt),
 89                             .dentry = dget(dentry)};
 90         int err = 0;
 91 
 92         err = follow_down(&path);
 93         if (err < 0)
 94                 goto out;
 95 
 96         exp2 = rqst_exp_get_by_name(rqstp, &path);
 97         if (IS_ERR(exp2)) {
 98                 err = PTR_ERR(exp2);
 99                 /*
100                  * We normally allow NFS clients to continue
101                  * "underneath" a mountpoint that is not exported.
102                  * The exception is V4ROOT, where no traversal is ever
103                  * allowed without an explicit export of the new
104                  * directory.
105                  */
106                 if (err == -ENOENT && !(exp->ex_flags & NFSEXP_V4ROOT))
107                         err = 0;
108                 path_put(&path);
109                 goto out;
110         }
111         if (nfsd_v4client(rqstp) ||
112                 (exp->ex_flags & NFSEXP_CROSSMOUNT) || EX_NOHIDE(exp2)) {
113                 /* successfully crossed mount point */
114                 /*
115                  * This is subtle: path.dentry is *not* on path.mnt
116                  * at this point.  The only reason we are safe is that
117                  * original mnt is pinned down by exp, so we should
118                  * put path *before* putting exp
119                  */
120                 *dpp = path.dentry;
121                 path.dentry = dentry;
122                 *expp = exp2;
123                 exp2 = exp;
124         }
125         path_put(&path);
126         exp_put(exp2);
127 out:
128         return err;
129 }
130 
131 static void follow_to_parent(struct path *path)
132 {
133         struct dentry *dp;
134 
135         while (path->dentry == path->mnt->mnt_root && follow_up(path))
136                 ;
137         dp = dget_parent(path->dentry);
138         dput(path->dentry);
139         path->dentry = dp;
140 }
141 
142 static int nfsd_lookup_parent(struct svc_rqst *rqstp, struct dentry *dparent, struct svc_export **exp, struct dentry **dentryp)
143 {
144         struct svc_export *exp2;
145         struct path path = {.mnt = mntget((*exp)->ex_path.mnt),
146                             .dentry = dget(dparent)};
147 
148         follow_to_parent(&path);
149 
150         exp2 = rqst_exp_parent(rqstp, &path);
151         if (PTR_ERR(exp2) == -ENOENT) {
152                 *dentryp = dget(dparent);
153         } else if (IS_ERR(exp2)) {
154                 path_put(&path);
155                 return PTR_ERR(exp2);
156         } else {
157                 *dentryp = dget(path.dentry);
158                 exp_put(*exp);
159                 *exp = exp2;
160         }
161         path_put(&path);
162         return 0;
163 }
164 
165 /*
166  * For nfsd purposes, we treat V4ROOT exports as though there was an
167  * export at *every* directory.
168  */
169 int nfsd_mountpoint(struct dentry *dentry, struct svc_export *exp)
170 {
171         if (d_mountpoint(dentry))
172                 return 1;
173         if (nfsd4_is_junction(dentry))
174                 return 1;
175         if (!(exp->ex_flags & NFSEXP_V4ROOT))
176                 return 0;
177         return d_inode(dentry) != NULL;
178 }
179 
180 __be32
181 nfsd_lookup_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp,
182                    const char *name, unsigned int len,
183                    struct svc_export **exp_ret, struct dentry **dentry_ret)
184 {
185         struct svc_export       *exp;
186         struct dentry           *dparent;
187         struct dentry           *dentry;
188         int                     host_err;
189 
190         dprintk("nfsd: nfsd_lookup(fh %s, %.*s)\n", SVCFH_fmt(fhp), len,name);
191 
192         dparent = fhp->fh_dentry;
193         exp = exp_get(fhp->fh_export);
194 
195         /* Lookup the name, but don't follow links */
196         if (isdotent(name, len)) {
197                 if (len==1)
198                         dentry = dget(dparent);
199                 else if (dparent != exp->ex_path.dentry)
200                         dentry = dget_parent(dparent);
201                 else if (!EX_NOHIDE(exp) && !nfsd_v4client(rqstp))
202                         dentry = dget(dparent); /* .. == . just like at / */
203                 else {
204                         /* checking mountpoint crossing is very different when stepping up */
205                         host_err = nfsd_lookup_parent(rqstp, dparent, &exp, &dentry);
206                         if (host_err)
207                                 goto out_nfserr;
208                 }
209         } else {
210                 /*
211                  * In the nfsd4_open() case, this may be held across
212                  * subsequent open and delegation acquisition which may
213                  * need to take the child's i_mutex:
214                  */
215                 fh_lock_nested(fhp, I_MUTEX_PARENT);
216                 dentry = lookup_one_len(name, dparent, len);
217                 host_err = PTR_ERR(dentry);
218                 if (IS_ERR(dentry))
219                         goto out_nfserr;
220                 /*
221                  * check if we have crossed a mount point ...
222                  */
223                 if (nfsd_mountpoint(dentry, exp)) {
224                         if ((host_err = nfsd_cross_mnt(rqstp, &dentry, &exp))) {
225                                 dput(dentry);
226                                 goto out_nfserr;
227                         }
228                 }
229         }
230         *dentry_ret = dentry;
231         *exp_ret = exp;
232         return 0;
233 
234 out_nfserr:
235         exp_put(exp);
236         return nfserrno(host_err);
237 }
238 
239 /*
240  * Look up one component of a pathname.
241  * N.B. After this call _both_ fhp and resfh need an fh_put
242  *
243  * If the lookup would cross a mountpoint, and the mounted filesystem
244  * is exported to the client with NFSEXP_NOHIDE, then the lookup is
245  * accepted as it stands and the mounted directory is
246  * returned. Otherwise the covered directory is returned.
247  * NOTE: this mountpoint crossing is not supported properly by all
248  *   clients and is explicitly disallowed for NFSv3
249  *      NeilBrown <neilb@cse.unsw.edu.au>
250  */
251 __be32
252 nfsd_lookup(struct svc_rqst *rqstp, struct svc_fh *fhp, const char *name,
253                                 unsigned int len, struct svc_fh *resfh)
254 {
255         struct svc_export       *exp;
256         struct dentry           *dentry;
257         __be32 err;
258 
259         err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC);
260         if (err)
261                 return err;
262         err = nfsd_lookup_dentry(rqstp, fhp, name, len, &exp, &dentry);
263         if (err)
264                 return err;
265         err = check_nfsd_access(exp, rqstp);
266         if (err)
267                 goto out;
268         /*
269          * Note: we compose the file handle now, but as the
270          * dentry may be negative, it may need to be updated.
271          */
272         err = fh_compose(resfh, exp, dentry, fhp);
273         if (!err && d_really_is_negative(dentry))
274                 err = nfserr_noent;
275 out:
276         dput(dentry);
277         exp_put(exp);
278         return err;
279 }
280 
281 /*
282  * Commit metadata changes to stable storage.
283  */
284 static int
285 commit_metadata(struct svc_fh *fhp)
286 {
287         struct inode *inode = d_inode(fhp->fh_dentry);
288         const struct export_operations *export_ops = inode->i_sb->s_export_op;
289 
290         if (!EX_ISSYNC(fhp->fh_export))
291                 return 0;
292 
293         if (export_ops->commit_metadata)
294                 return export_ops->commit_metadata(inode);
295         return sync_inode_metadata(inode, 1);
296 }
297 
298 /*
299  * Go over the attributes and take care of the small differences between
300  * NFS semantics and what Linux expects.
301  */
302 static void
303 nfsd_sanitize_attrs(struct inode *inode, struct iattr *iap)
304 {
305         /* sanitize the mode change */
306         if (iap->ia_valid & ATTR_MODE) {
307                 iap->ia_mode &= S_IALLUGO;
308                 iap->ia_mode |= (inode->i_mode & ~S_IALLUGO);
309         }
310 
311         /* Revoke setuid/setgid on chown */
312         if (!S_ISDIR(inode->i_mode) &&
313             ((iap->ia_valid & ATTR_UID) || (iap->ia_valid & ATTR_GID))) {
314                 iap->ia_valid |= ATTR_KILL_PRIV;
315                 if (iap->ia_valid & ATTR_MODE) {
316                         /* we're setting mode too, just clear the s*id bits */
317                         iap->ia_mode &= ~S_ISUID;
318                         if (iap->ia_mode & S_IXGRP)
319                                 iap->ia_mode &= ~S_ISGID;
320                 } else {
321                         /* set ATTR_KILL_* bits and let VFS handle it */
322                         iap->ia_valid |= (ATTR_KILL_SUID | ATTR_KILL_SGID);
323                 }
324         }
325 }
326 
327 static __be32
328 nfsd_get_write_access(struct svc_rqst *rqstp, struct svc_fh *fhp,
329                 struct iattr *iap)
330 {
331         struct inode *inode = d_inode(fhp->fh_dentry);
332         int host_err;
333 
334         if (iap->ia_size < inode->i_size) {
335                 __be32 err;
336 
337                 err = nfsd_permission(rqstp, fhp->fh_export, fhp->fh_dentry,
338                                 NFSD_MAY_TRUNC | NFSD_MAY_OWNER_OVERRIDE);
339                 if (err)
340                         return err;
341         }
342 
343         host_err = get_write_access(inode);
344         if (host_err)
345                 goto out_nfserrno;
346 
347         host_err = locks_verify_truncate(inode, NULL, iap->ia_size);
348         if (host_err)
349                 goto out_put_write_access;
350         return 0;
351 
352 out_put_write_access:
353         put_write_access(inode);
354 out_nfserrno:
355         return nfserrno(host_err);
356 }
357 
358 /*
359  * Set various file attributes.  After this call fhp needs an fh_put.
360  */
361 __be32
362 nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
363              int check_guard, time_t guardtime)
364 {
365         struct dentry   *dentry;
366         struct inode    *inode;
367         int             accmode = NFSD_MAY_SATTR;
368         umode_t         ftype = 0;
369         __be32          err;
370         int             host_err;
371         bool            get_write_count;
372         int             size_change = 0;
373 
374         if (iap->ia_valid & (ATTR_ATIME | ATTR_MTIME | ATTR_SIZE))
375                 accmode |= NFSD_MAY_WRITE|NFSD_MAY_OWNER_OVERRIDE;
376         if (iap->ia_valid & ATTR_SIZE)
377                 ftype = S_IFREG;
378 
379         /* Callers that do fh_verify should do the fh_want_write: */
380         get_write_count = !fhp->fh_dentry;
381 
382         /* Get inode */
383         err = fh_verify(rqstp, fhp, ftype, accmode);
384         if (err)
385                 goto out;
386         if (get_write_count) {
387                 host_err = fh_want_write(fhp);
388                 if (host_err)
389                         return nfserrno(host_err);
390         }
391 
392         dentry = fhp->fh_dentry;
393         inode = d_inode(dentry);
394 
395         /* Ignore any mode updates on symlinks */
396         if (S_ISLNK(inode->i_mode))
397                 iap->ia_valid &= ~ATTR_MODE;
398 
399         if (!iap->ia_valid)
400                 goto out;
401 
402         nfsd_sanitize_attrs(inode, iap);
403 
404         /*
405          * The size case is special, it changes the file in addition to the
406          * attributes.
407          */
408         if (iap->ia_valid & ATTR_SIZE) {
409                 err = nfsd_get_write_access(rqstp, fhp, iap);
410                 if (err)
411                         goto out;
412                 size_change = 1;
413 
414                 /*
415                  * RFC5661, Section 18.30.4:
416                  *   Changing the size of a file with SETATTR indirectly
417                  *   changes the time_modify and change attributes.
418                  *
419                  * (and similar for the older RFCs)
420                  */
421                 if (iap->ia_size != i_size_read(inode))
422                         iap->ia_valid |= ATTR_MTIME;
423         }
424 
425         iap->ia_valid |= ATTR_CTIME;
426 
427         if (check_guard && guardtime != inode->i_ctime.tv_sec) {
428                 err = nfserr_notsync;
429                 goto out_put_write_access;
430         }
431 
432         fh_lock(fhp);
433         host_err = notify_change(dentry, iap, NULL);
434         fh_unlock(fhp);
435         err = nfserrno(host_err);
436 
437 out_put_write_access:
438         if (size_change)
439                 put_write_access(inode);
440         if (!err)
441                 err = nfserrno(commit_metadata(fhp));
442 out:
443         return err;
444 }
445 
446 #if defined(CONFIG_NFSD_V4)
447 /*
448  * NFS junction information is stored in an extended attribute.
449  */
450 #define NFSD_JUNCTION_XATTR_NAME        XATTR_TRUSTED_PREFIX "junction.nfs"
451 
452 /**
453  * nfsd4_is_junction - Test if an object could be an NFS junction
454  *
455  * @dentry: object to test
456  *
457  * Returns 1 if "dentry" appears to contain NFS junction information.
458  * Otherwise 0 is returned.
459  */
460 int nfsd4_is_junction(struct dentry *dentry)
461 {
462         struct inode *inode = d_inode(dentry);
463 
464         if (inode == NULL)
465                 return 0;
466         if (inode->i_mode & S_IXUGO)
467                 return 0;
468         if (!(inode->i_mode & S_ISVTX))
469                 return 0;
470         if (vfs_getxattr(dentry, NFSD_JUNCTION_XATTR_NAME, NULL, 0) <= 0)
471                 return 0;
472         return 1;
473 }
474 #ifdef CONFIG_NFSD_V4_SECURITY_LABEL
475 __be32 nfsd4_set_nfs4_label(struct svc_rqst *rqstp, struct svc_fh *fhp,
476                 struct xdr_netobj *label)
477 {
478         __be32 error;
479         int host_error;
480         struct dentry *dentry;
481 
482         error = fh_verify(rqstp, fhp, 0 /* S_IFREG */, NFSD_MAY_SATTR);
483         if (error)
484                 return error;
485 
486         dentry = fhp->fh_dentry;
487 
488         mutex_lock(&d_inode(dentry)->i_mutex);
489         host_error = security_inode_setsecctx(dentry, label->data, label->len);
490         mutex_unlock(&d_inode(dentry)->i_mutex);
491         return nfserrno(host_error);
492 }
493 #else
494 __be32 nfsd4_set_nfs4_label(struct svc_rqst *rqstp, struct svc_fh *fhp,
495                 struct xdr_netobj *label)
496 {
497         return nfserr_notsupp;
498 }
499 #endif
500 
501 __be32 nfsd4_vfs_fallocate(struct svc_rqst *rqstp, struct svc_fh *fhp,
502                            struct file *file, loff_t offset, loff_t len,
503                            int flags)
504 {
505         int error;
506 
507         if (!S_ISREG(file_inode(file)->i_mode))
508                 return nfserr_inval;
509 
510         error = vfs_fallocate(file, flags, offset, len);
511         if (!error)
512                 error = commit_metadata(fhp);
513 
514         return nfserrno(error);
515 }
516 #endif /* defined(CONFIG_NFSD_V4) */
517 
518 #ifdef CONFIG_NFSD_V3
519 /*
520  * Check server access rights to a file system object
521  */
522 struct accessmap {
523         u32             access;
524         int             how;
525 };
526 static struct accessmap nfs3_regaccess[] = {
527     {   NFS3_ACCESS_READ,       NFSD_MAY_READ                   },
528     {   NFS3_ACCESS_EXECUTE,    NFSD_MAY_EXEC                   },
529     {   NFS3_ACCESS_MODIFY,     NFSD_MAY_WRITE|NFSD_MAY_TRUNC   },
530     {   NFS3_ACCESS_EXTEND,     NFSD_MAY_WRITE                  },
531 
532     {   0,                      0                               }
533 };
534 
535 static struct accessmap nfs3_diraccess[] = {
536     {   NFS3_ACCESS_READ,       NFSD_MAY_READ                   },
537     {   NFS3_ACCESS_LOOKUP,     NFSD_MAY_EXEC                   },
538     {   NFS3_ACCESS_MODIFY,     NFSD_MAY_EXEC|NFSD_MAY_WRITE|NFSD_MAY_TRUNC},
539     {   NFS3_ACCESS_EXTEND,     NFSD_MAY_EXEC|NFSD_MAY_WRITE    },
540     {   NFS3_ACCESS_DELETE,     NFSD_MAY_REMOVE                 },
541 
542     {   0,                      0                               }
543 };
544 
545 static struct accessmap nfs3_anyaccess[] = {
546         /* Some clients - Solaris 2.6 at least, make an access call
547          * to the server to check for access for things like /dev/null
548          * (which really, the server doesn't care about).  So
549          * We provide simple access checking for them, looking
550          * mainly at mode bits, and we make sure to ignore read-only
551          * filesystem checks
552          */
553     {   NFS3_ACCESS_READ,       NFSD_MAY_READ                   },
554     {   NFS3_ACCESS_EXECUTE,    NFSD_MAY_EXEC                   },
555     {   NFS3_ACCESS_MODIFY,     NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS    },
556     {   NFS3_ACCESS_EXTEND,     NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS    },
557 
558     {   0,                      0                               }
559 };
560 
561 __be32
562 nfsd_access(struct svc_rqst *rqstp, struct svc_fh *fhp, u32 *access, u32 *supported)
563 {
564         struct accessmap        *map;
565         struct svc_export       *export;
566         struct dentry           *dentry;
567         u32                     query, result = 0, sresult = 0;
568         __be32                  error;
569 
570         error = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP);
571         if (error)
572                 goto out;
573 
574         export = fhp->fh_export;
575         dentry = fhp->fh_dentry;
576 
577         if (d_is_reg(dentry))
578                 map = nfs3_regaccess;
579         else if (d_is_dir(dentry))
580                 map = nfs3_diraccess;
581         else
582                 map = nfs3_anyaccess;
583 
584 
585         query = *access;
586         for  (; map->access; map++) {
587                 if (map->access & query) {
588                         __be32 err2;
589 
590                         sresult |= map->access;
591 
592                         err2 = nfsd_permission(rqstp, export, dentry, map->how);
593                         switch (err2) {
594                         case nfs_ok:
595                                 result |= map->access;
596                                 break;
597                                 
598                         /* the following error codes just mean the access was not allowed,
599                          * rather than an error occurred */
600                         case nfserr_rofs:
601                         case nfserr_acces:
602                         case nfserr_perm:
603                                 /* simply don't "or" in the access bit. */
604                                 break;
605                         default:
606                                 error = err2;
607                                 goto out;
608                         }
609                 }
610         }
611         *access = result;
612         if (supported)
613                 *supported = sresult;
614 
615  out:
616         return error;
617 }
618 #endif /* CONFIG_NFSD_V3 */
619 
620 static int nfsd_open_break_lease(struct inode *inode, int access)
621 {
622         unsigned int mode;
623 
624         if (access & NFSD_MAY_NOT_BREAK_LEASE)
625                 return 0;
626         mode = (access & NFSD_MAY_WRITE) ? O_WRONLY : O_RDONLY;
627         return break_lease(inode, mode | O_NONBLOCK);
628 }
629 
630 /*
631  * Open an existing file or directory.
632  * The may_flags argument indicates the type of open (read/write/lock)
633  * and additional flags.
634  * N.B. After this call fhp needs an fh_put
635  */
636 __be32
637 nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type,
638                         int may_flags, struct file **filp)
639 {
640         struct path     path;
641         struct inode    *inode;
642         struct file     *file;
643         int             flags = O_RDONLY|O_LARGEFILE;
644         __be32          err;
645         int             host_err = 0;
646 
647         validate_process_creds();
648 
649         /*
650          * If we get here, then the client has already done an "open",
651          * and (hopefully) checked permission - so allow OWNER_OVERRIDE
652          * in case a chmod has now revoked permission.
653          *
654          * Arguably we should also allow the owner override for
655          * directories, but we never have and it doesn't seem to have
656          * caused anyone a problem.  If we were to change this, note
657          * also that our filldir callbacks would need a variant of
658          * lookup_one_len that doesn't check permissions.
659          */
660         if (type == S_IFREG)
661                 may_flags |= NFSD_MAY_OWNER_OVERRIDE;
662         err = fh_verify(rqstp, fhp, type, may_flags);
663         if (err)
664                 goto out;
665 
666         path.mnt = fhp->fh_export->ex_path.mnt;
667         path.dentry = fhp->fh_dentry;
668         inode = d_inode(path.dentry);
669 
670         /* Disallow write access to files with the append-only bit set
671          * or any access when mandatory locking enabled
672          */
673         err = nfserr_perm;
674         if (IS_APPEND(inode) && (may_flags & NFSD_MAY_WRITE))
675                 goto out;
676         /*
677          * We must ignore files (but only files) which might have mandatory
678          * locks on them because there is no way to know if the accesser has
679          * the lock.
680          */
681         if (S_ISREG((inode)->i_mode) && mandatory_lock(inode))
682                 goto out;
683 
684         if (!inode->i_fop)
685                 goto out;
686 
687         host_err = nfsd_open_break_lease(inode, may_flags);
688         if (host_err) /* NOMEM or WOULDBLOCK */
689                 goto out_nfserr;
690 
691         if (may_flags & NFSD_MAY_WRITE) {
692                 if (may_flags & NFSD_MAY_READ)
693                         flags = O_RDWR|O_LARGEFILE;
694                 else
695                         flags = O_WRONLY|O_LARGEFILE;
696         }
697 
698         file = dentry_open(&path, flags, current_cred());
699         if (IS_ERR(file)) {
700                 host_err = PTR_ERR(file);
701                 goto out_nfserr;
702         }
703 
704         host_err = ima_file_check(file, may_flags, 0);
705         if (host_err) {
706                 fput(file);
707                 goto out_nfserr;
708         }
709 
710         if (may_flags & NFSD_MAY_64BIT_COOKIE)
711                 file->f_mode |= FMODE_64BITHASH;
712         else
713                 file->f_mode |= FMODE_32BITHASH;
714 
715         *filp = file;
716 out_nfserr:
717         err = nfserrno(host_err);
718 out:
719         validate_process_creds();
720         return err;
721 }
722 
723 struct raparms *
724 nfsd_init_raparms(struct file *file)
725 {
726         struct inode *inode = file_inode(file);
727         dev_t dev = inode->i_sb->s_dev;
728         ino_t ino = inode->i_ino;
729         struct raparms  *ra, **rap, **frap = NULL;
730         int depth = 0;
731         unsigned int hash;
732         struct raparm_hbucket *rab;
733 
734         hash = jhash_2words(dev, ino, 0xfeedbeef) & RAPARM_HASH_MASK;
735         rab = &raparm_hash[hash];
736 
737         spin_lock(&rab->pb_lock);
738         for (rap = &rab->pb_head; (ra = *rap); rap = &ra->p_next) {
739                 if (ra->p_ino == ino && ra->p_dev == dev)
740                         goto found;
741                 depth++;
742                 if (ra->p_count == 0)
743                         frap = rap;
744         }
745         depth = nfsdstats.ra_size;
746         if (!frap) {    
747                 spin_unlock(&rab->pb_lock);
748                 return NULL;
749         }
750         rap = frap;
751         ra = *frap;
752         ra->p_dev = dev;
753         ra->p_ino = ino;
754         ra->p_set = 0;
755         ra->p_hindex = hash;
756 found:
757         if (rap != &rab->pb_head) {
758                 *rap = ra->p_next;
759                 ra->p_next   = rab->pb_head;
760                 rab->pb_head = ra;
761         }
762         ra->p_count++;
763         nfsdstats.ra_depth[depth*10/nfsdstats.ra_size]++;
764         spin_unlock(&rab->pb_lock);
765 
766         if (ra->p_set)
767                 file->f_ra = ra->p_ra;
768         return ra;
769 }
770 
771 void nfsd_put_raparams(struct file *file, struct raparms *ra)
772 {
773         struct raparm_hbucket *rab = &raparm_hash[ra->p_hindex];
774 
775         spin_lock(&rab->pb_lock);
776         ra->p_ra = file->f_ra;
777         ra->p_set = 1;
778         ra->p_count--;
779         spin_unlock(&rab->pb_lock);
780 }
781 
782 /*
783  * Grab and keep cached pages associated with a file in the svc_rqst
784  * so that they can be passed to the network sendmsg/sendpage routines
785  * directly. They will be released after the sending has completed.
786  */
787 static int
788 nfsd_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
789                   struct splice_desc *sd)
790 {
791         struct svc_rqst *rqstp = sd->u.data;
792         struct page **pp = rqstp->rq_next_page;
793         struct page *page = buf->page;
794         size_t size;
795 
796         size = sd->len;
797 
798         if (rqstp->rq_res.page_len == 0) {
799                 get_page(page);
800                 put_page(*rqstp->rq_next_page);
801                 *(rqstp->rq_next_page++) = page;
802                 rqstp->rq_res.page_base = buf->offset;
803                 rqstp->rq_res.page_len = size;
804         } else if (page != pp[-1]) {
805                 get_page(page);
806                 if (*rqstp->rq_next_page)
807                         put_page(*rqstp->rq_next_page);
808                 *(rqstp->rq_next_page++) = page;
809                 rqstp->rq_res.page_len += size;
810         } else
811                 rqstp->rq_res.page_len += size;
812 
813         return size;
814 }
815 
816 static int nfsd_direct_splice_actor(struct pipe_inode_info *pipe,
817                                     struct splice_desc *sd)
818 {
819         return __splice_from_pipe(pipe, sd, nfsd_splice_actor);
820 }
821 
822 static __be32
823 nfsd_finish_read(struct file *file, unsigned long *count, int host_err)
824 {
825         if (host_err >= 0) {
826                 nfsdstats.io_read += host_err;
827                 *count = host_err;
828                 fsnotify_access(file);
829                 return 0;
830         } else 
831                 return nfserrno(host_err);
832 }
833 
834 __be32 nfsd_splice_read(struct svc_rqst *rqstp,
835                      struct file *file, loff_t offset, unsigned long *count)
836 {
837         struct splice_desc sd = {
838                 .len            = 0,
839                 .total_len      = *count,
840                 .pos            = offset,
841                 .u.data         = rqstp,
842         };
843         int host_err;
844 
845         rqstp->rq_next_page = rqstp->rq_respages + 1;
846         host_err = splice_direct_to_actor(file, &sd, nfsd_direct_splice_actor);
847         return nfsd_finish_read(file, count, host_err);
848 }
849 
850 __be32 nfsd_readv(struct file *file, loff_t offset, struct kvec *vec, int vlen,
851                 unsigned long *count)
852 {
853         mm_segment_t oldfs;
854         int host_err;
855 
856         oldfs = get_fs();
857         set_fs(KERNEL_DS);
858         host_err = vfs_readv(file, (struct iovec __user *)vec, vlen, &offset);
859         set_fs(oldfs);
860         return nfsd_finish_read(file, count, host_err);
861 }
862 
863 static __be32
864 nfsd_vfs_read(struct svc_rqst *rqstp, struct file *file,
865               loff_t offset, struct kvec *vec, int vlen, unsigned long *count)
866 {
867         if (file->f_op->splice_read && test_bit(RQ_SPLICE_OK, &rqstp->rq_flags))
868                 return nfsd_splice_read(rqstp, file, offset, count);
869         else
870                 return nfsd_readv(file, offset, vec, vlen, count);
871 }
872 
873 /*
874  * Gathered writes: If another process is currently writing to the file,
875  * there's a high chance this is another nfsd (triggered by a bulk write
876  * from a client's biod). Rather than syncing the file with each write
877  * request, we sleep for 10 msec.
878  *
879  * I don't know if this roughly approximates C. Juszak's idea of
880  * gathered writes, but it's a nice and simple solution (IMHO), and it
881  * seems to work:-)
882  *
883  * Note: we do this only in the NFSv2 case, since v3 and higher have a
884  * better tool (separate unstable writes and commits) for solving this
885  * problem.
886  */
887 static int wait_for_concurrent_writes(struct file *file)
888 {
889         struct inode *inode = file_inode(file);
890         static ino_t last_ino;
891         static dev_t last_dev;
892         int err = 0;
893 
894         if (atomic_read(&inode->i_writecount) > 1
895             || (last_ino == inode->i_ino && last_dev == inode->i_sb->s_dev)) {
896                 dprintk("nfsd: write defer %d\n", task_pid_nr(current));
897                 msleep(10);
898                 dprintk("nfsd: write resume %d\n", task_pid_nr(current));
899         }
900 
901         if (inode->i_state & I_DIRTY) {
902                 dprintk("nfsd: write sync %d\n", task_pid_nr(current));
903                 err = vfs_fsync(file, 0);
904         }
905         last_ino = inode->i_ino;
906         last_dev = inode->i_sb->s_dev;
907         return err;
908 }
909 
910 __be32
911 nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
912                                 loff_t offset, struct kvec *vec, int vlen,
913                                 unsigned long *cnt, int *stablep)
914 {
915         struct svc_export       *exp;
916         struct inode            *inode;
917         mm_segment_t            oldfs;
918         __be32                  err = 0;
919         int                     host_err;
920         int                     stable = *stablep;
921         int                     use_wgather;
922         loff_t                  pos = offset;
923         loff_t                  end = LLONG_MAX;
924         unsigned int            pflags = current->flags;
925 
926         if (test_bit(RQ_LOCAL, &rqstp->rq_flags))
927                 /*
928                  * We want less throttling in balance_dirty_pages()
929                  * and shrink_inactive_list() so that nfs to
930                  * localhost doesn't cause nfsd to lock up due to all
931                  * the client's dirty pages or its congested queue.
932                  */
933                 current->flags |= PF_LESS_THROTTLE;
934 
935         inode = file_inode(file);
936         exp   = fhp->fh_export;
937 
938         use_wgather = (rqstp->rq_vers == 2) && EX_WGATHER(exp);
939 
940         if (!EX_ISSYNC(exp))
941                 stable = 0;
942 
943         /* Write the data. */
944         oldfs = get_fs(); set_fs(KERNEL_DS);
945         host_err = vfs_writev(file, (struct iovec __user *)vec, vlen, &pos);
946         set_fs(oldfs);
947         if (host_err < 0)
948                 goto out_nfserr;
949         *cnt = host_err;
950         nfsdstats.io_write += host_err;
951         fsnotify_modify(file);
952 
953         if (stable) {
954                 if (use_wgather) {
955                         host_err = wait_for_concurrent_writes(file);
956                 } else {
957                         if (*cnt)
958                                 end = offset + *cnt - 1;
959                         host_err = vfs_fsync_range(file, offset, end, 0);
960                 }
961         }
962 
963 out_nfserr:
964         dprintk("nfsd: write complete host_err=%d\n", host_err);
965         if (host_err >= 0)
966                 err = 0;
967         else
968                 err = nfserrno(host_err);
969         if (test_bit(RQ_LOCAL, &rqstp->rq_flags))
970                 tsk_restore_flags(current, pflags, PF_LESS_THROTTLE);
971         return err;
972 }
973 
974 /*
975  * Read data from a file. count must contain the requested read count
976  * on entry. On return, *count contains the number of bytes actually read.
977  * N.B. After this call fhp needs an fh_put
978  */
979 __be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
980         loff_t offset, struct kvec *vec, int vlen, unsigned long *count)
981 {
982         struct file *file;
983         struct raparms  *ra;
984         __be32 err;
985 
986         err = nfsd_open(rqstp, fhp, S_IFREG, NFSD_MAY_READ, &file);
987         if (err)
988                 return err;
989 
990         ra = nfsd_init_raparms(file);
991         err = nfsd_vfs_read(rqstp, file, offset, vec, vlen, count);
992         if (ra)
993                 nfsd_put_raparams(file, ra);
994         fput(file);
995 
996         return err;
997 }
998 
999 /*
1000  * Write data to a file.
1001  * The stable flag requests synchronous writes.
1002  * N.B. After this call fhp needs an fh_put
1003  */
1004 __be32
1005 nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
1006                 loff_t offset, struct kvec *vec, int vlen, unsigned long *cnt,
1007                 int *stablep)
1008 {
1009         __be32                  err = 0;
1010 
1011         if (file) {
1012                 err = nfsd_permission(rqstp, fhp->fh_export, fhp->fh_dentry,
1013                                 NFSD_MAY_WRITE|NFSD_MAY_OWNER_OVERRIDE);
1014                 if (err)
1015                         goto out;
1016                 err = nfsd_vfs_write(rqstp, fhp, file, offset, vec, vlen, cnt,
1017                                 stablep);
1018         } else {
1019                 err = nfsd_open(rqstp, fhp, S_IFREG, NFSD_MAY_WRITE, &file);
1020                 if (err)
1021                         goto out;
1022 
1023                 if (cnt)
1024                         err = nfsd_vfs_write(rqstp, fhp, file, offset, vec, vlen,
1025                                              cnt, stablep);
1026                 fput(file);
1027         }
1028 out:
1029         return err;
1030 }
1031 
1032 #ifdef CONFIG_NFSD_V3
1033 /*
1034  * Commit all pending writes to stable storage.
1035  *
1036  * Note: we only guarantee that data that lies within the range specified
1037  * by the 'offset' and 'count' parameters will be synced.
1038  *
1039  * Unfortunately we cannot lock the file to make sure we return full WCC
1040  * data to the client, as locking happens lower down in the filesystem.
1041  */
1042 __be32
1043 nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp,
1044                loff_t offset, unsigned long count)
1045 {
1046         struct file     *file;
1047         loff_t          end = LLONG_MAX;
1048         __be32          err = nfserr_inval;
1049 
1050         if (offset < 0)
1051                 goto out;
1052         if (count != 0) {
1053                 end = offset + (loff_t)count - 1;
1054                 if (end < offset)
1055                         goto out;
1056         }
1057 
1058         err = nfsd_open(rqstp, fhp, S_IFREG,
1059                         NFSD_MAY_WRITE|NFSD_MAY_NOT_BREAK_LEASE, &file);
1060         if (err)
1061                 goto out;
1062         if (EX_ISSYNC(fhp->fh_export)) {
1063                 int err2 = vfs_fsync_range(file, offset, end, 0);
1064 
1065                 if (err2 != -EINVAL)
1066                         err = nfserrno(err2);
1067                 else
1068                         err = nfserr_notsupp;
1069         }
1070 
1071         fput(file);
1072 out:
1073         return err;
1074 }
1075 #endif /* CONFIG_NFSD_V3 */
1076 
1077 static __be32
1078 nfsd_create_setattr(struct svc_rqst *rqstp, struct svc_fh *resfhp,
1079                         struct iattr *iap)
1080 {
1081         /*
1082          * Mode has already been set earlier in create:
1083          */
1084         iap->ia_valid &= ~ATTR_MODE;
1085         /*
1086          * Setting uid/gid works only for root.  Irix appears to
1087          * send along the gid on create when it tries to implement
1088          * setgid directories via NFS:
1089          */
1090         if (!uid_eq(current_fsuid(), GLOBAL_ROOT_UID))
1091                 iap->ia_valid &= ~(ATTR_UID|ATTR_GID);
1092         if (iap->ia_valid)
1093                 return nfsd_setattr(rqstp, resfhp, iap, 0, (time_t)0);
1094         /* Callers expect file metadata to be committed here */
1095         return nfserrno(commit_metadata(resfhp));
1096 }
1097 
1098 /* HPUX client sometimes creates a file in mode 000, and sets size to 0.
1099  * setting size to 0 may fail for some specific file systems by the permission
1100  * checking which requires WRITE permission but the mode is 000.
1101  * we ignore the resizing(to 0) on the just new created file, since the size is
1102  * 0 after file created.
1103  *
1104  * call this only after vfs_create() is called.
1105  * */
1106 static void
1107 nfsd_check_ignore_resizing(struct iattr *iap)
1108 {
1109         if ((iap->ia_valid & ATTR_SIZE) && (iap->ia_size == 0))
1110                 iap->ia_valid &= ~ATTR_SIZE;
1111 }
1112 
1113 /*
1114  * Create a file (regular, directory, device, fifo); UNIX sockets 
1115  * not yet implemented.
1116  * If the response fh has been verified, the parent directory should
1117  * already be locked. Note that the parent directory is left locked.
1118  *
1119  * N.B. Every call to nfsd_create needs an fh_put for _both_ fhp and resfhp
1120  */
1121 __be32
1122 nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
1123                 char *fname, int flen, struct iattr *iap,
1124                 int type, dev_t rdev, struct svc_fh *resfhp)
1125 {
1126         struct dentry   *dentry, *dchild = NULL;
1127         struct inode    *dirp;
1128         __be32          err;
1129         __be32          err2;
1130         int             host_err;
1131 
1132         err = nfserr_perm;
1133         if (!flen)
1134                 goto out;
1135         err = nfserr_exist;
1136         if (isdotent(fname, flen))
1137                 goto out;
1138 
1139         err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
1140         if (err)
1141                 goto out;
1142 
1143         dentry = fhp->fh_dentry;
1144         dirp = d_inode(dentry);
1145 
1146         err = nfserr_notdir;
1147         if (!dirp->i_op->lookup)
1148                 goto out;
1149         /*
1150          * Check whether the response file handle has been verified yet.
1151          * If it has, the parent directory should already be locked.
1152          */
1153         if (!resfhp->fh_dentry) {
1154                 host_err = fh_want_write(fhp);
1155                 if (host_err)
1156                         goto out_nfserr;
1157 
1158                 /* called from nfsd_proc_mkdir, or possibly nfsd3_proc_create */
1159                 fh_lock_nested(fhp, I_MUTEX_PARENT);
1160                 dchild = lookup_one_len(fname, dentry, flen);
1161                 host_err = PTR_ERR(dchild);
1162                 if (IS_ERR(dchild))
1163                         goto out_nfserr;
1164                 err = fh_compose(resfhp, fhp->fh_export, dchild, fhp);
1165                 if (err)
1166                         goto out;
1167         } else {
1168                 /* called from nfsd_proc_create */
1169                 dchild = dget(resfhp->fh_dentry);
1170                 if (!fhp->fh_locked) {
1171                         /* not actually possible */
1172                         printk(KERN_ERR
1173                                 "nfsd_create: parent %pd2 not locked!\n",
1174                                 dentry);
1175                         err = nfserr_io;
1176                         goto out;
1177                 }
1178         }
1179         /*
1180          * Make sure the child dentry is still negative ...
1181          */
1182         err = nfserr_exist;
1183         if (d_really_is_positive(dchild)) {
1184                 dprintk("nfsd_create: dentry %pd/%pd not negative!\n",
1185                         dentry, dchild);
1186                 goto out; 
1187         }
1188 
1189         if (!(iap->ia_valid & ATTR_MODE))
1190                 iap->ia_mode = 0;
1191         iap->ia_mode = (iap->ia_mode & S_IALLUGO) | type;
1192 
1193         err = nfserr_inval;
1194         if (!S_ISREG(type) && !S_ISDIR(type) && !special_file(type)) {
1195                 printk(KERN_WARNING "nfsd: bad file type %o in nfsd_create\n",
1196                        type);
1197                 goto out;
1198         }
1199 
1200         /*
1201          * Get the dir op function pointer.
1202          */
1203         err = 0;
1204         host_err = 0;
1205         switch (type) {
1206         case S_IFREG:
1207                 host_err = vfs_create(dirp, dchild, iap->ia_mode, true);
1208                 if (!host_err)
1209                         nfsd_check_ignore_resizing(iap);
1210                 break;
1211         case S_IFDIR:
1212                 host_err = vfs_mkdir(dirp, dchild, iap->ia_mode);
1213                 break;
1214         case S_IFCHR:
1215         case S_IFBLK:
1216         case S_IFIFO:
1217         case S_IFSOCK:
1218                 host_err = vfs_mknod(dirp, dchild, iap->ia_mode, rdev);
1219                 break;
1220         }
1221         if (host_err < 0)
1222                 goto out_nfserr;
1223 
1224         err = nfsd_create_setattr(rqstp, resfhp, iap);
1225 
1226         /*
1227          * nfsd_create_setattr already committed the child.  Transactional
1228          * filesystems had a chance to commit changes for both parent and
1229          * child * simultaneously making the following commit_metadata a
1230          * noop.
1231          */
1232         err2 = nfserrno(commit_metadata(fhp));
1233         if (err2)
1234                 err = err2;
1235         /*
1236          * Update the file handle to get the new inode info.
1237          */
1238         if (!err)
1239                 err = fh_update(resfhp);
1240 out:
1241         if (dchild && !IS_ERR(dchild))
1242                 dput(dchild);
1243         return err;
1244 
1245 out_nfserr:
1246         err = nfserrno(host_err);
1247         goto out;
1248 }
1249 
1250 #ifdef CONFIG_NFSD_V3
1251 
1252 /*
1253  * NFSv3 and NFSv4 version of nfsd_create
1254  */
1255 __be32
1256 do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
1257                 char *fname, int flen, struct iattr *iap,
1258                 struct svc_fh *resfhp, int createmode, u32 *verifier,
1259                 bool *truncp, bool *created)
1260 {
1261         struct dentry   *dentry, *dchild = NULL;
1262         struct inode    *dirp;
1263         __be32          err;
1264         int             host_err;
1265         __u32           v_mtime=0, v_atime=0;
1266 
1267         err = nfserr_perm;
1268         if (!flen)
1269                 goto out;
1270         err = nfserr_exist;
1271         if (isdotent(fname, flen))
1272                 goto out;
1273         if (!(iap->ia_valid & ATTR_MODE))
1274                 iap->ia_mode = 0;
1275         err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC);
1276         if (err)
1277                 goto out;
1278 
1279         dentry = fhp->fh_dentry;
1280         dirp = d_inode(dentry);
1281 
1282         /* Get all the sanity checks out of the way before
1283          * we lock the parent. */
1284         err = nfserr_notdir;
1285         if (!dirp->i_op->lookup)
1286                 goto out;
1287 
1288         host_err = fh_want_write(fhp);
1289         if (host_err)
1290                 goto out_nfserr;
1291 
1292         fh_lock_nested(fhp, I_MUTEX_PARENT);
1293 
1294         /*
1295          * Compose the response file handle.
1296          */
1297         dchild = lookup_one_len(fname, dentry, flen);
1298         host_err = PTR_ERR(dchild);
1299         if (IS_ERR(dchild))
1300                 goto out_nfserr;
1301 
1302         /* If file doesn't exist, check for permissions to create one */
1303         if (d_really_is_negative(dchild)) {
1304                 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
1305                 if (err)
1306                         goto out;
1307         }
1308 
1309         err = fh_compose(resfhp, fhp->fh_export, dchild, fhp);
1310         if (err)
1311                 goto out;
1312 
1313         if (nfsd_create_is_exclusive(createmode)) {
1314                 /* solaris7 gets confused (bugid 4218508) if these have
1315                  * the high bit set, so just clear the high bits. If this is
1316                  * ever changed to use different attrs for storing the
1317                  * verifier, then do_open_lookup() will also need to be fixed
1318                  * accordingly.
1319                  */
1320                 v_mtime = verifier[0]&0x7fffffff;
1321                 v_atime = verifier[1]&0x7fffffff;
1322         }
1323         
1324         if (d_really_is_positive(dchild)) {
1325                 err = 0;
1326 
1327                 switch (createmode) {
1328                 case NFS3_CREATE_UNCHECKED:
1329                         if (! d_is_reg(dchild))
1330                                 goto out;
1331                         else if (truncp) {
1332                                 /* in nfsv4, we need to treat this case a little
1333                                  * differently.  we don't want to truncate the
1334                                  * file now; this would be wrong if the OPEN
1335                                  * fails for some other reason.  furthermore,
1336                                  * if the size is nonzero, we should ignore it
1337                                  * according to spec!
1338                                  */
1339                                 *truncp = (iap->ia_valid & ATTR_SIZE) && !iap->ia_size;
1340                         }
1341                         else {
1342                                 iap->ia_valid &= ATTR_SIZE;
1343                                 goto set_attr;
1344                         }
1345                         break;
1346                 case NFS3_CREATE_EXCLUSIVE:
1347                         if (   d_inode(dchild)->i_mtime.tv_sec == v_mtime
1348                             && d_inode(dchild)->i_atime.tv_sec == v_atime
1349                             && d_inode(dchild)->i_size  == 0 ) {
1350                                 if (created)
1351                                         *created = 1;
1352                                 break;
1353                         }
1354                 case NFS4_CREATE_EXCLUSIVE4_1:
1355                         if (   d_inode(dchild)->i_mtime.tv_sec == v_mtime
1356                             && d_inode(dchild)->i_atime.tv_sec == v_atime
1357                             && d_inode(dchild)->i_size  == 0 ) {
1358                                 if (created)
1359                                         *created = 1;
1360                                 goto set_attr;
1361                         }
1362                          /* fallthru */
1363                 case NFS3_CREATE_GUARDED:
1364                         err = nfserr_exist;
1365                 }
1366                 fh_drop_write(fhp);
1367                 goto out;
1368         }
1369 
1370         host_err = vfs_create(dirp, dchild, iap->ia_mode, true);
1371         if (host_err < 0) {
1372                 fh_drop_write(fhp);
1373                 goto out_nfserr;
1374         }
1375         if (created)
1376                 *created = 1;
1377 
1378         nfsd_check_ignore_resizing(iap);
1379 
1380         if (nfsd_create_is_exclusive(createmode)) {
1381                 /* Cram the verifier into atime/mtime */
1382                 iap->ia_valid = ATTR_MTIME|ATTR_ATIME
1383                         | ATTR_MTIME_SET|ATTR_ATIME_SET;
1384                 /* XXX someone who knows this better please fix it for nsec */ 
1385                 iap->ia_mtime.tv_sec = v_mtime;
1386                 iap->ia_atime.tv_sec = v_atime;
1387                 iap->ia_mtime.tv_nsec = 0;
1388                 iap->ia_atime.tv_nsec = 0;
1389         }
1390 
1391  set_attr:
1392         err = nfsd_create_setattr(rqstp, resfhp, iap);
1393 
1394         /*
1395          * nfsd_create_setattr already committed the child
1396          * (and possibly also the parent).
1397          */
1398         if (!err)
1399                 err = nfserrno(commit_metadata(fhp));
1400 
1401         /*
1402          * Update the filehandle to get the new inode info.
1403          */
1404         if (!err)
1405                 err = fh_update(resfhp);
1406 
1407  out:
1408         fh_unlock(fhp);
1409         if (dchild && !IS_ERR(dchild))
1410                 dput(dchild);
1411         fh_drop_write(fhp);
1412         return err;
1413  
1414  out_nfserr:
1415         err = nfserrno(host_err);
1416         goto out;
1417 }
1418 #endif /* CONFIG_NFSD_V3 */
1419 
1420 /*
1421  * Read a symlink. On entry, *lenp must contain the maximum path length that
1422  * fits into the buffer. On return, it contains the true length.
1423  * N.B. After this call fhp needs an fh_put
1424  */
1425 __be32
1426 nfsd_readlink(struct svc_rqst *rqstp, struct svc_fh *fhp, char *buf, int *lenp)
1427 {
1428         struct inode    *inode;
1429         mm_segment_t    oldfs;
1430         __be32          err;
1431         int             host_err;
1432         struct path path;
1433 
1434         err = fh_verify(rqstp, fhp, S_IFLNK, NFSD_MAY_NOP);
1435         if (err)
1436                 goto out;
1437 
1438         path.mnt = fhp->fh_export->ex_path.mnt;
1439         path.dentry = fhp->fh_dentry;
1440         inode = d_inode(path.dentry);
1441 
1442         err = nfserr_inval;
1443         if (!inode->i_op->readlink)
1444                 goto out;
1445 
1446         touch_atime(&path);
1447         /* N.B. Why does this call need a get_fs()??
1448          * Remove the set_fs and watch the fireworks:-) --okir
1449          */
1450 
1451         oldfs = get_fs(); set_fs(KERNEL_DS);
1452         host_err = inode->i_op->readlink(path.dentry, (char __user *)buf, *lenp);
1453         set_fs(oldfs);
1454 
1455         if (host_err < 0)
1456                 goto out_nfserr;
1457         *lenp = host_err;
1458         err = 0;
1459 out:
1460         return err;
1461 
1462 out_nfserr:
1463         err = nfserrno(host_err);
1464         goto out;
1465 }
1466 
1467 /*
1468  * Create a symlink and look up its inode
1469  * N.B. After this call _both_ fhp and resfhp need an fh_put
1470  */
1471 __be32
1472 nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp,
1473                                 char *fname, int flen,
1474                                 char *path,
1475                                 struct svc_fh *resfhp)
1476 {
1477         struct dentry   *dentry, *dnew;
1478         __be32          err, cerr;
1479         int             host_err;
1480 
1481         err = nfserr_noent;
1482         if (!flen || path[0] == '\0')
1483                 goto out;
1484         err = nfserr_exist;
1485         if (isdotent(fname, flen))
1486                 goto out;
1487 
1488         err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
1489         if (err)
1490                 goto out;
1491 
1492         host_err = fh_want_write(fhp);
1493         if (host_err)
1494                 goto out_nfserr;
1495 
1496         fh_lock(fhp);
1497         dentry = fhp->fh_dentry;
1498         dnew = lookup_one_len(fname, dentry, flen);
1499         host_err = PTR_ERR(dnew);
1500         if (IS_ERR(dnew))
1501                 goto out_nfserr;
1502 
1503         host_err = vfs_symlink(d_inode(dentry), dnew, path);
1504         err = nfserrno(host_err);
1505         if (!err)
1506                 err = nfserrno(commit_metadata(fhp));
1507         fh_unlock(fhp);
1508 
1509         fh_drop_write(fhp);
1510 
1511         cerr = fh_compose(resfhp, fhp->fh_export, dnew, fhp);
1512         dput(dnew);
1513         if (err==0) err = cerr;
1514 out:
1515         return err;
1516 
1517 out_nfserr:
1518         err = nfserrno(host_err);
1519         goto out;
1520 }
1521 
1522 /*
1523  * Create a hardlink
1524  * N.B. After this call _both_ ffhp and tfhp need an fh_put
1525  */
1526 __be32
1527 nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp,
1528                                 char *name, int len, struct svc_fh *tfhp)
1529 {
1530         struct dentry   *ddir, *dnew, *dold;
1531         struct inode    *dirp;
1532         __be32          err;
1533         int             host_err;
1534 
1535         err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_CREATE);
1536         if (err)
1537                 goto out;
1538         err = fh_verify(rqstp, tfhp, 0, NFSD_MAY_NOP);
1539         if (err)
1540                 goto out;
1541         err = nfserr_isdir;
1542         if (d_is_dir(tfhp->fh_dentry))
1543                 goto out;
1544         err = nfserr_perm;
1545         if (!len)
1546                 goto out;
1547         err = nfserr_exist;
1548         if (isdotent(name, len))
1549                 goto out;
1550 
1551         host_err = fh_want_write(tfhp);
1552         if (host_err) {
1553                 err = nfserrno(host_err);
1554                 goto out;
1555         }
1556 
1557         fh_lock_nested(ffhp, I_MUTEX_PARENT);
1558         ddir = ffhp->fh_dentry;
1559         dirp = d_inode(ddir);
1560 
1561         dnew = lookup_one_len(name, ddir, len);
1562         host_err = PTR_ERR(dnew);
1563         if (IS_ERR(dnew))
1564                 goto out_nfserr;
1565 
1566         dold = tfhp->fh_dentry;
1567 
1568         err = nfserr_noent;
1569         if (d_really_is_negative(dold))
1570                 goto out_dput;
1571         host_err = vfs_link(dold, dirp, dnew, NULL);
1572         if (!host_err) {
1573                 err = nfserrno(commit_metadata(ffhp));
1574                 if (!err)
1575                         err = nfserrno(commit_metadata(tfhp));
1576         } else {
1577                 if (host_err == -EXDEV && rqstp->rq_vers == 2)
1578                         err = nfserr_acces;
1579                 else
1580                         err = nfserrno(host_err);
1581         }
1582 out_dput:
1583         dput(dnew);
1584 out_unlock:
1585         fh_unlock(ffhp);
1586         fh_drop_write(tfhp);
1587 out:
1588         return err;
1589 
1590 out_nfserr:
1591         err = nfserrno(host_err);
1592         goto out_unlock;
1593 }
1594 
1595 /*
1596  * Rename a file
1597  * N.B. After this call _both_ ffhp and tfhp need an fh_put
1598  */
1599 __be32
1600 nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
1601                             struct svc_fh *tfhp, char *tname, int tlen)
1602 {
1603         struct dentry   *fdentry, *tdentry, *odentry, *ndentry, *trap;
1604         struct inode    *fdir, *tdir;
1605         __be32          err;
1606         int             host_err;
1607 
1608         err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_REMOVE);
1609         if (err)
1610                 goto out;
1611         err = fh_verify(rqstp, tfhp, S_IFDIR, NFSD_MAY_CREATE);
1612         if (err)
1613                 goto out;
1614 
1615         fdentry = ffhp->fh_dentry;
1616         fdir = d_inode(fdentry);
1617 
1618         tdentry = tfhp->fh_dentry;
1619         tdir = d_inode(tdentry);
1620 
1621         err = nfserr_perm;
1622         if (!flen || isdotent(fname, flen) || !tlen || isdotent(tname, tlen))
1623                 goto out;
1624 
1625         host_err = fh_want_write(ffhp);
1626         if (host_err) {
1627                 err = nfserrno(host_err);
1628                 goto out;
1629         }
1630 
1631         /* cannot use fh_lock as we need deadlock protective ordering
1632          * so do it by hand */
1633         trap = lock_rename(tdentry, fdentry);
1634         ffhp->fh_locked = tfhp->fh_locked = 1;
1635         fill_pre_wcc(ffhp);
1636         fill_pre_wcc(tfhp);
1637 
1638         odentry = lookup_one_len(fname, fdentry, flen);
1639         host_err = PTR_ERR(odentry);
1640         if (IS_ERR(odentry))
1641                 goto out_nfserr;
1642 
1643         host_err = -ENOENT;
1644         if (d_really_is_negative(odentry))
1645                 goto out_dput_old;
1646         host_err = -EINVAL;
1647         if (odentry == trap)
1648                 goto out_dput_old;
1649 
1650         ndentry = lookup_one_len(tname, tdentry, tlen);
1651         host_err = PTR_ERR(ndentry);
1652         if (IS_ERR(ndentry))
1653                 goto out_dput_old;
1654         host_err = -ENOTEMPTY;
1655         if (ndentry == trap)
1656                 goto out_dput_new;
1657 
1658         host_err = -EXDEV;
1659         if (ffhp->fh_export->ex_path.mnt != tfhp->fh_export->ex_path.mnt)
1660                 goto out_dput_new;
1661         if (ffhp->fh_export->ex_path.dentry != tfhp->fh_export->ex_path.dentry)
1662                 goto out_dput_new;
1663 
1664         host_err = vfs_rename(fdir, odentry, tdir, ndentry, NULL, 0);
1665         if (!host_err) {
1666                 host_err = commit_metadata(tfhp);
1667                 if (!host_err)
1668                         host_err = commit_metadata(ffhp);
1669         }
1670  out_dput_new:
1671         dput(ndentry);
1672  out_dput_old:
1673         dput(odentry);
1674  out_nfserr:
1675         err = nfserrno(host_err);
1676         /*
1677          * We cannot rely on fh_unlock on the two filehandles,
1678          * as that would do the wrong thing if the two directories
1679          * were the same, so again we do it by hand.
1680          */
1681         fill_post_wcc(ffhp);
1682         fill_post_wcc(tfhp);
1683         unlock_rename(tdentry, fdentry);
1684         ffhp->fh_locked = tfhp->fh_locked = 0;
1685         fh_drop_write(ffhp);
1686 
1687 out:
1688         return err;
1689 }
1690 
1691 /*
1692  * Unlink a file or directory
1693  * N.B. After this call fhp needs an fh_put
1694  */
1695 __be32
1696 nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
1697                                 char *fname, int flen)
1698 {
1699         struct dentry   *dentry, *rdentry;
1700         struct inode    *dirp;
1701         __be32          err;
1702         int             host_err;
1703 
1704         err = nfserr_acces;
1705         if (!flen || isdotent(fname, flen))
1706                 goto out;
1707         err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_REMOVE);
1708         if (err)
1709                 goto out;
1710 
1711         host_err = fh_want_write(fhp);
1712         if (host_err)
1713                 goto out_nfserr;
1714 
1715         fh_lock_nested(fhp, I_MUTEX_PARENT);
1716         dentry = fhp->fh_dentry;
1717         dirp = d_inode(dentry);
1718 
1719         rdentry = lookup_one_len(fname, dentry, flen);
1720         host_err = PTR_ERR(rdentry);
1721         if (IS_ERR(rdentry))
1722                 goto out_nfserr;
1723 
1724         if (d_really_is_negative(rdentry)) {
1725                 dput(rdentry);
1726                 err = nfserr_noent;
1727                 goto out;
1728         }
1729 
1730         if (!type)
1731                 type = d_inode(rdentry)->i_mode & S_IFMT;
1732 
1733         if (type != S_IFDIR)
1734                 host_err = vfs_unlink(dirp, rdentry, NULL);
1735         else
1736                 host_err = vfs_rmdir(dirp, rdentry);
1737         if (!host_err)
1738                 host_err = commit_metadata(fhp);
1739         dput(rdentry);
1740 
1741 out_nfserr:
1742         err = nfserrno(host_err);
1743 out:
1744         return err;
1745 }
1746 
1747 /*
1748  * We do this buffering because we must not call back into the file
1749  * system's ->lookup() method from the filldir callback. That may well
1750  * deadlock a number of file systems.
1751  *
1752  * This is based heavily on the implementation of same in XFS.
1753  */
1754 struct buffered_dirent {
1755         u64             ino;
1756         loff_t          offset;
1757         int             namlen;
1758         unsigned int    d_type;
1759         char            name[];
1760 };
1761 
1762 struct readdir_data {
1763         struct dir_context ctx;
1764         char            *dirent;
1765         size_t          used;
1766         int             full;
1767 };
1768 
1769 static int nfsd_buffered_filldir(struct dir_context *ctx, const char *name,
1770                                  int namlen, loff_t offset, u64 ino,
1771                                  unsigned int d_type)
1772 {
1773         struct readdir_data *buf =
1774                 container_of(ctx, struct readdir_data, ctx);
1775         struct buffered_dirent *de = (void *)(buf->dirent + buf->used);
1776         unsigned int reclen;
1777 
1778         reclen = ALIGN(sizeof(struct buffered_dirent) + namlen, sizeof(u64));
1779         if (buf->used + reclen > PAGE_SIZE) {
1780                 buf->full = 1;
1781                 return -EINVAL;
1782         }
1783 
1784         de->namlen = namlen;
1785         de->offset = offset;
1786         de->ino = ino;
1787         de->d_type = d_type;
1788         memcpy(de->name, name, namlen);
1789         buf->used += reclen;
1790 
1791         return 0;
1792 }
1793 
1794 static __be32 nfsd_buffered_readdir(struct file *file, nfsd_filldir_t func,
1795                                     struct readdir_cd *cdp, loff_t *offsetp)
1796 {
1797         struct buffered_dirent *de;
1798         int host_err;
1799         int size;
1800         loff_t offset;
1801         struct readdir_data buf = {
1802                 .ctx.actor = nfsd_buffered_filldir,
1803                 .dirent = (void *)__get_free_page(GFP_KERNEL)
1804         };
1805 
1806         if (!buf.dirent)
1807                 return nfserrno(-ENOMEM);
1808 
1809         offset = *offsetp;
1810 
1811         while (1) {
1812                 struct inode *dir_inode = file_inode(file);
1813                 unsigned int reclen;
1814 
1815                 cdp->err = nfserr_eof; /* will be cleared on successful read */
1816                 buf.used = 0;
1817                 buf.full = 0;
1818 
1819                 host_err = iterate_dir(file, &buf.ctx);
1820                 if (buf.full)
1821                         host_err = 0;
1822 
1823                 if (host_err < 0)
1824                         break;
1825 
1826                 size = buf.used;
1827 
1828                 if (!size)
1829                         break;
1830 
1831                 /*
1832                  * Various filldir functions may end up calling back into
1833                  * lookup_one_len() and the file system's ->lookup() method.
1834                  * These expect i_mutex to be held, as it would within readdir.
1835                  */
1836                 host_err = mutex_lock_killable(&dir_inode->i_mutex);
1837                 if (host_err)
1838                         break;
1839 
1840                 de = (struct buffered_dirent *)buf.dirent;
1841                 while (size > 0) {
1842                         offset = de->offset;
1843 
1844                         if (func(cdp, de->name, de->namlen, de->offset,
1845                                  de->ino, de->d_type))
1846                                 break;
1847 
1848                         if (cdp->err != nfs_ok)
1849                                 break;
1850 
1851                         reclen = ALIGN(sizeof(*de) + de->namlen,
1852                                        sizeof(u64));
1853                         size -= reclen;
1854                         de = (struct buffered_dirent *)((char *)de + reclen);
1855                 }
1856                 mutex_unlock(&dir_inode->i_mutex);
1857                 if (size > 0) /* We bailed out early */
1858                         break;
1859 
1860                 offset = vfs_llseek(file, 0, SEEK_CUR);
1861         }
1862 
1863         free_page((unsigned long)(buf.dirent));
1864 
1865         if (host_err)
1866                 return nfserrno(host_err);
1867 
1868         *offsetp = offset;
1869         return cdp->err;
1870 }
1871 
1872 /*
1873  * Read entries from a directory.
1874  * The  NFSv3/4 verifier we ignore for now.
1875  */
1876 __be32
1877 nfsd_readdir(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t *offsetp, 
1878              struct readdir_cd *cdp, nfsd_filldir_t func)
1879 {
1880         __be32          err;
1881         struct file     *file;
1882         loff_t          offset = *offsetp;
1883         int             may_flags = NFSD_MAY_READ;
1884 
1885         /* NFSv2 only supports 32 bit cookies */
1886         if (rqstp->rq_vers > 2)
1887                 may_flags |= NFSD_MAY_64BIT_COOKIE;
1888 
1889         err = nfsd_open(rqstp, fhp, S_IFDIR, may_flags, &file);
1890         if (err)
1891                 goto out;
1892 
1893         offset = vfs_llseek(file, offset, SEEK_SET);
1894         if (offset < 0) {
1895                 err = nfserrno((int)offset);
1896                 goto out_close;
1897         }
1898 
1899         err = nfsd_buffered_readdir(file, func, cdp, offsetp);
1900 
1901         if (err == nfserr_eof || err == nfserr_toosmall)
1902                 err = nfs_ok; /* can still be found in ->err */
1903 out_close:
1904         fput(file);
1905 out:
1906         return err;
1907 }
1908 
1909 /*
1910  * Get file system stats
1911  * N.B. After this call fhp needs an fh_put
1912  */
1913 __be32
1914 nfsd_statfs(struct svc_rqst *rqstp, struct svc_fh *fhp, struct kstatfs *stat, int access)
1915 {
1916         __be32 err;
1917 
1918         err = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP | access);
1919         if (!err) {
1920                 struct path path = {
1921                         .mnt    = fhp->fh_export->ex_path.mnt,
1922                         .dentry = fhp->fh_dentry,
1923                 };
1924                 if (vfs_statfs(&path, stat))
1925                         err = nfserr_io;
1926         }
1927         return err;
1928 }
1929 
1930 static int exp_rdonly(struct svc_rqst *rqstp, struct svc_export *exp)
1931 {
1932         return nfsexp_flags(rqstp, exp) & NFSEXP_READONLY;
1933 }
1934 
1935 /*
1936  * Check for a user's access permissions to this inode.
1937  */
1938 __be32
1939 nfsd_permission(struct svc_rqst *rqstp, struct svc_export *exp,
1940                                         struct dentry *dentry, int acc)
1941 {
1942         struct inode    *inode = d_inode(dentry);
1943         int             err;
1944 
1945         if ((acc & NFSD_MAY_MASK) == NFSD_MAY_NOP)
1946                 return 0;
1947 #if 0
1948         dprintk("nfsd: permission 0x%x%s%s%s%s%s%s%s mode 0%o%s%s%s\n",
1949                 acc,
1950                 (acc & NFSD_MAY_READ)?  " read"  : "",
1951                 (acc & NFSD_MAY_WRITE)? " write" : "",
1952                 (acc & NFSD_MAY_EXEC)?  " exec"  : "",
1953                 (acc & NFSD_MAY_SATTR)? " sattr" : "",
1954                 (acc & NFSD_MAY_TRUNC)? " trunc" : "",
1955                 (acc & NFSD_MAY_LOCK)?  " lock"  : "",
1956                 (acc & NFSD_MAY_OWNER_OVERRIDE)? " owneroverride" : "",
1957                 inode->i_mode,
1958                 IS_IMMUTABLE(inode)?    " immut" : "",
1959                 IS_APPEND(inode)?       " append" : "",
1960                 __mnt_is_readonly(exp->ex_path.mnt)?    " ro" : "");
1961         dprintk("      owner %d/%d user %d/%d\n",
1962                 inode->i_uid, inode->i_gid, current_fsuid(), current_fsgid());
1963 #endif
1964 
1965         /* Normally we reject any write/sattr etc access on a read-only file
1966          * system.  But if it is IRIX doing check on write-access for a 
1967          * device special file, we ignore rofs.
1968          */
1969         if (!(acc & NFSD_MAY_LOCAL_ACCESS))
1970                 if (acc & (NFSD_MAY_WRITE | NFSD_MAY_SATTR | NFSD_MAY_TRUNC)) {
1971                         if (exp_rdonly(rqstp, exp) ||
1972                             __mnt_is_readonly(exp->ex_path.mnt))
1973                                 return nfserr_rofs;
1974                         if (/* (acc & NFSD_MAY_WRITE) && */ IS_IMMUTABLE(inode))
1975                                 return nfserr_perm;
1976                 }
1977         if ((acc & NFSD_MAY_TRUNC) && IS_APPEND(inode))
1978                 return nfserr_perm;
1979 
1980         if (acc & NFSD_MAY_LOCK) {
1981                 /* If we cannot rely on authentication in NLM requests,
1982                  * just allow locks, otherwise require read permission, or
1983                  * ownership
1984                  */
1985                 if (exp->ex_flags & NFSEXP_NOAUTHNLM)
1986                         return 0;
1987                 else
1988                         acc = NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE;
1989         }
1990         /*
1991          * The file owner always gets access permission for accesses that
1992          * would normally be checked at open time. This is to make
1993          * file access work even when the client has done a fchmod(fd, 0).
1994          *
1995          * However, `cp foo bar' should fail nevertheless when bar is
1996          * readonly. A sensible way to do this might be to reject all
1997          * attempts to truncate a read-only file, because a creat() call
1998          * always implies file truncation.
1999          * ... but this isn't really fair.  A process may reasonably call
2000          * ftruncate on an open file descriptor on a file with perm 000.
2001          * We must trust the client to do permission checking - using "ACCESS"
2002          * with NFSv3.
2003          */
2004         if ((acc & NFSD_MAY_OWNER_OVERRIDE) &&
2005             uid_eq(inode->i_uid, current_fsuid()))
2006                 return 0;
2007 
2008         /* This assumes  NFSD_MAY_{READ,WRITE,EXEC} == MAY_{READ,WRITE,EXEC} */
2009         err = inode_permission(inode, acc & (MAY_READ|MAY_WRITE|MAY_EXEC));
2010 
2011         /* Allow read access to binaries even when mode 111 */
2012         if (err == -EACCES && S_ISREG(inode->i_mode) &&
2013              (acc == (NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE) ||
2014               acc == (NFSD_MAY_READ | NFSD_MAY_READ_IF_EXEC)))
2015                 err = inode_permission(inode, MAY_EXEC);
2016 
2017         return err? nfserrno(err) : 0;
2018 }
2019 
2020 void
2021 nfsd_racache_shutdown(void)
2022 {
2023         struct raparms *raparm, *last_raparm;
2024         unsigned int i;
2025 
2026         dprintk("nfsd: freeing readahead buffers.\n");
2027 
2028         for (i = 0; i < RAPARM_HASH_SIZE; i++) {
2029                 raparm = raparm_hash[i].pb_head;
2030                 while(raparm) {
2031                         last_raparm = raparm;
2032                         raparm = raparm->p_next;
2033                         kfree(last_raparm);
2034                 }
2035                 raparm_hash[i].pb_head = NULL;
2036         }
2037 }
2038 /*
2039  * Initialize readahead param cache
2040  */
2041 int
2042 nfsd_racache_init(int cache_size)
2043 {
2044         int     i;
2045         int     j = 0;
2046         int     nperbucket;
2047         struct raparms **raparm = NULL;
2048 
2049 
2050         if (raparm_hash[0].pb_head)
2051                 return 0;
2052         nperbucket = DIV_ROUND_UP(cache_size, RAPARM_HASH_SIZE);
2053         nperbucket = max(2, nperbucket);
2054         cache_size = nperbucket * RAPARM_HASH_SIZE;
2055 
2056         dprintk("nfsd: allocating %d readahead buffers.\n", cache_size);
2057 
2058         for (i = 0; i < RAPARM_HASH_SIZE; i++) {
2059                 spin_lock_init(&raparm_hash[i].pb_lock);
2060 
2061                 raparm = &raparm_hash[i].pb_head;
2062                 for (j = 0; j < nperbucket; j++) {
2063                         *raparm = kzalloc(sizeof(struct raparms), GFP_KERNEL);
2064                         if (!*raparm)
2065                                 goto out_nomem;
2066                         raparm = &(*raparm)->p_next;
2067                 }
2068                 *raparm = NULL;
2069         }
2070 
2071         nfsdstats.ra_size = cache_size;
2072         return 0;
2073 
2074 out_nomem:
2075         dprintk("nfsd: kmalloc failed, freeing readahead buffers\n");
2076         nfsd_racache_shutdown();
2077         return -ENOMEM;
2078 }
2079 

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