Trond Myklebust | 55a9759 | 2006-06-09 09:34:19 -0400 | [diff] [blame] | 1 | /* |
| 2 | * linux/fs/nfs/namespace.c |
| 3 | * |
| 4 | * Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com> |
David Howells | 54ceac4 | 2006-08-22 20:06:13 -0400 | [diff] [blame] | 5 | * - Modified by David Howells <dhowells@redhat.com> |
Trond Myklebust | 55a9759 | 2006-06-09 09:34:19 -0400 | [diff] [blame] | 6 | * |
| 7 | * NFS namespace |
| 8 | */ |
| 9 | |
Trond Myklebust | 55a9759 | 2006-06-09 09:34:19 -0400 | [diff] [blame] | 10 | #include <linux/dcache.h> |
| 11 | #include <linux/mount.h> |
| 12 | #include <linux/namei.h> |
| 13 | #include <linux/nfs_fs.h> |
| 14 | #include <linux/string.h> |
| 15 | #include <linux/sunrpc/clnt.h> |
| 16 | #include <linux/vfs.h> |
David Howells | f7b422b | 2006-06-09 09:34:33 -0400 | [diff] [blame] | 17 | #include "internal.h" |
Trond Myklebust | 55a9759 | 2006-06-09 09:34:19 -0400 | [diff] [blame] | 18 | |
| 19 | #define NFSDBG_FACILITY NFSDBG_VFS |
| 20 | |
David Howells | 65f27f3 | 2006-11-22 14:55:48 +0000 | [diff] [blame] | 21 | static void nfs_expire_automounts(struct work_struct *work); |
David Howells | f7b422b | 2006-06-09 09:34:33 -0400 | [diff] [blame] | 22 | |
Adrian Bunk | a3dab29 | 2008-04-14 21:41:32 +0300 | [diff] [blame] | 23 | static LIST_HEAD(nfs_automount_list); |
David Howells | 65f27f3 | 2006-11-22 14:55:48 +0000 | [diff] [blame] | 24 | static DECLARE_DELAYED_WORK(nfs_automount_task, nfs_expire_automounts); |
Trond Myklebust | 51d8fa6 | 2006-06-09 09:34:20 -0400 | [diff] [blame] | 25 | int nfs_mountpoint_expiry_timeout = 500 * HZ; |
| 26 | |
Adrian Bunk | 66f3750 | 2006-09-27 01:51:13 -0700 | [diff] [blame] | 27 | static struct vfsmount *nfs_do_submount(const struct vfsmount *mnt_parent, |
| 28 | const struct dentry *dentry, |
| 29 | struct nfs_fh *fh, |
| 30 | struct nfs_fattr *fattr); |
| 31 | |
Trond Myklebust | 55a9759 | 2006-06-09 09:34:19 -0400 | [diff] [blame] | 32 | /* |
David Howells | f7b422b | 2006-06-09 09:34:33 -0400 | [diff] [blame] | 33 | * nfs_path - reconstruct the path given an arbitrary dentry |
| 34 | * @base - arbitrary string to prepend to the path |
David Howells | 54ceac4 | 2006-08-22 20:06:13 -0400 | [diff] [blame] | 35 | * @droot - pointer to root dentry for mountpoint |
David Howells | f7b422b | 2006-06-09 09:34:33 -0400 | [diff] [blame] | 36 | * @dentry - pointer to dentry |
| 37 | * @buffer - result buffer |
| 38 | * @buflen - length of buffer |
| 39 | * |
| 40 | * Helper function for constructing the path from the |
| 41 | * root dentry to an arbitrary hashed dentry. |
| 42 | * |
| 43 | * This is mainly for use in figuring out the path on the |
| 44 | * server side when automounting on top of an existing partition. |
| 45 | */ |
David Howells | 54ceac4 | 2006-08-22 20:06:13 -0400 | [diff] [blame] | 46 | char *nfs_path(const char *base, |
| 47 | const struct dentry *droot, |
| 48 | const struct dentry *dentry, |
David Howells | f7b422b | 2006-06-09 09:34:33 -0400 | [diff] [blame] | 49 | char *buffer, ssize_t buflen) |
| 50 | { |
| 51 | char *end = buffer+buflen; |
| 52 | int namelen; |
| 53 | |
| 54 | *--end = '\0'; |
| 55 | buflen--; |
| 56 | spin_lock(&dcache_lock); |
David Howells | 54ceac4 | 2006-08-22 20:06:13 -0400 | [diff] [blame] | 57 | while (!IS_ROOT(dentry) && dentry != droot) { |
David Howells | f7b422b | 2006-06-09 09:34:33 -0400 | [diff] [blame] | 58 | namelen = dentry->d_name.len; |
| 59 | buflen -= namelen + 1; |
| 60 | if (buflen < 0) |
Josh Triplett | ce51019 | 2006-07-24 16:30:00 -0700 | [diff] [blame] | 61 | goto Elong_unlock; |
David Howells | f7b422b | 2006-06-09 09:34:33 -0400 | [diff] [blame] | 62 | end -= namelen; |
| 63 | memcpy(end, dentry->d_name.name, namelen); |
| 64 | *--end = '/'; |
| 65 | dentry = dentry->d_parent; |
| 66 | } |
| 67 | spin_unlock(&dcache_lock); |
Trond Myklebust | 0b75b35 | 2009-06-22 15:09:14 -0400 | [diff] [blame] | 68 | if (*end != '/') { |
| 69 | if (--buflen < 0) |
| 70 | goto Elong; |
| 71 | *--end = '/'; |
| 72 | } |
David Howells | f7b422b | 2006-06-09 09:34:33 -0400 | [diff] [blame] | 73 | namelen = strlen(base); |
| 74 | /* Strip off excess slashes in base string */ |
| 75 | while (namelen > 0 && base[namelen - 1] == '/') |
| 76 | namelen--; |
| 77 | buflen -= namelen; |
| 78 | if (buflen < 0) |
| 79 | goto Elong; |
| 80 | end -= namelen; |
| 81 | memcpy(end, base, namelen); |
| 82 | return end; |
Josh Triplett | ce51019 | 2006-07-24 16:30:00 -0700 | [diff] [blame] | 83 | Elong_unlock: |
| 84 | spin_unlock(&dcache_lock); |
David Howells | f7b422b | 2006-06-09 09:34:33 -0400 | [diff] [blame] | 85 | Elong: |
| 86 | return ERR_PTR(-ENAMETOOLONG); |
| 87 | } |
| 88 | |
| 89 | /* |
Trond Myklebust | 55a9759 | 2006-06-09 09:34:19 -0400 | [diff] [blame] | 90 | * nfs_follow_mountpoint - handle crossing a mountpoint on the server |
| 91 | * @dentry - dentry of mountpoint |
| 92 | * @nd - nameidata info |
| 93 | * |
| 94 | * When we encounter a mountpoint on the server, we want to set up |
| 95 | * a mountpoint on the client too, to prevent inode numbers from |
| 96 | * colliding, and to allow "df" to work properly. |
| 97 | * On NFSv4, we also want to allow for the fact that different |
| 98 | * filesystems may be migrated to different servers in a failover |
| 99 | * situation, and that different filesystems may want to use |
| 100 | * different security flavours. |
| 101 | */ |
| 102 | static void * nfs_follow_mountpoint(struct dentry *dentry, struct nameidata *nd) |
| 103 | { |
| 104 | struct vfsmount *mnt; |
| 105 | struct nfs_server *server = NFS_SERVER(dentry->d_inode); |
| 106 | struct dentry *parent; |
| 107 | struct nfs_fh fh; |
| 108 | struct nfs_fattr fattr; |
| 109 | int err; |
| 110 | |
David Howells | 54ceac4 | 2006-08-22 20:06:13 -0400 | [diff] [blame] | 111 | dprintk("--> nfs_follow_mountpoint()\n"); |
| 112 | |
Denis V. Lunev | 44d5759 | 2008-08-11 12:02:34 +0400 | [diff] [blame] | 113 | err = -ESTALE; |
| 114 | if (IS_ROOT(dentry)) |
| 115 | goto out_err; |
| 116 | |
Harvey Harrison | 3110ff8 | 2008-05-02 13:42:44 -0700 | [diff] [blame] | 117 | dprintk("%s: enter\n", __func__); |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 118 | dput(nd->path.dentry); |
| 119 | nd->path.dentry = dget(dentry); |
David Howells | 54ceac4 | 2006-08-22 20:06:13 -0400 | [diff] [blame] | 120 | |
Trond Myklebust | 55a9759 | 2006-06-09 09:34:19 -0400 | [diff] [blame] | 121 | /* Look it up again */ |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 122 | parent = dget_parent(nd->path.dentry); |
David Howells | 8fa5c00 | 2006-08-22 20:06:12 -0400 | [diff] [blame] | 123 | err = server->nfs_client->rpc_ops->lookup(parent->d_inode, |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 124 | &nd->path.dentry->d_name, |
David Howells | 8fa5c00 | 2006-08-22 20:06:12 -0400 | [diff] [blame] | 125 | &fh, &fattr); |
Trond Myklebust | 55a9759 | 2006-06-09 09:34:19 -0400 | [diff] [blame] | 126 | dput(parent); |
| 127 | if (err != 0) |
| 128 | goto out_err; |
| 129 | |
Manoj Naik | 6b97fd3 | 2006-06-09 09:34:29 -0400 | [diff] [blame] | 130 | if (fattr.valid & NFS_ATTR_FATTR_V4_REFERRAL) |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 131 | mnt = nfs_do_refmount(nd->path.mnt, nd->path.dentry); |
Manoj Naik | 6b97fd3 | 2006-06-09 09:34:29 -0400 | [diff] [blame] | 132 | else |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 133 | mnt = nfs_do_submount(nd->path.mnt, nd->path.dentry, &fh, |
| 134 | &fattr); |
Trond Myklebust | 55a9759 | 2006-06-09 09:34:19 -0400 | [diff] [blame] | 135 | err = PTR_ERR(mnt); |
| 136 | if (IS_ERR(mnt)) |
| 137 | goto out_err; |
| 138 | |
| 139 | mntget(mnt); |
Al Viro | 8d66bf5 | 2008-08-01 09:05:54 -0400 | [diff] [blame] | 140 | err = do_add_mount(mnt, &nd->path, nd->path.mnt->mnt_flags|MNT_SHRINKABLE, |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 141 | &nfs_automount_list); |
Trond Myklebust | 55a9759 | 2006-06-09 09:34:19 -0400 | [diff] [blame] | 142 | if (err < 0) { |
| 143 | mntput(mnt); |
| 144 | if (err == -EBUSY) |
| 145 | goto out_follow; |
| 146 | goto out_err; |
| 147 | } |
Jan Blunck | 31f31db1 | 2008-05-02 13:42:45 -0700 | [diff] [blame] | 148 | path_put(&nd->path); |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 149 | nd->path.mnt = mnt; |
| 150 | nd->path.dentry = dget(mnt->mnt_root); |
Trond Myklebust | 51d8fa6 | 2006-06-09 09:34:20 -0400 | [diff] [blame] | 151 | schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout); |
Trond Myklebust | 55a9759 | 2006-06-09 09:34:19 -0400 | [diff] [blame] | 152 | out: |
Harvey Harrison | 3110ff8 | 2008-05-02 13:42:44 -0700 | [diff] [blame] | 153 | dprintk("%s: done, returned %d\n", __func__, err); |
David Howells | 54ceac4 | 2006-08-22 20:06:13 -0400 | [diff] [blame] | 154 | |
| 155 | dprintk("<-- nfs_follow_mountpoint() = %d\n", err); |
Trond Myklebust | 55a9759 | 2006-06-09 09:34:19 -0400 | [diff] [blame] | 156 | return ERR_PTR(err); |
| 157 | out_err: |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 158 | path_put(&nd->path); |
Trond Myklebust | 55a9759 | 2006-06-09 09:34:19 -0400 | [diff] [blame] | 159 | goto out; |
| 160 | out_follow: |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 161 | while (d_mountpoint(nd->path.dentry) && |
Al Viro | 9393bd0 | 2009-04-18 13:58:15 -0400 | [diff] [blame] | 162 | follow_down(&nd->path)) |
Trond Myklebust | 55a9759 | 2006-06-09 09:34:19 -0400 | [diff] [blame] | 163 | ; |
| 164 | err = 0; |
| 165 | goto out; |
| 166 | } |
| 167 | |
Arjan van de Ven | 92e1d5b | 2007-02-12 00:55:39 -0800 | [diff] [blame] | 168 | const struct inode_operations nfs_mountpoint_inode_operations = { |
Trond Myklebust | 55a9759 | 2006-06-09 09:34:19 -0400 | [diff] [blame] | 169 | .follow_link = nfs_follow_mountpoint, |
| 170 | .getattr = nfs_getattr, |
| 171 | }; |
Trond Myklebust | 51d8fa6 | 2006-06-09 09:34:20 -0400 | [diff] [blame] | 172 | |
Arjan van de Ven | 92e1d5b | 2007-02-12 00:55:39 -0800 | [diff] [blame] | 173 | const struct inode_operations nfs_referral_inode_operations = { |
Manoj Naik | 6b97fd3 | 2006-06-09 09:34:29 -0400 | [diff] [blame] | 174 | .follow_link = nfs_follow_mountpoint, |
| 175 | }; |
| 176 | |
David Howells | 65f27f3 | 2006-11-22 14:55:48 +0000 | [diff] [blame] | 177 | static void nfs_expire_automounts(struct work_struct *work) |
Trond Myklebust | 51d8fa6 | 2006-06-09 09:34:20 -0400 | [diff] [blame] | 178 | { |
David Howells | 65f27f3 | 2006-11-22 14:55:48 +0000 | [diff] [blame] | 179 | struct list_head *list = &nfs_automount_list; |
Trond Myklebust | 51d8fa6 | 2006-06-09 09:34:20 -0400 | [diff] [blame] | 180 | |
| 181 | mark_mounts_for_expiry(list); |
| 182 | if (!list_empty(list)) |
| 183 | schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout); |
| 184 | } |
| 185 | |
| 186 | void nfs_release_automount_timer(void) |
| 187 | { |
Trond Myklebust | 3d39c69 | 2007-08-07 15:28:33 -0400 | [diff] [blame] | 188 | if (list_empty(&nfs_automount_list)) |
Trond Myklebust | 560aef7 | 2007-08-27 09:14:56 -0400 | [diff] [blame] | 189 | cancel_delayed_work(&nfs_automount_task); |
Trond Myklebust | 51d8fa6 | 2006-06-09 09:34:20 -0400 | [diff] [blame] | 190 | } |
David Howells | f7b422b | 2006-06-09 09:34:33 -0400 | [diff] [blame] | 191 | |
| 192 | /* |
| 193 | * Clone a mountpoint of the appropriate type |
| 194 | */ |
David Howells | 509de81 | 2006-08-22 20:06:11 -0400 | [diff] [blame] | 195 | static struct vfsmount *nfs_do_clone_mount(struct nfs_server *server, |
| 196 | const char *devname, |
David Howells | f7b422b | 2006-06-09 09:34:33 -0400 | [diff] [blame] | 197 | struct nfs_clone_mount *mountdata) |
| 198 | { |
| 199 | #ifdef CONFIG_NFS_V4 |
Denis V. Lunev | fd08d7e | 2008-07-31 09:38:55 +0400 | [diff] [blame] | 200 | struct vfsmount *mnt = ERR_PTR(-EINVAL); |
Trond Myklebust | 40c55319 | 2007-12-14 14:56:07 -0500 | [diff] [blame] | 201 | switch (server->nfs_client->rpc_ops->version) { |
David Howells | f7b422b | 2006-06-09 09:34:33 -0400 | [diff] [blame] | 202 | case 2: |
| 203 | case 3: |
David Howells | 54ceac4 | 2006-08-22 20:06:13 -0400 | [diff] [blame] | 204 | mnt = vfs_kern_mount(&nfs_xdev_fs_type, 0, devname, mountdata); |
David Howells | f7b422b | 2006-06-09 09:34:33 -0400 | [diff] [blame] | 205 | break; |
| 206 | case 4: |
David Howells | 54ceac4 | 2006-08-22 20:06:13 -0400 | [diff] [blame] | 207 | mnt = vfs_kern_mount(&nfs4_xdev_fs_type, 0, devname, mountdata); |
David Howells | f7b422b | 2006-06-09 09:34:33 -0400 | [diff] [blame] | 208 | } |
| 209 | return mnt; |
| 210 | #else |
David Howells | 54ceac4 | 2006-08-22 20:06:13 -0400 | [diff] [blame] | 211 | return vfs_kern_mount(&nfs_xdev_fs_type, 0, devname, mountdata); |
David Howells | f7b422b | 2006-06-09 09:34:33 -0400 | [diff] [blame] | 212 | #endif |
| 213 | } |
| 214 | |
| 215 | /** |
| 216 | * nfs_do_submount - set up mountpoint when crossing a filesystem boundary |
| 217 | * @mnt_parent - mountpoint of parent directory |
| 218 | * @dentry - parent directory |
| 219 | * @fh - filehandle for new root dentry |
| 220 | * @fattr - attributes for new root inode |
| 221 | * |
| 222 | */ |
Adrian Bunk | 66f3750 | 2006-09-27 01:51:13 -0700 | [diff] [blame] | 223 | static struct vfsmount *nfs_do_submount(const struct vfsmount *mnt_parent, |
| 224 | const struct dentry *dentry, |
| 225 | struct nfs_fh *fh, |
| 226 | struct nfs_fattr *fattr) |
David Howells | f7b422b | 2006-06-09 09:34:33 -0400 | [diff] [blame] | 227 | { |
| 228 | struct nfs_clone_mount mountdata = { |
| 229 | .sb = mnt_parent->mnt_sb, |
| 230 | .dentry = dentry, |
| 231 | .fh = fh, |
| 232 | .fattr = fattr, |
| 233 | }; |
| 234 | struct vfsmount *mnt = ERR_PTR(-ENOMEM); |
| 235 | char *page = (char *) __get_free_page(GFP_USER); |
| 236 | char *devname; |
| 237 | |
David Howells | 54ceac4 | 2006-08-22 20:06:13 -0400 | [diff] [blame] | 238 | dprintk("--> nfs_do_submount()\n"); |
| 239 | |
Harvey Harrison | 3110ff8 | 2008-05-02 13:42:44 -0700 | [diff] [blame] | 240 | dprintk("%s: submounting on %s/%s\n", __func__, |
David Howells | f7b422b | 2006-06-09 09:34:33 -0400 | [diff] [blame] | 241 | dentry->d_parent->d_name.name, |
| 242 | dentry->d_name.name); |
| 243 | if (page == NULL) |
| 244 | goto out; |
| 245 | devname = nfs_devname(mnt_parent, dentry, page, PAGE_SIZE); |
| 246 | mnt = (struct vfsmount *)devname; |
| 247 | if (IS_ERR(devname)) |
| 248 | goto free_page; |
| 249 | mnt = nfs_do_clone_mount(NFS_SB(mnt_parent->mnt_sb), devname, &mountdata); |
| 250 | free_page: |
| 251 | free_page((unsigned long)page); |
| 252 | out: |
Harvey Harrison | 3110ff8 | 2008-05-02 13:42:44 -0700 | [diff] [blame] | 253 | dprintk("%s: done\n", __func__); |
David Howells | 54ceac4 | 2006-08-22 20:06:13 -0400 | [diff] [blame] | 254 | |
| 255 | dprintk("<-- nfs_do_submount() = %p\n", mnt); |
David Howells | f7b422b | 2006-06-09 09:34:33 -0400 | [diff] [blame] | 256 | return mnt; |
| 257 | } |