Root/fs/nfsd/vfs.c

1/*
2 * File operations used by nfsd. Some of these have been ripped from
3 * other parts of the kernel because they weren't exported, others
4 * are partial duplicates with added or changed functionality.
5 *
6 * Note that several functions dget() the dentry upon which they want
7 * to act, most notably those that create directory entries. Response
8 * dentry's are dput()'d if necessary in the release callback.
9 * So if you notice code paths that apparently fail to dput() the
10 * dentry, don't worry--they have been taken care of.
11 *
12 * Copyright (C) 1995-1999 Olaf Kirch <okir@monad.swb.de>
13 * Zerocpy NFS support (C) 2002 Hirokazu Takahashi <taka@valinux.co.jp>
14 */
15
16#include <linux/fs.h>
17#include <linux/file.h>
18#include <linux/splice.h>
19#include <linux/fcntl.h>
20#include <linux/namei.h>
21#include <linux/delay.h>
22#include <linux/fsnotify.h>
23#include <linux/posix_acl_xattr.h>
24#include <linux/xattr.h>
25#include <linux/jhash.h>
26#include <linux/ima.h>
27#include <linux/slab.h>
28#include <asm/uaccess.h>
29#include <linux/exportfs.h>
30#include <linux/writeback.h>
31
32#ifdef CONFIG_NFSD_V3
33#include "xdr3.h"
34#endif /* CONFIG_NFSD_V3 */
35
36#ifdef CONFIG_NFSD_V4
37#include "acl.h"
38#include "idmap.h"
39#endif /* CONFIG_NFSD_V4 */
40
41#include "nfsd.h"
42#include "vfs.h"
43
44#define NFSDDBG_FACILITY NFSDDBG_FILEOP
45
46
47/*
48 * This is a cache of readahead params that help us choose the proper
49 * readahead strategy. Initially, we set all readahead parameters to 0
50 * and let the VFS handle things.
51 * If you increase the number of cached files very much, you'll need to
52 * add a hash table here.
53 */
54struct raparms {
55    struct raparms *p_next;
56    unsigned int p_count;
57    ino_t p_ino;
58    dev_t p_dev;
59    int p_set;
60    struct file_ra_state p_ra;
61    unsigned int p_hindex;
62};
63
64struct raparm_hbucket {
65    struct raparms *pb_head;
66    spinlock_t pb_lock;
67} ____cacheline_aligned_in_smp;
68
69#define RAPARM_HASH_BITS 4
70#define RAPARM_HASH_SIZE (1<<RAPARM_HASH_BITS)
71#define RAPARM_HASH_MASK (RAPARM_HASH_SIZE-1)
72static struct raparm_hbucket raparm_hash[RAPARM_HASH_SIZE];
73
74/*
75 * Called from nfsd_lookup and encode_dirent. Check if we have crossed
76 * a mount point.
77 * Returns -EAGAIN or -ETIMEDOUT leaving *dpp and *expp unchanged,
78 * or nfs_ok having possibly changed *dpp and *expp
79 */
80int
81nfsd_cross_mnt(struct svc_rqst *rqstp, struct dentry **dpp,
82                struct svc_export **expp)
83{
84    struct svc_export *exp = *expp, *exp2 = NULL;
85    struct dentry *dentry = *dpp;
86    struct path path = {.mnt = mntget(exp->ex_path.mnt),
87                .dentry = dget(dentry)};
88    int err = 0;
89
90    err = follow_down(&path);
91    if (err < 0)
92        goto out;
93
94    exp2 = rqst_exp_get_by_name(rqstp, &path);
95    if (IS_ERR(exp2)) {
96        err = PTR_ERR(exp2);
97        /*
98         * We normally allow NFS clients to continue
99         * "underneath" a mountpoint that is not exported.
100         * The exception is V4ROOT, where no traversal is ever
101         * allowed without an explicit export of the new
102         * directory.
103         */
104        if (err == -ENOENT && !(exp->ex_flags & NFSEXP_V4ROOT))
105            err = 0;
106        path_put(&path);
107        goto out;
108    }
109    if (nfsd_v4client(rqstp) ||
110        (exp->ex_flags & NFSEXP_CROSSMOUNT) || EX_NOHIDE(exp2)) {
111        /* successfully crossed mount point */
112        /*
113         * This is subtle: path.dentry is *not* on path.mnt
114         * at this point. The only reason we are safe is that
115         * original mnt is pinned down by exp, so we should
116         * put path *before* putting exp
117         */
118        *dpp = path.dentry;
119        path.dentry = dentry;
120        *expp = exp2;
121        exp2 = exp;
122    }
123    path_put(&path);
124    exp_put(exp2);
125out:
126    return err;
127}
128
129static void follow_to_parent(struct path *path)
130{
131    struct dentry *dp;
132
133    while (path->dentry == path->mnt->mnt_root && follow_up(path))
134        ;
135    dp = dget_parent(path->dentry);
136    dput(path->dentry);
137    path->dentry = dp;
138}
139
140static int nfsd_lookup_parent(struct svc_rqst *rqstp, struct dentry *dparent, struct svc_export **exp, struct dentry **dentryp)
141{
142    struct svc_export *exp2;
143    struct path path = {.mnt = mntget((*exp)->ex_path.mnt),
144                .dentry = dget(dparent)};
145
146    follow_to_parent(&path);
147
148    exp2 = rqst_exp_parent(rqstp, &path);
149    if (PTR_ERR(exp2) == -ENOENT) {
150        *dentryp = dget(dparent);
151    } else if (IS_ERR(exp2)) {
152        path_put(&path);
153        return PTR_ERR(exp2);
154    } else {
155        *dentryp = dget(path.dentry);
156        exp_put(*exp);
157        *exp = exp2;
158    }
159    path_put(&path);
160    return 0;
161}
162
163/*
164 * For nfsd purposes, we treat V4ROOT exports as though there was an
165 * export at *every* directory.
166 */
167int nfsd_mountpoint(struct dentry *dentry, struct svc_export *exp)
168{
169    if (d_mountpoint(dentry))
170        return 1;
171    if (!(exp->ex_flags & NFSEXP_V4ROOT))
172        return 0;
173    return dentry->d_inode != NULL;
174}
175
176__be32
177nfsd_lookup_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp,
178           const char *name, unsigned int len,
179           struct svc_export **exp_ret, struct dentry **dentry_ret)
180{
181    struct svc_export *exp;
182    struct dentry *dparent;
183    struct dentry *dentry;
184    int host_err;
185
186    dprintk("nfsd: nfsd_lookup(fh %s, %.*s)\n", SVCFH_fmt(fhp), len,name);
187
188    dparent = fhp->fh_dentry;
189    exp = fhp->fh_export;
190    exp_get(exp);
191
192    /* Lookup the name, but don't follow links */
193    if (isdotent(name, len)) {
194        if (len==1)
195            dentry = dget(dparent);
196        else if (dparent != exp->ex_path.dentry)
197            dentry = dget_parent(dparent);
198        else if (!EX_NOHIDE(exp) && !nfsd_v4client(rqstp))
199            dentry = dget(dparent); /* .. == . just like at / */
200        else {
201            /* checking mountpoint crossing is very different when stepping up */
202            host_err = nfsd_lookup_parent(rqstp, dparent, &exp, &dentry);
203            if (host_err)
204                goto out_nfserr;
205        }
206    } else {
207        fh_lock(fhp);
208        dentry = lookup_one_len(name, dparent, len);
209        host_err = PTR_ERR(dentry);
210        if (IS_ERR(dentry))
211            goto out_nfserr;
212        /*
213         * check if we have crossed a mount point ...
214         */
215        if (nfsd_mountpoint(dentry, exp)) {
216            if ((host_err = nfsd_cross_mnt(rqstp, &dentry, &exp))) {
217                dput(dentry);
218                goto out_nfserr;
219            }
220        }
221    }
222    *dentry_ret = dentry;
223    *exp_ret = exp;
224    return 0;
225
226out_nfserr:
227    exp_put(exp);
228    return nfserrno(host_err);
229}
230
231/*
232 * Look up one component of a pathname.
233 * N.B. After this call _both_ fhp and resfh need an fh_put
234 *
235 * If the lookup would cross a mountpoint, and the mounted filesystem
236 * is exported to the client with NFSEXP_NOHIDE, then the lookup is
237 * accepted as it stands and the mounted directory is
238 * returned. Otherwise the covered directory is returned.
239 * NOTE: this mountpoint crossing is not supported properly by all
240 * clients and is explicitly disallowed for NFSv3
241 * NeilBrown <neilb@cse.unsw.edu.au>
242 */
243__be32
244nfsd_lookup(struct svc_rqst *rqstp, struct svc_fh *fhp, const char *name,
245                unsigned int len, struct svc_fh *resfh)
246{
247    struct svc_export *exp;
248    struct dentry *dentry;
249    __be32 err;
250
251    err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC);
252    if (err)
253        return err;
254    err = nfsd_lookup_dentry(rqstp, fhp, name, len, &exp, &dentry);
255    if (err)
256        return err;
257    err = check_nfsd_access(exp, rqstp);
258    if (err)
259        goto out;
260    /*
261     * Note: we compose the file handle now, but as the
262     * dentry may be negative, it may need to be updated.
263     */
264    err = fh_compose(resfh, exp, dentry, fhp);
265    if (!err && !dentry->d_inode)
266        err = nfserr_noent;
267out:
268    dput(dentry);
269    exp_put(exp);
270    return err;
271}
272
273static int nfsd_break_lease(struct inode *inode)
274{
275    if (!S_ISREG(inode->i_mode))
276        return 0;
277    return break_lease(inode, O_WRONLY | O_NONBLOCK);
278}
279
280/*
281 * Commit metadata changes to stable storage.
282 */
283static int
284commit_metadata(struct svc_fh *fhp)
285{
286    struct inode *inode = fhp->fh_dentry->d_inode;
287    const struct export_operations *export_ops = inode->i_sb->s_export_op;
288
289    if (!EX_ISSYNC(fhp->fh_export))
290        return 0;
291
292    if (export_ops->commit_metadata)
293        return export_ops->commit_metadata(inode);
294    return sync_inode_metadata(inode, 1);
295}
296
297/*
298 * Set various file attributes.
299 * N.B. After this call fhp needs an fh_put
300 */
301__be32
302nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
303         int check_guard, time_t guardtime)
304{
305    struct dentry *dentry;
306    struct inode *inode;
307    int accmode = NFSD_MAY_SATTR;
308    int ftype = 0;
309    __be32 err;
310    int host_err;
311    int size_change = 0;
312
313    if (iap->ia_valid & (ATTR_ATIME | ATTR_MTIME | ATTR_SIZE))
314        accmode |= NFSD_MAY_WRITE|NFSD_MAY_OWNER_OVERRIDE;
315    if (iap->ia_valid & ATTR_SIZE)
316        ftype = S_IFREG;
317
318    /* Get inode */
319    err = fh_verify(rqstp, fhp, ftype, accmode);
320    if (err)
321        goto out;
322
323    dentry = fhp->fh_dentry;
324    inode = dentry->d_inode;
325
326    /* Ignore any mode updates on symlinks */
327    if (S_ISLNK(inode->i_mode))
328        iap->ia_valid &= ~ATTR_MODE;
329
330    if (!iap->ia_valid)
331        goto out;
332
333    /*
334     * NFSv2 does not differentiate between "set-[ac]time-to-now"
335     * which only requires access, and "set-[ac]time-to-X" which
336     * requires ownership.
337     * So if it looks like it might be "set both to the same time which
338     * is close to now", and if inode_change_ok fails, then we
339     * convert to "set to now" instead of "set to explicit time"
340     *
341     * We only call inode_change_ok as the last test as technically
342     * it is not an interface that we should be using. It is only
343     * valid if the filesystem does not define it's own i_op->setattr.
344     */
345#define BOTH_TIME_SET (ATTR_ATIME_SET | ATTR_MTIME_SET)
346#define MAX_TOUCH_TIME_ERROR (30*60)
347    if ((iap->ia_valid & BOTH_TIME_SET) == BOTH_TIME_SET &&
348        iap->ia_mtime.tv_sec == iap->ia_atime.tv_sec) {
349        /*
350         * Looks probable.
351         *
352         * Now just make sure time is in the right ballpark.
353         * Solaris, at least, doesn't seem to care what the time
354         * request is. We require it be within 30 minutes of now.
355         */
356        time_t delta = iap->ia_atime.tv_sec - get_seconds();
357        if (delta < 0)
358            delta = -delta;
359        if (delta < MAX_TOUCH_TIME_ERROR &&
360            inode_change_ok(inode, iap) != 0) {
361            /*
362             * Turn off ATTR_[AM]TIME_SET but leave ATTR_[AM]TIME.
363             * This will cause notify_change to set these times
364             * to "now"
365             */
366            iap->ia_valid &= ~BOTH_TIME_SET;
367        }
368    }
369        
370    /*
371     * The size case is special.
372     * It changes the file as well as the attributes.
373     */
374    if (iap->ia_valid & ATTR_SIZE) {
375        if (iap->ia_size < inode->i_size) {
376            err = nfsd_permission(rqstp, fhp->fh_export, dentry,
377                    NFSD_MAY_TRUNC|NFSD_MAY_OWNER_OVERRIDE);
378            if (err)
379                goto out;
380        }
381
382        host_err = get_write_access(inode);
383        if (host_err)
384            goto out_nfserr;
385
386        size_change = 1;
387        host_err = locks_verify_truncate(inode, NULL, iap->ia_size);
388        if (host_err) {
389            put_write_access(inode);
390            goto out_nfserr;
391        }
392    }
393
394    /* sanitize the mode change */
395    if (iap->ia_valid & ATTR_MODE) {
396        iap->ia_mode &= S_IALLUGO;
397        iap->ia_mode |= (inode->i_mode & ~S_IALLUGO);
398    }
399
400    /* Revoke setuid/setgid on chown */
401    if (!S_ISDIR(inode->i_mode) &&
402        (((iap->ia_valid & ATTR_UID) && iap->ia_uid != inode->i_uid) ||
403         ((iap->ia_valid & ATTR_GID) && iap->ia_gid != inode->i_gid))) {
404        iap->ia_valid |= ATTR_KILL_PRIV;
405        if (iap->ia_valid & ATTR_MODE) {
406            /* we're setting mode too, just clear the s*id bits */
407            iap->ia_mode &= ~S_ISUID;
408            if (iap->ia_mode & S_IXGRP)
409                iap->ia_mode &= ~S_ISGID;
410        } else {
411            /* set ATTR_KILL_* bits and let VFS handle it */
412            iap->ia_valid |= (ATTR_KILL_SUID | ATTR_KILL_SGID);
413        }
414    }
415
416    /* Change the attributes. */
417
418    iap->ia_valid |= ATTR_CTIME;
419
420    err = nfserr_notsync;
421    if (!check_guard || guardtime == inode->i_ctime.tv_sec) {
422        host_err = nfsd_break_lease(inode);
423        if (host_err)
424            goto out_nfserr;
425        fh_lock(fhp);
426
427        host_err = notify_change(dentry, iap);
428        err = nfserrno(host_err);
429        fh_unlock(fhp);
430    }
431    if (size_change)
432        put_write_access(inode);
433    if (!err)
434        commit_metadata(fhp);
435out:
436    return err;
437
438out_nfserr:
439    err = nfserrno(host_err);
440    goto out;
441}
442
443#if defined(CONFIG_NFSD_V2_ACL) || \
444    defined(CONFIG_NFSD_V3_ACL) || \
445    defined(CONFIG_NFSD_V4)
446static ssize_t nfsd_getxattr(struct dentry *dentry, char *key, void **buf)
447{
448    ssize_t buflen;
449    ssize_t ret;
450
451    buflen = vfs_getxattr(dentry, key, NULL, 0);
452    if (buflen <= 0)
453        return buflen;
454
455    *buf = kmalloc(buflen, GFP_KERNEL);
456    if (!*buf)
457        return -ENOMEM;
458
459    ret = vfs_getxattr(dentry, key, *buf, buflen);
460    if (ret < 0)
461        kfree(*buf);
462    return ret;
463}
464#endif
465
466#if defined(CONFIG_NFSD_V4)
467static int
468set_nfsv4_acl_one(struct dentry *dentry, struct posix_acl *pacl, char *key)
469{
470    int len;
471    size_t buflen;
472    char *buf = NULL;
473    int error = 0;
474
475    buflen = posix_acl_xattr_size(pacl->a_count);
476    buf = kmalloc(buflen, GFP_KERNEL);
477    error = -ENOMEM;
478    if (buf == NULL)
479        goto out;
480
481    len = posix_acl_to_xattr(pacl, buf, buflen);
482    if (len < 0) {
483        error = len;
484        goto out;
485    }
486
487    error = vfs_setxattr(dentry, key, buf, len, 0);
488out:
489    kfree(buf);
490    return error;
491}
492
493__be32
494nfsd4_set_nfs4_acl(struct svc_rqst *rqstp, struct svc_fh *fhp,
495    struct nfs4_acl *acl)
496{
497    __be32 error;
498    int host_error;
499    struct dentry *dentry;
500    struct inode *inode;
501    struct posix_acl *pacl = NULL, *dpacl = NULL;
502    unsigned int flags = 0;
503
504    /* Get inode */
505    error = fh_verify(rqstp, fhp, 0 /* S_IFREG */, NFSD_MAY_SATTR);
506    if (error)
507        return error;
508
509    dentry = fhp->fh_dentry;
510    inode = dentry->d_inode;
511    if (S_ISDIR(inode->i_mode))
512        flags = NFS4_ACL_DIR;
513
514    host_error = nfs4_acl_nfsv4_to_posix(acl, &pacl, &dpacl, flags);
515    if (host_error == -EINVAL) {
516        return nfserr_attrnotsupp;
517    } else if (host_error < 0)
518        goto out_nfserr;
519
520    host_error = set_nfsv4_acl_one(dentry, pacl, POSIX_ACL_XATTR_ACCESS);
521    if (host_error < 0)
522        goto out_release;
523
524    if (S_ISDIR(inode->i_mode))
525        host_error = set_nfsv4_acl_one(dentry, dpacl, POSIX_ACL_XATTR_DEFAULT);
526
527out_release:
528    posix_acl_release(pacl);
529    posix_acl_release(dpacl);
530out_nfserr:
531    if (host_error == -EOPNOTSUPP)
532        return nfserr_attrnotsupp;
533    else
534        return nfserrno(host_error);
535}
536
537static struct posix_acl *
538_get_posix_acl(struct dentry *dentry, char *key)
539{
540    void *buf = NULL;
541    struct posix_acl *pacl = NULL;
542    int buflen;
543
544    buflen = nfsd_getxattr(dentry, key, &buf);
545    if (!buflen)
546        buflen = -ENODATA;
547    if (buflen <= 0)
548        return ERR_PTR(buflen);
549
550    pacl = posix_acl_from_xattr(buf, buflen);
551    kfree(buf);
552    return pacl;
553}
554
555int
556nfsd4_get_nfs4_acl(struct svc_rqst *rqstp, struct dentry *dentry, struct nfs4_acl **acl)
557{
558    struct inode *inode = dentry->d_inode;
559    int error = 0;
560    struct posix_acl *pacl = NULL, *dpacl = NULL;
561    unsigned int flags = 0;
562
563    pacl = _get_posix_acl(dentry, POSIX_ACL_XATTR_ACCESS);
564    if (IS_ERR(pacl) && PTR_ERR(pacl) == -ENODATA)
565        pacl = posix_acl_from_mode(inode->i_mode, GFP_KERNEL);
566    if (IS_ERR(pacl)) {
567        error = PTR_ERR(pacl);
568        pacl = NULL;
569        goto out;
570    }
571
572    if (S_ISDIR(inode->i_mode)) {
573        dpacl = _get_posix_acl(dentry, POSIX_ACL_XATTR_DEFAULT);
574        if (IS_ERR(dpacl) && PTR_ERR(dpacl) == -ENODATA)
575            dpacl = NULL;
576        else if (IS_ERR(dpacl)) {
577            error = PTR_ERR(dpacl);
578            dpacl = NULL;
579            goto out;
580        }
581        flags = NFS4_ACL_DIR;
582    }
583
584    *acl = nfs4_acl_posix_to_nfsv4(pacl, dpacl, flags);
585    if (IS_ERR(*acl)) {
586        error = PTR_ERR(*acl);
587        *acl = NULL;
588    }
589 out:
590    posix_acl_release(pacl);
591    posix_acl_release(dpacl);
592    return error;
593}
594
595#endif /* defined(CONFIG_NFSD_V4) */
596
597#ifdef CONFIG_NFSD_V3
598/*
599 * Check server access rights to a file system object
600 */
601struct accessmap {
602    u32 access;
603    int how;
604};
605static struct accessmap nfs3_regaccess[] = {
606    { NFS3_ACCESS_READ, NFSD_MAY_READ },
607    { NFS3_ACCESS_EXECUTE, NFSD_MAY_EXEC },
608    { NFS3_ACCESS_MODIFY, NFSD_MAY_WRITE|NFSD_MAY_TRUNC },
609    { NFS3_ACCESS_EXTEND, NFSD_MAY_WRITE },
610
611    { 0, 0 }
612};
613
614static struct accessmap nfs3_diraccess[] = {
615    { NFS3_ACCESS_READ, NFSD_MAY_READ },
616    { NFS3_ACCESS_LOOKUP, NFSD_MAY_EXEC },
617    { NFS3_ACCESS_MODIFY, NFSD_MAY_EXEC|NFSD_MAY_WRITE|NFSD_MAY_TRUNC},
618    { NFS3_ACCESS_EXTEND, NFSD_MAY_EXEC|NFSD_MAY_WRITE },
619    { NFS3_ACCESS_DELETE, NFSD_MAY_REMOVE },
620
621    { 0, 0 }
622};
623
624static struct accessmap nfs3_anyaccess[] = {
625    /* Some clients - Solaris 2.6 at least, make an access call
626     * to the server to check for access for things like /dev/null
627     * (which really, the server doesn't care about). So
628     * We provide simple access checking for them, looking
629     * mainly at mode bits, and we make sure to ignore read-only
630     * filesystem checks
631     */
632    { NFS3_ACCESS_READ, NFSD_MAY_READ },
633    { NFS3_ACCESS_EXECUTE, NFSD_MAY_EXEC },
634    { NFS3_ACCESS_MODIFY, NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS },
635    { NFS3_ACCESS_EXTEND, NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS },
636
637    { 0, 0 }
638};
639
640__be32
641nfsd_access(struct svc_rqst *rqstp, struct svc_fh *fhp, u32 *access, u32 *supported)
642{
643    struct accessmap *map;
644    struct svc_export *export;
645    struct dentry *dentry;
646    u32 query, result = 0, sresult = 0;
647    __be32 error;
648
649    error = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP);
650    if (error)
651        goto out;
652
653    export = fhp->fh_export;
654    dentry = fhp->fh_dentry;
655
656    if (S_ISREG(dentry->d_inode->i_mode))
657        map = nfs3_regaccess;
658    else if (S_ISDIR(dentry->d_inode->i_mode))
659        map = nfs3_diraccess;
660    else
661        map = nfs3_anyaccess;
662
663
664    query = *access;
665    for (; map->access; map++) {
666        if (map->access & query) {
667            __be32 err2;
668
669            sresult |= map->access;
670
671            err2 = nfsd_permission(rqstp, export, dentry, map->how);
672            switch (err2) {
673            case nfs_ok:
674                result |= map->access;
675                break;
676                
677            /* the following error codes just mean the access was not allowed,
678             * rather than an error occurred */
679            case nfserr_rofs:
680            case nfserr_acces:
681            case nfserr_perm:
682                /* simply don't "or" in the access bit. */
683                break;
684            default:
685                error = err2;
686                goto out;
687            }
688        }
689    }
690    *access = result;
691    if (supported)
692        *supported = sresult;
693
694 out:
695    return error;
696}
697#endif /* CONFIG_NFSD_V3 */
698
699static int nfsd_open_break_lease(struct inode *inode, int access)
700{
701    unsigned int mode;
702
703    if (access & NFSD_MAY_NOT_BREAK_LEASE)
704        return 0;
705    mode = (access & NFSD_MAY_WRITE) ? O_WRONLY : O_RDONLY;
706    return break_lease(inode, mode | O_NONBLOCK);
707}
708
709/*
710 * Open an existing file or directory.
711 * The access argument indicates the type of open (read/write/lock)
712 * N.B. After this call fhp needs an fh_put
713 */
714__be32
715nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
716            int access, struct file **filp)
717{
718    struct dentry *dentry;
719    struct inode *inode;
720    int flags = O_RDONLY|O_LARGEFILE;
721    __be32 err;
722    int host_err = 0;
723
724    validate_process_creds();
725
726    /*
727     * If we get here, then the client has already done an "open",
728     * and (hopefully) checked permission - so allow OWNER_OVERRIDE
729     * in case a chmod has now revoked permission.
730     */
731    err = fh_verify(rqstp, fhp, type, access | NFSD_MAY_OWNER_OVERRIDE);
732    if (err)
733        goto out;
734
735    dentry = fhp->fh_dentry;
736    inode = dentry->d_inode;
737
738    /* Disallow write access to files with the append-only bit set
739     * or any access when mandatory locking enabled
740     */
741    err = nfserr_perm;
742    if (IS_APPEND(inode) && (access & NFSD_MAY_WRITE))
743        goto out;
744    /*
745     * We must ignore files (but only files) which might have mandatory
746     * locks on them because there is no way to know if the accesser has
747     * the lock.
748     */
749    if (S_ISREG((inode)->i_mode) && mandatory_lock(inode))
750        goto out;
751
752    if (!inode->i_fop)
753        goto out;
754
755    host_err = nfsd_open_break_lease(inode, access);
756    if (host_err) /* NOMEM or WOULDBLOCK */
757        goto out_nfserr;
758
759    if (access & NFSD_MAY_WRITE) {
760        if (access & NFSD_MAY_READ)
761            flags = O_RDWR|O_LARGEFILE;
762        else
763            flags = O_WRONLY|O_LARGEFILE;
764    }
765    *filp = dentry_open(dget(dentry), mntget(fhp->fh_export->ex_path.mnt),
766                flags, current_cred());
767    if (IS_ERR(*filp))
768        host_err = PTR_ERR(*filp);
769    else
770        host_err = ima_file_check(*filp, access);
771out_nfserr:
772    err = nfserrno(host_err);
773out:
774    validate_process_creds();
775    return err;
776}
777
778/*
779 * Close a file.
780 */
781void
782nfsd_close(struct file *filp)
783{
784    fput(filp);
785}
786
787/*
788 * Obtain the readahead parameters for the file
789 * specified by (dev, ino).
790 */
791
792static inline struct raparms *
793nfsd_get_raparms(dev_t dev, ino_t ino)
794{
795    struct raparms *ra, **rap, **frap = NULL;
796    int depth = 0;
797    unsigned int hash;
798    struct raparm_hbucket *rab;
799
800    hash = jhash_2words(dev, ino, 0xfeedbeef) & RAPARM_HASH_MASK;
801    rab = &raparm_hash[hash];
802
803    spin_lock(&rab->pb_lock);
804    for (rap = &rab->pb_head; (ra = *rap); rap = &ra->p_next) {
805        if (ra->p_ino == ino && ra->p_dev == dev)
806            goto found;
807        depth++;
808        if (ra->p_count == 0)
809            frap = rap;
810    }
811    depth = nfsdstats.ra_size;
812    if (!frap) {
813        spin_unlock(&rab->pb_lock);
814        return NULL;
815    }
816    rap = frap;
817    ra = *frap;
818    ra->p_dev = dev;
819    ra->p_ino = ino;
820    ra->p_set = 0;
821    ra->p_hindex = hash;
822found:
823    if (rap != &rab->pb_head) {
824        *rap = ra->p_next;
825        ra->p_next = rab->pb_head;
826        rab->pb_head = ra;
827    }
828    ra->p_count++;
829    nfsdstats.ra_depth[depth*10/nfsdstats.ra_size]++;
830    spin_unlock(&rab->pb_lock);
831    return ra;
832}
833
834/*
835 * Grab and keep cached pages associated with a file in the svc_rqst
836 * so that they can be passed to the network sendmsg/sendpage routines
837 * directly. They will be released after the sending has completed.
838 */
839static int
840nfsd_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
841          struct splice_desc *sd)
842{
843    struct svc_rqst *rqstp = sd->u.data;
844    struct page **pp = rqstp->rq_respages + rqstp->rq_resused;
845    struct page *page = buf->page;
846    size_t size;
847
848    size = sd->len;
849
850    if (rqstp->rq_res.page_len == 0) {
851        get_page(page);
852        put_page(*pp);
853        *pp = page;
854        rqstp->rq_resused++;
855        rqstp->rq_res.page_base = buf->offset;
856        rqstp->rq_res.page_len = size;
857    } else if (page != pp[-1]) {
858        get_page(page);
859        if (*pp)
860            put_page(*pp);
861        *pp = page;
862        rqstp->rq_resused++;
863        rqstp->rq_res.page_len += size;
864    } else
865        rqstp->rq_res.page_len += size;
866
867    return size;
868}
869
870static int nfsd_direct_splice_actor(struct pipe_inode_info *pipe,
871                    struct splice_desc *sd)
872{
873    return __splice_from_pipe(pipe, sd, nfsd_splice_actor);
874}
875
876static __be32
877nfsd_vfs_read(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
878              loff_t offset, struct kvec *vec, int vlen, unsigned long *count)
879{
880    mm_segment_t oldfs;
881    __be32 err;
882    int host_err;
883
884    err = nfserr_perm;
885
886    if (file->f_op->splice_read && rqstp->rq_splice_ok) {
887        struct splice_desc sd = {
888            .len = 0,
889            .total_len = *count,
890            .pos = offset,
891            .u.data = rqstp,
892        };
893
894        rqstp->rq_resused = 1;
895        host_err = splice_direct_to_actor(file, &sd, nfsd_direct_splice_actor);
896    } else {
897        oldfs = get_fs();
898        set_fs(KERNEL_DS);
899        host_err = vfs_readv(file, (struct iovec __user *)vec, vlen, &offset);
900        set_fs(oldfs);
901    }
902
903    if (host_err >= 0) {
904        nfsdstats.io_read += host_err;
905        *count = host_err;
906        err = 0;
907        fsnotify_access(file);
908    } else
909        err = nfserrno(host_err);
910    return err;
911}
912
913static void kill_suid(struct dentry *dentry)
914{
915    struct iattr ia;
916    ia.ia_valid = ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_KILL_PRIV;
917
918    mutex_lock(&dentry->d_inode->i_mutex);
919    notify_change(dentry, &ia);
920    mutex_unlock(&dentry->d_inode->i_mutex);
921}
922
923/*
924 * Gathered writes: If another process is currently writing to the file,
925 * there's a high chance this is another nfsd (triggered by a bulk write
926 * from a client's biod). Rather than syncing the file with each write
927 * request, we sleep for 10 msec.
928 *
929 * I don't know if this roughly approximates C. Juszak's idea of
930 * gathered writes, but it's a nice and simple solution (IMHO), and it
931 * seems to work:-)
932 *
933 * Note: we do this only in the NFSv2 case, since v3 and higher have a
934 * better tool (separate unstable writes and commits) for solving this
935 * problem.
936 */
937static int wait_for_concurrent_writes(struct file *file)
938{
939    struct inode *inode = file->f_path.dentry->d_inode;
940    static ino_t last_ino;
941    static dev_t last_dev;
942    int err = 0;
943
944    if (atomic_read(&inode->i_writecount) > 1
945        || (last_ino == inode->i_ino && last_dev == inode->i_sb->s_dev)) {
946        dprintk("nfsd: write defer %d\n", task_pid_nr(current));
947        msleep(10);
948        dprintk("nfsd: write resume %d\n", task_pid_nr(current));
949    }
950
951    if (inode->i_state & I_DIRTY) {
952        dprintk("nfsd: write sync %d\n", task_pid_nr(current));
953        err = vfs_fsync(file, 0);
954    }
955    last_ino = inode->i_ino;
956    last_dev = inode->i_sb->s_dev;
957    return err;
958}
959
960static __be32
961nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
962                loff_t offset, struct kvec *vec, int vlen,
963                unsigned long *cnt, int *stablep)
964{
965    struct svc_export *exp;
966    struct dentry *dentry;
967    struct inode *inode;
968    mm_segment_t oldfs;
969    __be32 err = 0;
970    int host_err;
971    int stable = *stablep;
972    int use_wgather;
973
974    dentry = file->f_path.dentry;
975    inode = dentry->d_inode;
976    exp = fhp->fh_export;
977
978    /*
979     * Request sync writes if
980     * - the sync export option has been set, or
981     * - the client requested O_SYNC behavior (NFSv3 feature).
982     * - The file system doesn't support fsync().
983     * When NFSv2 gathered writes have been configured for this volume,
984     * flushing the data to disk is handled separately below.
985     */
986    use_wgather = (rqstp->rq_vers == 2) && EX_WGATHER(exp);
987
988    if (!file->f_op->fsync) {/* COMMIT3 cannot work */
989           stable = 2;
990           *stablep = 2; /* FILE_SYNC */
991    }
992
993    if (!EX_ISSYNC(exp))
994        stable = 0;
995    if (stable && !use_wgather) {
996        spin_lock(&file->f_lock);
997        file->f_flags |= O_SYNC;
998        spin_unlock(&file->f_lock);
999    }
1000
1001    /* Write the data. */
1002    oldfs = get_fs(); set_fs(KERNEL_DS);
1003    host_err = vfs_writev(file, (struct iovec __user *)vec, vlen, &offset);
1004    set_fs(oldfs);
1005    if (host_err < 0)
1006        goto out_nfserr;
1007    *cnt = host_err;
1008    nfsdstats.io_write += host_err;
1009    fsnotify_modify(file);
1010
1011    /* clear setuid/setgid flag after write */
1012    if (inode->i_mode & (S_ISUID | S_ISGID))
1013        kill_suid(dentry);
1014
1015    if (stable && use_wgather)
1016        host_err = wait_for_concurrent_writes(file);
1017
1018out_nfserr:
1019    dprintk("nfsd: write complete host_err=%d\n", host_err);
1020    if (host_err >= 0)
1021        err = 0;
1022    else
1023        err = nfserrno(host_err);
1024    return err;
1025}
1026
1027/*
1028 * Read data from a file. count must contain the requested read count
1029 * on entry. On return, *count contains the number of bytes actually read.
1030 * N.B. After this call fhp needs an fh_put
1031 */
1032__be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
1033    loff_t offset, struct kvec *vec, int vlen, unsigned long *count)
1034{
1035    struct file *file;
1036    struct inode *inode;
1037    struct raparms *ra;
1038    __be32 err;
1039
1040    err = nfsd_open(rqstp, fhp, S_IFREG, NFSD_MAY_READ, &file);
1041    if (err)
1042        return err;
1043
1044    inode = file->f_path.dentry->d_inode;
1045
1046    /* Get readahead parameters */
1047    ra = nfsd_get_raparms(inode->i_sb->s_dev, inode->i_ino);
1048
1049    if (ra && ra->p_set)
1050        file->f_ra = ra->p_ra;
1051
1052    err = nfsd_vfs_read(rqstp, fhp, file, offset, vec, vlen, count);
1053
1054    /* Write back readahead params */
1055    if (ra) {
1056        struct raparm_hbucket *rab = &raparm_hash[ra->p_hindex];
1057        spin_lock(&rab->pb_lock);
1058        ra->p_ra = file->f_ra;
1059        ra->p_set = 1;
1060        ra->p_count--;
1061        spin_unlock(&rab->pb_lock);
1062    }
1063
1064    nfsd_close(file);
1065    return err;
1066}
1067
1068/* As above, but use the provided file descriptor. */
1069__be32
1070nfsd_read_file(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
1071        loff_t offset, struct kvec *vec, int vlen,
1072        unsigned long *count)
1073{
1074    __be32 err;
1075
1076    if (file) {
1077        err = nfsd_permission(rqstp, fhp->fh_export, fhp->fh_dentry,
1078                NFSD_MAY_READ|NFSD_MAY_OWNER_OVERRIDE);
1079        if (err)
1080            goto out;
1081        err = nfsd_vfs_read(rqstp, fhp, file, offset, vec, vlen, count);
1082    } else /* Note file may still be NULL in NFSv4 special stateid case: */
1083        err = nfsd_read(rqstp, fhp, offset, vec, vlen, count);
1084out:
1085    return err;
1086}
1087
1088/*
1089 * Write data to a file.
1090 * The stable flag requests synchronous writes.
1091 * N.B. After this call fhp needs an fh_put
1092 */
1093__be32
1094nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
1095        loff_t offset, struct kvec *vec, int vlen, unsigned long *cnt,
1096        int *stablep)
1097{
1098    __be32 err = 0;
1099
1100    if (file) {
1101        err = nfsd_permission(rqstp, fhp->fh_export, fhp->fh_dentry,
1102                NFSD_MAY_WRITE|NFSD_MAY_OWNER_OVERRIDE);
1103        if (err)
1104            goto out;
1105        err = nfsd_vfs_write(rqstp, fhp, file, offset, vec, vlen, cnt,
1106                stablep);
1107    } else {
1108        err = nfsd_open(rqstp, fhp, S_IFREG, NFSD_MAY_WRITE, &file);
1109        if (err)
1110            goto out;
1111
1112        if (cnt)
1113            err = nfsd_vfs_write(rqstp, fhp, file, offset, vec, vlen,
1114                         cnt, stablep);
1115        nfsd_close(file);
1116    }
1117out:
1118    return err;
1119}
1120
1121#ifdef CONFIG_NFSD_V3
1122/*
1123 * Commit all pending writes to stable storage.
1124 *
1125 * Note: we only guarantee that data that lies within the range specified
1126 * by the 'offset' and 'count' parameters will be synced.
1127 *
1128 * Unfortunately we cannot lock the file to make sure we return full WCC
1129 * data to the client, as locking happens lower down in the filesystem.
1130 */
1131__be32
1132nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp,
1133               loff_t offset, unsigned long count)
1134{
1135    struct file *file;
1136    loff_t end = LLONG_MAX;
1137    __be32 err = nfserr_inval;
1138
1139    if (offset < 0)
1140        goto out;
1141    if (count != 0) {
1142        end = offset + (loff_t)count - 1;
1143        if (end < offset)
1144            goto out;
1145    }
1146
1147    err = nfsd_open(rqstp, fhp, S_IFREG,
1148            NFSD_MAY_WRITE|NFSD_MAY_NOT_BREAK_LEASE, &file);
1149    if (err)
1150        goto out;
1151    if (EX_ISSYNC(fhp->fh_export)) {
1152        int err2 = vfs_fsync_range(file, offset, end, 0);
1153
1154        if (err2 != -EINVAL)
1155            err = nfserrno(err2);
1156        else
1157            err = nfserr_notsupp;
1158    }
1159
1160    nfsd_close(file);
1161out:
1162    return err;
1163}
1164#endif /* CONFIG_NFSD_V3 */
1165
1166static __be32
1167nfsd_create_setattr(struct svc_rqst *rqstp, struct svc_fh *resfhp,
1168            struct iattr *iap)
1169{
1170    /*
1171     * Mode has already been set earlier in create:
1172     */
1173    iap->ia_valid &= ~ATTR_MODE;
1174    /*
1175     * Setting uid/gid works only for root. Irix appears to
1176     * send along the gid on create when it tries to implement
1177     * setgid directories via NFS:
1178     */
1179    if (current_fsuid() != 0)
1180        iap->ia_valid &= ~(ATTR_UID|ATTR_GID);
1181    if (iap->ia_valid)
1182        return nfsd_setattr(rqstp, resfhp, iap, 0, (time_t)0);
1183    return 0;
1184}
1185
1186/* HPUX client sometimes creates a file in mode 000, and sets size to 0.
1187 * setting size to 0 may fail for some specific file systems by the permission
1188 * checking which requires WRITE permission but the mode is 000.
1189 * we ignore the resizing(to 0) on the just new created file, since the size is
1190 * 0 after file created.
1191 *
1192 * call this only after vfs_create() is called.
1193 * */
1194static void
1195nfsd_check_ignore_resizing(struct iattr *iap)
1196{
1197    if ((iap->ia_valid & ATTR_SIZE) && (iap->ia_size == 0))
1198        iap->ia_valid &= ~ATTR_SIZE;
1199}
1200
1201/*
1202 * Create a file (regular, directory, device, fifo); UNIX sockets
1203 * not yet implemented.
1204 * If the response fh has been verified, the parent directory should
1205 * already be locked. Note that the parent directory is left locked.
1206 *
1207 * N.B. Every call to nfsd_create needs an fh_put for _both_ fhp and resfhp
1208 */
1209__be32
1210nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
1211        char *fname, int flen, struct iattr *iap,
1212        int type, dev_t rdev, struct svc_fh *resfhp)
1213{
1214    struct dentry *dentry, *dchild = NULL;
1215    struct inode *dirp;
1216    __be32 err;
1217    __be32 err2;
1218    int host_err;
1219
1220    err = nfserr_perm;
1221    if (!flen)
1222        goto out;
1223    err = nfserr_exist;
1224    if (isdotent(fname, flen))
1225        goto out;
1226
1227    err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
1228    if (err)
1229        goto out;
1230
1231    dentry = fhp->fh_dentry;
1232    dirp = dentry->d_inode;
1233
1234    err = nfserr_notdir;
1235    if (!dirp->i_op->lookup)
1236        goto out;
1237    /*
1238     * Check whether the response file handle has been verified yet.
1239     * If it has, the parent directory should already be locked.
1240     */
1241    if (!resfhp->fh_dentry) {
1242        /* called from nfsd_proc_mkdir, or possibly nfsd3_proc_create */
1243        fh_lock_nested(fhp, I_MUTEX_PARENT);
1244        dchild = lookup_one_len(fname, dentry, flen);
1245        host_err = PTR_ERR(dchild);
1246        if (IS_ERR(dchild))
1247            goto out_nfserr;
1248        err = fh_compose(resfhp, fhp->fh_export, dchild, fhp);
1249        if (err)
1250            goto out;
1251    } else {
1252        /* called from nfsd_proc_create */
1253        dchild = dget(resfhp->fh_dentry);
1254        if (!fhp->fh_locked) {
1255            /* not actually possible */
1256            printk(KERN_ERR
1257                "nfsd_create: parent %s/%s not locked!\n",
1258                dentry->d_parent->d_name.name,
1259                dentry->d_name.name);
1260            err = nfserr_io;
1261            goto out;
1262        }
1263    }
1264    /*
1265     * Make sure the child dentry is still negative ...
1266     */
1267    err = nfserr_exist;
1268    if (dchild->d_inode) {
1269        dprintk("nfsd_create: dentry %s/%s not negative!\n",
1270            dentry->d_name.name, dchild->d_name.name);
1271        goto out;
1272    }
1273
1274    if (!(iap->ia_valid & ATTR_MODE))
1275        iap->ia_mode = 0;
1276    iap->ia_mode = (iap->ia_mode & S_IALLUGO) | type;
1277
1278    err = nfserr_inval;
1279    if (!S_ISREG(type) && !S_ISDIR(type) && !special_file(type)) {
1280        printk(KERN_WARNING "nfsd: bad file type %o in nfsd_create\n",
1281               type);
1282        goto out;
1283    }
1284
1285    host_err = mnt_want_write(fhp->fh_export->ex_path.mnt);
1286    if (host_err)
1287        goto out_nfserr;
1288
1289    /*
1290     * Get the dir op function pointer.
1291     */
1292    err = 0;
1293    switch (type) {
1294    case S_IFREG:
1295        host_err = vfs_create(dirp, dchild, iap->ia_mode, NULL);
1296        if (!host_err)
1297            nfsd_check_ignore_resizing(iap);
1298        break;
1299    case S_IFDIR:
1300        host_err = vfs_mkdir(dirp, dchild, iap->ia_mode);
1301        break;
1302    case S_IFCHR:
1303    case S_IFBLK:
1304    case S_IFIFO:
1305    case S_IFSOCK:
1306        host_err = vfs_mknod(dirp, dchild, iap->ia_mode, rdev);
1307        break;
1308    }
1309    if (host_err < 0) {
1310        mnt_drop_write(fhp->fh_export->ex_path.mnt);
1311        goto out_nfserr;
1312    }
1313
1314    err = nfsd_create_setattr(rqstp, resfhp, iap);
1315
1316    /*
1317     * nfsd_setattr already committed the child. Transactional filesystems
1318     * had a chance to commit changes for both parent and child
1319     * simultaneously making the following commit_metadata a noop.
1320     */
1321    err2 = nfserrno(commit_metadata(fhp));
1322    if (err2)
1323        err = err2;
1324    mnt_drop_write(fhp->fh_export->ex_path.mnt);
1325    /*
1326     * Update the file handle to get the new inode info.
1327     */
1328    if (!err)
1329        err = fh_update(resfhp);
1330out:
1331    if (dchild && !IS_ERR(dchild))
1332        dput(dchild);
1333    return err;
1334
1335out_nfserr:
1336    err = nfserrno(host_err);
1337    goto out;
1338}
1339
1340#ifdef CONFIG_NFSD_V3
1341
1342static inline int nfsd_create_is_exclusive(int createmode)
1343{
1344    return createmode == NFS3_CREATE_EXCLUSIVE
1345           || createmode == NFS4_CREATE_EXCLUSIVE4_1;
1346}
1347
1348/*
1349 * NFSv3 and NFSv4 version of nfsd_create
1350 */
1351__be32
1352do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
1353        char *fname, int flen, struct iattr *iap,
1354        struct svc_fh *resfhp, int createmode, u32 *verifier,
1355            int *truncp, int *created)
1356{
1357    struct dentry *dentry, *dchild = NULL;
1358    struct inode *dirp;
1359    __be32 err;
1360    int host_err;
1361    __u32 v_mtime=0, v_atime=0;
1362
1363    err = nfserr_perm;
1364    if (!flen)
1365        goto out;
1366    err = nfserr_exist;
1367    if (isdotent(fname, flen))
1368        goto out;
1369    if (!(iap->ia_valid & ATTR_MODE))
1370        iap->ia_mode = 0;
1371    err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC);
1372    if (err)
1373        goto out;
1374
1375    dentry = fhp->fh_dentry;
1376    dirp = dentry->d_inode;
1377
1378    /* Get all the sanity checks out of the way before
1379     * we lock the parent. */
1380    err = nfserr_notdir;
1381    if (!dirp->i_op->lookup)
1382        goto out;
1383    fh_lock_nested(fhp, I_MUTEX_PARENT);
1384
1385    /*
1386     * Compose the response file handle.
1387     */
1388    dchild = lookup_one_len(fname, dentry, flen);
1389    host_err = PTR_ERR(dchild);
1390    if (IS_ERR(dchild))
1391        goto out_nfserr;
1392
1393    /* If file doesn't exist, check for permissions to create one */
1394    if (!dchild->d_inode) {
1395        err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
1396        if (err)
1397            goto out;
1398    }
1399
1400    err = fh_compose(resfhp, fhp->fh_export, dchild, fhp);
1401    if (err)
1402        goto out;
1403
1404    if (nfsd_create_is_exclusive(createmode)) {
1405        /* solaris7 gets confused (bugid 4218508) if these have
1406         * the high bit set, so just clear the high bits. If this is
1407         * ever changed to use different attrs for storing the
1408         * verifier, then do_open_lookup() will also need to be fixed
1409         * accordingly.
1410         */
1411        v_mtime = verifier[0]&0x7fffffff;
1412        v_atime = verifier[1]&0x7fffffff;
1413    }
1414    
1415    host_err = mnt_want_write(fhp->fh_export->ex_path.mnt);
1416    if (host_err)
1417        goto out_nfserr;
1418    if (dchild->d_inode) {
1419        err = 0;
1420
1421        switch (createmode) {
1422        case NFS3_CREATE_UNCHECKED:
1423            if (! S_ISREG(dchild->d_inode->i_mode))
1424                err = nfserr_exist;
1425            else if (truncp) {
1426                /* in nfsv4, we need to treat this case a little
1427                 * differently. we don't want to truncate the
1428                 * file now; this would be wrong if the OPEN
1429                 * fails for some other reason. furthermore,
1430                 * if the size is nonzero, we should ignore it
1431                 * according to spec!
1432                 */
1433                *truncp = (iap->ia_valid & ATTR_SIZE) && !iap->ia_size;
1434            }
1435            else {
1436                iap->ia_valid &= ATTR_SIZE;
1437                goto set_attr;
1438            }
1439            break;
1440        case NFS3_CREATE_EXCLUSIVE:
1441            if ( dchild->d_inode->i_mtime.tv_sec == v_mtime
1442                && dchild->d_inode->i_atime.tv_sec == v_atime
1443                && dchild->d_inode->i_size == 0 )
1444                break;
1445        case NFS4_CREATE_EXCLUSIVE4_1:
1446            if ( dchild->d_inode->i_mtime.tv_sec == v_mtime
1447                && dchild->d_inode->i_atime.tv_sec == v_atime
1448                && dchild->d_inode->i_size == 0 )
1449                goto set_attr;
1450             /* fallthru */
1451        case NFS3_CREATE_GUARDED:
1452            err = nfserr_exist;
1453        }
1454        mnt_drop_write(fhp->fh_export->ex_path.mnt);
1455        goto out;
1456    }
1457
1458    host_err = vfs_create(dirp, dchild, iap->ia_mode, NULL);
1459    if (host_err < 0) {
1460        mnt_drop_write(fhp->fh_export->ex_path.mnt);
1461        goto out_nfserr;
1462    }
1463    if (created)
1464        *created = 1;
1465
1466    nfsd_check_ignore_resizing(iap);
1467
1468    if (nfsd_create_is_exclusive(createmode)) {
1469        /* Cram the verifier into atime/mtime */
1470        iap->ia_valid = ATTR_MTIME|ATTR_ATIME
1471            | ATTR_MTIME_SET|ATTR_ATIME_SET;
1472        /* XXX someone who knows this better please fix it for nsec */
1473        iap->ia_mtime.tv_sec = v_mtime;
1474        iap->ia_atime.tv_sec = v_atime;
1475        iap->ia_mtime.tv_nsec = 0;
1476        iap->ia_atime.tv_nsec = 0;
1477    }
1478
1479 set_attr:
1480    err = nfsd_create_setattr(rqstp, resfhp, iap);
1481
1482    /*
1483     * nfsd_setattr already committed the child (and possibly also the parent).
1484     */
1485    if (!err)
1486        err = nfserrno(commit_metadata(fhp));
1487
1488    mnt_drop_write(fhp->fh_export->ex_path.mnt);
1489    /*
1490     * Update the filehandle to get the new inode info.
1491     */
1492    if (!err)
1493        err = fh_update(resfhp);
1494
1495 out:
1496    fh_unlock(fhp);
1497    if (dchild && !IS_ERR(dchild))
1498        dput(dchild);
1499     return err;
1500 
1501 out_nfserr:
1502    err = nfserrno(host_err);
1503    goto out;
1504}
1505#endif /* CONFIG_NFSD_V3 */
1506
1507/*
1508 * Read a symlink. On entry, *lenp must contain the maximum path length that
1509 * fits into the buffer. On return, it contains the true length.
1510 * N.B. After this call fhp needs an fh_put
1511 */
1512__be32
1513nfsd_readlink(struct svc_rqst *rqstp, struct svc_fh *fhp, char *buf, int *lenp)
1514{
1515    struct dentry *dentry;
1516    struct inode *inode;
1517    mm_segment_t oldfs;
1518    __be32 err;
1519    int host_err;
1520
1521    err = fh_verify(rqstp, fhp, S_IFLNK, NFSD_MAY_NOP);
1522    if (err)
1523        goto out;
1524
1525    dentry = fhp->fh_dentry;
1526    inode = dentry->d_inode;
1527
1528    err = nfserr_inval;
1529    if (!inode->i_op->readlink)
1530        goto out;
1531
1532    touch_atime(fhp->fh_export->ex_path.mnt, dentry);
1533    /* N.B. Why does this call need a get_fs()??
1534     * Remove the set_fs and watch the fireworks:-) --okir
1535     */
1536
1537    oldfs = get_fs(); set_fs(KERNEL_DS);
1538    host_err = inode->i_op->readlink(dentry, buf, *lenp);
1539    set_fs(oldfs);
1540
1541    if (host_err < 0)
1542        goto out_nfserr;
1543    *lenp = host_err;
1544    err = 0;
1545out:
1546    return err;
1547
1548out_nfserr:
1549    err = nfserrno(host_err);
1550    goto out;
1551}
1552
1553/*
1554 * Create a symlink and look up its inode
1555 * N.B. After this call _both_ fhp and resfhp need an fh_put
1556 */
1557__be32
1558nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp,
1559                char *fname, int flen,
1560                char *path, int plen,
1561                struct svc_fh *resfhp,
1562                struct iattr *iap)
1563{
1564    struct dentry *dentry, *dnew;
1565    __be32 err, cerr;
1566    int host_err;
1567
1568    err = nfserr_noent;
1569    if (!flen || !plen)
1570        goto out;
1571    err = nfserr_exist;
1572    if (isdotent(fname, flen))
1573        goto out;
1574
1575    err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
1576    if (err)
1577        goto out;
1578    fh_lock(fhp);
1579    dentry = fhp->fh_dentry;
1580    dnew = lookup_one_len(fname, dentry, flen);
1581    host_err = PTR_ERR(dnew);
1582    if (IS_ERR(dnew))
1583        goto out_nfserr;
1584
1585    host_err = mnt_want_write(fhp->fh_export->ex_path.mnt);
1586    if (host_err)
1587        goto out_nfserr;
1588
1589    if (unlikely(path[plen] != 0)) {
1590        char *path_alloced = kmalloc(plen+1, GFP_KERNEL);
1591        if (path_alloced == NULL)
1592            host_err = -ENOMEM;
1593        else {
1594            strncpy(path_alloced, path, plen);
1595            path_alloced[plen] = 0;
1596            host_err = vfs_symlink(dentry->d_inode, dnew, path_alloced);
1597            kfree(path_alloced);
1598        }
1599    } else
1600        host_err = vfs_symlink(dentry->d_inode, dnew, path);
1601    err = nfserrno(host_err);
1602    if (!err)
1603        err = nfserrno(commit_metadata(fhp));
1604    fh_unlock(fhp);
1605
1606    mnt_drop_write(fhp->fh_export->ex_path.mnt);
1607
1608    cerr = fh_compose(resfhp, fhp->fh_export, dnew, fhp);
1609    dput(dnew);
1610    if (err==0) err = cerr;
1611out:
1612    return err;
1613
1614out_nfserr:
1615    err = nfserrno(host_err);
1616    goto out;
1617}
1618
1619/*
1620 * Create a hardlink
1621 * N.B. After this call _both_ ffhp and tfhp need an fh_put
1622 */
1623__be32
1624nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp,
1625                char *name, int len, struct svc_fh *tfhp)
1626{
1627    struct dentry *ddir, *dnew, *dold;
1628    struct inode *dirp;
1629    __be32 err;
1630    int host_err;
1631
1632    err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_CREATE);
1633    if (err)
1634        goto out;
1635    err = fh_verify(rqstp, tfhp, -S_IFDIR, NFSD_MAY_NOP);
1636    if (err)
1637        goto out;
1638
1639    err = nfserr_perm;
1640    if (!len)
1641        goto out;
1642    err = nfserr_exist;
1643    if (isdotent(name, len))
1644        goto out;
1645
1646    fh_lock_nested(ffhp, I_MUTEX_PARENT);
1647    ddir = ffhp->fh_dentry;
1648    dirp = ddir->d_inode;
1649
1650    dnew = lookup_one_len(name, ddir, len);
1651    host_err = PTR_ERR(dnew);
1652    if (IS_ERR(dnew))
1653        goto out_nfserr;
1654
1655    dold = tfhp->fh_dentry;
1656
1657    host_err = mnt_want_write(tfhp->fh_export->ex_path.mnt);
1658    if (host_err) {
1659        err = nfserrno(host_err);
1660        goto out_dput;
1661    }
1662    err = nfserr_noent;
1663    if (!dold->d_inode)
1664        goto out_drop_write;
1665    host_err = nfsd_break_lease(dold->d_inode);
1666    if (host_err) {
1667        err = nfserrno(host_err);
1668        goto out_drop_write;
1669    }
1670    host_err = vfs_link(dold, dirp, dnew);
1671    if (!host_err) {
1672        err = nfserrno(commit_metadata(ffhp));
1673        if (!err)
1674            err = nfserrno(commit_metadata(tfhp));
1675    } else {
1676        if (host_err == -EXDEV && rqstp->rq_vers == 2)
1677            err = nfserr_acces;
1678        else
1679            err = nfserrno(host_err);
1680    }
1681out_drop_write:
1682    mnt_drop_write(tfhp->fh_export->ex_path.mnt);
1683out_dput:
1684    dput(dnew);
1685out_unlock:
1686    fh_unlock(ffhp);
1687out:
1688    return err;
1689
1690out_nfserr:
1691    err = nfserrno(host_err);
1692    goto out_unlock;
1693}
1694
1695/*
1696 * Rename a file
1697 * N.B. After this call _both_ ffhp and tfhp need an fh_put
1698 */
1699__be32
1700nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
1701                struct svc_fh *tfhp, char *tname, int tlen)
1702{
1703    struct dentry *fdentry, *tdentry, *odentry, *ndentry, *trap;
1704    struct inode *fdir, *tdir;
1705    __be32 err;
1706    int host_err;
1707
1708    err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_REMOVE);
1709    if (err)
1710        goto out;
1711    err = fh_verify(rqstp, tfhp, S_IFDIR, NFSD_MAY_CREATE);
1712    if (err)
1713        goto out;
1714
1715    fdentry = ffhp->fh_dentry;
1716    fdir = fdentry->d_inode;
1717
1718    tdentry = tfhp->fh_dentry;
1719    tdir = tdentry->d_inode;
1720
1721    err = (rqstp->rq_vers == 2) ? nfserr_acces : nfserr_xdev;
1722    if (ffhp->fh_export != tfhp->fh_export)
1723        goto out;
1724
1725    err = nfserr_perm;
1726    if (!flen || isdotent(fname, flen) || !tlen || isdotent(tname, tlen))
1727        goto out;
1728
1729    /* cannot use fh_lock as we need deadlock protective ordering
1730     * so do it by hand */
1731    trap = lock_rename(tdentry, fdentry);
1732    ffhp->fh_locked = tfhp->fh_locked = 1;
1733    fill_pre_wcc(ffhp);
1734    fill_pre_wcc(tfhp);
1735
1736    odentry = lookup_one_len(fname, fdentry, flen);
1737    host_err = PTR_ERR(odentry);
1738    if (IS_ERR(odentry))
1739        goto out_nfserr;
1740
1741    host_err = -ENOENT;
1742    if (!odentry->d_inode)
1743        goto out_dput_old;
1744    host_err = -EINVAL;
1745    if (odentry == trap)
1746        goto out_dput_old;
1747
1748    ndentry = lookup_one_len(tname, tdentry, tlen);
1749    host_err = PTR_ERR(ndentry);
1750    if (IS_ERR(ndentry))
1751        goto out_dput_old;
1752    host_err = -ENOTEMPTY;
1753    if (ndentry == trap)
1754        goto out_dput_new;
1755
1756    host_err = -EXDEV;
1757    if (ffhp->fh_export->ex_path.mnt != tfhp->fh_export->ex_path.mnt)
1758        goto out_dput_new;
1759    host_err = mnt_want_write(ffhp->fh_export->ex_path.mnt);
1760    if (host_err)
1761        goto out_dput_new;
1762
1763    host_err = nfsd_break_lease(odentry->d_inode);
1764    if (host_err)
1765        goto out_drop_write;
1766    if (ndentry->d_inode) {
1767        host_err = nfsd_break_lease(ndentry->d_inode);
1768        if (host_err)
1769            goto out_drop_write;
1770    }
1771    host_err = vfs_rename(fdir, odentry, tdir, ndentry);
1772    if (!host_err) {
1773        host_err = commit_metadata(tfhp);
1774        if (!host_err)
1775            host_err = commit_metadata(ffhp);
1776    }
1777out_drop_write:
1778    mnt_drop_write(ffhp->fh_export->ex_path.mnt);
1779 out_dput_new:
1780    dput(ndentry);
1781 out_dput_old:
1782    dput(odentry);
1783 out_nfserr:
1784    err = nfserrno(host_err);
1785
1786    /* we cannot reply on fh_unlock on the two filehandles,
1787     * as that would do the wrong thing if the two directories
1788     * were the same, so again we do it by hand
1789     */
1790    fill_post_wcc(ffhp);
1791    fill_post_wcc(tfhp);
1792    unlock_rename(tdentry, fdentry);
1793    ffhp->fh_locked = tfhp->fh_locked = 0;
1794
1795out:
1796    return err;
1797}
1798
1799/*
1800 * Unlink a file or directory
1801 * N.B. After this call fhp needs an fh_put
1802 */
1803__be32
1804nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
1805                char *fname, int flen)
1806{
1807    struct dentry *dentry, *rdentry;
1808    struct inode *dirp;
1809    __be32 err;
1810    int host_err;
1811
1812    err = nfserr_acces;
1813    if (!flen || isdotent(fname, flen))
1814        goto out;
1815    err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_REMOVE);
1816    if (err)
1817        goto out;
1818
1819    fh_lock_nested(fhp, I_MUTEX_PARENT);
1820    dentry = fhp->fh_dentry;
1821    dirp = dentry->d_inode;
1822
1823    rdentry = lookup_one_len(fname, dentry, flen);
1824    host_err = PTR_ERR(rdentry);
1825    if (IS_ERR(rdentry))
1826        goto out_nfserr;
1827
1828    if (!rdentry->d_inode) {
1829        dput(rdentry);
1830        err = nfserr_noent;
1831        goto out;
1832    }
1833
1834    if (!type)
1835        type = rdentry->d_inode->i_mode & S_IFMT;
1836
1837    host_err = mnt_want_write(fhp->fh_export->ex_path.mnt);
1838    if (host_err)
1839        goto out_put;
1840
1841    host_err = nfsd_break_lease(rdentry->d_inode);
1842    if (host_err)
1843        goto out_drop_write;
1844    if (type != S_IFDIR)
1845        host_err = vfs_unlink(dirp, rdentry);
1846    else
1847        host_err = vfs_rmdir(dirp, rdentry);
1848    if (!host_err)
1849        host_err = commit_metadata(fhp);
1850out_drop_write:
1851    mnt_drop_write(fhp->fh_export->ex_path.mnt);
1852out_put:
1853    dput(rdentry);
1854
1855out_nfserr:
1856    err = nfserrno(host_err);
1857out:
1858    return err;
1859}
1860
1861/*
1862 * We do this buffering because we must not call back into the file
1863 * system's ->lookup() method from the filldir callback. That may well
1864 * deadlock a number of file systems.
1865 *
1866 * This is based heavily on the implementation of same in XFS.
1867 */
1868struct buffered_dirent {
1869    u64 ino;
1870    loff_t offset;
1871    int namlen;
1872    unsigned int d_type;
1873    char name[];
1874};
1875
1876struct readdir_data {
1877    char *dirent;
1878    size_t used;
1879    int full;
1880};
1881
1882static int nfsd_buffered_filldir(void *__buf, const char *name, int namlen,
1883                 loff_t offset, u64 ino, unsigned int d_type)
1884{
1885    struct readdir_data *buf = __buf;
1886    struct buffered_dirent *de = (void *)(buf->dirent + buf->used);
1887    unsigned int reclen;
1888
1889    reclen = ALIGN(sizeof(struct buffered_dirent) + namlen, sizeof(u64));
1890    if (buf->used + reclen > PAGE_SIZE) {
1891        buf->full = 1;
1892        return -EINVAL;
1893    }
1894
1895    de->namlen = namlen;
1896    de->offset = offset;
1897    de->ino = ino;
1898    de->d_type = d_type;
1899    memcpy(de->name, name, namlen);
1900    buf->used += reclen;
1901
1902    return 0;
1903}
1904
1905static __be32 nfsd_buffered_readdir(struct file *file, filldir_t func,
1906                    struct readdir_cd *cdp, loff_t *offsetp)
1907{
1908    struct readdir_data buf;
1909    struct buffered_dirent *de;
1910    int host_err;
1911    int size;
1912    loff_t offset;
1913
1914    buf.dirent = (void *)__get_free_page(GFP_KERNEL);
1915    if (!buf.dirent)
1916        return nfserrno(-ENOMEM);
1917
1918    offset = *offsetp;
1919
1920    while (1) {
1921        struct inode *dir_inode = file->f_path.dentry->d_inode;
1922        unsigned int reclen;
1923
1924        cdp->err = nfserr_eof; /* will be cleared on successful read */
1925        buf.used = 0;
1926        buf.full = 0;
1927
1928        host_err = vfs_readdir(file, nfsd_buffered_filldir, &buf);
1929        if (buf.full)
1930            host_err = 0;
1931
1932        if (host_err < 0)
1933            break;
1934
1935        size = buf.used;
1936
1937        if (!size)
1938            break;
1939
1940        /*
1941         * Various filldir functions may end up calling back into
1942         * lookup_one_len() and the file system's ->lookup() method.
1943         * These expect i_mutex to be held, as it would within readdir.
1944         */
1945        host_err = mutex_lock_killable(&dir_inode->i_mutex);
1946        if (host_err)
1947            break;
1948
1949        de = (struct buffered_dirent *)buf.dirent;
1950        while (size > 0) {
1951            offset = de->offset;
1952
1953            if (func(cdp, de->name, de->namlen, de->offset,
1954                 de->ino, de->d_type))
1955                break;
1956
1957            if (cdp->err != nfs_ok)
1958                break;
1959
1960            reclen = ALIGN(sizeof(*de) + de->namlen,
1961                       sizeof(u64));
1962            size -= reclen;
1963            de = (struct buffered_dirent *)((char *)de + reclen);
1964        }
1965        mutex_unlock(&dir_inode->i_mutex);
1966        if (size > 0) /* We bailed out early */
1967            break;
1968
1969        offset = vfs_llseek(file, 0, SEEK_CUR);
1970    }
1971
1972    free_page((unsigned long)(buf.dirent));
1973
1974    if (host_err)
1975        return nfserrno(host_err);
1976
1977    *offsetp = offset;
1978    return cdp->err;
1979}
1980
1981/*
1982 * Read entries from a directory.
1983 * The NFSv3/4 verifier we ignore for now.
1984 */
1985__be32
1986nfsd_readdir(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t *offsetp,
1987         struct readdir_cd *cdp, filldir_t func)
1988{
1989    __be32 err;
1990    struct file *file;
1991    loff_t offset = *offsetp;
1992
1993    err = nfsd_open(rqstp, fhp, S_IFDIR, NFSD_MAY_READ, &file);
1994    if (err)
1995        goto out;
1996
1997    offset = vfs_llseek(file, offset, 0);
1998    if (offset < 0) {
1999        err = nfserrno((int)offset);
2000        goto out_close;
2001    }
2002
2003    err = nfsd_buffered_readdir(file, func, cdp, offsetp);
2004
2005    if (err == nfserr_eof || err == nfserr_toosmall)
2006        err = nfs_ok; /* can still be found in ->err */
2007out_close:
2008    nfsd_close(file);
2009out:
2010    return err;
2011}
2012
2013/*
2014 * Get file system stats
2015 * N.B. After this call fhp needs an fh_put
2016 */
2017__be32
2018nfsd_statfs(struct svc_rqst *rqstp, struct svc_fh *fhp, struct kstatfs *stat, int access)
2019{
2020    __be32 err;
2021
2022    err = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP | access);
2023    if (!err) {
2024        struct path path = {
2025            .mnt = fhp->fh_export->ex_path.mnt,
2026            .dentry = fhp->fh_dentry,
2027        };
2028        if (vfs_statfs(&path, stat))
2029            err = nfserr_io;
2030    }
2031    return err;
2032}
2033
2034static int exp_rdonly(struct svc_rqst *rqstp, struct svc_export *exp)
2035{
2036    return nfsexp_flags(rqstp, exp) & NFSEXP_READONLY;
2037}
2038
2039/*
2040 * Check for a user's access permissions to this inode.
2041 */
2042__be32
2043nfsd_permission(struct svc_rqst *rqstp, struct svc_export *exp,
2044                    struct dentry *dentry, int acc)
2045{
2046    struct inode *inode = dentry->d_inode;
2047    int err;
2048
2049    if ((acc & NFSD_MAY_MASK) == NFSD_MAY_NOP)
2050        return 0;
2051#if 0
2052    dprintk("nfsd: permission 0x%x%s%s%s%s%s%s%s mode 0%o%s%s%s\n",
2053        acc,
2054        (acc & NFSD_MAY_READ)? " read" : "",
2055        (acc & NFSD_MAY_WRITE)? " write" : "",
2056        (acc & NFSD_MAY_EXEC)? " exec" : "",
2057        (acc & NFSD_MAY_SATTR)? " sattr" : "",
2058        (acc & NFSD_MAY_TRUNC)? " trunc" : "",
2059        (acc & NFSD_MAY_LOCK)? " lock" : "",
2060        (acc & NFSD_MAY_OWNER_OVERRIDE)? " owneroverride" : "",
2061        inode->i_mode,
2062        IS_IMMUTABLE(inode)? " immut" : "",
2063        IS_APPEND(inode)? " append" : "",
2064        __mnt_is_readonly(exp->ex_path.mnt)? " ro" : "");
2065    dprintk(" owner %d/%d user %d/%d\n",
2066        inode->i_uid, inode->i_gid, current_fsuid(), current_fsgid());
2067#endif
2068
2069    /* Normally we reject any write/sattr etc access on a read-only file
2070     * system. But if it is IRIX doing check on write-access for a
2071     * device special file, we ignore rofs.
2072     */
2073    if (!(acc & NFSD_MAY_LOCAL_ACCESS))
2074        if (acc & (NFSD_MAY_WRITE | NFSD_MAY_SATTR | NFSD_MAY_TRUNC)) {
2075            if (exp_rdonly(rqstp, exp) ||
2076                __mnt_is_readonly(exp->ex_path.mnt))
2077                return nfserr_rofs;
2078            if (/* (acc & NFSD_MAY_WRITE) && */ IS_IMMUTABLE(inode))
2079                return nfserr_perm;
2080        }
2081    if ((acc & NFSD_MAY_TRUNC) && IS_APPEND(inode))
2082        return nfserr_perm;
2083
2084    if (acc & NFSD_MAY_LOCK) {
2085        /* If we cannot rely on authentication in NLM requests,
2086         * just allow locks, otherwise require read permission, or
2087         * ownership
2088         */
2089        if (exp->ex_flags & NFSEXP_NOAUTHNLM)
2090            return 0;
2091        else
2092            acc = NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE;
2093    }
2094    /*
2095     * The file owner always gets access permission for accesses that
2096     * would normally be checked at open time. This is to make
2097     * file access work even when the client has done a fchmod(fd, 0).
2098     *
2099     * However, `cp foo bar' should fail nevertheless when bar is
2100     * readonly. A sensible way to do this might be to reject all
2101     * attempts to truncate a read-only file, because a creat() call
2102     * always implies file truncation.
2103     * ... but this isn't really fair. A process may reasonably call
2104     * ftruncate on an open file descriptor on a file with perm 000.
2105     * We must trust the client to do permission checking - using "ACCESS"
2106     * with NFSv3.
2107     */
2108    if ((acc & NFSD_MAY_OWNER_OVERRIDE) &&
2109        inode->i_uid == current_fsuid())
2110        return 0;
2111
2112    /* This assumes NFSD_MAY_{READ,WRITE,EXEC} == MAY_{READ,WRITE,EXEC} */
2113    err = inode_permission(inode, acc & (MAY_READ|MAY_WRITE|MAY_EXEC));
2114
2115    /* Allow read access to binaries even when mode 111 */
2116    if (err == -EACCES && S_ISREG(inode->i_mode) &&
2117        acc == (NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE))
2118        err = inode_permission(inode, MAY_EXEC);
2119
2120    return err? nfserrno(err) : 0;
2121}
2122
2123void
2124nfsd_racache_shutdown(void)
2125{
2126    struct raparms *raparm, *last_raparm;
2127    unsigned int i;
2128
2129    dprintk("nfsd: freeing readahead buffers.\n");
2130
2131    for (i = 0; i < RAPARM_HASH_SIZE; i++) {
2132        raparm = raparm_hash[i].pb_head;
2133        while(raparm) {
2134            last_raparm = raparm;
2135            raparm = raparm->p_next;
2136            kfree(last_raparm);
2137        }
2138        raparm_hash[i].pb_head = NULL;
2139    }
2140}
2141/*
2142 * Initialize readahead param cache
2143 */
2144int
2145nfsd_racache_init(int cache_size)
2146{
2147    int i;
2148    int j = 0;
2149    int nperbucket;
2150    struct raparms **raparm = NULL;
2151
2152
2153    if (raparm_hash[0].pb_head)
2154        return 0;
2155    nperbucket = DIV_ROUND_UP(cache_size, RAPARM_HASH_SIZE);
2156    if (nperbucket < 2)
2157        nperbucket = 2;
2158    cache_size = nperbucket * RAPARM_HASH_SIZE;
2159
2160    dprintk("nfsd: allocating %d readahead buffers.\n", cache_size);
2161
2162    for (i = 0; i < RAPARM_HASH_SIZE; i++) {
2163        spin_lock_init(&raparm_hash[i].pb_lock);
2164
2165        raparm = &raparm_hash[i].pb_head;
2166        for (j = 0; j < nperbucket; j++) {
2167            *raparm = kzalloc(sizeof(struct raparms), GFP_KERNEL);
2168            if (!*raparm)
2169                goto out_nomem;
2170            raparm = &(*raparm)->p_next;
2171        }
2172        *raparm = NULL;
2173    }
2174
2175    nfsdstats.ra_size = cache_size;
2176    return 0;
2177
2178out_nomem:
2179    dprintk("nfsd: kmalloc failed, freeing readahead buffers\n");
2180    nfsd_racache_shutdown();
2181    return -ENOMEM;
2182}
2183
2184#if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
2185struct posix_acl *
2186nfsd_get_posix_acl(struct svc_fh *fhp, int type)
2187{
2188    struct inode *inode = fhp->fh_dentry->d_inode;
2189    char *name;
2190    void *value = NULL;
2191    ssize_t size;
2192    struct posix_acl *acl;
2193
2194    if (!IS_POSIXACL(inode))
2195        return ERR_PTR(-EOPNOTSUPP);
2196
2197    switch (type) {
2198    case ACL_TYPE_ACCESS:
2199        name = POSIX_ACL_XATTR_ACCESS;
2200        break;
2201    case ACL_TYPE_DEFAULT:
2202        name = POSIX_ACL_XATTR_DEFAULT;
2203        break;
2204    default:
2205        return ERR_PTR(-EOPNOTSUPP);
2206    }
2207
2208    size = nfsd_getxattr(fhp->fh_dentry, name, &value);
2209    if (size < 0)
2210        return ERR_PTR(size);
2211
2212    acl = posix_acl_from_xattr(value, size);
2213    kfree(value);
2214    return acl;
2215}
2216
2217int
2218nfsd_set_posix_acl(struct svc_fh *fhp, int type, struct posix_acl *acl)
2219{
2220    struct inode *inode = fhp->fh_dentry->d_inode;
2221    char *name;
2222    void *value = NULL;
2223    size_t size;
2224    int error;
2225
2226    if (!IS_POSIXACL(inode) ||
2227        !inode->i_op->setxattr || !inode->i_op->removexattr)
2228        return -EOPNOTSUPP;
2229    switch(type) {
2230        case ACL_TYPE_ACCESS:
2231            name = POSIX_ACL_XATTR_ACCESS;
2232            break;
2233        case ACL_TYPE_DEFAULT:
2234            name = POSIX_ACL_XATTR_DEFAULT;
2235            break;
2236        default:
2237            return -EOPNOTSUPP;
2238    }
2239
2240    if (acl && acl->a_count) {
2241        size = posix_acl_xattr_size(acl->a_count);
2242        value = kmalloc(size, GFP_KERNEL);
2243        if (!value)
2244            return -ENOMEM;
2245        error = posix_acl_to_xattr(acl, value, size);
2246        if (error < 0)
2247            goto getout;
2248        size = error;
2249    } else
2250        size = 0;
2251
2252    error = mnt_want_write(fhp->fh_export->ex_path.mnt);
2253    if (error)
2254        goto getout;
2255    if (size)
2256        error = vfs_setxattr(fhp->fh_dentry, name, value, size, 0);
2257    else {
2258        if (!S_ISDIR(inode->i_mode) && type == ACL_TYPE_DEFAULT)
2259            error = 0;
2260        else {
2261            error = vfs_removexattr(fhp->fh_dentry, name);
2262            if (error == -ENODATA)
2263                error = 0;
2264        }
2265    }
2266    mnt_drop_write(fhp->fh_export->ex_path.mnt);
2267
2268getout:
2269    kfree(value);
2270    return error;
2271}
2272#endif /* defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) */
2273

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