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/pagemap.h>
30 #include <linux/slab.h>
31 #include <linux/uaccess.h>
32 #include <linux/exportfs.h>
33 #include <linux/writeback.h>
34 #include <linux/security.h>
39 #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);
337 if (iap->ia_size < inode->i_size) {
340 err = nfsd_permission(rqstp, fhp->fh_export, fhp->fh_dentry,
341 NFSD_MAY_TRUNC | NFSD_MAY_OWNER_OVERRIDE);
345 return nfserrno(get_write_access(inode));
349 * Set various file attributes. After this call fhp needs an fh_put.
352 nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
353 int check_guard, time64_t guardtime)
355 struct dentry *dentry;
357 int accmode = NFSD_MAY_SATTR;
361 bool get_write_count;
362 bool size_change = (iap->ia_valid & ATTR_SIZE);
364 if (iap->ia_valid & ATTR_SIZE) {
365 accmode |= NFSD_MAY_WRITE|NFSD_MAY_OWNER_OVERRIDE;
370 * If utimes(2) and friends are called with times not NULL, we should
371 * not set NFSD_MAY_WRITE bit. Otherwise fh_verify->nfsd_permission
372 * will return EACCES, when the caller's effective UID does not match
373 * the owner of the file, and the caller is not privileged. In this
374 * situation, we should return EPERM(notify_change will return this).
376 if (iap->ia_valid & (ATTR_ATIME | ATTR_MTIME)) {
377 accmode |= NFSD_MAY_OWNER_OVERRIDE;
378 if (!(iap->ia_valid & (ATTR_ATIME_SET | ATTR_MTIME_SET)))
379 accmode |= NFSD_MAY_WRITE;
382 /* Callers that do fh_verify should do the fh_want_write: */
383 get_write_count = !fhp->fh_dentry;
386 err = fh_verify(rqstp, fhp, ftype, accmode);
389 if (get_write_count) {
390 host_err = fh_want_write(fhp);
395 dentry = fhp->fh_dentry;
396 inode = d_inode(dentry);
398 /* Ignore any mode updates on symlinks */
399 if (S_ISLNK(inode->i_mode))
400 iap->ia_valid &= ~ATTR_MODE;
405 nfsd_sanitize_attrs(inode, iap);
407 if (check_guard && guardtime != inode->i_ctime.tv_sec)
408 return nfserr_notsync;
411 * The size case is special, it changes the file in addition to the
412 * attributes, and file systems don't expect it to be mixed with
413 * "random" attribute changes. We thus split out the size change
414 * into a separate call to ->setattr, and do the rest as a separate
418 err = nfsd_get_write_access(rqstp, fhp, iap);
426 * RFC5661, Section 18.30.4:
427 * Changing the size of a file with SETATTR indirectly
428 * changes the time_modify and change attributes.
430 * (and similar for the older RFCs)
432 struct iattr size_attr = {
433 .ia_valid = ATTR_SIZE | ATTR_CTIME | ATTR_MTIME,
434 .ia_size = iap->ia_size,
438 if (iap->ia_size < 0)
441 host_err = notify_change(&init_user_ns, dentry, &size_attr, NULL);
444 iap->ia_valid &= ~ATTR_SIZE;
447 * Avoid the additional setattr call below if the only other
448 * attribute that the client sends is the mtime, as we update
449 * it as part of the size change above.
451 if ((iap->ia_valid & ~ATTR_MTIME) == 0)
455 iap->ia_valid |= ATTR_CTIME;
456 host_err = notify_change(&init_user_ns, dentry, iap, NULL);
461 put_write_access(inode);
464 host_err = commit_metadata(fhp);
465 return nfserrno(host_err);
468 #if defined(CONFIG_NFSD_V4)
470 * NFS junction information is stored in an extended attribute.
472 #define NFSD_JUNCTION_XATTR_NAME XATTR_TRUSTED_PREFIX "junction.nfs"
475 * nfsd4_is_junction - Test if an object could be an NFS junction
477 * @dentry: object to test
479 * Returns 1 if "dentry" appears to contain NFS junction information.
480 * Otherwise 0 is returned.
482 int nfsd4_is_junction(struct dentry *dentry)
484 struct inode *inode = d_inode(dentry);
488 if (inode->i_mode & S_IXUGO)
490 if (!(inode->i_mode & S_ISVTX))
492 if (vfs_getxattr(&init_user_ns, dentry, NFSD_JUNCTION_XATTR_NAME,
497 #ifdef CONFIG_NFSD_V4_SECURITY_LABEL
498 __be32 nfsd4_set_nfs4_label(struct svc_rqst *rqstp, struct svc_fh *fhp,
499 struct xdr_netobj *label)
503 struct dentry *dentry;
505 error = fh_verify(rqstp, fhp, 0 /* S_IFREG */, NFSD_MAY_SATTR);
509 dentry = fhp->fh_dentry;
511 inode_lock(d_inode(dentry));
512 host_error = security_inode_setsecctx(dentry, label->data, label->len);
513 inode_unlock(d_inode(dentry));
514 return nfserrno(host_error);
517 __be32 nfsd4_set_nfs4_label(struct svc_rqst *rqstp, struct svc_fh *fhp,
518 struct xdr_netobj *label)
520 return nfserr_notsupp;
524 static struct nfsd4_compound_state *nfsd4_get_cstate(struct svc_rqst *rqstp)
526 return &((struct nfsd4_compoundres *)rqstp->rq_resp)->cstate;
529 __be32 nfsd4_clone_file_range(struct svc_rqst *rqstp,
530 struct nfsd_file *nf_src, u64 src_pos,
531 struct nfsd_file *nf_dst, u64 dst_pos,
532 u64 count, bool sync)
534 struct file *src = nf_src->nf_file;
535 struct file *dst = nf_dst->nf_file;
540 since = READ_ONCE(dst->f_wb_err);
541 cloned = vfs_clone_file_range(src, src_pos, dst, dst_pos, count, 0);
543 ret = nfserrno(cloned);
546 if (count && cloned != count) {
547 ret = nfserrno(-EINVAL);
551 loff_t dst_end = count ? dst_pos + count - 1 : LLONG_MAX;
552 int status = vfs_fsync_range(dst, dst_pos, dst_end, 0);
555 status = filemap_check_wb_err(dst->f_mapping, since);
557 status = commit_inode_metadata(file_inode(src));
559 struct nfsd_net *nn = net_generic(nf_dst->nf_net,
562 trace_nfsd_clone_file_range_err(rqstp,
563 &nfsd4_get_cstate(rqstp)->save_fh,
565 &nfsd4_get_cstate(rqstp)->current_fh,
568 nfsd_reset_write_verifier(nn);
569 trace_nfsd_writeverf_reset(nn, rqstp, status);
570 ret = nfserrno(status);
577 ssize_t nfsd_copy_file_range(struct file *src, u64 src_pos, struct file *dst,
578 u64 dst_pos, u64 count)
582 * Limit copy to 4MB to prevent indefinitely blocking an nfsd
583 * thread and client rpc slot. The choice of 4MB is somewhat
584 * arbitrary. We might instead base this on r/wsize, or make it
585 * tunable, or use a time instead of a byte limit, or implement
586 * asynchronous copy. In theory a client could also recognize a
587 * limit like this and pipeline multiple COPY requests.
589 count = min_t(u64, count, 1 << 22);
590 return vfs_copy_file_range(src, src_pos, dst, dst_pos, count, 0);
593 __be32 nfsd4_vfs_fallocate(struct svc_rqst *rqstp, struct svc_fh *fhp,
594 struct file *file, loff_t offset, loff_t len,
599 if (!S_ISREG(file_inode(file)->i_mode))
602 error = vfs_fallocate(file, flags, offset, len);
604 error = commit_metadata(fhp);
606 return nfserrno(error);
608 #endif /* defined(CONFIG_NFSD_V4) */
611 * Check server access rights to a file system object
617 static struct accessmap nfs3_regaccess[] = {
618 { NFS3_ACCESS_READ, NFSD_MAY_READ },
619 { NFS3_ACCESS_EXECUTE, NFSD_MAY_EXEC },
620 { NFS3_ACCESS_MODIFY, NFSD_MAY_WRITE|NFSD_MAY_TRUNC },
621 { NFS3_ACCESS_EXTEND, NFSD_MAY_WRITE },
623 #ifdef CONFIG_NFSD_V4
624 { NFS4_ACCESS_XAREAD, NFSD_MAY_READ },
625 { NFS4_ACCESS_XAWRITE, NFSD_MAY_WRITE },
626 { NFS4_ACCESS_XALIST, NFSD_MAY_READ },
632 static struct accessmap nfs3_diraccess[] = {
633 { NFS3_ACCESS_READ, NFSD_MAY_READ },
634 { NFS3_ACCESS_LOOKUP, NFSD_MAY_EXEC },
635 { NFS3_ACCESS_MODIFY, NFSD_MAY_EXEC|NFSD_MAY_WRITE|NFSD_MAY_TRUNC},
636 { NFS3_ACCESS_EXTEND, NFSD_MAY_EXEC|NFSD_MAY_WRITE },
637 { NFS3_ACCESS_DELETE, NFSD_MAY_REMOVE },
639 #ifdef CONFIG_NFSD_V4
640 { NFS4_ACCESS_XAREAD, NFSD_MAY_READ },
641 { NFS4_ACCESS_XAWRITE, NFSD_MAY_WRITE },
642 { NFS4_ACCESS_XALIST, NFSD_MAY_READ },
648 static struct accessmap nfs3_anyaccess[] = {
649 /* Some clients - Solaris 2.6 at least, make an access call
650 * to the server to check for access for things like /dev/null
651 * (which really, the server doesn't care about). So
652 * We provide simple access checking for them, looking
653 * mainly at mode bits, and we make sure to ignore read-only
656 { NFS3_ACCESS_READ, NFSD_MAY_READ },
657 { NFS3_ACCESS_EXECUTE, NFSD_MAY_EXEC },
658 { NFS3_ACCESS_MODIFY, NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS },
659 { NFS3_ACCESS_EXTEND, NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS },
665 nfsd_access(struct svc_rqst *rqstp, struct svc_fh *fhp, u32 *access, u32 *supported)
667 struct accessmap *map;
668 struct svc_export *export;
669 struct dentry *dentry;
670 u32 query, result = 0, sresult = 0;
673 error = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP);
677 export = fhp->fh_export;
678 dentry = fhp->fh_dentry;
680 if (d_is_reg(dentry))
681 map = nfs3_regaccess;
682 else if (d_is_dir(dentry))
683 map = nfs3_diraccess;
685 map = nfs3_anyaccess;
689 for (; map->access; map++) {
690 if (map->access & query) {
693 sresult |= map->access;
695 err2 = nfsd_permission(rqstp, export, dentry, map->how);
698 result |= map->access;
701 /* the following error codes just mean the access was not allowed,
702 * rather than an error occurred */
706 /* simply don't "or" in the access bit. */
716 *supported = sresult;
722 int nfsd_open_break_lease(struct inode *inode, int access)
726 if (access & NFSD_MAY_NOT_BREAK_LEASE)
728 mode = (access & NFSD_MAY_WRITE) ? O_WRONLY : O_RDONLY;
729 return break_lease(inode, mode | O_NONBLOCK);
733 * Open an existing file or directory.
734 * The may_flags argument indicates the type of open (read/write/lock)
735 * and additional flags.
736 * N.B. After this call fhp needs an fh_put
739 __nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type,
740 int may_flags, struct file **filp)
745 int flags = O_RDONLY|O_LARGEFILE;
749 path.mnt = fhp->fh_export->ex_path.mnt;
750 path.dentry = fhp->fh_dentry;
751 inode = d_inode(path.dentry);
754 if (IS_APPEND(inode) && (may_flags & NFSD_MAY_WRITE))
760 host_err = nfsd_open_break_lease(inode, may_flags);
761 if (host_err) /* NOMEM or WOULDBLOCK */
764 if (may_flags & NFSD_MAY_WRITE) {
765 if (may_flags & NFSD_MAY_READ)
766 flags = O_RDWR|O_LARGEFILE;
768 flags = O_WRONLY|O_LARGEFILE;
771 file = dentry_open(&path, flags, current_cred());
773 host_err = PTR_ERR(file);
777 host_err = ima_file_check(file, may_flags);
783 if (may_flags & NFSD_MAY_64BIT_COOKIE)
784 file->f_mode |= FMODE_64BITHASH;
786 file->f_mode |= FMODE_32BITHASH;
790 err = nfserrno(host_err);
796 nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type,
797 int may_flags, struct file **filp)
800 bool retried = false;
802 validate_process_creds();
804 * If we get here, then the client has already done an "open",
805 * and (hopefully) checked permission - so allow OWNER_OVERRIDE
806 * in case a chmod has now revoked permission.
808 * Arguably we should also allow the owner override for
809 * directories, but we never have and it doesn't seem to have
810 * caused anyone a problem. If we were to change this, note
811 * also that our filldir callbacks would need a variant of
812 * lookup_one_len that doesn't check permissions.
815 may_flags |= NFSD_MAY_OWNER_OVERRIDE;
817 err = fh_verify(rqstp, fhp, type, may_flags);
819 err = __nfsd_open(rqstp, fhp, type, may_flags, filp);
820 if (err == nfserr_stale && !retried) {
826 validate_process_creds();
831 * nfsd_open_verified - Open a regular file for the filecache
832 * @rqstp: RPC request
833 * @fhp: NFS filehandle of the file to open
834 * @may_flags: internal permission flags
835 * @filp: OUT: open "struct file *"
837 * Returns an nfsstat value in network byte order.
840 nfsd_open_verified(struct svc_rqst *rqstp, struct svc_fh *fhp, int may_flags,
845 validate_process_creds();
846 err = __nfsd_open(rqstp, fhp, S_IFREG, may_flags, filp);
847 validate_process_creds();
852 * Grab and keep cached pages associated with a file in the svc_rqst
853 * so that they can be passed to the network sendmsg/sendpage routines
854 * directly. They will be released after the sending has completed.
857 nfsd_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
858 struct splice_desc *sd)
860 struct svc_rqst *rqstp = sd->u.data;
862 svc_rqst_replace_page(rqstp, buf->page);
863 if (rqstp->rq_res.page_len == 0)
864 rqstp->rq_res.page_base = buf->offset;
865 rqstp->rq_res.page_len += sd->len;
869 static int nfsd_direct_splice_actor(struct pipe_inode_info *pipe,
870 struct splice_desc *sd)
872 return __splice_from_pipe(pipe, sd, nfsd_splice_actor);
875 static u32 nfsd_eof_on_read(struct file *file, loff_t offset, ssize_t len,
878 if (expected != 0 && len == 0)
880 if (offset+len >= i_size_read(file_inode(file)))
885 static __be32 nfsd_finish_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
886 struct file *file, loff_t offset,
887 unsigned long *count, u32 *eof, ssize_t host_err)
890 nfsd_stats_io_read_add(fhp->fh_export, host_err);
891 *eof = nfsd_eof_on_read(file, offset, host_err, *count);
893 fsnotify_access(file);
894 trace_nfsd_read_io_done(rqstp, fhp, offset, *count);
897 trace_nfsd_read_err(rqstp, fhp, offset, host_err);
898 return nfserrno(host_err);
902 __be32 nfsd_splice_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
903 struct file *file, loff_t offset, unsigned long *count,
906 struct splice_desc sd = {
914 trace_nfsd_read_splice(rqstp, fhp, offset, *count);
915 rqstp->rq_next_page = rqstp->rq_respages + 1;
916 host_err = splice_direct_to_actor(file, &sd, nfsd_direct_splice_actor);
917 return nfsd_finish_read(rqstp, fhp, file, offset, count, eof, host_err);
920 __be32 nfsd_readv(struct svc_rqst *rqstp, struct svc_fh *fhp,
921 struct file *file, loff_t offset,
922 struct kvec *vec, int vlen, unsigned long *count,
925 struct iov_iter iter;
926 loff_t ppos = offset;
929 trace_nfsd_read_vector(rqstp, fhp, offset, *count);
930 iov_iter_kvec(&iter, READ, vec, vlen, *count);
931 host_err = vfs_iter_read(file, &iter, &ppos, 0);
932 return nfsd_finish_read(rqstp, fhp, file, offset, count, eof, host_err);
936 * Gathered writes: If another process is currently writing to the file,
937 * there's a high chance this is another nfsd (triggered by a bulk write
938 * from a client's biod). Rather than syncing the file with each write
939 * request, we sleep for 10 msec.
941 * I don't know if this roughly approximates C. Juszak's idea of
942 * gathered writes, but it's a nice and simple solution (IMHO), and it
945 * Note: we do this only in the NFSv2 case, since v3 and higher have a
946 * better tool (separate unstable writes and commits) for solving this
949 static int wait_for_concurrent_writes(struct file *file)
951 struct inode *inode = file_inode(file);
952 static ino_t last_ino;
953 static dev_t last_dev;
956 if (atomic_read(&inode->i_writecount) > 1
957 || (last_ino == inode->i_ino && last_dev == inode->i_sb->s_dev)) {
958 dprintk("nfsd: write defer %d\n", task_pid_nr(current));
960 dprintk("nfsd: write resume %d\n", task_pid_nr(current));
963 if (inode->i_state & I_DIRTY) {
964 dprintk("nfsd: write sync %d\n", task_pid_nr(current));
965 err = vfs_fsync(file, 0);
967 last_ino = inode->i_ino;
968 last_dev = inode->i_sb->s_dev;
973 nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf,
974 loff_t offset, struct kvec *vec, int vlen,
975 unsigned long *cnt, int stable,
978 struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
979 struct file *file = nf->nf_file;
980 struct super_block *sb = file_inode(file)->i_sb;
981 struct svc_export *exp;
982 struct iov_iter iter;
988 unsigned long exp_op_flags = 0;
989 unsigned int pflags = current->flags;
991 bool restore_flags = false;
993 trace_nfsd_write_opened(rqstp, fhp, offset, *cnt);
996 exp_op_flags = sb->s_export_op->flags;
998 if (test_bit(RQ_LOCAL, &rqstp->rq_flags) &&
999 !(exp_op_flags & EXPORT_OP_REMOTE_FS)) {
1001 * We want throttling in balance_dirty_pages()
1002 * and shrink_inactive_list() to only consider
1003 * the backingdev we are writing to, so that nfs to
1004 * localhost doesn't cause nfsd to lock up due to all
1005 * the client's dirty pages or its congested queue.
1007 current->flags |= PF_LOCAL_THROTTLE;
1008 restore_flags = true;
1011 exp = fhp->fh_export;
1012 use_wgather = (rqstp->rq_vers == 2) && EX_WGATHER(exp);
1014 if (!EX_ISSYNC(exp))
1015 stable = NFS_UNSTABLE;
1017 if (stable && !use_wgather)
1020 iov_iter_kvec(&iter, WRITE, vec, vlen, *cnt);
1021 since = READ_ONCE(file->f_wb_err);
1023 nfsd_copy_write_verifier(verf, nn);
1024 host_err = vfs_iter_write(file, &iter, &pos, flags);
1026 nfsd_reset_write_verifier(nn);
1027 trace_nfsd_writeverf_reset(nn, rqstp, host_err);
1031 nfsd_stats_io_write_add(exp, *cnt);
1032 fsnotify_modify(file);
1033 host_err = filemap_check_wb_err(file->f_mapping, since);
1037 if (stable && use_wgather) {
1038 host_err = wait_for_concurrent_writes(file);
1040 nfsd_reset_write_verifier(nn);
1041 trace_nfsd_writeverf_reset(nn, rqstp, host_err);
1046 if (host_err >= 0) {
1047 trace_nfsd_write_io_done(rqstp, fhp, offset, *cnt);
1050 trace_nfsd_write_err(rqstp, fhp, offset, host_err);
1051 nfserr = nfserrno(host_err);
1054 current_restore_flags(pflags, PF_LOCAL_THROTTLE);
1059 * Read data from a file. count must contain the requested read count
1060 * on entry. On return, *count contains the number of bytes actually read.
1061 * N.B. After this call fhp needs an fh_put
1063 __be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
1064 loff_t offset, struct kvec *vec, int vlen, unsigned long *count,
1067 struct nfsd_file *nf;
1071 trace_nfsd_read_start(rqstp, fhp, offset, *count);
1072 err = nfsd_file_acquire(rqstp, fhp, NFSD_MAY_READ, &nf);
1077 if (file->f_op->splice_read && test_bit(RQ_SPLICE_OK, &rqstp->rq_flags))
1078 err = nfsd_splice_read(rqstp, fhp, file, offset, count, eof);
1080 err = nfsd_readv(rqstp, fhp, file, offset, vec, vlen, count, eof);
1084 trace_nfsd_read_done(rqstp, fhp, offset, *count);
1090 * Write data to a file.
1091 * The stable flag requests synchronous writes.
1092 * N.B. After this call fhp needs an fh_put
1095 nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t offset,
1096 struct kvec *vec, int vlen, unsigned long *cnt, int stable,
1099 struct nfsd_file *nf;
1102 trace_nfsd_write_start(rqstp, fhp, offset, *cnt);
1104 err = nfsd_file_acquire(rqstp, fhp, NFSD_MAY_WRITE, &nf);
1108 err = nfsd_vfs_write(rqstp, fhp, nf, offset, vec,
1109 vlen, cnt, stable, verf);
1112 trace_nfsd_write_done(rqstp, fhp, offset, *cnt);
1117 * nfsd_commit - Commit pending writes to stable storage
1118 * @rqstp: RPC request being processed
1119 * @fhp: NFS filehandle
1120 * @offset: raw offset from beginning of file
1121 * @count: raw count of bytes to sync
1122 * @verf: filled in with the server's current write verifier
1124 * Note: we guarantee that data that lies within the range specified
1125 * by the 'offset' and 'count' parameters will be synced. The server
1126 * is permitted to sync data that lies outside this range at the
1129 * Unfortunately we cannot lock the file to make sure we return full WCC
1130 * data to the client, as locking happens lower down in the filesystem.
1133 * An nfsstat value in network byte order.
1136 nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp, u64 offset,
1137 u32 count, __be32 *verf)
1141 struct nfsd_net *nn;
1142 struct nfsd_file *nf;
1145 err = nfsd_file_acquire(rqstp, fhp,
1146 NFSD_MAY_WRITE|NFSD_MAY_NOT_BREAK_LEASE, &nf);
1151 * Convert the client-provided (offset, count) range to a
1152 * (start, end) range. If the client-provided range falls
1153 * outside the maximum file size of the underlying FS,
1154 * clamp the sync range appropriately.
1158 maxbytes = (u64)fhp->fh_dentry->d_sb->s_maxbytes;
1159 if (offset < maxbytes) {
1161 if (count && (offset + count - 1 < maxbytes))
1162 end = offset + count - 1;
1165 nn = net_generic(nf->nf_net, nfsd_net_id);
1166 if (EX_ISSYNC(fhp->fh_export)) {
1167 errseq_t since = READ_ONCE(nf->nf_file->f_wb_err);
1170 err2 = vfs_fsync_range(nf->nf_file, start, end, 0);
1173 nfsd_copy_write_verifier(verf, nn);
1174 err2 = filemap_check_wb_err(nf->nf_file->f_mapping,
1176 err = nfserrno(err2);
1179 err = nfserr_notsupp;
1182 nfsd_reset_write_verifier(nn);
1183 trace_nfsd_writeverf_reset(nn, rqstp, err2);
1184 err = nfserrno(err2);
1187 nfsd_copy_write_verifier(verf, nn);
1195 * nfsd_create_setattr - Set a created file's attributes
1196 * @rqstp: RPC transaction being executed
1197 * @fhp: NFS filehandle of parent directory
1198 * @resfhp: NFS filehandle of new object
1199 * @iap: requested attributes of new object
1201 * Returns nfs_ok on success, or an nfsstat in network byte order.
1204 nfsd_create_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp,
1205 struct svc_fh *resfhp, struct iattr *iap)
1210 * Mode has already been set by file creation.
1212 iap->ia_valid &= ~ATTR_MODE;
1215 * Setting uid/gid works only for root. Irix appears to
1216 * send along the gid on create when it tries to implement
1217 * setgid directories via NFS:
1219 if (!uid_eq(current_fsuid(), GLOBAL_ROOT_UID))
1220 iap->ia_valid &= ~(ATTR_UID|ATTR_GID);
1223 * Callers expect new file metadata to be committed even
1224 * if the attributes have not changed.
1227 status = nfsd_setattr(rqstp, resfhp, iap, 0, (time64_t)0);
1229 status = nfserrno(commit_metadata(resfhp));
1232 * Transactional filesystems had a chance to commit changes
1233 * for both parent and child simultaneously making the
1234 * following commit_metadata a noop in many cases.
1237 status = nfserrno(commit_metadata(fhp));
1240 * Update the new filehandle to pick up the new attributes.
1243 status = fh_update(resfhp);
1248 /* HPUX client sometimes creates a file in mode 000, and sets size to 0.
1249 * setting size to 0 may fail for some specific file systems by the permission
1250 * checking which requires WRITE permission but the mode is 000.
1251 * we ignore the resizing(to 0) on the just new created file, since the size is
1252 * 0 after file created.
1254 * call this only after vfs_create() is called.
1257 nfsd_check_ignore_resizing(struct iattr *iap)
1259 if ((iap->ia_valid & ATTR_SIZE) && (iap->ia_size == 0))
1260 iap->ia_valid &= ~ATTR_SIZE;
1263 /* The parent directory should already be locked: */
1265 nfsd_create_locked(struct svc_rqst *rqstp, struct svc_fh *fhp,
1266 char *fname, int flen, struct iattr *iap,
1267 int type, dev_t rdev, struct svc_fh *resfhp)
1269 struct dentry *dentry, *dchild;
1274 dentry = fhp->fh_dentry;
1275 dirp = d_inode(dentry);
1277 dchild = dget(resfhp->fh_dentry);
1278 if (!fhp->fh_locked) {
1279 WARN_ONCE(1, "nfsd_create: parent %pd2 not locked!\n",
1285 err = nfsd_permission(rqstp, fhp->fh_export, dentry, NFSD_MAY_CREATE);
1289 if (!(iap->ia_valid & ATTR_MODE))
1291 iap->ia_mode = (iap->ia_mode & S_IALLUGO) | type;
1293 if (!IS_POSIXACL(dirp))
1294 iap->ia_mode &= ~current_umask();
1300 host_err = vfs_create(&init_user_ns, dirp, dchild, iap->ia_mode, true);
1302 nfsd_check_ignore_resizing(iap);
1305 host_err = vfs_mkdir(&init_user_ns, dirp, dchild, iap->ia_mode);
1306 if (!host_err && unlikely(d_unhashed(dchild))) {
1308 d = lookup_one_len(dchild->d_name.name,
1310 dchild->d_name.len);
1312 host_err = PTR_ERR(d);
1315 if (unlikely(d_is_negative(d))) {
1317 err = nfserr_serverfault;
1320 dput(resfhp->fh_dentry);
1321 resfhp->fh_dentry = dget(d);
1322 err = fh_update(resfhp);
1333 host_err = vfs_mknod(&init_user_ns, dirp, dchild,
1334 iap->ia_mode, rdev);
1337 printk(KERN_WARNING "nfsd: bad file type %o in nfsd_create\n",
1344 err = nfsd_create_setattr(rqstp, fhp, resfhp, iap);
1351 err = nfserrno(host_err);
1356 * Create a filesystem object (regular, directory, special).
1357 * Note that the parent directory is left locked.
1359 * N.B. Every call to nfsd_create needs an fh_put for _both_ fhp and resfhp
1362 nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
1363 char *fname, int flen, struct iattr *iap,
1364 int type, dev_t rdev, struct svc_fh *resfhp)
1366 struct dentry *dentry, *dchild = NULL;
1370 if (isdotent(fname, flen))
1371 return nfserr_exist;
1373 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_NOP);
1377 dentry = fhp->fh_dentry;
1379 host_err = fh_want_write(fhp);
1381 return nfserrno(host_err);
1383 fh_lock_nested(fhp, I_MUTEX_PARENT);
1384 dchild = lookup_one_len(fname, dentry, flen);
1385 host_err = PTR_ERR(dchild);
1387 return nfserrno(host_err);
1388 err = fh_compose(resfhp, fhp->fh_export, dchild, fhp);
1390 * We unconditionally drop our ref to dchild as fh_compose will have
1391 * already grabbed its own ref for it.
1396 return nfsd_create_locked(rqstp, fhp, fname, flen, iap, type,
1401 * Read a symlink. On entry, *lenp must contain the maximum path length that
1402 * fits into the buffer. On return, it contains the true length.
1403 * N.B. After this call fhp needs an fh_put
1406 nfsd_readlink(struct svc_rqst *rqstp, struct svc_fh *fhp, char *buf, int *lenp)
1411 DEFINE_DELAYED_CALL(done);
1414 err = fh_verify(rqstp, fhp, S_IFLNK, NFSD_MAY_NOP);
1418 path.mnt = fhp->fh_export->ex_path.mnt;
1419 path.dentry = fhp->fh_dentry;
1421 if (unlikely(!d_is_symlink(path.dentry)))
1422 return nfserr_inval;
1426 link = vfs_get_link(path.dentry, &done);
1428 return nfserrno(PTR_ERR(link));
1433 memcpy(buf, link, *lenp);
1434 do_delayed_call(&done);
1439 * Create a symlink and look up its inode
1440 * N.B. After this call _both_ fhp and resfhp need an fh_put
1443 nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp,
1444 char *fname, int flen,
1446 struct svc_fh *resfhp)
1448 struct dentry *dentry, *dnew;
1453 if (!flen || path[0] == '\0')
1456 if (isdotent(fname, flen))
1459 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
1463 host_err = fh_want_write(fhp);
1468 dentry = fhp->fh_dentry;
1469 dnew = lookup_one_len(fname, dentry, flen);
1470 host_err = PTR_ERR(dnew);
1474 host_err = vfs_symlink(&init_user_ns, d_inode(dentry), dnew, path);
1475 err = nfserrno(host_err);
1478 err = nfserrno(commit_metadata(fhp));
1482 cerr = fh_compose(resfhp, fhp->fh_export, dnew, fhp);
1484 if (err==0) err = cerr;
1489 err = nfserrno(host_err);
1495 * N.B. After this call _both_ ffhp and tfhp need an fh_put
1498 nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp,
1499 char *name, int len, struct svc_fh *tfhp)
1501 struct dentry *ddir, *dnew, *dold;
1506 err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_CREATE);
1509 err = fh_verify(rqstp, tfhp, 0, NFSD_MAY_NOP);
1513 if (d_is_dir(tfhp->fh_dentry))
1519 if (isdotent(name, len))
1522 host_err = fh_want_write(tfhp);
1524 err = nfserrno(host_err);
1528 fh_lock_nested(ffhp, I_MUTEX_PARENT);
1529 ddir = ffhp->fh_dentry;
1530 dirp = d_inode(ddir);
1532 dnew = lookup_one_len(name, ddir, len);
1533 host_err = PTR_ERR(dnew);
1537 dold = tfhp->fh_dentry;
1540 if (d_really_is_negative(dold))
1542 host_err = vfs_link(dold, &init_user_ns, dirp, dnew, NULL);
1545 err = nfserrno(commit_metadata(ffhp));
1547 err = nfserrno(commit_metadata(tfhp));
1549 if (host_err == -EXDEV && rqstp->rq_vers == 2)
1552 err = nfserrno(host_err);
1558 fh_drop_write(tfhp);
1563 err = nfserrno(host_err);
1568 nfsd_close_cached_files(struct dentry *dentry)
1570 struct inode *inode = d_inode(dentry);
1572 if (inode && S_ISREG(inode->i_mode))
1573 nfsd_file_close_inode_sync(inode);
1577 nfsd_has_cached_files(struct dentry *dentry)
1580 struct inode *inode = d_inode(dentry);
1582 if (inode && S_ISREG(inode->i_mode))
1583 ret = nfsd_file_is_cached(inode);
1589 * N.B. After this call _both_ ffhp and tfhp need an fh_put
1592 nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
1593 struct svc_fh *tfhp, char *tname, int tlen)
1595 struct dentry *fdentry, *tdentry, *odentry, *ndentry, *trap;
1596 struct inode *fdir, *tdir;
1599 bool close_cached = false;
1601 err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_REMOVE);
1604 err = fh_verify(rqstp, tfhp, S_IFDIR, NFSD_MAY_CREATE);
1608 fdentry = ffhp->fh_dentry;
1609 fdir = d_inode(fdentry);
1611 tdentry = tfhp->fh_dentry;
1612 tdir = d_inode(tdentry);
1615 if (!flen || isdotent(fname, flen) || !tlen || isdotent(tname, tlen))
1619 host_err = fh_want_write(ffhp);
1621 err = nfserrno(host_err);
1625 /* cannot use fh_lock as we need deadlock protective ordering
1626 * so do it by hand */
1627 trap = lock_rename(tdentry, fdentry);
1628 ffhp->fh_locked = tfhp->fh_locked = true;
1629 fh_fill_pre_attrs(ffhp);
1630 fh_fill_pre_attrs(tfhp);
1632 odentry = lookup_one_len(fname, fdentry, flen);
1633 host_err = PTR_ERR(odentry);
1634 if (IS_ERR(odentry))
1638 if (d_really_is_negative(odentry))
1641 if (odentry == trap)
1644 ndentry = lookup_one_len(tname, tdentry, tlen);
1645 host_err = PTR_ERR(ndentry);
1646 if (IS_ERR(ndentry))
1648 host_err = -ENOTEMPTY;
1649 if (ndentry == trap)
1653 if (ffhp->fh_export->ex_path.mnt != tfhp->fh_export->ex_path.mnt)
1655 if (ffhp->fh_export->ex_path.dentry != tfhp->fh_export->ex_path.dentry)
1658 if ((ndentry->d_sb->s_export_op->flags & EXPORT_OP_CLOSE_BEFORE_UNLINK) &&
1659 nfsd_has_cached_files(ndentry)) {
1660 close_cached = true;
1663 struct renamedata rd = {
1664 .old_mnt_userns = &init_user_ns,
1666 .old_dentry = odentry,
1667 .new_mnt_userns = &init_user_ns,
1669 .new_dentry = ndentry,
1671 host_err = vfs_rename(&rd);
1673 host_err = commit_metadata(tfhp);
1675 host_err = commit_metadata(ffhp);
1683 err = nfserrno(host_err);
1685 * We cannot rely on fh_unlock on the two filehandles,
1686 * as that would do the wrong thing if the two directories
1687 * were the same, so again we do it by hand.
1689 if (!close_cached) {
1690 fh_fill_post_attrs(ffhp);
1691 fh_fill_post_attrs(tfhp);
1693 unlock_rename(tdentry, fdentry);
1694 ffhp->fh_locked = tfhp->fh_locked = false;
1695 fh_drop_write(ffhp);
1698 * If the target dentry has cached open files, then we need to try to
1699 * close them prior to doing the rename. Flushing delayed fput
1700 * shouldn't be done with locks held however, so we delay it until this
1701 * point and then reattempt the whole shebang.
1704 close_cached = false;
1705 nfsd_close_cached_files(ndentry);
1714 * Unlink a file or directory
1715 * N.B. After this call fhp needs an fh_put
1718 nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
1719 char *fname, int flen)
1721 struct dentry *dentry, *rdentry;
1723 struct inode *rinode;
1728 if (!flen || isdotent(fname, flen))
1730 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_REMOVE);
1734 host_err = fh_want_write(fhp);
1738 fh_lock_nested(fhp, I_MUTEX_PARENT);
1739 dentry = fhp->fh_dentry;
1740 dirp = d_inode(dentry);
1742 rdentry = lookup_one_len(fname, dentry, flen);
1743 host_err = PTR_ERR(rdentry);
1744 if (IS_ERR(rdentry))
1745 goto out_drop_write;
1747 if (d_really_is_negative(rdentry)) {
1750 goto out_drop_write;
1752 rinode = d_inode(rdentry);
1756 type = d_inode(rdentry)->i_mode & S_IFMT;
1758 if (type != S_IFDIR) {
1759 if (rdentry->d_sb->s_export_op->flags & EXPORT_OP_CLOSE_BEFORE_UNLINK)
1760 nfsd_close_cached_files(rdentry);
1761 host_err = vfs_unlink(&init_user_ns, dirp, rdentry, NULL);
1763 host_err = vfs_rmdir(&init_user_ns, dirp, rdentry);
1768 host_err = commit_metadata(fhp);
1770 iput(rinode); /* truncate the inode here */
1775 if (host_err == -EBUSY) {
1776 /* name is mounted-on. There is no perfect
1779 if (nfsd_v4client(rqstp))
1780 err = nfserr_file_open;
1784 err = nfserrno(host_err);
1791 * We do this buffering because we must not call back into the file
1792 * system's ->lookup() method from the filldir callback. That may well
1793 * deadlock a number of file systems.
1795 * This is based heavily on the implementation of same in XFS.
1797 struct buffered_dirent {
1801 unsigned int d_type;
1805 struct readdir_data {
1806 struct dir_context ctx;
1812 static int nfsd_buffered_filldir(struct dir_context *ctx, const char *name,
1813 int namlen, loff_t offset, u64 ino,
1814 unsigned int d_type)
1816 struct readdir_data *buf =
1817 container_of(ctx, struct readdir_data, ctx);
1818 struct buffered_dirent *de = (void *)(buf->dirent + buf->used);
1819 unsigned int reclen;
1821 reclen = ALIGN(sizeof(struct buffered_dirent) + namlen, sizeof(u64));
1822 if (buf->used + reclen > PAGE_SIZE) {
1827 de->namlen = namlen;
1828 de->offset = offset;
1830 de->d_type = d_type;
1831 memcpy(de->name, name, namlen);
1832 buf->used += reclen;
1837 static __be32 nfsd_buffered_readdir(struct file *file, struct svc_fh *fhp,
1838 nfsd_filldir_t func, struct readdir_cd *cdp,
1841 struct buffered_dirent *de;
1845 struct readdir_data buf = {
1846 .ctx.actor = nfsd_buffered_filldir,
1847 .dirent = (void *)__get_free_page(GFP_KERNEL)
1851 return nfserrno(-ENOMEM);
1856 unsigned int reclen;
1858 cdp->err = nfserr_eof; /* will be cleared on successful read */
1862 host_err = iterate_dir(file, &buf.ctx);
1874 de = (struct buffered_dirent *)buf.dirent;
1876 offset = de->offset;
1878 if (func(cdp, de->name, de->namlen, de->offset,
1879 de->ino, de->d_type))
1882 if (cdp->err != nfs_ok)
1885 trace_nfsd_dirent(fhp, de->ino, de->name, de->namlen);
1887 reclen = ALIGN(sizeof(*de) + de->namlen,
1890 de = (struct buffered_dirent *)((char *)de + reclen);
1892 if (size > 0) /* We bailed out early */
1895 offset = vfs_llseek(file, 0, SEEK_CUR);
1898 free_page((unsigned long)(buf.dirent));
1901 return nfserrno(host_err);
1908 * Read entries from a directory.
1909 * The NFSv3/4 verifier we ignore for now.
1912 nfsd_readdir(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t *offsetp,
1913 struct readdir_cd *cdp, nfsd_filldir_t func)
1917 loff_t offset = *offsetp;
1918 int may_flags = NFSD_MAY_READ;
1920 /* NFSv2 only supports 32 bit cookies */
1921 if (rqstp->rq_vers > 2)
1922 may_flags |= NFSD_MAY_64BIT_COOKIE;
1924 err = nfsd_open(rqstp, fhp, S_IFDIR, may_flags, &file);
1928 offset = vfs_llseek(file, offset, SEEK_SET);
1930 err = nfserrno((int)offset);
1934 err = nfsd_buffered_readdir(file, fhp, func, cdp, offsetp);
1936 if (err == nfserr_eof || err == nfserr_toosmall)
1937 err = nfs_ok; /* can still be found in ->err */
1945 * Get file system stats
1946 * N.B. After this call fhp needs an fh_put
1949 nfsd_statfs(struct svc_rqst *rqstp, struct svc_fh *fhp, struct kstatfs *stat, int access)
1953 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP | access);
1955 struct path path = {
1956 .mnt = fhp->fh_export->ex_path.mnt,
1957 .dentry = fhp->fh_dentry,
1959 if (vfs_statfs(&path, stat))
1965 static int exp_rdonly(struct svc_rqst *rqstp, struct svc_export *exp)
1967 return nfsexp_flags(rqstp, exp) & NFSEXP_READONLY;
1970 #ifdef CONFIG_NFSD_V4
1972 * Helper function to translate error numbers. In the case of xattr operations,
1973 * some error codes need to be translated outside of the standard translations.
1975 * ENODATA needs to be translated to nfserr_noxattr.
1976 * E2BIG to nfserr_xattr2big.
1978 * Additionally, vfs_listxattr can return -ERANGE. This means that the
1979 * file has too many extended attributes to retrieve inside an
1980 * XATTR_LIST_MAX sized buffer. This is a bug in the xattr implementation:
1981 * filesystems will allow the adding of extended attributes until they hit
1982 * their own internal limit. This limit may be larger than XATTR_LIST_MAX.
1983 * So, at that point, the attributes are present and valid, but can't
1984 * be retrieved using listxattr, since the upper level xattr code enforces
1985 * the XATTR_LIST_MAX limit.
1987 * This bug means that we need to deal with listxattr returning -ERANGE. The
1988 * best mapping is to return TOOSMALL.
1991 nfsd_xattr_errno(int err)
1995 return nfserr_noxattr;
1997 return nfserr_xattr2big;
1999 return nfserr_toosmall;
2001 return nfserrno(err);
2005 * Retrieve the specified user extended attribute. To avoid always
2006 * having to allocate the maximum size (since we are not getting
2007 * a maximum size from the RPC), do a probe + alloc. Hold a reader
2008 * lock on i_rwsem to prevent the extended attribute from changing
2009 * size while we're doing this.
2012 nfsd_getxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name,
2013 void **bufp, int *lenp)
2018 struct inode *inode;
2019 struct dentry *dentry;
2021 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_READ);
2026 dentry = fhp->fh_dentry;
2027 inode = d_inode(dentry);
2029 inode_lock_shared(inode);
2031 len = vfs_getxattr(&init_user_ns, dentry, name, NULL, 0);
2034 * Zero-length attribute, just return.
2043 err = nfsd_xattr_errno(len);
2048 err = nfserr_toosmall;
2052 buf = kvmalloc(len, GFP_KERNEL | GFP_NOFS);
2054 err = nfserr_jukebox;
2058 len = vfs_getxattr(&init_user_ns, dentry, name, buf, len);
2062 err = nfsd_xattr_errno(len);
2069 inode_unlock_shared(inode);
2075 * Retrieve the xattr names. Since we can't know how many are
2076 * user extended attributes, we must get all attributes here,
2077 * and have the XDR encode filter out the "user." ones.
2079 * While this could always just allocate an XATTR_LIST_MAX
2080 * buffer, that's a waste, so do a probe + allocate. To
2081 * avoid any changes between the probe and allocate, wrap
2082 * this in inode_lock.
2085 nfsd_listxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char **bufp,
2091 struct inode *inode;
2092 struct dentry *dentry;
2094 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_READ);
2098 dentry = fhp->fh_dentry;
2099 inode = d_inode(dentry);
2102 inode_lock_shared(inode);
2104 len = vfs_listxattr(dentry, NULL, 0);
2106 err = nfsd_xattr_errno(len);
2110 if (len > XATTR_LIST_MAX) {
2111 err = nfserr_xattr2big;
2116 * We're holding i_rwsem - use GFP_NOFS.
2118 buf = kvmalloc(len, GFP_KERNEL | GFP_NOFS);
2120 err = nfserr_jukebox;
2124 len = vfs_listxattr(dentry, buf, len);
2127 err = nfsd_xattr_errno(len);
2136 inode_unlock_shared(inode);
2142 * Removexattr and setxattr need to call fh_lock to both lock the inode
2143 * and set the change attribute. Since the top-level vfs_removexattr
2144 * and vfs_setxattr calls already do their own inode_lock calls, call
2145 * the _locked variant. Pass in a NULL pointer for delegated_inode,
2146 * and let the client deal with NFS4ERR_DELAY (same as with e.g.
2147 * setattr and remove).
2150 nfsd_removexattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name)
2155 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_WRITE);
2159 ret = fh_want_write(fhp);
2161 return nfserrno(ret);
2165 ret = __vfs_removexattr_locked(&init_user_ns, fhp->fh_dentry,
2171 return nfsd_xattr_errno(ret);
2175 nfsd_setxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name,
2176 void *buf, u32 len, u32 flags)
2181 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_WRITE);
2185 ret = fh_want_write(fhp);
2187 return nfserrno(ret);
2190 ret = __vfs_setxattr_locked(&init_user_ns, fhp->fh_dentry, name, buf,
2196 return nfsd_xattr_errno(ret);
2201 * Check for a user's access permissions to this inode.
2204 nfsd_permission(struct svc_rqst *rqstp, struct svc_export *exp,
2205 struct dentry *dentry, int acc)
2207 struct inode *inode = d_inode(dentry);
2210 if ((acc & NFSD_MAY_MASK) == NFSD_MAY_NOP)
2213 dprintk("nfsd: permission 0x%x%s%s%s%s%s%s%s mode 0%o%s%s%s\n",
2215 (acc & NFSD_MAY_READ)? " read" : "",
2216 (acc & NFSD_MAY_WRITE)? " write" : "",
2217 (acc & NFSD_MAY_EXEC)? " exec" : "",
2218 (acc & NFSD_MAY_SATTR)? " sattr" : "",
2219 (acc & NFSD_MAY_TRUNC)? " trunc" : "",
2220 (acc & NFSD_MAY_LOCK)? " lock" : "",
2221 (acc & NFSD_MAY_OWNER_OVERRIDE)? " owneroverride" : "",
2223 IS_IMMUTABLE(inode)? " immut" : "",
2224 IS_APPEND(inode)? " append" : "",
2225 __mnt_is_readonly(exp->ex_path.mnt)? " ro" : "");
2226 dprintk(" owner %d/%d user %d/%d\n",
2227 inode->i_uid, inode->i_gid, current_fsuid(), current_fsgid());
2230 /* Normally we reject any write/sattr etc access on a read-only file
2231 * system. But if it is IRIX doing check on write-access for a
2232 * device special file, we ignore rofs.
2234 if (!(acc & NFSD_MAY_LOCAL_ACCESS))
2235 if (acc & (NFSD_MAY_WRITE | NFSD_MAY_SATTR | NFSD_MAY_TRUNC)) {
2236 if (exp_rdonly(rqstp, exp) ||
2237 __mnt_is_readonly(exp->ex_path.mnt))
2239 if (/* (acc & NFSD_MAY_WRITE) && */ IS_IMMUTABLE(inode))
2242 if ((acc & NFSD_MAY_TRUNC) && IS_APPEND(inode))
2245 if (acc & NFSD_MAY_LOCK) {
2246 /* If we cannot rely on authentication in NLM requests,
2247 * just allow locks, otherwise require read permission, or
2250 if (exp->ex_flags & NFSEXP_NOAUTHNLM)
2253 acc = NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE;
2256 * The file owner always gets access permission for accesses that
2257 * would normally be checked at open time. This is to make
2258 * file access work even when the client has done a fchmod(fd, 0).
2260 * However, `cp foo bar' should fail nevertheless when bar is
2261 * readonly. A sensible way to do this might be to reject all
2262 * attempts to truncate a read-only file, because a creat() call
2263 * always implies file truncation.
2264 * ... but this isn't really fair. A process may reasonably call
2265 * ftruncate on an open file descriptor on a file with perm 000.
2266 * We must trust the client to do permission checking - using "ACCESS"
2269 if ((acc & NFSD_MAY_OWNER_OVERRIDE) &&
2270 uid_eq(inode->i_uid, current_fsuid()))
2273 /* This assumes NFSD_MAY_{READ,WRITE,EXEC} == MAY_{READ,WRITE,EXEC} */
2274 err = inode_permission(&init_user_ns, inode,
2275 acc & (MAY_READ | MAY_WRITE | MAY_EXEC));
2277 /* Allow read access to binaries even when mode 111 */
2278 if (err == -EACCES && S_ISREG(inode->i_mode) &&
2279 (acc == (NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE) ||
2280 acc == (NFSD_MAY_READ | NFSD_MAY_READ_IF_EXEC)))
2281 err = inode_permission(&init_user_ns, inode, MAY_EXEC);
2283 return err? nfserrno(err) : 0;