1 // SPDX-License-Identifier: GPL-2.0
3 * File operations used by nfsd. Some of these have been ripped from
4 * other parts of the kernel because they weren't exported, others
5 * are partial duplicates with added or changed functionality.
7 * Note that several functions dget() the dentry upon which they want
8 * to act, most notably those that create directory entries. Response
9 * dentry's are dput()'d if necessary in the release callback.
10 * So if you notice code paths that apparently fail to dput() the
11 * dentry, don't worry--they have been taken care of.
13 * Copyright (C) 1995-1999 Olaf Kirch <okir@monad.swb.de>
14 * Zerocpy NFS support (C) 2002 Hirokazu Takahashi <taka@valinux.co.jp>
18 #include <linux/file.h>
19 #include <linux/splice.h>
20 #include <linux/falloc.h>
21 #include <linux/fcntl.h>
22 #include <linux/namei.h>
23 #include <linux/delay.h>
24 #include <linux/fsnotify.h>
25 #include <linux/posix_acl_xattr.h>
26 #include <linux/xattr.h>
27 #include <linux/jhash.h>
28 #include <linux/ima.h>
29 #include <linux/slab.h>
30 #include <linux/uaccess.h>
31 #include <linux/exportfs.h>
32 #include <linux/writeback.h>
33 #include <linux/security.h>
37 #endif /* CONFIG_NFSD_V3 */
40 #include "../internal.h"
43 #endif /* CONFIG_NFSD_V4 */
47 #include "filecache.h"
50 #define NFSDDBG_FACILITY NFSDDBG_FILEOP
53 * Called from nfsd_lookup and encode_dirent. Check if we have crossed
55 * Returns -EAGAIN or -ETIMEDOUT leaving *dpp and *expp unchanged,
56 * or nfs_ok having possibly changed *dpp and *expp
59 nfsd_cross_mnt(struct svc_rqst *rqstp, struct dentry **dpp,
60 struct svc_export **expp)
62 struct svc_export *exp = *expp, *exp2 = NULL;
63 struct dentry *dentry = *dpp;
64 struct path path = {.mnt = mntget(exp->ex_path.mnt),
65 .dentry = dget(dentry)};
68 err = follow_down(&path);
71 if (path.mnt == exp->ex_path.mnt && path.dentry == dentry &&
72 nfsd_mountpoint(dentry, exp) == 2) {
73 /* This is only a mountpoint in some other namespace */
78 exp2 = rqst_exp_get_by_name(rqstp, &path);
82 * We normally allow NFS clients to continue
83 * "underneath" a mountpoint that is not exported.
84 * The exception is V4ROOT, where no traversal is ever
85 * allowed without an explicit export of the new
88 if (err == -ENOENT && !(exp->ex_flags & NFSEXP_V4ROOT))
93 if (nfsd_v4client(rqstp) ||
94 (exp->ex_flags & NFSEXP_CROSSMOUNT) || EX_NOHIDE(exp2)) {
95 /* successfully crossed mount point */
97 * This is subtle: path.dentry is *not* on path.mnt
98 * at this point. The only reason we are safe is that
99 * original mnt is pinned down by exp, so we should
100 * put path *before* putting exp
103 path.dentry = dentry;
113 static void follow_to_parent(struct path *path)
117 while (path->dentry == path->mnt->mnt_root && follow_up(path))
119 dp = dget_parent(path->dentry);
124 static int nfsd_lookup_parent(struct svc_rqst *rqstp, struct dentry *dparent, struct svc_export **exp, struct dentry **dentryp)
126 struct svc_export *exp2;
127 struct path path = {.mnt = mntget((*exp)->ex_path.mnt),
128 .dentry = dget(dparent)};
130 follow_to_parent(&path);
132 exp2 = rqst_exp_parent(rqstp, &path);
133 if (PTR_ERR(exp2) == -ENOENT) {
134 *dentryp = dget(dparent);
135 } else if (IS_ERR(exp2)) {
137 return PTR_ERR(exp2);
139 *dentryp = dget(path.dentry);
148 * For nfsd purposes, we treat V4ROOT exports as though there was an
149 * export at *every* directory.
151 * '1' if this dentry *must* be an export point,
152 * '2' if it might be, if there is really a mount here, and
153 * '0' if there is no chance of an export point here.
155 int nfsd_mountpoint(struct dentry *dentry, struct svc_export *exp)
157 if (!d_inode(dentry))
159 if (exp->ex_flags & NFSEXP_V4ROOT)
161 if (nfsd4_is_junction(dentry))
163 if (d_mountpoint(dentry))
165 * Might only be a mountpoint in a different namespace,
166 * but we need to check.
173 nfsd_lookup_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp,
174 const char *name, unsigned int len,
175 struct svc_export **exp_ret, struct dentry **dentry_ret)
177 struct svc_export *exp;
178 struct dentry *dparent;
179 struct dentry *dentry;
182 dprintk("nfsd: nfsd_lookup(fh %s, %.*s)\n", SVCFH_fmt(fhp), len,name);
184 dparent = fhp->fh_dentry;
185 exp = exp_get(fhp->fh_export);
187 /* Lookup the name, but don't follow links */
188 if (isdotent(name, len)) {
190 dentry = dget(dparent);
191 else if (dparent != exp->ex_path.dentry)
192 dentry = dget_parent(dparent);
193 else if (!EX_NOHIDE(exp) && !nfsd_v4client(rqstp))
194 dentry = dget(dparent); /* .. == . just like at / */
196 /* checking mountpoint crossing is very different when stepping up */
197 host_err = nfsd_lookup_parent(rqstp, dparent, &exp, &dentry);
203 * In the nfsd4_open() case, this may be held across
204 * subsequent open and delegation acquisition which may
205 * need to take the child's i_mutex:
207 fh_lock_nested(fhp, I_MUTEX_PARENT);
208 dentry = lookup_one_len(name, dparent, len);
209 host_err = PTR_ERR(dentry);
212 if (nfsd_mountpoint(dentry, exp)) {
214 * We don't need the i_mutex after all. It's
215 * still possible we could open this (regular
216 * files can be mountpoints too), but the
217 * i_mutex is just there to prevent renames of
218 * something that we might be about to delegate,
219 * and a mountpoint won't be renamed:
222 if ((host_err = nfsd_cross_mnt(rqstp, &dentry, &exp))) {
228 *dentry_ret = dentry;
234 return nfserrno(host_err);
238 * Look up one component of a pathname.
239 * N.B. After this call _both_ fhp and resfh need an fh_put
241 * If the lookup would cross a mountpoint, and the mounted filesystem
242 * is exported to the client with NFSEXP_NOHIDE, then the lookup is
243 * accepted as it stands and the mounted directory is
244 * returned. Otherwise the covered directory is returned.
245 * NOTE: this mountpoint crossing is not supported properly by all
246 * clients and is explicitly disallowed for NFSv3
247 * NeilBrown <neilb@cse.unsw.edu.au>
250 nfsd_lookup(struct svc_rqst *rqstp, struct svc_fh *fhp, const char *name,
251 unsigned int len, struct svc_fh *resfh)
253 struct svc_export *exp;
254 struct dentry *dentry;
257 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC);
260 err = nfsd_lookup_dentry(rqstp, fhp, name, len, &exp, &dentry);
263 err = check_nfsd_access(exp, rqstp);
267 * Note: we compose the file handle now, but as the
268 * dentry may be negative, it may need to be updated.
270 err = fh_compose(resfh, exp, dentry, fhp);
271 if (!err && d_really_is_negative(dentry))
280 * Commit metadata changes to stable storage.
283 commit_inode_metadata(struct inode *inode)
285 const struct export_operations *export_ops = inode->i_sb->s_export_op;
287 if (export_ops->commit_metadata)
288 return export_ops->commit_metadata(inode);
289 return sync_inode_metadata(inode, 1);
293 commit_metadata(struct svc_fh *fhp)
295 struct inode *inode = d_inode(fhp->fh_dentry);
297 if (!EX_ISSYNC(fhp->fh_export))
299 return commit_inode_metadata(inode);
303 * Go over the attributes and take care of the small differences between
304 * NFS semantics and what Linux expects.
307 nfsd_sanitize_attrs(struct inode *inode, struct iattr *iap)
309 /* sanitize the mode change */
310 if (iap->ia_valid & ATTR_MODE) {
311 iap->ia_mode &= S_IALLUGO;
312 iap->ia_mode |= (inode->i_mode & ~S_IALLUGO);
315 /* Revoke setuid/setgid on chown */
316 if (!S_ISDIR(inode->i_mode) &&
317 ((iap->ia_valid & ATTR_UID) || (iap->ia_valid & ATTR_GID))) {
318 iap->ia_valid |= ATTR_KILL_PRIV;
319 if (iap->ia_valid & ATTR_MODE) {
320 /* we're setting mode too, just clear the s*id bits */
321 iap->ia_mode &= ~S_ISUID;
322 if (iap->ia_mode & S_IXGRP)
323 iap->ia_mode &= ~S_ISGID;
325 /* set ATTR_KILL_* bits and let VFS handle it */
326 iap->ia_valid |= (ATTR_KILL_SUID | ATTR_KILL_SGID);
332 nfsd_get_write_access(struct svc_rqst *rqstp, struct svc_fh *fhp,
335 struct inode *inode = d_inode(fhp->fh_dentry);
338 if (iap->ia_size < inode->i_size) {
341 err = nfsd_permission(rqstp, fhp->fh_export, fhp->fh_dentry,
342 NFSD_MAY_TRUNC | NFSD_MAY_OWNER_OVERRIDE);
347 host_err = get_write_access(inode);
351 host_err = locks_verify_truncate(inode, NULL, iap->ia_size);
353 goto out_put_write_access;
356 out_put_write_access:
357 put_write_access(inode);
359 return nfserrno(host_err);
363 * Set various file attributes. After this call fhp needs an fh_put.
366 nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
367 int check_guard, time_t guardtime)
369 struct dentry *dentry;
371 int accmode = NFSD_MAY_SATTR;
375 bool get_write_count;
376 bool size_change = (iap->ia_valid & ATTR_SIZE);
378 if (iap->ia_valid & ATTR_SIZE) {
379 accmode |= NFSD_MAY_WRITE|NFSD_MAY_OWNER_OVERRIDE;
384 * If utimes(2) and friends are called with times not NULL, we should
385 * not set NFSD_MAY_WRITE bit. Otherwise fh_verify->nfsd_permission
386 * will return EACCES, when the caller's effective UID does not match
387 * the owner of the file, and the caller is not privileged. In this
388 * situation, we should return EPERM(notify_change will return this).
390 if (iap->ia_valid & (ATTR_ATIME | ATTR_MTIME)) {
391 accmode |= NFSD_MAY_OWNER_OVERRIDE;
392 if (!(iap->ia_valid & (ATTR_ATIME_SET | ATTR_MTIME_SET)))
393 accmode |= NFSD_MAY_WRITE;
396 /* Callers that do fh_verify should do the fh_want_write: */
397 get_write_count = !fhp->fh_dentry;
400 err = fh_verify(rqstp, fhp, ftype, accmode);
403 if (get_write_count) {
404 host_err = fh_want_write(fhp);
409 dentry = fhp->fh_dentry;
410 inode = d_inode(dentry);
412 /* Ignore any mode updates on symlinks */
413 if (S_ISLNK(inode->i_mode))
414 iap->ia_valid &= ~ATTR_MODE;
419 nfsd_sanitize_attrs(inode, iap);
421 if (check_guard && guardtime != inode->i_ctime.tv_sec)
422 return nfserr_notsync;
425 * The size case is special, it changes the file in addition to the
426 * attributes, and file systems don't expect it to be mixed with
427 * "random" attribute changes. We thus split out the size change
428 * into a separate call to ->setattr, and do the rest as a separate
432 err = nfsd_get_write_access(rqstp, fhp, iap);
440 * RFC5661, Section 18.30.4:
441 * Changing the size of a file with SETATTR indirectly
442 * changes the time_modify and change attributes.
444 * (and similar for the older RFCs)
446 struct iattr size_attr = {
447 .ia_valid = ATTR_SIZE | ATTR_CTIME | ATTR_MTIME,
448 .ia_size = iap->ia_size,
451 host_err = notify_change(dentry, &size_attr, NULL);
454 iap->ia_valid &= ~ATTR_SIZE;
457 * Avoid the additional setattr call below if the only other
458 * attribute that the client sends is the mtime, as we update
459 * it as part of the size change above.
461 if ((iap->ia_valid & ~ATTR_MTIME) == 0)
465 iap->ia_valid |= ATTR_CTIME;
466 host_err = notify_change(dentry, iap, NULL);
471 put_write_access(inode);
474 host_err = commit_metadata(fhp);
475 return nfserrno(host_err);
478 #if defined(CONFIG_NFSD_V4)
480 * NFS junction information is stored in an extended attribute.
482 #define NFSD_JUNCTION_XATTR_NAME XATTR_TRUSTED_PREFIX "junction.nfs"
485 * nfsd4_is_junction - Test if an object could be an NFS junction
487 * @dentry: object to test
489 * Returns 1 if "dentry" appears to contain NFS junction information.
490 * Otherwise 0 is returned.
492 int nfsd4_is_junction(struct dentry *dentry)
494 struct inode *inode = d_inode(dentry);
498 if (inode->i_mode & S_IXUGO)
500 if (!(inode->i_mode & S_ISVTX))
502 if (vfs_getxattr(dentry, NFSD_JUNCTION_XATTR_NAME, NULL, 0) <= 0)
506 #ifdef CONFIG_NFSD_V4_SECURITY_LABEL
507 __be32 nfsd4_set_nfs4_label(struct svc_rqst *rqstp, struct svc_fh *fhp,
508 struct xdr_netobj *label)
512 struct dentry *dentry;
514 error = fh_verify(rqstp, fhp, 0 /* S_IFREG */, NFSD_MAY_SATTR);
518 dentry = fhp->fh_dentry;
520 inode_lock(d_inode(dentry));
521 host_error = security_inode_setsecctx(dentry, label->data, label->len);
522 inode_unlock(d_inode(dentry));
523 return nfserrno(host_error);
526 __be32 nfsd4_set_nfs4_label(struct svc_rqst *rqstp, struct svc_fh *fhp,
527 struct xdr_netobj *label)
529 return nfserr_notsupp;
533 __be32 nfsd4_clone_file_range(struct file *src, u64 src_pos, struct file *dst,
534 u64 dst_pos, u64 count, bool sync)
538 cloned = vfs_clone_file_range(src, src_pos, dst, dst_pos, count, 0);
540 return nfserrno(cloned);
541 if (count && cloned != count)
542 return nfserrno(-EINVAL);
544 loff_t dst_end = count ? dst_pos + count - 1 : LLONG_MAX;
545 int status = vfs_fsync_range(dst, dst_pos, dst_end, 0);
548 status = commit_inode_metadata(file_inode(src));
550 return nfserrno(status);
555 ssize_t nfsd_copy_file_range(struct file *src, u64 src_pos, struct file *dst,
556 u64 dst_pos, u64 count)
560 * Limit copy to 4MB to prevent indefinitely blocking an nfsd
561 * thread and client rpc slot. The choice of 4MB is somewhat
562 * arbitrary. We might instead base this on r/wsize, or make it
563 * tunable, or use a time instead of a byte limit, or implement
564 * asynchronous copy. In theory a client could also recognize a
565 * limit like this and pipeline multiple COPY requests.
567 count = min_t(u64, count, 1 << 22);
568 return vfs_copy_file_range(src, src_pos, dst, dst_pos, count, 0);
571 __be32 nfsd4_vfs_fallocate(struct svc_rqst *rqstp, struct svc_fh *fhp,
572 struct file *file, loff_t offset, loff_t len,
577 if (!S_ISREG(file_inode(file)->i_mode))
580 error = vfs_fallocate(file, flags, offset, len);
582 error = commit_metadata(fhp);
584 return nfserrno(error);
586 #endif /* defined(CONFIG_NFSD_V4) */
588 #ifdef CONFIG_NFSD_V3
590 * Check server access rights to a file system object
596 static struct accessmap nfs3_regaccess[] = {
597 { NFS3_ACCESS_READ, NFSD_MAY_READ },
598 { NFS3_ACCESS_EXECUTE, NFSD_MAY_EXEC },
599 { NFS3_ACCESS_MODIFY, NFSD_MAY_WRITE|NFSD_MAY_TRUNC },
600 { NFS3_ACCESS_EXTEND, NFSD_MAY_WRITE },
605 static struct accessmap nfs3_diraccess[] = {
606 { NFS3_ACCESS_READ, NFSD_MAY_READ },
607 { NFS3_ACCESS_LOOKUP, NFSD_MAY_EXEC },
608 { NFS3_ACCESS_MODIFY, NFSD_MAY_EXEC|NFSD_MAY_WRITE|NFSD_MAY_TRUNC},
609 { NFS3_ACCESS_EXTEND, NFSD_MAY_EXEC|NFSD_MAY_WRITE },
610 { NFS3_ACCESS_DELETE, NFSD_MAY_REMOVE },
615 static struct accessmap nfs3_anyaccess[] = {
616 /* Some clients - Solaris 2.6 at least, make an access call
617 * to the server to check for access for things like /dev/null
618 * (which really, the server doesn't care about). So
619 * We provide simple access checking for them, looking
620 * mainly at mode bits, and we make sure to ignore read-only
623 { NFS3_ACCESS_READ, NFSD_MAY_READ },
624 { NFS3_ACCESS_EXECUTE, NFSD_MAY_EXEC },
625 { NFS3_ACCESS_MODIFY, NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS },
626 { NFS3_ACCESS_EXTEND, NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS },
632 nfsd_access(struct svc_rqst *rqstp, struct svc_fh *fhp, u32 *access, u32 *supported)
634 struct accessmap *map;
635 struct svc_export *export;
636 struct dentry *dentry;
637 u32 query, result = 0, sresult = 0;
640 error = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP);
644 export = fhp->fh_export;
645 dentry = fhp->fh_dentry;
647 if (d_is_reg(dentry))
648 map = nfs3_regaccess;
649 else if (d_is_dir(dentry))
650 map = nfs3_diraccess;
652 map = nfs3_anyaccess;
656 for (; map->access; map++) {
657 if (map->access & query) {
660 sresult |= map->access;
662 err2 = nfsd_permission(rqstp, export, dentry, map->how);
665 result |= map->access;
668 /* the following error codes just mean the access was not allowed,
669 * rather than an error occurred */
673 /* simply don't "or" in the access bit. */
683 *supported = sresult;
688 #endif /* CONFIG_NFSD_V3 */
690 int nfsd_open_break_lease(struct inode *inode, int access)
694 if (access & NFSD_MAY_NOT_BREAK_LEASE)
696 mode = (access & NFSD_MAY_WRITE) ? O_WRONLY : O_RDONLY;
697 return break_lease(inode, mode | O_NONBLOCK);
701 * Open an existing file or directory.
702 * The may_flags argument indicates the type of open (read/write/lock)
703 * and additional flags.
704 * N.B. After this call fhp needs an fh_put
707 __nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type,
708 int may_flags, struct file **filp)
713 int flags = O_RDONLY|O_LARGEFILE;
717 path.mnt = fhp->fh_export->ex_path.mnt;
718 path.dentry = fhp->fh_dentry;
719 inode = d_inode(path.dentry);
721 /* Disallow write access to files with the append-only bit set
722 * or any access when mandatory locking enabled
725 if (IS_APPEND(inode) && (may_flags & NFSD_MAY_WRITE))
728 * We must ignore files (but only files) which might have mandatory
729 * locks on them because there is no way to know if the accesser has
732 if (S_ISREG((inode)->i_mode) && mandatory_lock(inode))
738 host_err = nfsd_open_break_lease(inode, may_flags);
739 if (host_err) /* NOMEM or WOULDBLOCK */
742 if (may_flags & NFSD_MAY_WRITE) {
743 if (may_flags & NFSD_MAY_READ)
744 flags = O_RDWR|O_LARGEFILE;
746 flags = O_WRONLY|O_LARGEFILE;
749 file = dentry_open(&path, flags, current_cred());
751 host_err = PTR_ERR(file);
755 host_err = ima_file_check(file, may_flags);
761 if (may_flags & NFSD_MAY_64BIT_COOKIE)
762 file->f_mode |= FMODE_64BITHASH;
764 file->f_mode |= FMODE_32BITHASH;
768 err = nfserrno(host_err);
774 nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type,
775 int may_flags, struct file **filp)
779 validate_process_creds();
781 * If we get here, then the client has already done an "open",
782 * and (hopefully) checked permission - so allow OWNER_OVERRIDE
783 * in case a chmod has now revoked permission.
785 * Arguably we should also allow the owner override for
786 * directories, but we never have and it doesn't seem to have
787 * caused anyone a problem. If we were to change this, note
788 * also that our filldir callbacks would need a variant of
789 * lookup_one_len that doesn't check permissions.
792 may_flags |= NFSD_MAY_OWNER_OVERRIDE;
793 err = fh_verify(rqstp, fhp, type, may_flags);
795 err = __nfsd_open(rqstp, fhp, type, may_flags, filp);
796 validate_process_creds();
801 nfsd_open_verified(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type,
802 int may_flags, struct file **filp)
806 validate_process_creds();
807 err = __nfsd_open(rqstp, fhp, type, may_flags, filp);
808 validate_process_creds();
813 * Grab and keep cached pages associated with a file in the svc_rqst
814 * so that they can be passed to the network sendmsg/sendpage routines
815 * directly. They will be released after the sending has completed.
818 nfsd_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
819 struct splice_desc *sd)
821 struct svc_rqst *rqstp = sd->u.data;
822 struct page **pp = rqstp->rq_next_page;
823 struct page *page = buf->page;
828 if (rqstp->rq_res.page_len == 0) {
830 put_page(*rqstp->rq_next_page);
831 *(rqstp->rq_next_page++) = page;
832 rqstp->rq_res.page_base = buf->offset;
833 rqstp->rq_res.page_len = size;
834 } else if (page != pp[-1]) {
836 if (*rqstp->rq_next_page)
837 put_page(*rqstp->rq_next_page);
838 *(rqstp->rq_next_page++) = page;
839 rqstp->rq_res.page_len += size;
841 rqstp->rq_res.page_len += size;
846 static int nfsd_direct_splice_actor(struct pipe_inode_info *pipe,
847 struct splice_desc *sd)
849 return __splice_from_pipe(pipe, sd, nfsd_splice_actor);
852 static u32 nfsd_eof_on_read(struct file *file, loff_t offset, ssize_t len,
855 if (expected != 0 && len == 0)
857 if (offset+len >= i_size_read(file_inode(file)))
862 static __be32 nfsd_finish_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
863 struct file *file, loff_t offset,
864 unsigned long *count, u32 *eof, ssize_t host_err)
867 nfsdstats.io_read += host_err;
868 *eof = nfsd_eof_on_read(file, offset, host_err, *count);
870 fsnotify_access(file);
871 trace_nfsd_read_io_done(rqstp, fhp, offset, *count);
874 trace_nfsd_read_err(rqstp, fhp, offset, host_err);
875 return nfserrno(host_err);
879 __be32 nfsd_splice_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
880 struct file *file, loff_t offset, unsigned long *count,
883 struct splice_desc sd = {
891 trace_nfsd_read_splice(rqstp, fhp, offset, *count);
892 rqstp->rq_next_page = rqstp->rq_respages + 1;
893 host_err = splice_direct_to_actor(file, &sd, nfsd_direct_splice_actor);
894 return nfsd_finish_read(rqstp, fhp, file, offset, count, eof, host_err);
897 __be32 nfsd_readv(struct svc_rqst *rqstp, struct svc_fh *fhp,
898 struct file *file, loff_t offset,
899 struct kvec *vec, int vlen, unsigned long *count,
902 struct iov_iter iter;
903 loff_t ppos = offset;
906 trace_nfsd_read_vector(rqstp, fhp, offset, *count);
907 iov_iter_kvec(&iter, READ, vec, vlen, *count);
908 host_err = vfs_iter_read(file, &iter, &ppos, 0);
909 return nfsd_finish_read(rqstp, fhp, file, offset, count, eof, host_err);
913 * Gathered writes: If another process is currently writing to the file,
914 * there's a high chance this is another nfsd (triggered by a bulk write
915 * from a client's biod). Rather than syncing the file with each write
916 * request, we sleep for 10 msec.
918 * I don't know if this roughly approximates C. Juszak's idea of
919 * gathered writes, but it's a nice and simple solution (IMHO), and it
922 * Note: we do this only in the NFSv2 case, since v3 and higher have a
923 * better tool (separate unstable writes and commits) for solving this
926 static int wait_for_concurrent_writes(struct file *file)
928 struct inode *inode = file_inode(file);
929 static ino_t last_ino;
930 static dev_t last_dev;
933 if (atomic_read(&inode->i_writecount) > 1
934 || (last_ino == inode->i_ino && last_dev == inode->i_sb->s_dev)) {
935 dprintk("nfsd: write defer %d\n", task_pid_nr(current));
937 dprintk("nfsd: write resume %d\n", task_pid_nr(current));
940 if (inode->i_state & I_DIRTY) {
941 dprintk("nfsd: write sync %d\n", task_pid_nr(current));
942 err = vfs_fsync(file, 0);
944 last_ino = inode->i_ino;
945 last_dev = inode->i_sb->s_dev;
950 nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
951 loff_t offset, struct kvec *vec, int vlen,
952 unsigned long *cnt, int stable)
954 struct svc_export *exp;
955 struct iov_iter iter;
960 unsigned int pflags = current->flags;
963 trace_nfsd_write_opened(rqstp, fhp, offset, *cnt);
965 if (test_bit(RQ_LOCAL, &rqstp->rq_flags))
967 * We want less throttling in balance_dirty_pages()
968 * and shrink_inactive_list() so that nfs to
969 * localhost doesn't cause nfsd to lock up due to all
970 * the client's dirty pages or its congested queue.
972 current->flags |= PF_LESS_THROTTLE;
974 exp = fhp->fh_export;
975 use_wgather = (rqstp->rq_vers == 2) && EX_WGATHER(exp);
978 stable = NFS_UNSTABLE;
980 if (stable && !use_wgather)
983 iov_iter_kvec(&iter, WRITE, vec, vlen, *cnt);
984 host_err = vfs_iter_write(file, &iter, &pos, flags);
988 nfsdstats.io_write += *cnt;
989 fsnotify_modify(file);
991 if (stable && use_wgather) {
992 host_err = wait_for_concurrent_writes(file);
994 nfsd_reset_boot_verifier(net_generic(SVC_NET(rqstp),
1000 trace_nfsd_write_io_done(rqstp, fhp, offset, *cnt);
1003 trace_nfsd_write_err(rqstp, fhp, offset, host_err);
1004 nfserr = nfserrno(host_err);
1006 if (test_bit(RQ_LOCAL, &rqstp->rq_flags))
1007 current_restore_flags(pflags, PF_LESS_THROTTLE);
1012 * Read data from a file. count must contain the requested read count
1013 * on entry. On return, *count contains the number of bytes actually read.
1014 * N.B. After this call fhp needs an fh_put
1016 __be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
1017 loff_t offset, struct kvec *vec, int vlen, unsigned long *count,
1020 struct nfsd_file *nf;
1024 trace_nfsd_read_start(rqstp, fhp, offset, *count);
1025 err = nfsd_file_acquire(rqstp, fhp, NFSD_MAY_READ, &nf);
1030 if (file->f_op->splice_read && test_bit(RQ_SPLICE_OK, &rqstp->rq_flags))
1031 err = nfsd_splice_read(rqstp, fhp, file, offset, count, eof);
1033 err = nfsd_readv(rqstp, fhp, file, offset, vec, vlen, count, eof);
1037 trace_nfsd_read_done(rqstp, fhp, offset, *count);
1043 * Write data to a file.
1044 * The stable flag requests synchronous writes.
1045 * N.B. After this call fhp needs an fh_put
1048 nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t offset,
1049 struct kvec *vec, int vlen, unsigned long *cnt, int stable)
1051 struct nfsd_file *nf;
1054 trace_nfsd_write_start(rqstp, fhp, offset, *cnt);
1056 err = nfsd_file_acquire(rqstp, fhp, NFSD_MAY_WRITE, &nf);
1060 err = nfsd_vfs_write(rqstp, fhp, nf->nf_file, offset, vec,
1064 trace_nfsd_write_done(rqstp, fhp, offset, *cnt);
1068 #ifdef CONFIG_NFSD_V3
1070 * Commit all pending writes to stable storage.
1072 * Note: we only guarantee that data that lies within the range specified
1073 * by the 'offset' and 'count' parameters will be synced.
1075 * Unfortunately we cannot lock the file to make sure we return full WCC
1076 * data to the client, as locking happens lower down in the filesystem.
1079 nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp,
1080 loff_t offset, unsigned long count)
1082 struct nfsd_file *nf;
1083 loff_t end = LLONG_MAX;
1084 __be32 err = nfserr_inval;
1089 end = offset + (loff_t)count - 1;
1094 err = nfsd_file_acquire(rqstp, fhp,
1095 NFSD_MAY_WRITE|NFSD_MAY_NOT_BREAK_LEASE, &nf);
1098 if (EX_ISSYNC(fhp->fh_export)) {
1099 int err2 = vfs_fsync_range(nf->nf_file, offset, end, 0);
1105 err = nfserr_notsupp;
1108 err = nfserrno(err2);
1109 nfsd_reset_boot_verifier(net_generic(nf->nf_net,
1118 #endif /* CONFIG_NFSD_V3 */
1121 nfsd_create_setattr(struct svc_rqst *rqstp, struct svc_fh *resfhp,
1125 * Mode has already been set earlier in create:
1127 iap->ia_valid &= ~ATTR_MODE;
1129 * Setting uid/gid works only for root. Irix appears to
1130 * send along the gid on create when it tries to implement
1131 * setgid directories via NFS:
1133 if (!uid_eq(current_fsuid(), GLOBAL_ROOT_UID))
1134 iap->ia_valid &= ~(ATTR_UID|ATTR_GID);
1136 return nfsd_setattr(rqstp, resfhp, iap, 0, (time_t)0);
1137 /* Callers expect file metadata to be committed here */
1138 return nfserrno(commit_metadata(resfhp));
1141 /* HPUX client sometimes creates a file in mode 000, and sets size to 0.
1142 * setting size to 0 may fail for some specific file systems by the permission
1143 * checking which requires WRITE permission but the mode is 000.
1144 * we ignore the resizing(to 0) on the just new created file, since the size is
1145 * 0 after file created.
1147 * call this only after vfs_create() is called.
1150 nfsd_check_ignore_resizing(struct iattr *iap)
1152 if ((iap->ia_valid & ATTR_SIZE) && (iap->ia_size == 0))
1153 iap->ia_valid &= ~ATTR_SIZE;
1156 /* The parent directory should already be locked: */
1158 nfsd_create_locked(struct svc_rqst *rqstp, struct svc_fh *fhp,
1159 char *fname, int flen, struct iattr *iap,
1160 int type, dev_t rdev, struct svc_fh *resfhp)
1162 struct dentry *dentry, *dchild;
1168 dentry = fhp->fh_dentry;
1169 dirp = d_inode(dentry);
1171 dchild = dget(resfhp->fh_dentry);
1172 if (!fhp->fh_locked) {
1173 WARN_ONCE(1, "nfsd_create: parent %pd2 not locked!\n",
1179 err = nfsd_permission(rqstp, fhp->fh_export, dentry, NFSD_MAY_CREATE);
1183 if (!(iap->ia_valid & ATTR_MODE))
1185 iap->ia_mode = (iap->ia_mode & S_IALLUGO) | type;
1187 if (!IS_POSIXACL(dirp))
1188 iap->ia_mode &= ~current_umask();
1194 host_err = vfs_create(dirp, dchild, iap->ia_mode, true);
1196 nfsd_check_ignore_resizing(iap);
1199 host_err = vfs_mkdir(dirp, dchild, iap->ia_mode);
1200 if (!host_err && unlikely(d_unhashed(dchild))) {
1202 d = lookup_one_len(dchild->d_name.name,
1204 dchild->d_name.len);
1206 host_err = PTR_ERR(d);
1209 if (unlikely(d_is_negative(d))) {
1211 err = nfserr_serverfault;
1214 dput(resfhp->fh_dentry);
1215 resfhp->fh_dentry = dget(d);
1216 err = fh_update(resfhp);
1227 host_err = vfs_mknod(dirp, dchild, iap->ia_mode, rdev);
1230 printk(KERN_WARNING "nfsd: bad file type %o in nfsd_create\n",
1237 err = nfsd_create_setattr(rqstp, resfhp, iap);
1240 * nfsd_create_setattr already committed the child. Transactional
1241 * filesystems had a chance to commit changes for both parent and
1242 * child simultaneously making the following commit_metadata a
1245 err2 = nfserrno(commit_metadata(fhp));
1249 * Update the file handle to get the new inode info.
1252 err = fh_update(resfhp);
1258 err = nfserrno(host_err);
1263 * Create a filesystem object (regular, directory, special).
1264 * Note that the parent directory is left locked.
1266 * N.B. Every call to nfsd_create needs an fh_put for _both_ fhp and resfhp
1269 nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
1270 char *fname, int flen, struct iattr *iap,
1271 int type, dev_t rdev, struct svc_fh *resfhp)
1273 struct dentry *dentry, *dchild = NULL;
1277 if (isdotent(fname, flen))
1278 return nfserr_exist;
1280 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_NOP);
1284 dentry = fhp->fh_dentry;
1286 host_err = fh_want_write(fhp);
1288 return nfserrno(host_err);
1290 fh_lock_nested(fhp, I_MUTEX_PARENT);
1291 dchild = lookup_one_len(fname, dentry, flen);
1292 host_err = PTR_ERR(dchild);
1294 return nfserrno(host_err);
1295 err = fh_compose(resfhp, fhp->fh_export, dchild, fhp);
1297 * We unconditionally drop our ref to dchild as fh_compose will have
1298 * already grabbed its own ref for it.
1303 return nfsd_create_locked(rqstp, fhp, fname, flen, iap, type,
1307 #ifdef CONFIG_NFSD_V3
1310 * NFSv3 and NFSv4 version of nfsd_create
1313 do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
1314 char *fname, int flen, struct iattr *iap,
1315 struct svc_fh *resfhp, int createmode, u32 *verifier,
1316 bool *truncp, bool *created)
1318 struct dentry *dentry, *dchild = NULL;
1322 __u32 v_mtime=0, v_atime=0;
1328 if (isdotent(fname, flen))
1330 if (!(iap->ia_valid & ATTR_MODE))
1332 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC);
1336 dentry = fhp->fh_dentry;
1337 dirp = d_inode(dentry);
1339 host_err = fh_want_write(fhp);
1343 fh_lock_nested(fhp, I_MUTEX_PARENT);
1346 * Compose the response file handle.
1348 dchild = lookup_one_len(fname, dentry, flen);
1349 host_err = PTR_ERR(dchild);
1353 /* If file doesn't exist, check for permissions to create one */
1354 if (d_really_is_negative(dchild)) {
1355 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
1360 err = fh_compose(resfhp, fhp->fh_export, dchild, fhp);
1364 if (nfsd_create_is_exclusive(createmode)) {
1365 /* solaris7 gets confused (bugid 4218508) if these have
1366 * the high bit set, so just clear the high bits. If this is
1367 * ever changed to use different attrs for storing the
1368 * verifier, then do_open_lookup() will also need to be fixed
1371 v_mtime = verifier[0]&0x7fffffff;
1372 v_atime = verifier[1]&0x7fffffff;
1375 if (d_really_is_positive(dchild)) {
1378 switch (createmode) {
1379 case NFS3_CREATE_UNCHECKED:
1380 if (! d_is_reg(dchild))
1383 /* in nfsv4, we need to treat this case a little
1384 * differently. we don't want to truncate the
1385 * file now; this would be wrong if the OPEN
1386 * fails for some other reason. furthermore,
1387 * if the size is nonzero, we should ignore it
1388 * according to spec!
1390 *truncp = (iap->ia_valid & ATTR_SIZE) && !iap->ia_size;
1393 iap->ia_valid &= ATTR_SIZE;
1397 case NFS3_CREATE_EXCLUSIVE:
1398 if ( d_inode(dchild)->i_mtime.tv_sec == v_mtime
1399 && d_inode(dchild)->i_atime.tv_sec == v_atime
1400 && d_inode(dchild)->i_size == 0 ) {
1406 case NFS4_CREATE_EXCLUSIVE4_1:
1407 if ( d_inode(dchild)->i_mtime.tv_sec == v_mtime
1408 && d_inode(dchild)->i_atime.tv_sec == v_atime
1409 && d_inode(dchild)->i_size == 0 ) {
1415 case NFS3_CREATE_GUARDED:
1422 if (!IS_POSIXACL(dirp))
1423 iap->ia_mode &= ~current_umask();
1425 host_err = vfs_create(dirp, dchild, iap->ia_mode, true);
1433 nfsd_check_ignore_resizing(iap);
1435 if (nfsd_create_is_exclusive(createmode)) {
1436 /* Cram the verifier into atime/mtime */
1437 iap->ia_valid = ATTR_MTIME|ATTR_ATIME
1438 | ATTR_MTIME_SET|ATTR_ATIME_SET;
1439 /* XXX someone who knows this better please fix it for nsec */
1440 iap->ia_mtime.tv_sec = v_mtime;
1441 iap->ia_atime.tv_sec = v_atime;
1442 iap->ia_mtime.tv_nsec = 0;
1443 iap->ia_atime.tv_nsec = 0;
1447 err = nfsd_create_setattr(rqstp, resfhp, iap);
1450 * nfsd_create_setattr already committed the child
1451 * (and possibly also the parent).
1454 err = nfserrno(commit_metadata(fhp));
1457 * Update the filehandle to get the new inode info.
1460 err = fh_update(resfhp);
1464 if (dchild && !IS_ERR(dchild))
1470 err = nfserrno(host_err);
1473 #endif /* CONFIG_NFSD_V3 */
1476 * Read a symlink. On entry, *lenp must contain the maximum path length that
1477 * fits into the buffer. On return, it contains the true length.
1478 * N.B. After this call fhp needs an fh_put
1481 nfsd_readlink(struct svc_rqst *rqstp, struct svc_fh *fhp, char *buf, int *lenp)
1486 DEFINE_DELAYED_CALL(done);
1489 err = fh_verify(rqstp, fhp, S_IFLNK, NFSD_MAY_NOP);
1493 path.mnt = fhp->fh_export->ex_path.mnt;
1494 path.dentry = fhp->fh_dentry;
1496 if (unlikely(!d_is_symlink(path.dentry)))
1497 return nfserr_inval;
1501 link = vfs_get_link(path.dentry, &done);
1503 return nfserrno(PTR_ERR(link));
1508 memcpy(buf, link, *lenp);
1509 do_delayed_call(&done);
1514 * Create a symlink and look up its inode
1515 * N.B. After this call _both_ fhp and resfhp need an fh_put
1518 nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp,
1519 char *fname, int flen,
1521 struct svc_fh *resfhp)
1523 struct dentry *dentry, *dnew;
1528 if (!flen || path[0] == '\0')
1531 if (isdotent(fname, flen))
1534 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
1538 host_err = fh_want_write(fhp);
1543 dentry = fhp->fh_dentry;
1544 dnew = lookup_one_len(fname, dentry, flen);
1545 host_err = PTR_ERR(dnew);
1549 host_err = vfs_symlink(d_inode(dentry), dnew, path);
1550 err = nfserrno(host_err);
1552 err = nfserrno(commit_metadata(fhp));
1557 cerr = fh_compose(resfhp, fhp->fh_export, dnew, fhp);
1559 if (err==0) err = cerr;
1564 err = nfserrno(host_err);
1570 * N.B. After this call _both_ ffhp and tfhp need an fh_put
1573 nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp,
1574 char *name, int len, struct svc_fh *tfhp)
1576 struct dentry *ddir, *dnew, *dold;
1581 err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_CREATE);
1584 err = fh_verify(rqstp, tfhp, 0, NFSD_MAY_NOP);
1588 if (d_is_dir(tfhp->fh_dentry))
1594 if (isdotent(name, len))
1597 host_err = fh_want_write(tfhp);
1599 err = nfserrno(host_err);
1603 fh_lock_nested(ffhp, I_MUTEX_PARENT);
1604 ddir = ffhp->fh_dentry;
1605 dirp = d_inode(ddir);
1607 dnew = lookup_one_len(name, ddir, len);
1608 host_err = PTR_ERR(dnew);
1612 dold = tfhp->fh_dentry;
1615 if (d_really_is_negative(dold))
1617 host_err = vfs_link(dold, dirp, dnew, NULL);
1619 err = nfserrno(commit_metadata(ffhp));
1621 err = nfserrno(commit_metadata(tfhp));
1623 if (host_err == -EXDEV && rqstp->rq_vers == 2)
1626 err = nfserrno(host_err);
1632 fh_drop_write(tfhp);
1637 err = nfserrno(host_err);
1642 nfsd_close_cached_files(struct dentry *dentry)
1644 struct inode *inode = d_inode(dentry);
1646 if (inode && S_ISREG(inode->i_mode))
1647 nfsd_file_close_inode_sync(inode);
1651 nfsd_has_cached_files(struct dentry *dentry)
1654 struct inode *inode = d_inode(dentry);
1656 if (inode && S_ISREG(inode->i_mode))
1657 ret = nfsd_file_is_cached(inode);
1663 * N.B. After this call _both_ ffhp and tfhp need an fh_put
1666 nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
1667 struct svc_fh *tfhp, char *tname, int tlen)
1669 struct dentry *fdentry, *tdentry, *odentry, *ndentry, *trap;
1670 struct inode *fdir, *tdir;
1673 bool has_cached = false;
1675 err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_REMOVE);
1678 err = fh_verify(rqstp, tfhp, S_IFDIR, NFSD_MAY_CREATE);
1682 fdentry = ffhp->fh_dentry;
1683 fdir = d_inode(fdentry);
1685 tdentry = tfhp->fh_dentry;
1686 tdir = d_inode(tdentry);
1689 if (!flen || isdotent(fname, flen) || !tlen || isdotent(tname, tlen))
1693 host_err = fh_want_write(ffhp);
1695 err = nfserrno(host_err);
1699 /* cannot use fh_lock as we need deadlock protective ordering
1700 * so do it by hand */
1701 trap = lock_rename(tdentry, fdentry);
1702 ffhp->fh_locked = tfhp->fh_locked = true;
1706 odentry = lookup_one_len(fname, fdentry, flen);
1707 host_err = PTR_ERR(odentry);
1708 if (IS_ERR(odentry))
1712 if (d_really_is_negative(odentry))
1715 if (odentry == trap)
1718 ndentry = lookup_one_len(tname, tdentry, tlen);
1719 host_err = PTR_ERR(ndentry);
1720 if (IS_ERR(ndentry))
1722 host_err = -ENOTEMPTY;
1723 if (ndentry == trap)
1727 if (ffhp->fh_export->ex_path.mnt != tfhp->fh_export->ex_path.mnt)
1729 if (ffhp->fh_export->ex_path.dentry != tfhp->fh_export->ex_path.dentry)
1732 if (nfsd_has_cached_files(ndentry)) {
1736 host_err = vfs_rename(fdir, odentry, tdir, ndentry, NULL, 0);
1738 host_err = commit_metadata(tfhp);
1740 host_err = commit_metadata(ffhp);
1748 err = nfserrno(host_err);
1750 * We cannot rely on fh_unlock on the two filehandles,
1751 * as that would do the wrong thing if the two directories
1752 * were the same, so again we do it by hand.
1755 fill_post_wcc(ffhp);
1756 fill_post_wcc(tfhp);
1758 unlock_rename(tdentry, fdentry);
1759 ffhp->fh_locked = tfhp->fh_locked = false;
1760 fh_drop_write(ffhp);
1763 * If the target dentry has cached open files, then we need to try to
1764 * close them prior to doing the rename. Flushing delayed fput
1765 * shouldn't be done with locks held however, so we delay it until this
1766 * point and then reattempt the whole shebang.
1770 nfsd_close_cached_files(ndentry);
1779 * Unlink a file or directory
1780 * N.B. After this call fhp needs an fh_put
1783 nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
1784 char *fname, int flen)
1786 struct dentry *dentry, *rdentry;
1792 if (!flen || isdotent(fname, flen))
1794 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_REMOVE);
1798 host_err = fh_want_write(fhp);
1802 fh_lock_nested(fhp, I_MUTEX_PARENT);
1803 dentry = fhp->fh_dentry;
1804 dirp = d_inode(dentry);
1806 rdentry = lookup_one_len(fname, dentry, flen);
1807 host_err = PTR_ERR(rdentry);
1808 if (IS_ERR(rdentry))
1809 goto out_drop_write;
1811 if (d_really_is_negative(rdentry)) {
1814 goto out_drop_write;
1818 type = d_inode(rdentry)->i_mode & S_IFMT;
1820 if (type != S_IFDIR) {
1821 nfsd_close_cached_files(rdentry);
1822 host_err = vfs_unlink(dirp, rdentry, NULL);
1824 host_err = vfs_rmdir(dirp, rdentry);
1828 host_err = commit_metadata(fhp);
1834 err = nfserrno(host_err);
1840 * We do this buffering because we must not call back into the file
1841 * system's ->lookup() method from the filldir callback. That may well
1842 * deadlock a number of file systems.
1844 * This is based heavily on the implementation of same in XFS.
1846 struct buffered_dirent {
1850 unsigned int d_type;
1854 struct readdir_data {
1855 struct dir_context ctx;
1861 static int nfsd_buffered_filldir(struct dir_context *ctx, const char *name,
1862 int namlen, loff_t offset, u64 ino,
1863 unsigned int d_type)
1865 struct readdir_data *buf =
1866 container_of(ctx, struct readdir_data, ctx);
1867 struct buffered_dirent *de = (void *)(buf->dirent + buf->used);
1868 unsigned int reclen;
1870 reclen = ALIGN(sizeof(struct buffered_dirent) + namlen, sizeof(u64));
1871 if (buf->used + reclen > PAGE_SIZE) {
1876 de->namlen = namlen;
1877 de->offset = offset;
1879 de->d_type = d_type;
1880 memcpy(de->name, name, namlen);
1881 buf->used += reclen;
1886 static __be32 nfsd_buffered_readdir(struct file *file, nfsd_filldir_t func,
1887 struct readdir_cd *cdp, loff_t *offsetp)
1889 struct buffered_dirent *de;
1893 struct readdir_data buf = {
1894 .ctx.actor = nfsd_buffered_filldir,
1895 .dirent = (void *)__get_free_page(GFP_KERNEL)
1899 return nfserrno(-ENOMEM);
1904 unsigned int reclen;
1906 cdp->err = nfserr_eof; /* will be cleared on successful read */
1910 host_err = iterate_dir(file, &buf.ctx);
1922 de = (struct buffered_dirent *)buf.dirent;
1924 offset = de->offset;
1926 if (func(cdp, de->name, de->namlen, de->offset,
1927 de->ino, de->d_type))
1930 if (cdp->err != nfs_ok)
1933 reclen = ALIGN(sizeof(*de) + de->namlen,
1936 de = (struct buffered_dirent *)((char *)de + reclen);
1938 if (size > 0) /* We bailed out early */
1941 offset = vfs_llseek(file, 0, SEEK_CUR);
1944 free_page((unsigned long)(buf.dirent));
1947 return nfserrno(host_err);
1954 * Read entries from a directory.
1955 * The NFSv3/4 verifier we ignore for now.
1958 nfsd_readdir(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t *offsetp,
1959 struct readdir_cd *cdp, nfsd_filldir_t func)
1963 loff_t offset = *offsetp;
1964 int may_flags = NFSD_MAY_READ;
1966 /* NFSv2 only supports 32 bit cookies */
1967 if (rqstp->rq_vers > 2)
1968 may_flags |= NFSD_MAY_64BIT_COOKIE;
1970 err = nfsd_open(rqstp, fhp, S_IFDIR, may_flags, &file);
1974 offset = vfs_llseek(file, offset, SEEK_SET);
1976 err = nfserrno((int)offset);
1980 err = nfsd_buffered_readdir(file, func, cdp, offsetp);
1982 if (err == nfserr_eof || err == nfserr_toosmall)
1983 err = nfs_ok; /* can still be found in ->err */
1991 * Get file system stats
1992 * N.B. After this call fhp needs an fh_put
1995 nfsd_statfs(struct svc_rqst *rqstp, struct svc_fh *fhp, struct kstatfs *stat, int access)
1999 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP | access);
2001 struct path path = {
2002 .mnt = fhp->fh_export->ex_path.mnt,
2003 .dentry = fhp->fh_dentry,
2005 if (vfs_statfs(&path, stat))
2011 static int exp_rdonly(struct svc_rqst *rqstp, struct svc_export *exp)
2013 return nfsexp_flags(rqstp, exp) & NFSEXP_READONLY;
2017 * Check for a user's access permissions to this inode.
2020 nfsd_permission(struct svc_rqst *rqstp, struct svc_export *exp,
2021 struct dentry *dentry, int acc)
2023 struct inode *inode = d_inode(dentry);
2026 if ((acc & NFSD_MAY_MASK) == NFSD_MAY_NOP)
2029 dprintk("nfsd: permission 0x%x%s%s%s%s%s%s%s mode 0%o%s%s%s\n",
2031 (acc & NFSD_MAY_READ)? " read" : "",
2032 (acc & NFSD_MAY_WRITE)? " write" : "",
2033 (acc & NFSD_MAY_EXEC)? " exec" : "",
2034 (acc & NFSD_MAY_SATTR)? " sattr" : "",
2035 (acc & NFSD_MAY_TRUNC)? " trunc" : "",
2036 (acc & NFSD_MAY_LOCK)? " lock" : "",
2037 (acc & NFSD_MAY_OWNER_OVERRIDE)? " owneroverride" : "",
2039 IS_IMMUTABLE(inode)? " immut" : "",
2040 IS_APPEND(inode)? " append" : "",
2041 __mnt_is_readonly(exp->ex_path.mnt)? " ro" : "");
2042 dprintk(" owner %d/%d user %d/%d\n",
2043 inode->i_uid, inode->i_gid, current_fsuid(), current_fsgid());
2046 /* Normally we reject any write/sattr etc access on a read-only file
2047 * system. But if it is IRIX doing check on write-access for a
2048 * device special file, we ignore rofs.
2050 if (!(acc & NFSD_MAY_LOCAL_ACCESS))
2051 if (acc & (NFSD_MAY_WRITE | NFSD_MAY_SATTR | NFSD_MAY_TRUNC)) {
2052 if (exp_rdonly(rqstp, exp) ||
2053 __mnt_is_readonly(exp->ex_path.mnt))
2055 if (/* (acc & NFSD_MAY_WRITE) && */ IS_IMMUTABLE(inode))
2058 if ((acc & NFSD_MAY_TRUNC) && IS_APPEND(inode))
2061 if (acc & NFSD_MAY_LOCK) {
2062 /* If we cannot rely on authentication in NLM requests,
2063 * just allow locks, otherwise require read permission, or
2066 if (exp->ex_flags & NFSEXP_NOAUTHNLM)
2069 acc = NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE;
2072 * The file owner always gets access permission for accesses that
2073 * would normally be checked at open time. This is to make
2074 * file access work even when the client has done a fchmod(fd, 0).
2076 * However, `cp foo bar' should fail nevertheless when bar is
2077 * readonly. A sensible way to do this might be to reject all
2078 * attempts to truncate a read-only file, because a creat() call
2079 * always implies file truncation.
2080 * ... but this isn't really fair. A process may reasonably call
2081 * ftruncate on an open file descriptor on a file with perm 000.
2082 * We must trust the client to do permission checking - using "ACCESS"
2085 if ((acc & NFSD_MAY_OWNER_OVERRIDE) &&
2086 uid_eq(inode->i_uid, current_fsuid()))
2089 /* This assumes NFSD_MAY_{READ,WRITE,EXEC} == MAY_{READ,WRITE,EXEC} */
2090 err = inode_permission(inode, acc & (MAY_READ|MAY_WRITE|MAY_EXEC));
2092 /* Allow read access to binaries even when mode 111 */
2093 if (err == -EACCES && S_ISREG(inode->i_mode) &&
2094 (acc == (NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE) ||
2095 acc == (NFSD_MAY_READ | NFSD_MAY_READ_IF_EXEC)))
2096 err = inode_permission(inode, MAY_EXEC);
2098 return err? nfserrno(err) : 0;