/* * linux/fs/nfs/nfs4namespace.c * * Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com> * - Modified by David Howells <dhowells@redhat.com> * * NFSv4 namespace */ #include <linux/dcache.h> #include <linux/mount.h> #include <linux/namei.h> #include <linux/nfs_fs.h> #include <linux/slab.h> #include <linux/string.h> #include <linux/sunrpc/clnt.h> #include <linux/vfs.h> #include <linux/inet.h> #include "internal.h" #include "nfs4_fs.h" #include "dns_resolve.h" #define NFSDBG_FACILITY NFSDBG_VFS /* * Convert the NFSv4 pathname components into a standard posix path. * * Note that the resulting string will be placed at the end of the buffer */ static inline char *nfs4_pathname_string(const struct nfs4_pathname *pathname, char *buffer, ssize_t buflen) { char *end = buffer + buflen; int n; *--end = '\0'; buflen--; n = pathname->ncomponents; while (--n >= 0) { const struct nfs4_string *component = &pathname->components[n]; buflen -= component->len + 1; if (buflen < 0) goto Elong; end -= component->len; memcpy(end, component->data, component->len); *--end = '/'; } return end; Elong: return ERR_PTR(-ENAMETOOLONG); } /* * Determine the mount path as a string */ static char *nfs4_path(const struct vfsmount *mnt_parent, const struct dentry *dentry, char *buffer, ssize_t buflen) { const char *srvpath; srvpath = strchr(mnt_parent->mnt_devname, ':'); if (srvpath) srvpath++; else srvpath = mnt_parent->mnt_devname; return nfs_path(srvpath, mnt_parent->mnt_root, dentry, buffer, buflen); } /* * Check that fs_locations::fs_root [RFC3530 6.3] is a prefix for what we * believe to be the server path to this dentry */ static int nfs4_validate_fspath(const struct vfsmount *mnt_parent, const struct dentry *dentry, const struct nfs4_fs_locations *locations, char *page, char *page2) { const char *path, *fs_path; path = nfs4_path(mnt_parent, dentry, page, PAGE_SIZE); if (IS_ERR(path)) return PTR_ERR(path); fs_path = nfs4_pathname_string(&locations->fs_path, page2, PAGE_SIZE); if (IS_ERR(fs_path)) return PTR_ERR(fs_path); if (strncmp(path, fs_path, strlen(fs_path)) != 0) { dprintk("%s: path %s does not begin with fsroot %s\n", __func__, path, fs_path); return -ENOENT; } return 0; } static size_t nfs_parse_server_name(char *string, size_t len, struct sockaddr *sa, size_t salen) { ssize_t ret; ret = rpc_pton(string, len, sa, salen); if (ret == 0) { ret = nfs_dns_resolve_name(string, len, sa, salen); if (ret < 0) ret = 0; } return ret; } static struct vfsmount *try_location(struct nfs_clone_mount *mountdata, char *page, char *page2, const struct nfs4_fs_location *location) { const size_t addr_bufsize = sizeof(struct sockaddr_storage); struct vfsmount *mnt = ERR_PTR(-ENOENT); char *mnt_path; unsigned int maxbuflen; unsigned int s; mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE); if (IS_ERR(mnt_path)) return ERR_CAST(mnt_path); mountdata->mnt_path = mnt_path; maxbuflen = mnt_path - 1 - page2; mountdata->addr = kmalloc(addr_bufsize, GFP_KERNEL); if (mountdata->addr == NULL) return ERR_PTR(-ENOMEM); for (s = 0; s < location->nservers; s++) { const struct nfs4_string *buf = &location->servers[s]; if (buf->len <= 0 || buf->len >= maxbuflen) continue; if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len)) continue; mountdata->addrlen = nfs_parse_server_name(buf->data, buf->len, mountdata->addr, addr_bufsize); if (mountdata->addrlen == 0) continue; rpc_set_port(mountdata->addr, NFS_PORT); memcpy(page2, buf->data, buf->len); page2[buf->len] = '\0'; mountdata->hostname = page2; snprintf(page, PAGE_SIZE, "%s:%s", mountdata->hostname, mountdata->mnt_path); mnt = vfs_kern_mount(&nfs4_referral_fs_type, 0, page, mountdata); if (!IS_ERR(mnt)) break; } kfree(mountdata->addr); return mnt; } /** * nfs_follow_referral - set up mountpoint when hitting a referral on moved error * @mnt_parent - mountpoint of parent directory * @dentry - parent directory * @locations - array of NFSv4 server location information * */ static struct vfsmount *nfs_follow_referral(const struct vfsmount *mnt_parent, const struct dentry *dentry, const struct nfs4_fs_locations *locations) { struct vfsmount *mnt = ERR_PTR(-ENOENT); struct nfs_clone_mount mountdata = { .sb = mnt_parent->mnt_sb, .dentry = dentry, .authflavor = NFS_SB(mnt_parent->mnt_sb)->client->cl_auth->au_flavor, }; char *page = NULL, *page2 = NULL; int loc, error; if (locations == NULL || locations->nlocations <= 0) goto out; dprintk("%s: referral at %s/%s\n", __func__, dentry->d_parent->d_name.name, dentry->d_name.name); page = (char *) __get_free_page(GFP_USER); if (!page) goto out; page2 = (char *) __get_free_page(GFP_USER); if (!page2) goto out; /* Ensure fs path is a prefix of current dentry path */ error = nfs4_validate_fspath(mnt_parent, dentry, locations, page, page2); if (error < 0) { mnt = ERR_PTR(error); goto out; } for (loc = 0; loc < locations->nlocations; loc++) { const struct nfs4_fs_location *location = &locations->locations[loc]; if (location == NULL || location->nservers <= 0 || location->rootpath.ncomponents == 0) continue; mnt = try_location(&mountdata, page, page2, location); if (!IS_ERR(mnt)) break; } out: free_page((unsigned long) page); free_page((unsigned long) page2); dprintk("%s: done\n", __func__); return mnt; } /* * nfs_do_refmount - handle crossing a referral on server * @mnt_parent - mountpoint of referral * @dentry - dentry of referral * */ struct vfsmount *nfs_do_refmount(const struct vfsmount *mnt_parent, struct dentry *dentry) { struct vfsmount *mnt = ERR_PTR(-ENOMEM); struct dentry *parent; struct nfs4_fs_locations *fs_locations = NULL; struct page *page; int err; /* BUG_ON(IS_ROOT(dentry)); */ dprintk("%s: enter\n", __func__); page = alloc_page(GFP_KERNEL); if (page == NULL) goto out; fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL); if (fs_locations == NULL) goto out_free; /* Get locations */ mnt = ERR_PTR(-ENOENT); parent = dget_parent(dentry); dprintk("%s: getting locations for %s/%s\n", __func__, parent->d_name.name, dentry->d_name.name); err = nfs4_proc_fs_locations(parent->d_inode, &dentry->d_name, fs_locations, page); dput(parent); if (err != 0 || fs_locations->nlocations <= 0 || fs_locations->fs_path.ncomponents <= 0) goto out_free; mnt = nfs_follow_referral(mnt_parent, dentry, fs_locations); out_free: __free_page(page); kfree(fs_locations); out: dprintk("%s: done\n", __func__); return mnt; }