1 /* 2 * linux/fs/nfs/nfs4namespace.c 3 * 4 * Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com> 5 * 6 * NFSv4 namespace 7 */ 8 9 #include <linux/config.h> 10 11 #include <linux/dcache.h> 12 #include <linux/mount.h> 13 #include <linux/namei.h> 14 #include <linux/nfs_fs.h> 15 #include <linux/string.h> 16 #include <linux/sunrpc/clnt.h> 17 #include <linux/vfs.h> 18 #include <linux/inet.h> 19 #include "internal.h" 20 21 #define NFSDBG_FACILITY NFSDBG_VFS 22 23 /* 24 * Check if fs_root is valid 25 */ 26 static inline char *nfs4_pathname_string(struct nfs4_pathname *pathname, 27 char *buffer, ssize_t buflen) 28 { 29 char *end = buffer + buflen; 30 int n; 31 32 *--end = '\0'; 33 buflen--; 34 35 n = pathname->ncomponents; 36 while (--n >= 0) { 37 struct nfs4_string *component = &pathname->components[n]; 38 buflen -= component->len + 1; 39 if (buflen < 0) 40 goto Elong; 41 end -= component->len; 42 memcpy(end, component->data, component->len); 43 *--end = '/'; 44 } 45 return end; 46 Elong: 47 return ERR_PTR(-ENAMETOOLONG); 48 } 49 50 51 /** 52 * nfs_follow_referral - set up mountpoint when hitting a referral on moved error 53 * @mnt_parent - mountpoint of parent directory 54 * @dentry - parent directory 55 * @fspath - fs path returned in fs_locations 56 * @mntpath - mount path to new server 57 * @hostname - hostname of new server 58 * @addr - host addr of new server 59 * 60 */ 61 static struct vfsmount *nfs_follow_referral(const struct vfsmount *mnt_parent, 62 const struct dentry *dentry, 63 struct nfs4_fs_locations *locations) 64 { 65 struct vfsmount *mnt = ERR_PTR(-ENOENT); 66 struct nfs_clone_mount mountdata = { 67 .sb = mnt_parent->mnt_sb, 68 .dentry = dentry, 69 .authflavor = NFS_SB(mnt_parent->mnt_sb)->client->cl_auth->au_flavor, 70 }; 71 char *page, *page2; 72 char *path, *fs_path; 73 char *devname; 74 int loc, s; 75 76 if (locations == NULL || locations->nlocations <= 0) 77 goto out; 78 79 dprintk("%s: referral at %s/%s\n", __FUNCTION__, 80 dentry->d_parent->d_name.name, dentry->d_name.name); 81 82 /* Ensure fs path is a prefix of current dentry path */ 83 page = (char *) __get_free_page(GFP_USER); 84 if (page == NULL) 85 goto out; 86 page2 = (char *) __get_free_page(GFP_USER); 87 if (page2 == NULL) 88 goto out; 89 90 path = nfs4_path(dentry, page, PAGE_SIZE); 91 if (IS_ERR(path)) 92 goto out_free; 93 94 fs_path = nfs4_pathname_string(&locations->fs_path, page2, PAGE_SIZE); 95 if (IS_ERR(fs_path)) 96 goto out_free; 97 98 if (strncmp(path, fs_path, strlen(fs_path)) != 0) { 99 dprintk("%s: path %s does not begin with fsroot %s\n", __FUNCTION__, path, fs_path); 100 goto out_free; 101 } 102 103 devname = nfs_devname(mnt_parent, dentry, page, PAGE_SIZE); 104 if (IS_ERR(devname)) { 105 mnt = (struct vfsmount *)devname; 106 goto out_free; 107 } 108 109 loc = 0; 110 while (loc < locations->nlocations && IS_ERR(mnt)) { 111 struct nfs4_fs_location *location = &locations->locations[loc]; 112 char *mnt_path; 113 114 if (location == NULL || location->nservers <= 0 || 115 location->rootpath.ncomponents == 0) { 116 loc++; 117 continue; 118 } 119 120 mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE); 121 if (IS_ERR(mnt_path)) { 122 loc++; 123 continue; 124 } 125 mountdata.mnt_path = mnt_path; 126 127 s = 0; 128 while (s < location->nservers) { 129 struct sockaddr_in addr = {}; 130 131 if (location->servers[s].len <= 0 || 132 valid_ipaddr4(location->servers[s].data) < 0) { 133 s++; 134 continue; 135 } 136 137 mountdata.hostname = location->servers[s].data; 138 addr.sin_addr.s_addr = in_aton(mountdata.hostname); 139 addr.sin_family = AF_INET; 140 addr.sin_port = htons(NFS_PORT); 141 mountdata.addr = &addr; 142 143 mnt = vfs_kern_mount(&nfs_referral_nfs4_fs_type, 0, devname, &mountdata); 144 if (!IS_ERR(mnt)) { 145 break; 146 } 147 s++; 148 } 149 loc++; 150 } 151 152 out_free: 153 free_page((unsigned long)page); 154 free_page((unsigned long)page2); 155 out: 156 dprintk("%s: done\n", __FUNCTION__); 157 return mnt; 158 } 159 160 /* 161 * nfs_do_refmount - handle crossing a referral on server 162 * @dentry - dentry of referral 163 * @nd - nameidata info 164 * 165 */ 166 struct vfsmount *nfs_do_refmount(const struct vfsmount *mnt_parent, struct dentry *dentry) 167 { 168 struct vfsmount *mnt = ERR_PTR(-ENOENT); 169 struct dentry *parent; 170 struct nfs4_fs_locations *fs_locations = NULL; 171 struct page *page; 172 int err; 173 174 /* BUG_ON(IS_ROOT(dentry)); */ 175 dprintk("%s: enter\n", __FUNCTION__); 176 177 page = alloc_page(GFP_KERNEL); 178 if (page == NULL) 179 goto out; 180 181 fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL); 182 if (fs_locations == NULL) 183 goto out_free; 184 185 /* Get locations */ 186 parent = dget_parent(dentry); 187 dprintk("%s: getting locations for %s/%s\n", __FUNCTION__, parent->d_name.name, dentry->d_name.name); 188 err = nfs4_proc_fs_locations(parent->d_inode, dentry, fs_locations, page); 189 dput(parent); 190 if (err != 0 || fs_locations->nlocations <= 0 || 191 fs_locations->fs_path.ncomponents <= 0) 192 goto out_free; 193 194 mnt = nfs_follow_referral(mnt_parent, dentry, fs_locations); 195 out_free: 196 __free_page(page); 197 kfree(fs_locations); 198 out: 199 dprintk("%s: done\n", __FUNCTION__); 200 return mnt; 201 } 202