// SPDX-License-Identifier: GPL-2.0 /* * File operations used by nfsd. Some of these have been ripped from * other parts of the kernel because they weren't exported, others * are partial duplicates with added or changed functionality. * * Note that several functions dget() the dentry upon which they want * to act, most notably those that create directory entries. Response * dentry's are dput()'d if necessary in the release callback. * So if you notice code paths that apparently fail to dput() the * dentry, don't worry--they have been taken care of. * * Copyright (C) 1995-1999 Olaf Kirch * Zerocpy NFS support (C) 2002 Hirokazu Takahashi */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "xdr3.h" #ifdef CONFIG_NFSD_V4 #include "../internal.h" #include "acl.h" #include "idmap.h" #include "xdr4.h" #endif /* CONFIG_NFSD_V4 */ #include "nfsd.h" #include "vfs.h" #include "filecache.h" #include "trace.h" #define NFSDDBG_FACILITY NFSDDBG_FILEOP /* * Called from nfsd_lookup and encode_dirent. Check if we have crossed * a mount point. * Returns -EAGAIN or -ETIMEDOUT leaving *dpp and *expp unchanged, * or nfs_ok having possibly changed *dpp and *expp */ int nfsd_cross_mnt(struct svc_rqst *rqstp, struct dentry **dpp, struct svc_export **expp) { struct svc_export *exp = *expp, *exp2 = NULL; struct dentry *dentry = *dpp; struct path path = {.mnt = mntget(exp->ex_path.mnt), .dentry = dget(dentry)}; int err = 0; err = follow_down(&path); if (err < 0) goto out; if (path.mnt == exp->ex_path.mnt && path.dentry == dentry && nfsd_mountpoint(dentry, exp) == 2) { /* This is only a mountpoint in some other namespace */ path_put(&path); goto out; } exp2 = rqst_exp_get_by_name(rqstp, &path); if (IS_ERR(exp2)) { err = PTR_ERR(exp2); /* * We normally allow NFS clients to continue * "underneath" a mountpoint that is not exported. * The exception is V4ROOT, where no traversal is ever * allowed without an explicit export of the new * directory. */ if (err == -ENOENT && !(exp->ex_flags & NFSEXP_V4ROOT)) err = 0; path_put(&path); goto out; } if (nfsd_v4client(rqstp) || (exp->ex_flags & NFSEXP_CROSSMOUNT) || EX_NOHIDE(exp2)) { /* successfully crossed mount point */ /* * This is subtle: path.dentry is *not* on path.mnt * at this point. The only reason we are safe is that * original mnt is pinned down by exp, so we should * put path *before* putting exp */ *dpp = path.dentry; path.dentry = dentry; *expp = exp2; exp2 = exp; } path_put(&path); exp_put(exp2); out: return err; } static void follow_to_parent(struct path *path) { struct dentry *dp; while (path->dentry == path->mnt->mnt_root && follow_up(path)) ; dp = dget_parent(path->dentry); dput(path->dentry); path->dentry = dp; } static int nfsd_lookup_parent(struct svc_rqst *rqstp, struct dentry *dparent, struct svc_export **exp, struct dentry **dentryp) { struct svc_export *exp2; struct path path = {.mnt = mntget((*exp)->ex_path.mnt), .dentry = dget(dparent)}; follow_to_parent(&path); exp2 = rqst_exp_parent(rqstp, &path); if (PTR_ERR(exp2) == -ENOENT) { *dentryp = dget(dparent); } else if (IS_ERR(exp2)) { path_put(&path); return PTR_ERR(exp2); } else { *dentryp = dget(path.dentry); exp_put(*exp); *exp = exp2; } path_put(&path); return 0; } /* * For nfsd purposes, we treat V4ROOT exports as though there was an * export at *every* directory. * We return: * '1' if this dentry *must* be an export point, * '2' if it might be, if there is really a mount here, and * '0' if there is no chance of an export point here. */ int nfsd_mountpoint(struct dentry *dentry, struct svc_export *exp) { if (!d_inode(dentry)) return 0; if (exp->ex_flags & NFSEXP_V4ROOT) return 1; if (nfsd4_is_junction(dentry)) return 1; if (d_mountpoint(dentry)) /* * Might only be a mountpoint in a different namespace, * but we need to check. */ return 2; return 0; } __be32 nfsd_lookup_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp, const char *name, unsigned int len, struct svc_export **exp_ret, struct dentry **dentry_ret) { struct svc_export *exp; struct dentry *dparent; struct dentry *dentry; int host_err; dprintk("nfsd: nfsd_lookup(fh %s, %.*s)\n", SVCFH_fmt(fhp), len,name); dparent = fhp->fh_dentry; exp = exp_get(fhp->fh_export); /* Lookup the name, but don't follow links */ if (isdotent(name, len)) { if (len==1) dentry = dget(dparent); else if (dparent != exp->ex_path.dentry) dentry = dget_parent(dparent); else if (!EX_NOHIDE(exp) && !nfsd_v4client(rqstp)) dentry = dget(dparent); /* .. == . just like at / */ else { /* checking mountpoint crossing is very different when stepping up */ host_err = nfsd_lookup_parent(rqstp, dparent, &exp, &dentry); if (host_err) goto out_nfserr; } } else { dentry = lookup_one_len_unlocked(name, dparent, len); host_err = PTR_ERR(dentry); if (IS_ERR(dentry)) goto out_nfserr; if (nfsd_mountpoint(dentry, exp)) { host_err = nfsd_cross_mnt(rqstp, &dentry, &exp); if (host_err) { dput(dentry); goto out_nfserr; } } } *dentry_ret = dentry; *exp_ret = exp; return 0; out_nfserr: exp_put(exp); return nfserrno(host_err); } /** * nfsd_lookup - look up a single path component for nfsd * * @rqstp: the request context * @fhp: the file handle of the directory * @name: the component name, or %NULL to look up parent * @len: length of name to examine * @resfh: pointer to pre-initialised filehandle to hold result. * * Look up one component of a pathname. * N.B. After this call _both_ fhp and resfh need an fh_put * * If the lookup would cross a mountpoint, and the mounted filesystem * is exported to the client with NFSEXP_NOHIDE, then the lookup is * accepted as it stands and the mounted directory is * returned. Otherwise the covered directory is returned. * NOTE: this mountpoint crossing is not supported properly by all * clients and is explicitly disallowed for NFSv3 * */ __be32 nfsd_lookup(struct svc_rqst *rqstp, struct svc_fh *fhp, const char *name, unsigned int len, struct svc_fh *resfh) { struct svc_export *exp; struct dentry *dentry; __be32 err; err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC); if (err) return err; err = nfsd_lookup_dentry(rqstp, fhp, name, len, &exp, &dentry); if (err) return err; err = check_nfsd_access(exp, rqstp); if (err) goto out; /* * Note: we compose the file handle now, but as the * dentry may be negative, it may need to be updated. */ err = fh_compose(resfh, exp, dentry, fhp); if (!err && d_really_is_negative(dentry)) err = nfserr_noent; out: dput(dentry); exp_put(exp); return err; } /* * Commit metadata changes to stable storage. */ static int commit_inode_metadata(struct inode *inode) { const struct export_operations *export_ops = inode->i_sb->s_export_op; if (export_ops->commit_metadata) return export_ops->commit_metadata(inode); return sync_inode_metadata(inode, 1); } static int commit_metadata(struct svc_fh *fhp) { struct inode *inode = d_inode(fhp->fh_dentry); if (!EX_ISSYNC(fhp->fh_export)) return 0; return commit_inode_metadata(inode); } /* * Go over the attributes and take care of the small differences between * NFS semantics and what Linux expects. */ static void nfsd_sanitize_attrs(struct inode *inode, struct iattr *iap) { /* Ignore mode updates on symlinks */ if (S_ISLNK(inode->i_mode)) iap->ia_valid &= ~ATTR_MODE; /* sanitize the mode change */ if (iap->ia_valid & ATTR_MODE) { iap->ia_mode &= S_IALLUGO; iap->ia_mode |= (inode->i_mode & ~S_IALLUGO); } /* Revoke setuid/setgid on chown */ if (!S_ISDIR(inode->i_mode) && ((iap->ia_valid & ATTR_UID) || (iap->ia_valid & ATTR_GID))) { iap->ia_valid |= ATTR_KILL_PRIV; if (iap->ia_valid & ATTR_MODE) { /* we're setting mode too, just clear the s*id bits */ iap->ia_mode &= ~S_ISUID; if (iap->ia_mode & S_IXGRP) iap->ia_mode &= ~S_ISGID; } else { /* set ATTR_KILL_* bits and let VFS handle it */ iap->ia_valid |= (ATTR_KILL_SUID | ATTR_KILL_SGID); } } } static __be32 nfsd_get_write_access(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap) { struct inode *inode = d_inode(fhp->fh_dentry); if (iap->ia_size < inode->i_size) { __be32 err; err = nfsd_permission(rqstp, fhp->fh_export, fhp->fh_dentry, NFSD_MAY_TRUNC | NFSD_MAY_OWNER_OVERRIDE); if (err) return err; } return nfserrno(get_write_access(inode)); } /* * Set various file attributes. After this call fhp needs an fh_put. */ __be32 nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_attrs *attr, int check_guard, time64_t guardtime) { struct dentry *dentry; struct inode *inode; struct iattr *iap = attr->na_iattr; int accmode = NFSD_MAY_SATTR; umode_t ftype = 0; __be32 err; int host_err = 0; bool get_write_count; bool size_change = (iap->ia_valid & ATTR_SIZE); if (iap->ia_valid & ATTR_SIZE) { accmode |= NFSD_MAY_WRITE|NFSD_MAY_OWNER_OVERRIDE; ftype = S_IFREG; } /* * If utimes(2) and friends are called with times not NULL, we should * not set NFSD_MAY_WRITE bit. Otherwise fh_verify->nfsd_permission * will return EACCES, when the caller's effective UID does not match * the owner of the file, and the caller is not privileged. In this * situation, we should return EPERM(notify_change will return this). */ if (iap->ia_valid & (ATTR_ATIME | ATTR_MTIME)) { accmode |= NFSD_MAY_OWNER_OVERRIDE; if (!(iap->ia_valid & (ATTR_ATIME_SET | ATTR_MTIME_SET))) accmode |= NFSD_MAY_WRITE; } /* Callers that do fh_verify should do the fh_want_write: */ get_write_count = !fhp->fh_dentry; /* Get inode */ err = fh_verify(rqstp, fhp, ftype, accmode); if (err) return err; if (get_write_count) { host_err = fh_want_write(fhp); if (host_err) goto out; } dentry = fhp->fh_dentry; inode = d_inode(dentry); nfsd_sanitize_attrs(inode, iap); if (check_guard && guardtime != inode->i_ctime.tv_sec) return nfserr_notsync; /* * The size case is special, it changes the file in addition to the * attributes, and file systems don't expect it to be mixed with * "random" attribute changes. We thus split out the size change * into a separate call to ->setattr, and do the rest as a separate * setattr call. */ if (size_change) { err = nfsd_get_write_access(rqstp, fhp, iap); if (err) return err; } inode_lock(inode); if (size_change) { /* * RFC5661, Section 18.30.4: * Changing the size of a file with SETATTR indirectly * changes the time_modify and change attributes. * * (and similar for the older RFCs) */ struct iattr size_attr = { .ia_valid = ATTR_SIZE | ATTR_CTIME | ATTR_MTIME, .ia_size = iap->ia_size, }; host_err = -EFBIG; if (iap->ia_size < 0) goto out_unlock; host_err = notify_change(&init_user_ns, dentry, &size_attr, NULL); if (host_err) goto out_unlock; iap->ia_valid &= ~ATTR_SIZE; /* * Avoid the additional setattr call below if the only other * attribute that the client sends is the mtime, as we update * it as part of the size change above. */ if ((iap->ia_valid & ~ATTR_MTIME) == 0) goto out_unlock; } if (iap->ia_valid) { iap->ia_valid |= ATTR_CTIME; host_err = notify_change(&init_user_ns, dentry, iap, NULL); } out_unlock: if (attr->na_seclabel && attr->na_seclabel->len) attr->na_labelerr = security_inode_setsecctx(dentry, attr->na_seclabel->data, attr->na_seclabel->len); if (IS_ENABLED(CONFIG_FS_POSIX_ACL) && attr->na_pacl) attr->na_aclerr = set_posix_acl(&init_user_ns, inode, ACL_TYPE_ACCESS, attr->na_pacl); if (IS_ENABLED(CONFIG_FS_POSIX_ACL) && !attr->na_aclerr && attr->na_dpacl && S_ISDIR(inode->i_mode)) attr->na_aclerr = set_posix_acl(&init_user_ns, inode, ACL_TYPE_DEFAULT, attr->na_dpacl); inode_unlock(inode); if (size_change) put_write_access(inode); out: if (!host_err) host_err = commit_metadata(fhp); return nfserrno(host_err); } #if defined(CONFIG_NFSD_V4) /* * NFS junction information is stored in an extended attribute. */ #define NFSD_JUNCTION_XATTR_NAME XATTR_TRUSTED_PREFIX "junction.nfs" /** * nfsd4_is_junction - Test if an object could be an NFS junction * * @dentry: object to test * * Returns 1 if "dentry" appears to contain NFS junction information. * Otherwise 0 is returned. */ int nfsd4_is_junction(struct dentry *dentry) { struct inode *inode = d_inode(dentry); if (inode == NULL) return 0; if (inode->i_mode & S_IXUGO) return 0; if (!(inode->i_mode & S_ISVTX)) return 0; if (vfs_getxattr(&init_user_ns, dentry, NFSD_JUNCTION_XATTR_NAME, NULL, 0) <= 0) return 0; return 1; } static struct nfsd4_compound_state *nfsd4_get_cstate(struct svc_rqst *rqstp) { return &((struct nfsd4_compoundres *)rqstp->rq_resp)->cstate; } __be32 nfsd4_clone_file_range(struct svc_rqst *rqstp, struct nfsd_file *nf_src, u64 src_pos, struct nfsd_file *nf_dst, u64 dst_pos, u64 count, bool sync) { struct file *src = nf_src->nf_file; struct file *dst = nf_dst->nf_file; errseq_t since; loff_t cloned; __be32 ret = 0; since = READ_ONCE(dst->f_wb_err); cloned = vfs_clone_file_range(src, src_pos, dst, dst_pos, count, 0); if (cloned < 0) { ret = nfserrno(cloned); goto out_err; } if (count && cloned != count) { ret = nfserrno(-EINVAL); goto out_err; } if (sync) { loff_t dst_end = count ? dst_pos + count - 1 : LLONG_MAX; int status = vfs_fsync_range(dst, dst_pos, dst_end, 0); if (!status) status = filemap_check_wb_err(dst->f_mapping, since); if (!status) status = commit_inode_metadata(file_inode(src)); if (status < 0) { struct nfsd_net *nn = net_generic(nf_dst->nf_net, nfsd_net_id); trace_nfsd_clone_file_range_err(rqstp, &nfsd4_get_cstate(rqstp)->save_fh, src_pos, &nfsd4_get_cstate(rqstp)->current_fh, dst_pos, count, status); nfsd_reset_write_verifier(nn); trace_nfsd_writeverf_reset(nn, rqstp, status); ret = nfserrno(status); } } out_err: return ret; } ssize_t nfsd_copy_file_range(struct file *src, u64 src_pos, struct file *dst, u64 dst_pos, u64 count) { ssize_t ret; /* * Limit copy to 4MB to prevent indefinitely blocking an nfsd * thread and client rpc slot. The choice of 4MB is somewhat * arbitrary. We might instead base this on r/wsize, or make it * tunable, or use a time instead of a byte limit, or implement * asynchronous copy. In theory a client could also recognize a * limit like this and pipeline multiple COPY requests. */ count = min_t(u64, count, 1 << 22); ret = vfs_copy_file_range(src, src_pos, dst, dst_pos, count, 0); if (ret == -EOPNOTSUPP || ret == -EXDEV) ret = generic_copy_file_range(src, src_pos, dst, dst_pos, count, 0); return ret; } __be32 nfsd4_vfs_fallocate(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file, loff_t offset, loff_t len, int flags) { int error; if (!S_ISREG(file_inode(file)->i_mode)) return nfserr_inval; error = vfs_fallocate(file, flags, offset, len); if (!error) error = commit_metadata(fhp); return nfserrno(error); } #endif /* defined(CONFIG_NFSD_V4) */ /* * Check server access rights to a file system object */ struct accessmap { u32 access; int how; }; static struct accessmap nfs3_regaccess[] = { { NFS3_ACCESS_READ, NFSD_MAY_READ }, { NFS3_ACCESS_EXECUTE, NFSD_MAY_EXEC }, { NFS3_ACCESS_MODIFY, NFSD_MAY_WRITE|NFSD_MAY_TRUNC }, { NFS3_ACCESS_EXTEND, NFSD_MAY_WRITE }, #ifdef CONFIG_NFSD_V4 { NFS4_ACCESS_XAREAD, NFSD_MAY_READ }, { NFS4_ACCESS_XAWRITE, NFSD_MAY_WRITE }, { NFS4_ACCESS_XALIST, NFSD_MAY_READ }, #endif { 0, 0 } }; static struct accessmap nfs3_diraccess[] = { { NFS3_ACCESS_READ, NFSD_MAY_READ }, { NFS3_ACCESS_LOOKUP, NFSD_MAY_EXEC }, { NFS3_ACCESS_MODIFY, NFSD_MAY_EXEC|NFSD_MAY_WRITE|NFSD_MAY_TRUNC}, { NFS3_ACCESS_EXTEND, NFSD_MAY_EXEC|NFSD_MAY_WRITE }, { NFS3_ACCESS_DELETE, NFSD_MAY_REMOVE }, #ifdef CONFIG_NFSD_V4 { NFS4_ACCESS_XAREAD, NFSD_MAY_READ }, { NFS4_ACCESS_XAWRITE, NFSD_MAY_WRITE }, { NFS4_ACCESS_XALIST, NFSD_MAY_READ }, #endif { 0, 0 } }; static struct accessmap nfs3_anyaccess[] = { /* Some clients - Solaris 2.6 at least, make an access call * to the server to check for access for things like /dev/null * (which really, the server doesn't care about). So * We provide simple access checking for them, looking * mainly at mode bits, and we make sure to ignore read-only * filesystem checks */ { NFS3_ACCESS_READ, NFSD_MAY_READ }, { NFS3_ACCESS_EXECUTE, NFSD_MAY_EXEC }, { NFS3_ACCESS_MODIFY, NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS }, { NFS3_ACCESS_EXTEND, NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS }, { 0, 0 } }; __be32 nfsd_access(struct svc_rqst *rqstp, struct svc_fh *fhp, u32 *access, u32 *supported) { struct accessmap *map; struct svc_export *export; struct dentry *dentry; u32 query, result = 0, sresult = 0; __be32 error; error = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP); if (error) goto out; export = fhp->fh_export; dentry = fhp->fh_dentry; if (d_is_reg(dentry)) map = nfs3_regaccess; else if (d_is_dir(dentry)) map = nfs3_diraccess; else map = nfs3_anyaccess; query = *access; for (; map->access; map++) { if (map->access & query) { __be32 err2; sresult |= map->access; err2 = nfsd_permission(rqstp, export, dentry, map->how); switch (err2) { case nfs_ok: result |= map->access; break; /* the following error codes just mean the access was not allowed, * rather than an error occurred */ case nfserr_rofs: case nfserr_acces: case nfserr_perm: /* simply don't "or" in the access bit. */ break; default: error = err2; goto out; } } } *access = result; if (supported) *supported = sresult; out: return error; } int nfsd_open_break_lease(struct inode *inode, int access) { unsigned int mode; if (access & NFSD_MAY_NOT_BREAK_LEASE) return 0; mode = (access & NFSD_MAY_WRITE) ? O_WRONLY : O_RDONLY; return break_lease(inode, mode | O_NONBLOCK); } /* * Open an existing file or directory. * The may_flags argument indicates the type of open (read/write/lock) * and additional flags. * N.B. After this call fhp needs an fh_put */ static __be32 __nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type, int may_flags, struct file **filp) { struct path path; struct inode *inode; struct file *file; int flags = O_RDONLY|O_LARGEFILE; __be32 err; int host_err = 0; path.mnt = fhp->fh_export->ex_path.mnt; path.dentry = fhp->fh_dentry; inode = d_inode(path.dentry); err = nfserr_perm; if (IS_APPEND(inode) && (may_flags & NFSD_MAY_WRITE)) goto out; if (!inode->i_fop) goto out; host_err = nfsd_open_break_lease(inode, may_flags); if (host_err) /* NOMEM or WOULDBLOCK */ goto out_nfserr; if (may_flags & NFSD_MAY_WRITE) { if (may_flags & NFSD_MAY_READ) flags = O_RDWR|O_LARGEFILE; else flags = O_WRONLY|O_LARGEFILE; } file = dentry_open(&path, flags, current_cred()); if (IS_ERR(file)) { host_err = PTR_ERR(file); goto out_nfserr; } host_err = ima_file_check(file, may_flags); if (host_err) { fput(file); goto out_nfserr; } if (may_flags & NFSD_MAY_64BIT_COOKIE) file->f_mode |= FMODE_64BITHASH; else file->f_mode |= FMODE_32BITHASH; *filp = file; out_nfserr: err = nfserrno(host_err); out: return err; } __be32 nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type, int may_flags, struct file **filp) { __be32 err; bool retried = false; validate_process_creds(); /* * If we get here, then the client has already done an "open", * and (hopefully) checked permission - so allow OWNER_OVERRIDE * in case a chmod has now revoked permission. * * Arguably we should also allow the owner override for * directories, but we never have and it doesn't seem to have * caused anyone a problem. If we were to change this, note * also that our filldir callbacks would need a variant of * lookup_one_len that doesn't check permissions. */ if (type == S_IFREG) may_flags |= NFSD_MAY_OWNER_OVERRIDE; retry: err = fh_verify(rqstp, fhp, type, may_flags); if (!err) { err = __nfsd_open(rqstp, fhp, type, may_flags, filp); if (err == nfserr_stale && !retried) { retried = true; fh_put(fhp); goto retry; } } validate_process_creds(); return err; } /** * nfsd_open_verified - Open a regular file for the filecache * @rqstp: RPC request * @fhp: NFS filehandle of the file to open * @may_flags: internal permission flags * @filp: OUT: open "struct file *" * * Returns an nfsstat value in network byte order. */ __be32 nfsd_open_verified(struct svc_rqst *rqstp, struct svc_fh *fhp, int may_flags, struct file **filp) { __be32 err; validate_process_creds(); err = __nfsd_open(rqstp, fhp, S_IFREG, may_flags, filp); validate_process_creds(); return err; } /* * Grab and keep cached pages associated with a file in the svc_rqst * so that they can be passed to the network sendmsg/sendpage routines * directly. They will be released after the sending has completed. */ static int nfsd_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf, struct splice_desc *sd) { struct svc_rqst *rqstp = sd->u.data; struct page *page = buf->page; // may be a compound one unsigned offset = buf->offset; page += offset / PAGE_SIZE; for (int i = sd->len; i > 0; i -= PAGE_SIZE) svc_rqst_replace_page(rqstp, page++); if (rqstp->rq_res.page_len == 0) // first call rqstp->rq_res.page_base = offset % PAGE_SIZE; rqstp->rq_res.page_len += sd->len; return sd->len; } static int nfsd_direct_splice_actor(struct pipe_inode_info *pipe, struct splice_desc *sd) { return __splice_from_pipe(pipe, sd, nfsd_splice_actor); } static u32 nfsd_eof_on_read(struct file *file, loff_t offset, ssize_t len, size_t expected) { if (expected != 0 && len == 0) return 1; if (offset+len >= i_size_read(file_inode(file))) return 1; return 0; } static __be32 nfsd_finish_read(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file, loff_t offset, unsigned long *count, u32 *eof, ssize_t host_err) { if (host_err >= 0) { nfsd_stats_io_read_add(fhp->fh_export, host_err); *eof = nfsd_eof_on_read(file, offset, host_err, *count); *count = host_err; fsnotify_access(file); trace_nfsd_read_io_done(rqstp, fhp, offset, *count); return 0; } else { trace_nfsd_read_err(rqstp, fhp, offset, host_err); return nfserrno(host_err); } } __be32 nfsd_splice_read(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file, loff_t offset, unsigned long *count, u32 *eof) { struct splice_desc sd = { .len = 0, .total_len = *count, .pos = offset, .u.data = rqstp, }; ssize_t host_err; trace_nfsd_read_splice(rqstp, fhp, offset, *count); rqstp->rq_next_page = rqstp->rq_respages + 1; host_err = splice_direct_to_actor(file, &sd, nfsd_direct_splice_actor); return nfsd_finish_read(rqstp, fhp, file, offset, count, eof, host_err); } __be32 nfsd_readv(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file, loff_t offset, struct kvec *vec, int vlen, unsigned long *count, u32 *eof) { struct iov_iter iter; loff_t ppos = offset; ssize_t host_err; trace_nfsd_read_vector(rqstp, fhp, offset, *count); iov_iter_kvec(&iter, READ, vec, vlen, *count); host_err = vfs_iter_read(file, &iter, &ppos, 0); return nfsd_finish_read(rqstp, fhp, file, offset, count, eof, host_err); } /* * Gathered writes: If another process is currently writing to the file, * there's a high chance this is another nfsd (triggered by a bulk write * from a client's biod). Rather than syncing the file with each write * request, we sleep for 10 msec. * * I don't know if this roughly approximates C. Juszak's idea of * gathered writes, but it's a nice and simple solution (IMHO), and it * seems to work:-) * * Note: we do this only in the NFSv2 case, since v3 and higher have a * better tool (separate unstable writes and commits) for solving this * problem. */ static int wait_for_concurrent_writes(struct file *file) { struct inode *inode = file_inode(file); static ino_t last_ino; static dev_t last_dev; int err = 0; if (atomic_read(&inode->i_writecount) > 1 || (last_ino == inode->i_ino && last_dev == inode->i_sb->s_dev)) { dprintk("nfsd: write defer %d\n", task_pid_nr(current)); msleep(10); dprintk("nfsd: write resume %d\n", task_pid_nr(current)); } if (inode->i_state & I_DIRTY) { dprintk("nfsd: write sync %d\n", task_pid_nr(current)); err = vfs_fsync(file, 0); } last_ino = inode->i_ino; last_dev = inode->i_sb->s_dev; return err; } __be32 nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf, loff_t offset, struct kvec *vec, int vlen, unsigned long *cnt, int stable, __be32 *verf) { struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id); struct file *file = nf->nf_file; struct super_block *sb = file_inode(file)->i_sb; struct svc_export *exp; struct iov_iter iter; errseq_t since; __be32 nfserr; int host_err; int use_wgather; loff_t pos = offset; unsigned long exp_op_flags = 0; unsigned int pflags = current->flags; rwf_t flags = 0; bool restore_flags = false; trace_nfsd_write_opened(rqstp, fhp, offset, *cnt); if (sb->s_export_op) exp_op_flags = sb->s_export_op->flags; if (test_bit(RQ_LOCAL, &rqstp->rq_flags) && !(exp_op_flags & EXPORT_OP_REMOTE_FS)) { /* * We want throttling in balance_dirty_pages() * and shrink_inactive_list() to only consider * the backingdev we are writing to, so that nfs to * localhost doesn't cause nfsd to lock up due to all * the client's dirty pages or its congested queue. */ current->flags |= PF_LOCAL_THROTTLE; restore_flags = true; } exp = fhp->fh_export; use_wgather = (rqstp->rq_vers == 2) && EX_WGATHER(exp); if (!EX_ISSYNC(exp)) stable = NFS_UNSTABLE; if (stable && !use_wgather) flags |= RWF_SYNC; iov_iter_kvec(&iter, WRITE, vec, vlen, *cnt); since = READ_ONCE(file->f_wb_err); if (verf) nfsd_copy_write_verifier(verf, nn); host_err = vfs_iter_write(file, &iter, &pos, flags); if (host_err < 0) { nfsd_reset_write_verifier(nn); trace_nfsd_writeverf_reset(nn, rqstp, host_err); goto out_nfserr; } *cnt = host_err; nfsd_stats_io_write_add(exp, *cnt); fsnotify_modify(file); host_err = filemap_check_wb_err(file->f_mapping, since); if (host_err < 0) goto out_nfserr; if (stable && use_wgather) { host_err = wait_for_concurrent_writes(file); if (host_err < 0) { nfsd_reset_write_verifier(nn); trace_nfsd_writeverf_reset(nn, rqstp, host_err); } } out_nfserr: if (host_err >= 0) { trace_nfsd_write_io_done(rqstp, fhp, offset, *cnt); nfserr = nfs_ok; } else { trace_nfsd_write_err(rqstp, fhp, offset, host_err); nfserr = nfserrno(host_err); } if (restore_flags) current_restore_flags(pflags, PF_LOCAL_THROTTLE); return nfserr; } /* * Read data from a file. count must contain the requested read count * on entry. On return, *count contains the number of bytes actually read. * N.B. After this call fhp needs an fh_put */ __be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t offset, struct kvec *vec, int vlen, unsigned long *count, u32 *eof) { struct nfsd_file *nf; struct file *file; __be32 err; trace_nfsd_read_start(rqstp, fhp, offset, *count); err = nfsd_file_acquire(rqstp, fhp, NFSD_MAY_READ, &nf); if (err) return err; file = nf->nf_file; if (file->f_op->splice_read && test_bit(RQ_SPLICE_OK, &rqstp->rq_flags)) err = nfsd_splice_read(rqstp, fhp, file, offset, count, eof); else err = nfsd_readv(rqstp, fhp, file, offset, vec, vlen, count, eof); nfsd_file_put(nf); trace_nfsd_read_done(rqstp, fhp, offset, *count); return err; } /* * Write data to a file. * The stable flag requests synchronous writes. * N.B. After this call fhp needs an fh_put */ __be32 nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t offset, struct kvec *vec, int vlen, unsigned long *cnt, int stable, __be32 *verf) { struct nfsd_file *nf; __be32 err; trace_nfsd_write_start(rqstp, fhp, offset, *cnt); err = nfsd_file_acquire(rqstp, fhp, NFSD_MAY_WRITE, &nf); if (err) goto out; err = nfsd_vfs_write(rqstp, fhp, nf, offset, vec, vlen, cnt, stable, verf); nfsd_file_put(nf); out: trace_nfsd_write_done(rqstp, fhp, offset, *cnt); return err; } /** * nfsd_commit - Commit pending writes to stable storage * @rqstp: RPC request being processed * @fhp: NFS filehandle * @offset: raw offset from beginning of file * @count: raw count of bytes to sync * @verf: filled in with the server's current write verifier * * Note: we guarantee that data that lies within the range specified * by the 'offset' and 'count' parameters will be synced. The server * is permitted to sync data that lies outside this range at the * same time. * * Unfortunately we cannot lock the file to make sure we return full WCC * data to the client, as locking happens lower down in the filesystem. * * Return values: * An nfsstat value in network byte order. */ __be32 nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp, u64 offset, u32 count, __be32 *verf) { u64 maxbytes; loff_t start, end; struct nfsd_net *nn; struct nfsd_file *nf; __be32 err; err = nfsd_file_acquire(rqstp, fhp, NFSD_MAY_WRITE|NFSD_MAY_NOT_BREAK_LEASE, &nf); if (err) goto out; /* * Convert the client-provided (offset, count) range to a * (start, end) range. If the client-provided range falls * outside the maximum file size of the underlying FS, * clamp the sync range appropriately. */ start = 0; end = LLONG_MAX; maxbytes = (u64)fhp->fh_dentry->d_sb->s_maxbytes; if (offset < maxbytes) { start = offset; if (count && (offset + count - 1 < maxbytes)) end = offset + count - 1; } nn = net_generic(nf->nf_net, nfsd_net_id); if (EX_ISSYNC(fhp->fh_export)) { errseq_t since = READ_ONCE(nf->nf_file->f_wb_err); int err2; err2 = vfs_fsync_range(nf->nf_file, start, end, 0); switch (err2) { case 0: nfsd_copy_write_verifier(verf, nn); err2 = filemap_check_wb_err(nf->nf_file->f_mapping, since); err = nfserrno(err2); break; case -EINVAL: err = nfserr_notsupp; break; default: nfsd_reset_write_verifier(nn); trace_nfsd_writeverf_reset(nn, rqstp, err2); err = nfserrno(err2); } } else nfsd_copy_write_verifier(verf, nn); nfsd_file_put(nf); out: return err; } /** * nfsd_create_setattr - Set a created file's attributes * @rqstp: RPC transaction being executed * @fhp: NFS filehandle of parent directory * @resfhp: NFS filehandle of new object * @attrs: requested attributes of new object * * Returns nfs_ok on success, or an nfsstat in network byte order. */ __be32 nfsd_create_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct svc_fh *resfhp, struct nfsd_attrs *attrs) { struct iattr *iap = attrs->na_iattr; __be32 status; /* * Mode has already been set by file creation. */ iap->ia_valid &= ~ATTR_MODE; /* * Setting uid/gid works only for root. Irix appears to * send along the gid on create when it tries to implement * setgid directories via NFS: */ if (!uid_eq(current_fsuid(), GLOBAL_ROOT_UID)) iap->ia_valid &= ~(ATTR_UID|ATTR_GID); /* * Callers expect new file metadata to be committed even * if the attributes have not changed. */ if (iap->ia_valid) status = nfsd_setattr(rqstp, resfhp, attrs, 0, (time64_t)0); else status = nfserrno(commit_metadata(resfhp)); /* * Transactional filesystems had a chance to commit changes * for both parent and child simultaneously making the * following commit_metadata a noop in many cases. */ if (!status) status = nfserrno(commit_metadata(fhp)); /* * Update the new filehandle to pick up the new attributes. */ if (!status) status = fh_update(resfhp); return status; } /* HPUX client sometimes creates a file in mode 000, and sets size to 0. * setting size to 0 may fail for some specific file systems by the permission * checking which requires WRITE permission but the mode is 000. * we ignore the resizing(to 0) on the just new created file, since the size is * 0 after file created. * * call this only after vfs_create() is called. * */ static void nfsd_check_ignore_resizing(struct iattr *iap) { if ((iap->ia_valid & ATTR_SIZE) && (iap->ia_size == 0)) iap->ia_valid &= ~ATTR_SIZE; } /* The parent directory should already be locked: */ __be32 nfsd_create_locked(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_attrs *attrs, int type, dev_t rdev, struct svc_fh *resfhp) { struct dentry *dentry, *dchild; struct inode *dirp; struct iattr *iap = attrs->na_iattr; __be32 err; int host_err; dentry = fhp->fh_dentry; dirp = d_inode(dentry); dchild = dget(resfhp->fh_dentry); err = nfsd_permission(rqstp, fhp->fh_export, dentry, NFSD_MAY_CREATE); if (err) goto out; if (!(iap->ia_valid & ATTR_MODE)) iap->ia_mode = 0; iap->ia_mode = (iap->ia_mode & S_IALLUGO) | type; if (!IS_POSIXACL(dirp)) iap->ia_mode &= ~current_umask(); err = 0; host_err = 0; switch (type) { case S_IFREG: host_err = vfs_create(&init_user_ns, dirp, dchild, iap->ia_mode, true); if (!host_err) nfsd_check_ignore_resizing(iap); break; case S_IFDIR: host_err = vfs_mkdir(&init_user_ns, dirp, dchild, iap->ia_mode); if (!host_err && unlikely(d_unhashed(dchild))) { struct dentry *d; d = lookup_one_len(dchild->d_name.name, dchild->d_parent, dchild->d_name.len); if (IS_ERR(d)) { host_err = PTR_ERR(d); break; } if (unlikely(d_is_negative(d))) { dput(d); err = nfserr_serverfault; goto out; } dput(resfhp->fh_dentry); resfhp->fh_dentry = dget(d); err = fh_update(resfhp); dput(dchild); dchild = d; if (err) goto out; } break; case S_IFCHR: case S_IFBLK: case S_IFIFO: case S_IFSOCK: host_err = vfs_mknod(&init_user_ns, dirp, dchild, iap->ia_mode, rdev); break; default: printk(KERN_WARNING "nfsd: bad file type %o in nfsd_create\n", type); host_err = -EINVAL; } if (host_err < 0) goto out_nfserr; err = nfsd_create_setattr(rqstp, fhp, resfhp, attrs); out: dput(dchild); return err; out_nfserr: err = nfserrno(host_err); goto out; } /* * Create a filesystem object (regular, directory, special). * Note that the parent directory is left locked. * * N.B. Every call to nfsd_create needs an fh_put for _both_ fhp and resfhp */ __be32 nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, char *fname, int flen, struct nfsd_attrs *attrs, int type, dev_t rdev, struct svc_fh *resfhp) { struct dentry *dentry, *dchild = NULL; __be32 err; int host_err; if (isdotent(fname, flen)) return nfserr_exist; err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_NOP); if (err) return err; dentry = fhp->fh_dentry; host_err = fh_want_write(fhp); if (host_err) return nfserrno(host_err); inode_lock_nested(dentry->d_inode, I_MUTEX_PARENT); dchild = lookup_one_len(fname, dentry, flen); host_err = PTR_ERR(dchild); if (IS_ERR(dchild)) { err = nfserrno(host_err); goto out_unlock; } err = fh_compose(resfhp, fhp->fh_export, dchild, fhp); /* * We unconditionally drop our ref to dchild as fh_compose will have * already grabbed its own ref for it. */ dput(dchild); if (err) goto out_unlock; fh_fill_pre_attrs(fhp); err = nfsd_create_locked(rqstp, fhp, attrs, type, rdev, resfhp); fh_fill_post_attrs(fhp); out_unlock: inode_unlock(dentry->d_inode); return err; } /* * Read a symlink. On entry, *lenp must contain the maximum path length that * fits into the buffer. On return, it contains the true length. * N.B. After this call fhp needs an fh_put */ __be32 nfsd_readlink(struct svc_rqst *rqstp, struct svc_fh *fhp, char *buf, int *lenp) { __be32 err; const char *link; struct path path; DEFINE_DELAYED_CALL(done); int len; err = fh_verify(rqstp, fhp, S_IFLNK, NFSD_MAY_NOP); if (unlikely(err)) return err; path.mnt = fhp->fh_export->ex_path.mnt; path.dentry = fhp->fh_dentry; if (unlikely(!d_is_symlink(path.dentry))) return nfserr_inval; touch_atime(&path); link = vfs_get_link(path.dentry, &done); if (IS_ERR(link)) return nfserrno(PTR_ERR(link)); len = strlen(link); if (len < *lenp) *lenp = len; memcpy(buf, link, *lenp); do_delayed_call(&done); return 0; } /** * nfsd_symlink - Create a symlink and look up its inode * @rqstp: RPC transaction being executed * @fhp: NFS filehandle of parent directory * @fname: filename of the new symlink * @flen: length of @fname * @path: content of the new symlink (NUL-terminated) * @attrs: requested attributes of new object * @resfhp: NFS filehandle of new object * * N.B. After this call _both_ fhp and resfhp need an fh_put * * Returns nfs_ok on success, or an nfsstat in network byte order. */ __be32 nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp, char *fname, int flen, char *path, struct nfsd_attrs *attrs, struct svc_fh *resfhp) { struct dentry *dentry, *dnew; __be32 err, cerr; int host_err; err = nfserr_noent; if (!flen || path[0] == '\0') goto out; err = nfserr_exist; if (isdotent(fname, flen)) goto out; err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE); if (err) goto out; host_err = fh_want_write(fhp); if (host_err) { err = nfserrno(host_err); goto out; } dentry = fhp->fh_dentry; inode_lock_nested(dentry->d_inode, I_MUTEX_PARENT); dnew = lookup_one_len(fname, dentry, flen); if (IS_ERR(dnew)) { err = nfserrno(PTR_ERR(dnew)); inode_unlock(dentry->d_inode); goto out_drop_write; } fh_fill_pre_attrs(fhp); host_err = vfs_symlink(&init_user_ns, d_inode(dentry), dnew, path); err = nfserrno(host_err); cerr = fh_compose(resfhp, fhp->fh_export, dnew, fhp); if (!err) nfsd_create_setattr(rqstp, fhp, resfhp, attrs); fh_fill_post_attrs(fhp); inode_unlock(dentry->d_inode); if (!err) err = nfserrno(commit_metadata(fhp)); dput(dnew); if (err==0) err = cerr; out_drop_write: fh_drop_write(fhp); out: return err; } /* * Create a hardlink * N.B. After this call _both_ ffhp and tfhp need an fh_put */ __be32 nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *name, int len, struct svc_fh *tfhp) { struct dentry *ddir, *dnew, *dold; struct inode *dirp; __be32 err; int host_err; err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_CREATE); if (err) goto out; err = fh_verify(rqstp, tfhp, 0, NFSD_MAY_NOP); if (err) goto out; err = nfserr_isdir; if (d_is_dir(tfhp->fh_dentry)) goto out; err = nfserr_perm; if (!len) goto out; err = nfserr_exist; if (isdotent(name, len)) goto out; host_err = fh_want_write(tfhp); if (host_err) { err = nfserrno(host_err); goto out; } ddir = ffhp->fh_dentry; dirp = d_inode(ddir); inode_lock_nested(dirp, I_MUTEX_PARENT); dnew = lookup_one_len(name, ddir, len); if (IS_ERR(dnew)) { err = nfserrno(PTR_ERR(dnew)); goto out_unlock; } dold = tfhp->fh_dentry; err = nfserr_noent; if (d_really_is_negative(dold)) goto out_dput; fh_fill_pre_attrs(ffhp); host_err = vfs_link(dold, &init_user_ns, dirp, dnew, NULL); fh_fill_post_attrs(ffhp); inode_unlock(dirp); if (!host_err) { err = nfserrno(commit_metadata(ffhp)); if (!err) err = nfserrno(commit_metadata(tfhp)); } else { if (host_err == -EXDEV && rqstp->rq_vers == 2) err = nfserr_acces; else err = nfserrno(host_err); } dput(dnew); out_drop_write: fh_drop_write(tfhp); out: return err; out_dput: dput(dnew); out_unlock: inode_unlock(dirp); goto out_drop_write; } static void nfsd_close_cached_files(struct dentry *dentry) { struct inode *inode = d_inode(dentry); if (inode && S_ISREG(inode->i_mode)) nfsd_file_close_inode_sync(inode); } static bool nfsd_has_cached_files(struct dentry *dentry) { bool ret = false; struct inode *inode = d_inode(dentry); if (inode && S_ISREG(inode->i_mode)) ret = nfsd_file_is_cached(inode); return ret; } /* * Rename a file * N.B. After this call _both_ ffhp and tfhp need an fh_put */ __be32 nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, struct svc_fh *tfhp, char *tname, int tlen) { struct dentry *fdentry, *tdentry, *odentry, *ndentry, *trap; struct inode *fdir, *tdir; __be32 err; int host_err; bool close_cached = false; err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_REMOVE); if (err) goto out; err = fh_verify(rqstp, tfhp, S_IFDIR, NFSD_MAY_CREATE); if (err) goto out; fdentry = ffhp->fh_dentry; fdir = d_inode(fdentry); tdentry = tfhp->fh_dentry; tdir = d_inode(tdentry); err = nfserr_perm; if (!flen || isdotent(fname, flen) || !tlen || isdotent(tname, tlen)) goto out; retry: host_err = fh_want_write(ffhp); if (host_err) { err = nfserrno(host_err); goto out; } trap = lock_rename(tdentry, fdentry); fh_fill_pre_attrs(ffhp); fh_fill_pre_attrs(tfhp); odentry = lookup_one_len(fname, fdentry, flen); host_err = PTR_ERR(odentry); if (IS_ERR(odentry)) goto out_nfserr; host_err = -ENOENT; if (d_really_is_negative(odentry)) goto out_dput_old; host_err = -EINVAL; if (odentry == trap) goto out_dput_old; ndentry = lookup_one_len(tname, tdentry, tlen); host_err = PTR_ERR(ndentry); if (IS_ERR(ndentry)) goto out_dput_old; host_err = -ENOTEMPTY; if (ndentry == trap) goto out_dput_new; host_err = -EXDEV; if (ffhp->fh_export->ex_path.mnt != tfhp->fh_export->ex_path.mnt) goto out_dput_new; if (ffhp->fh_export->ex_path.dentry != tfhp->fh_export->ex_path.dentry) goto out_dput_new; if ((ndentry->d_sb->s_export_op->flags & EXPORT_OP_CLOSE_BEFORE_UNLINK) && nfsd_has_cached_files(ndentry)) { close_cached = true; goto out_dput_old; } else { struct renamedata rd = { .old_mnt_userns = &init_user_ns, .old_dir = fdir, .old_dentry = odentry, .new_mnt_userns = &init_user_ns, .new_dir = tdir, .new_dentry = ndentry, }; host_err = vfs_rename(&rd); if (!host_err) { host_err = commit_metadata(tfhp); if (!host_err) host_err = commit_metadata(ffhp); } } out_dput_new: dput(ndentry); out_dput_old: dput(odentry); out_nfserr: err = nfserrno(host_err); if (!close_cached) { fh_fill_post_attrs(ffhp); fh_fill_post_attrs(tfhp); } unlock_rename(tdentry, fdentry); fh_drop_write(ffhp); /* * If the target dentry has cached open files, then we need to try to * close them prior to doing the rename. Flushing delayed fput * shouldn't be done with locks held however, so we delay it until this * point and then reattempt the whole shebang. */ if (close_cached) { close_cached = false; nfsd_close_cached_files(ndentry); dput(ndentry); goto retry; } out: return err; } /* * Unlink a file or directory * N.B. After this call fhp needs an fh_put */ __be32 nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, char *fname, int flen) { struct dentry *dentry, *rdentry; struct inode *dirp; struct inode *rinode; __be32 err; int host_err; err = nfserr_acces; if (!flen || isdotent(fname, flen)) goto out; err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_REMOVE); if (err) goto out; host_err = fh_want_write(fhp); if (host_err) goto out_nfserr; dentry = fhp->fh_dentry; dirp = d_inode(dentry); inode_lock_nested(dirp, I_MUTEX_PARENT); rdentry = lookup_one_len(fname, dentry, flen); host_err = PTR_ERR(rdentry); if (IS_ERR(rdentry)) goto out_unlock; if (d_really_is_negative(rdentry)) { dput(rdentry); host_err = -ENOENT; goto out_unlock; } rinode = d_inode(rdentry); ihold(rinode); if (!type) type = d_inode(rdentry)->i_mode & S_IFMT; fh_fill_pre_attrs(fhp); if (type != S_IFDIR) { if (rdentry->d_sb->s_export_op->flags & EXPORT_OP_CLOSE_BEFORE_UNLINK) nfsd_close_cached_files(rdentry); host_err = vfs_unlink(&init_user_ns, dirp, rdentry, NULL); } else { host_err = vfs_rmdir(&init_user_ns, dirp, rdentry); } fh_fill_post_attrs(fhp); inode_unlock(dirp); if (!host_err) host_err = commit_metadata(fhp); dput(rdentry); iput(rinode); /* truncate the inode here */ out_drop_write: fh_drop_write(fhp); out_nfserr: if (host_err == -EBUSY) { /* name is mounted-on. There is no perfect * error status. */ if (nfsd_v4client(rqstp)) err = nfserr_file_open; else err = nfserr_acces; } else { err = nfserrno(host_err); } out: return err; out_unlock: inode_unlock(dirp); goto out_drop_write; } /* * We do this buffering because we must not call back into the file * system's ->lookup() method from the filldir callback. That may well * deadlock a number of file systems. * * This is based heavily on the implementation of same in XFS. */ struct buffered_dirent { u64 ino; loff_t offset; int namlen; unsigned int d_type; char name[]; }; struct readdir_data { struct dir_context ctx; char *dirent; size_t used; int full; }; static int nfsd_buffered_filldir(struct dir_context *ctx, const char *name, int namlen, loff_t offset, u64 ino, unsigned int d_type) { struct readdir_data *buf = container_of(ctx, struct readdir_data, ctx); struct buffered_dirent *de = (void *)(buf->dirent + buf->used); unsigned int reclen; reclen = ALIGN(sizeof(struct buffered_dirent) + namlen, sizeof(u64)); if (buf->used + reclen > PAGE_SIZE) { buf->full = 1; return -EINVAL; } de->namlen = namlen; de->offset = offset; de->ino = ino; de->d_type = d_type; memcpy(de->name, name, namlen); buf->used += reclen; return 0; } static __be32 nfsd_buffered_readdir(struct file *file, struct svc_fh *fhp, nfsd_filldir_t func, struct readdir_cd *cdp, loff_t *offsetp) { struct buffered_dirent *de; int host_err; int size; loff_t offset; struct readdir_data buf = { .ctx.actor = nfsd_buffered_filldir, .dirent = (void *)__get_free_page(GFP_KERNEL) }; if (!buf.dirent) return nfserrno(-ENOMEM); offset = *offsetp; while (1) { unsigned int reclen; cdp->err = nfserr_eof; /* will be cleared on successful read */ buf.used = 0; buf.full = 0; host_err = iterate_dir(file, &buf.ctx); if (buf.full) host_err = 0; if (host_err < 0) break; size = buf.used; if (!size) break; de = (struct buffered_dirent *)buf.dirent; while (size > 0) { offset = de->offset; if (func(cdp, de->name, de->namlen, de->offset, de->ino, de->d_type)) break; if (cdp->err != nfs_ok) break; trace_nfsd_dirent(fhp, de->ino, de->name, de->namlen); reclen = ALIGN(sizeof(*de) + de->namlen, sizeof(u64)); size -= reclen; de = (struct buffered_dirent *)((char *)de + reclen); } if (size > 0) /* We bailed out early */ break; offset = vfs_llseek(file, 0, SEEK_CUR); } free_page((unsigned long)(buf.dirent)); if (host_err) return nfserrno(host_err); *offsetp = offset; return cdp->err; } /* * Read entries from a directory. * The NFSv3/4 verifier we ignore for now. */ __be32 nfsd_readdir(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t *offsetp, struct readdir_cd *cdp, nfsd_filldir_t func) { __be32 err; struct file *file; loff_t offset = *offsetp; int may_flags = NFSD_MAY_READ; /* NFSv2 only supports 32 bit cookies */ if (rqstp->rq_vers > 2) may_flags |= NFSD_MAY_64BIT_COOKIE; err = nfsd_open(rqstp, fhp, S_IFDIR, may_flags, &file); if (err) goto out; offset = vfs_llseek(file, offset, SEEK_SET); if (offset < 0) { err = nfserrno((int)offset); goto out_close; } err = nfsd_buffered_readdir(file, fhp, func, cdp, offsetp); if (err == nfserr_eof || err == nfserr_toosmall) err = nfs_ok; /* can still be found in ->err */ out_close: fput(file); out: return err; } /* * Get file system stats * N.B. After this call fhp needs an fh_put */ __be32 nfsd_statfs(struct svc_rqst *rqstp, struct svc_fh *fhp, struct kstatfs *stat, int access) { __be32 err; err = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP | access); if (!err) { struct path path = { .mnt = fhp->fh_export->ex_path.mnt, .dentry = fhp->fh_dentry, }; if (vfs_statfs(&path, stat)) err = nfserr_io; } return err; } static int exp_rdonly(struct svc_rqst *rqstp, struct svc_export *exp) { return nfsexp_flags(rqstp, exp) & NFSEXP_READONLY; } #ifdef CONFIG_NFSD_V4 /* * Helper function to translate error numbers. In the case of xattr operations, * some error codes need to be translated outside of the standard translations. * * ENODATA needs to be translated to nfserr_noxattr. * E2BIG to nfserr_xattr2big. * * Additionally, vfs_listxattr can return -ERANGE. This means that the * file has too many extended attributes to retrieve inside an * XATTR_LIST_MAX sized buffer. This is a bug in the xattr implementation: * filesystems will allow the adding of extended attributes until they hit * their own internal limit. This limit may be larger than XATTR_LIST_MAX. * So, at that point, the attributes are present and valid, but can't * be retrieved using listxattr, since the upper level xattr code enforces * the XATTR_LIST_MAX limit. * * This bug means that we need to deal with listxattr returning -ERANGE. The * best mapping is to return TOOSMALL. */ static __be32 nfsd_xattr_errno(int err) { switch (err) { case -ENODATA: return nfserr_noxattr; case -E2BIG: return nfserr_xattr2big; case -ERANGE: return nfserr_toosmall; } return nfserrno(err); } /* * Retrieve the specified user extended attribute. To avoid always * having to allocate the maximum size (since we are not getting * a maximum size from the RPC), do a probe + alloc. Hold a reader * lock on i_rwsem to prevent the extended attribute from changing * size while we're doing this. */ __be32 nfsd_getxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name, void **bufp, int *lenp) { ssize_t len; __be32 err; char *buf; struct inode *inode; struct dentry *dentry; err = fh_verify(rqstp, fhp, 0, NFSD_MAY_READ); if (err) return err; err = nfs_ok; dentry = fhp->fh_dentry; inode = d_inode(dentry); inode_lock_shared(inode); len = vfs_getxattr(&init_user_ns, dentry, name, NULL, 0); /* * Zero-length attribute, just return. */ if (len == 0) { *bufp = NULL; *lenp = 0; goto out; } if (len < 0) { err = nfsd_xattr_errno(len); goto out; } if (len > *lenp) { err = nfserr_toosmall; goto out; } buf = kvmalloc(len, GFP_KERNEL | GFP_NOFS); if (buf == NULL) { err = nfserr_jukebox; goto out; } len = vfs_getxattr(&init_user_ns, dentry, name, buf, len); if (len <= 0) { kvfree(buf); buf = NULL; err = nfsd_xattr_errno(len); } *lenp = len; *bufp = buf; out: inode_unlock_shared(inode); return err; } /* * Retrieve the xattr names. Since we can't know how many are * user extended attributes, we must get all attributes here, * and have the XDR encode filter out the "user." ones. * * While this could always just allocate an XATTR_LIST_MAX * buffer, that's a waste, so do a probe + allocate. To * avoid any changes between the probe and allocate, wrap * this in inode_lock. */ __be32 nfsd_listxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char **bufp, int *lenp) { ssize_t len; __be32 err; char *buf; struct inode *inode; struct dentry *dentry; err = fh_verify(rqstp, fhp, 0, NFSD_MAY_READ); if (err) return err; dentry = fhp->fh_dentry; inode = d_inode(dentry); *lenp = 0; inode_lock_shared(inode); len = vfs_listxattr(dentry, NULL, 0); if (len <= 0) { err = nfsd_xattr_errno(len); goto out; } if (len > XATTR_LIST_MAX) { err = nfserr_xattr2big; goto out; } /* * We're holding i_rwsem - use GFP_NOFS. */ buf = kvmalloc(len, GFP_KERNEL | GFP_NOFS); if (buf == NULL) { err = nfserr_jukebox; goto out; } len = vfs_listxattr(dentry, buf, len); if (len <= 0) { kvfree(buf); err = nfsd_xattr_errno(len); goto out; } *lenp = len; *bufp = buf; err = nfs_ok; out: inode_unlock_shared(inode); return err; } /** * nfsd_removexattr - Remove an extended attribute * @rqstp: RPC transaction being executed * @fhp: NFS filehandle of object with xattr to remove * @name: name of xattr to remove (NUL-terminate) * * Pass in a NULL pointer for delegated_inode, and let the client deal * with NFS4ERR_DELAY (same as with e.g. setattr and remove). * * Returns nfs_ok on success, or an nfsstat in network byte order. */ __be32 nfsd_removexattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name) { __be32 err; int ret; err = fh_verify(rqstp, fhp, 0, NFSD_MAY_WRITE); if (err) return err; ret = fh_want_write(fhp); if (ret) return nfserrno(ret); inode_lock(fhp->fh_dentry->d_inode); fh_fill_pre_attrs(fhp); ret = __vfs_removexattr_locked(&init_user_ns, fhp->fh_dentry, name, NULL); fh_fill_post_attrs(fhp); inode_unlock(fhp->fh_dentry->d_inode); fh_drop_write(fhp); return nfsd_xattr_errno(ret); } __be32 nfsd_setxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name, void *buf, u32 len, u32 flags) { __be32 err; int ret; err = fh_verify(rqstp, fhp, 0, NFSD_MAY_WRITE); if (err) return err; ret = fh_want_write(fhp); if (ret) return nfserrno(ret); inode_lock(fhp->fh_dentry->d_inode); fh_fill_pre_attrs(fhp); ret = __vfs_setxattr_locked(&init_user_ns, fhp->fh_dentry, name, buf, len, flags, NULL); fh_fill_post_attrs(fhp); inode_unlock(fhp->fh_dentry->d_inode); fh_drop_write(fhp); return nfsd_xattr_errno(ret); } #endif /* * Check for a user's access permissions to this inode. */ __be32 nfsd_permission(struct svc_rqst *rqstp, struct svc_export *exp, struct dentry *dentry, int acc) { struct inode *inode = d_inode(dentry); int err; if ((acc & NFSD_MAY_MASK) == NFSD_MAY_NOP) return 0; #if 0 dprintk("nfsd: permission 0x%x%s%s%s%s%s%s%s mode 0%o%s%s%s\n", acc, (acc & NFSD_MAY_READ)? " read" : "", (acc & NFSD_MAY_WRITE)? " write" : "", (acc & NFSD_MAY_EXEC)? " exec" : "", (acc & NFSD_MAY_SATTR)? " sattr" : "", (acc & NFSD_MAY_TRUNC)? " trunc" : "", (acc & NFSD_MAY_LOCK)? " lock" : "", (acc & NFSD_MAY_OWNER_OVERRIDE)? " owneroverride" : "", inode->i_mode, IS_IMMUTABLE(inode)? " immut" : "", IS_APPEND(inode)? " append" : "", __mnt_is_readonly(exp->ex_path.mnt)? " ro" : ""); dprintk(" owner %d/%d user %d/%d\n", inode->i_uid, inode->i_gid, current_fsuid(), current_fsgid()); #endif /* Normally we reject any write/sattr etc access on a read-only file * system. But if it is IRIX doing check on write-access for a * device special file, we ignore rofs. */ if (!(acc & NFSD_MAY_LOCAL_ACCESS)) if (acc & (NFSD_MAY_WRITE | NFSD_MAY_SATTR | NFSD_MAY_TRUNC)) { if (exp_rdonly(rqstp, exp) || __mnt_is_readonly(exp->ex_path.mnt)) return nfserr_rofs; if (/* (acc & NFSD_MAY_WRITE) && */ IS_IMMUTABLE(inode)) return nfserr_perm; } if ((acc & NFSD_MAY_TRUNC) && IS_APPEND(inode)) return nfserr_perm; if (acc & NFSD_MAY_LOCK) { /* If we cannot rely on authentication in NLM requests, * just allow locks, otherwise require read permission, or * ownership */ if (exp->ex_flags & NFSEXP_NOAUTHNLM) return 0; else acc = NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE; } /* * The file owner always gets access permission for accesses that * would normally be checked at open time. This is to make * file access work even when the client has done a fchmod(fd, 0). * * However, `cp foo bar' should fail nevertheless when bar is * readonly. A sensible way to do this might be to reject all * attempts to truncate a read-only file, because a creat() call * always implies file truncation. * ... but this isn't really fair. A process may reasonably call * ftruncate on an open file descriptor on a file with perm 000. * We must trust the client to do permission checking - using "ACCESS" * with NFSv3. */ if ((acc & NFSD_MAY_OWNER_OVERRIDE) && uid_eq(inode->i_uid, current_fsuid())) return 0; /* This assumes NFSD_MAY_{READ,WRITE,EXEC} == MAY_{READ,WRITE,EXEC} */ err = inode_permission(&init_user_ns, inode, acc & (MAY_READ | MAY_WRITE | MAY_EXEC)); /* Allow read access to binaries even when mode 111 */ if (err == -EACCES && S_ISREG(inode->i_mode) && (acc == (NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE) || acc == (NFSD_MAY_READ | NFSD_MAY_READ_IF_EXEC))) err = inode_permission(&init_user_ns, inode, MAY_EXEC); return err? nfserrno(err) : 0; }