Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/fs/namespace.c |
| 3 | * |
| 4 | * (C) Copyright Al Viro 2000, 2001 |
| 5 | * Released under GPL v2. |
| 6 | * |
| 7 | * Based on code from fs/super.c, copyright Linus Torvalds and others. |
| 8 | * Heavily rewritten. |
| 9 | */ |
| 10 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 11 | #include <linux/syscalls.h> |
| 12 | #include <linux/slab.h> |
| 13 | #include <linux/sched.h> |
| 14 | #include <linux/smp_lock.h> |
| 15 | #include <linux/init.h> |
Randy Dunlap | 15a67dd | 2006-09-29 01:58:57 -0700 | [diff] [blame] | 16 | #include <linux/kernel.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 17 | #include <linux/quotaops.h> |
| 18 | #include <linux/acct.h> |
Randy Dunlap | 16f7e0f | 2006-01-11 12:17:46 -0800 | [diff] [blame] | 19 | #include <linux/capability.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 20 | #include <linux/module.h> |
Andrew Morton | f20a9ea | 2006-08-14 22:43:23 -0700 | [diff] [blame] | 21 | #include <linux/sysfs.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 22 | #include <linux/seq_file.h> |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 23 | #include <linux/mnt_namespace.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 24 | #include <linux/namei.h> |
| 25 | #include <linux/security.h> |
| 26 | #include <linux/mount.h> |
David Howells | 07f3f05 | 2006-09-30 20:52:18 +0200 | [diff] [blame] | 27 | #include <linux/ramfs.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 28 | #include <asm/uaccess.h> |
| 29 | #include <asm/unistd.h> |
Ram Pai | 07b2088 | 2005-11-07 17:19:07 -0500 | [diff] [blame] | 30 | #include "pnode.h" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 31 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 32 | /* spinlock for vfsmount related operations, inplace of dcache_lock */ |
Al Viro | 5addc5d | 2005-11-07 17:15:49 -0500 | [diff] [blame] | 33 | __cacheline_aligned_in_smp DEFINE_SPINLOCK(vfsmount_lock); |
| 34 | |
| 35 | static int event; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 36 | |
Eric Dumazet | fa3536c | 2006-03-26 01:37:24 -0800 | [diff] [blame] | 37 | static struct list_head *mount_hashtable __read_mostly; |
Ravikiran G Thirumalai | 6c231b7 | 2005-09-06 15:17:45 -0700 | [diff] [blame] | 38 | static int hash_mask __read_mostly, hash_bits __read_mostly; |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 39 | static struct kmem_cache *mnt_cache __read_mostly; |
Ram Pai | 390c684 | 2005-11-07 17:17:51 -0500 | [diff] [blame] | 40 | static struct rw_semaphore namespace_sem; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 41 | |
Miklos Szeredi | f87fd4c | 2006-01-16 22:14:23 -0800 | [diff] [blame] | 42 | /* /sys/fs */ |
| 43 | decl_subsys(fs, NULL, NULL); |
| 44 | EXPORT_SYMBOL_GPL(fs_subsys); |
| 45 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 46 | static inline unsigned long hash(struct vfsmount *mnt, struct dentry *dentry) |
| 47 | { |
Ram Pai | b58fed8 | 2005-11-07 17:16:09 -0500 | [diff] [blame] | 48 | unsigned long tmp = ((unsigned long)mnt / L1_CACHE_BYTES); |
| 49 | tmp += ((unsigned long)dentry / L1_CACHE_BYTES); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 50 | tmp = tmp + (tmp >> hash_bits); |
| 51 | return tmp & hash_mask; |
| 52 | } |
| 53 | |
| 54 | struct vfsmount *alloc_vfsmnt(const char *name) |
| 55 | { |
Robert P. J. Day | c376222 | 2007-02-10 01:45:03 -0800 | [diff] [blame] | 56 | struct vfsmount *mnt = kmem_cache_zalloc(mnt_cache, GFP_KERNEL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 57 | if (mnt) { |
Ram Pai | b58fed8 | 2005-11-07 17:16:09 -0500 | [diff] [blame] | 58 | atomic_set(&mnt->mnt_count, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 59 | INIT_LIST_HEAD(&mnt->mnt_hash); |
| 60 | INIT_LIST_HEAD(&mnt->mnt_child); |
| 61 | INIT_LIST_HEAD(&mnt->mnt_mounts); |
| 62 | INIT_LIST_HEAD(&mnt->mnt_list); |
Miklos Szeredi | 55e700b | 2005-07-07 17:57:30 -0700 | [diff] [blame] | 63 | INIT_LIST_HEAD(&mnt->mnt_expire); |
Ram Pai | 03e06e6 | 2005-11-07 17:19:33 -0500 | [diff] [blame] | 64 | INIT_LIST_HEAD(&mnt->mnt_share); |
Ram Pai | a58b0eb | 2005-11-07 17:20:48 -0500 | [diff] [blame] | 65 | INIT_LIST_HEAD(&mnt->mnt_slave_list); |
| 66 | INIT_LIST_HEAD(&mnt->mnt_slave); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 67 | if (name) { |
Ram Pai | b58fed8 | 2005-11-07 17:16:09 -0500 | [diff] [blame] | 68 | int size = strlen(name) + 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 69 | char *newname = kmalloc(size, GFP_KERNEL); |
| 70 | if (newname) { |
| 71 | memcpy(newname, name, size); |
| 72 | mnt->mnt_devname = newname; |
| 73 | } |
| 74 | } |
| 75 | } |
| 76 | return mnt; |
| 77 | } |
| 78 | |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 79 | int simple_set_mnt(struct vfsmount *mnt, struct super_block *sb) |
| 80 | { |
| 81 | mnt->mnt_sb = sb; |
| 82 | mnt->mnt_root = dget(sb->s_root); |
| 83 | return 0; |
| 84 | } |
| 85 | |
| 86 | EXPORT_SYMBOL(simple_set_mnt); |
| 87 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 88 | void free_vfsmnt(struct vfsmount *mnt) |
| 89 | { |
| 90 | kfree(mnt->mnt_devname); |
| 91 | kmem_cache_free(mnt_cache, mnt); |
| 92 | } |
| 93 | |
| 94 | /* |
Ram Pai | a05964f | 2005-11-07 17:20:17 -0500 | [diff] [blame] | 95 | * find the first or last mount at @dentry on vfsmount @mnt depending on |
| 96 | * @dir. If @dir is set return the first mount else return the last mount. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 97 | */ |
Ram Pai | a05964f | 2005-11-07 17:20:17 -0500 | [diff] [blame] | 98 | struct vfsmount *__lookup_mnt(struct vfsmount *mnt, struct dentry *dentry, |
| 99 | int dir) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 100 | { |
Ram Pai | b58fed8 | 2005-11-07 17:16:09 -0500 | [diff] [blame] | 101 | struct list_head *head = mount_hashtable + hash(mnt, dentry); |
| 102 | struct list_head *tmp = head; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 103 | struct vfsmount *p, *found = NULL; |
| 104 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 105 | for (;;) { |
Ram Pai | a05964f | 2005-11-07 17:20:17 -0500 | [diff] [blame] | 106 | tmp = dir ? tmp->next : tmp->prev; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 107 | p = NULL; |
| 108 | if (tmp == head) |
| 109 | break; |
| 110 | p = list_entry(tmp, struct vfsmount, mnt_hash); |
| 111 | if (p->mnt_parent == mnt && p->mnt_mountpoint == dentry) { |
Ram Pai | a05964f | 2005-11-07 17:20:17 -0500 | [diff] [blame] | 112 | found = p; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 113 | break; |
| 114 | } |
| 115 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 116 | return found; |
| 117 | } |
| 118 | |
Ram Pai | a05964f | 2005-11-07 17:20:17 -0500 | [diff] [blame] | 119 | /* |
| 120 | * lookup_mnt increments the ref count before returning |
| 121 | * the vfsmount struct. |
| 122 | */ |
| 123 | struct vfsmount *lookup_mnt(struct vfsmount *mnt, struct dentry *dentry) |
| 124 | { |
| 125 | struct vfsmount *child_mnt; |
| 126 | spin_lock(&vfsmount_lock); |
| 127 | if ((child_mnt = __lookup_mnt(mnt, dentry, 1))) |
| 128 | mntget(child_mnt); |
| 129 | spin_unlock(&vfsmount_lock); |
| 130 | return child_mnt; |
| 131 | } |
| 132 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 133 | static inline int check_mnt(struct vfsmount *mnt) |
| 134 | { |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 135 | return mnt->mnt_ns == current->nsproxy->mnt_ns; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 136 | } |
| 137 | |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 138 | static void touch_mnt_namespace(struct mnt_namespace *ns) |
Al Viro | 5addc5d | 2005-11-07 17:15:49 -0500 | [diff] [blame] | 139 | { |
| 140 | if (ns) { |
| 141 | ns->event = ++event; |
| 142 | wake_up_interruptible(&ns->poll); |
| 143 | } |
| 144 | } |
| 145 | |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 146 | static void __touch_mnt_namespace(struct mnt_namespace *ns) |
Al Viro | 5addc5d | 2005-11-07 17:15:49 -0500 | [diff] [blame] | 147 | { |
| 148 | if (ns && ns->event != event) { |
| 149 | ns->event = event; |
| 150 | wake_up_interruptible(&ns->poll); |
| 151 | } |
| 152 | } |
| 153 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 154 | static void detach_mnt(struct vfsmount *mnt, struct nameidata *old_nd) |
| 155 | { |
| 156 | old_nd->dentry = mnt->mnt_mountpoint; |
| 157 | old_nd->mnt = mnt->mnt_parent; |
| 158 | mnt->mnt_parent = mnt; |
| 159 | mnt->mnt_mountpoint = mnt->mnt_root; |
| 160 | list_del_init(&mnt->mnt_child); |
| 161 | list_del_init(&mnt->mnt_hash); |
| 162 | old_nd->dentry->d_mounted--; |
| 163 | } |
| 164 | |
Ram Pai | b90fa9a | 2005-11-07 17:19:50 -0500 | [diff] [blame] | 165 | void mnt_set_mountpoint(struct vfsmount *mnt, struct dentry *dentry, |
| 166 | struct vfsmount *child_mnt) |
| 167 | { |
| 168 | child_mnt->mnt_parent = mntget(mnt); |
| 169 | child_mnt->mnt_mountpoint = dget(dentry); |
| 170 | dentry->d_mounted++; |
| 171 | } |
| 172 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 173 | static void attach_mnt(struct vfsmount *mnt, struct nameidata *nd) |
| 174 | { |
Ram Pai | b90fa9a | 2005-11-07 17:19:50 -0500 | [diff] [blame] | 175 | mnt_set_mountpoint(nd->mnt, nd->dentry, mnt); |
| 176 | list_add_tail(&mnt->mnt_hash, mount_hashtable + |
| 177 | hash(nd->mnt, nd->dentry)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 178 | list_add_tail(&mnt->mnt_child, &nd->mnt->mnt_mounts); |
Ram Pai | b90fa9a | 2005-11-07 17:19:50 -0500 | [diff] [blame] | 179 | } |
| 180 | |
| 181 | /* |
| 182 | * the caller must hold vfsmount_lock |
| 183 | */ |
| 184 | static void commit_tree(struct vfsmount *mnt) |
| 185 | { |
| 186 | struct vfsmount *parent = mnt->mnt_parent; |
| 187 | struct vfsmount *m; |
| 188 | LIST_HEAD(head); |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 189 | struct mnt_namespace *n = parent->mnt_ns; |
Ram Pai | b90fa9a | 2005-11-07 17:19:50 -0500 | [diff] [blame] | 190 | |
| 191 | BUG_ON(parent == mnt); |
| 192 | |
| 193 | list_add_tail(&head, &mnt->mnt_list); |
| 194 | list_for_each_entry(m, &head, mnt_list) |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 195 | m->mnt_ns = n; |
Ram Pai | b90fa9a | 2005-11-07 17:19:50 -0500 | [diff] [blame] | 196 | list_splice(&head, n->list.prev); |
| 197 | |
| 198 | list_add_tail(&mnt->mnt_hash, mount_hashtable + |
| 199 | hash(parent, mnt->mnt_mountpoint)); |
| 200 | list_add_tail(&mnt->mnt_child, &parent->mnt_mounts); |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 201 | touch_mnt_namespace(n); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 202 | } |
| 203 | |
| 204 | static struct vfsmount *next_mnt(struct vfsmount *p, struct vfsmount *root) |
| 205 | { |
| 206 | struct list_head *next = p->mnt_mounts.next; |
| 207 | if (next == &p->mnt_mounts) { |
| 208 | while (1) { |
| 209 | if (p == root) |
| 210 | return NULL; |
| 211 | next = p->mnt_child.next; |
| 212 | if (next != &p->mnt_parent->mnt_mounts) |
| 213 | break; |
| 214 | p = p->mnt_parent; |
| 215 | } |
| 216 | } |
| 217 | return list_entry(next, struct vfsmount, mnt_child); |
| 218 | } |
| 219 | |
Ram Pai | 9676f0c | 2005-11-07 17:21:20 -0500 | [diff] [blame] | 220 | static struct vfsmount *skip_mnt_tree(struct vfsmount *p) |
| 221 | { |
| 222 | struct list_head *prev = p->mnt_mounts.prev; |
| 223 | while (prev != &p->mnt_mounts) { |
| 224 | p = list_entry(prev, struct vfsmount, mnt_child); |
| 225 | prev = p->mnt_mounts.prev; |
| 226 | } |
| 227 | return p; |
| 228 | } |
| 229 | |
Ram Pai | 36341f6 | 2005-11-07 17:17:22 -0500 | [diff] [blame] | 230 | static struct vfsmount *clone_mnt(struct vfsmount *old, struct dentry *root, |
| 231 | int flag) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 232 | { |
| 233 | struct super_block *sb = old->mnt_sb; |
| 234 | struct vfsmount *mnt = alloc_vfsmnt(old->mnt_devname); |
| 235 | |
| 236 | if (mnt) { |
| 237 | mnt->mnt_flags = old->mnt_flags; |
| 238 | atomic_inc(&sb->s_active); |
| 239 | mnt->mnt_sb = sb; |
| 240 | mnt->mnt_root = dget(root); |
| 241 | mnt->mnt_mountpoint = mnt->mnt_root; |
| 242 | mnt->mnt_parent = mnt; |
Ram Pai | b90fa9a | 2005-11-07 17:19:50 -0500 | [diff] [blame] | 243 | |
Ram Pai | 5afe002 | 2005-11-07 17:21:01 -0500 | [diff] [blame] | 244 | if (flag & CL_SLAVE) { |
| 245 | list_add(&mnt->mnt_slave, &old->mnt_slave_list); |
| 246 | mnt->mnt_master = old; |
| 247 | CLEAR_MNT_SHARED(mnt); |
| 248 | } else { |
| 249 | if ((flag & CL_PROPAGATION) || IS_MNT_SHARED(old)) |
| 250 | list_add(&mnt->mnt_share, &old->mnt_share); |
| 251 | if (IS_MNT_SLAVE(old)) |
| 252 | list_add(&mnt->mnt_slave, &old->mnt_slave); |
| 253 | mnt->mnt_master = old->mnt_master; |
| 254 | } |
Ram Pai | b90fa9a | 2005-11-07 17:19:50 -0500 | [diff] [blame] | 255 | if (flag & CL_MAKE_SHARED) |
| 256 | set_mnt_shared(mnt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 257 | |
| 258 | /* stick the duplicate mount on the same expiry list |
| 259 | * as the original if that was on one */ |
Ram Pai | 36341f6 | 2005-11-07 17:17:22 -0500 | [diff] [blame] | 260 | if (flag & CL_EXPIRE) { |
| 261 | spin_lock(&vfsmount_lock); |
| 262 | if (!list_empty(&old->mnt_expire)) |
| 263 | list_add(&mnt->mnt_expire, &old->mnt_expire); |
| 264 | spin_unlock(&vfsmount_lock); |
| 265 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 266 | } |
| 267 | return mnt; |
| 268 | } |
| 269 | |
Al Viro | 7b7b1ac | 2005-11-07 17:13:39 -0500 | [diff] [blame] | 270 | static inline void __mntput(struct vfsmount *mnt) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 271 | { |
| 272 | struct super_block *sb = mnt->mnt_sb; |
| 273 | dput(mnt->mnt_root); |
| 274 | free_vfsmnt(mnt); |
| 275 | deactivate_super(sb); |
| 276 | } |
| 277 | |
Al Viro | 7b7b1ac | 2005-11-07 17:13:39 -0500 | [diff] [blame] | 278 | void mntput_no_expire(struct vfsmount *mnt) |
| 279 | { |
| 280 | repeat: |
| 281 | if (atomic_dec_and_lock(&mnt->mnt_count, &vfsmount_lock)) { |
| 282 | if (likely(!mnt->mnt_pinned)) { |
| 283 | spin_unlock(&vfsmount_lock); |
| 284 | __mntput(mnt); |
| 285 | return; |
| 286 | } |
| 287 | atomic_add(mnt->mnt_pinned + 1, &mnt->mnt_count); |
| 288 | mnt->mnt_pinned = 0; |
| 289 | spin_unlock(&vfsmount_lock); |
| 290 | acct_auto_close_mnt(mnt); |
| 291 | security_sb_umount_close(mnt); |
| 292 | goto repeat; |
| 293 | } |
| 294 | } |
| 295 | |
| 296 | EXPORT_SYMBOL(mntput_no_expire); |
| 297 | |
| 298 | void mnt_pin(struct vfsmount *mnt) |
| 299 | { |
| 300 | spin_lock(&vfsmount_lock); |
| 301 | mnt->mnt_pinned++; |
| 302 | spin_unlock(&vfsmount_lock); |
| 303 | } |
| 304 | |
| 305 | EXPORT_SYMBOL(mnt_pin); |
| 306 | |
| 307 | void mnt_unpin(struct vfsmount *mnt) |
| 308 | { |
| 309 | spin_lock(&vfsmount_lock); |
| 310 | if (mnt->mnt_pinned) { |
| 311 | atomic_inc(&mnt->mnt_count); |
| 312 | mnt->mnt_pinned--; |
| 313 | } |
| 314 | spin_unlock(&vfsmount_lock); |
| 315 | } |
| 316 | |
| 317 | EXPORT_SYMBOL(mnt_unpin); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 318 | |
| 319 | /* iterator */ |
| 320 | static void *m_start(struct seq_file *m, loff_t *pos) |
| 321 | { |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 322 | struct mnt_namespace *n = m->private; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 323 | |
Ram Pai | 390c684 | 2005-11-07 17:17:51 -0500 | [diff] [blame] | 324 | down_read(&namespace_sem); |
Pavel Emelianov | b0765fb | 2007-07-15 23:39:55 -0700 | [diff] [blame^] | 325 | return seq_list_start(&n->list, *pos); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 326 | } |
| 327 | |
| 328 | static void *m_next(struct seq_file *m, void *v, loff_t *pos) |
| 329 | { |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 330 | struct mnt_namespace *n = m->private; |
Pavel Emelianov | b0765fb | 2007-07-15 23:39:55 -0700 | [diff] [blame^] | 331 | |
| 332 | return seq_list_next(v, &n->list, pos); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 333 | } |
| 334 | |
| 335 | static void m_stop(struct seq_file *m, void *v) |
| 336 | { |
Ram Pai | 390c684 | 2005-11-07 17:17:51 -0500 | [diff] [blame] | 337 | up_read(&namespace_sem); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 338 | } |
| 339 | |
| 340 | static inline void mangle(struct seq_file *m, const char *s) |
| 341 | { |
| 342 | seq_escape(m, s, " \t\n\\"); |
| 343 | } |
| 344 | |
| 345 | static int show_vfsmnt(struct seq_file *m, void *v) |
| 346 | { |
Pavel Emelianov | b0765fb | 2007-07-15 23:39:55 -0700 | [diff] [blame^] | 347 | struct vfsmount *mnt = list_entry(v, struct vfsmount, mnt_list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 348 | int err = 0; |
| 349 | static struct proc_fs_info { |
| 350 | int flag; |
| 351 | char *str; |
| 352 | } fs_info[] = { |
| 353 | { MS_SYNCHRONOUS, ",sync" }, |
| 354 | { MS_DIRSYNC, ",dirsync" }, |
| 355 | { MS_MANDLOCK, ",mand" }, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 356 | { 0, NULL } |
| 357 | }; |
| 358 | static struct proc_fs_info mnt_info[] = { |
| 359 | { MNT_NOSUID, ",nosuid" }, |
| 360 | { MNT_NODEV, ",nodev" }, |
| 361 | { MNT_NOEXEC, ",noexec" }, |
Christoph Hellwig | fc33a7b | 2006-01-09 20:52:17 -0800 | [diff] [blame] | 362 | { MNT_NOATIME, ",noatime" }, |
| 363 | { MNT_NODIRATIME, ",nodiratime" }, |
Valerie Henson | 47ae32d | 2006-12-13 00:34:34 -0800 | [diff] [blame] | 364 | { MNT_RELATIME, ",relatime" }, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 365 | { 0, NULL } |
| 366 | }; |
| 367 | struct proc_fs_info *fs_infop; |
| 368 | |
| 369 | mangle(m, mnt->mnt_devname ? mnt->mnt_devname : "none"); |
| 370 | seq_putc(m, ' '); |
| 371 | seq_path(m, mnt, mnt->mnt_root, " \t\n\\"); |
| 372 | seq_putc(m, ' '); |
| 373 | mangle(m, mnt->mnt_sb->s_type->name); |
Miklos Szeredi | 79c0b2d | 2007-05-08 00:25:43 -0700 | [diff] [blame] | 374 | if (mnt->mnt_sb->s_subtype && mnt->mnt_sb->s_subtype[0]) { |
| 375 | seq_putc(m, '.'); |
| 376 | mangle(m, mnt->mnt_sb->s_subtype); |
| 377 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 378 | seq_puts(m, mnt->mnt_sb->s_flags & MS_RDONLY ? " ro" : " rw"); |
| 379 | for (fs_infop = fs_info; fs_infop->flag; fs_infop++) { |
| 380 | if (mnt->mnt_sb->s_flags & fs_infop->flag) |
| 381 | seq_puts(m, fs_infop->str); |
| 382 | } |
| 383 | for (fs_infop = mnt_info; fs_infop->flag; fs_infop++) { |
| 384 | if (mnt->mnt_flags & fs_infop->flag) |
| 385 | seq_puts(m, fs_infop->str); |
| 386 | } |
| 387 | if (mnt->mnt_sb->s_op->show_options) |
| 388 | err = mnt->mnt_sb->s_op->show_options(m, mnt); |
| 389 | seq_puts(m, " 0 0\n"); |
| 390 | return err; |
| 391 | } |
| 392 | |
| 393 | struct seq_operations mounts_op = { |
| 394 | .start = m_start, |
| 395 | .next = m_next, |
| 396 | .stop = m_stop, |
| 397 | .show = show_vfsmnt |
| 398 | }; |
| 399 | |
Chuck Lever | b4629fe | 2006-03-20 13:44:12 -0500 | [diff] [blame] | 400 | static int show_vfsstat(struct seq_file *m, void *v) |
| 401 | { |
Pavel Emelianov | b0765fb | 2007-07-15 23:39:55 -0700 | [diff] [blame^] | 402 | struct vfsmount *mnt = list_entry(v, struct vfsmount, mnt_list); |
Chuck Lever | b4629fe | 2006-03-20 13:44:12 -0500 | [diff] [blame] | 403 | int err = 0; |
| 404 | |
| 405 | /* device */ |
| 406 | if (mnt->mnt_devname) { |
| 407 | seq_puts(m, "device "); |
| 408 | mangle(m, mnt->mnt_devname); |
| 409 | } else |
| 410 | seq_puts(m, "no device"); |
| 411 | |
| 412 | /* mount point */ |
| 413 | seq_puts(m, " mounted on "); |
| 414 | seq_path(m, mnt, mnt->mnt_root, " \t\n\\"); |
| 415 | seq_putc(m, ' '); |
| 416 | |
| 417 | /* file system type */ |
| 418 | seq_puts(m, "with fstype "); |
| 419 | mangle(m, mnt->mnt_sb->s_type->name); |
| 420 | |
| 421 | /* optional statistics */ |
| 422 | if (mnt->mnt_sb->s_op->show_stats) { |
| 423 | seq_putc(m, ' '); |
| 424 | err = mnt->mnt_sb->s_op->show_stats(m, mnt); |
| 425 | } |
| 426 | |
| 427 | seq_putc(m, '\n'); |
| 428 | return err; |
| 429 | } |
| 430 | |
| 431 | struct seq_operations mountstats_op = { |
| 432 | .start = m_start, |
| 433 | .next = m_next, |
| 434 | .stop = m_stop, |
| 435 | .show = show_vfsstat, |
| 436 | }; |
| 437 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 438 | /** |
| 439 | * may_umount_tree - check if a mount tree is busy |
| 440 | * @mnt: root of mount tree |
| 441 | * |
| 442 | * This is called to check if a tree of mounts has any |
| 443 | * open files, pwds, chroots or sub mounts that are |
| 444 | * busy. |
| 445 | */ |
| 446 | int may_umount_tree(struct vfsmount *mnt) |
| 447 | { |
Ram Pai | 36341f6 | 2005-11-07 17:17:22 -0500 | [diff] [blame] | 448 | int actual_refs = 0; |
| 449 | int minimum_refs = 0; |
| 450 | struct vfsmount *p; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 451 | |
| 452 | spin_lock(&vfsmount_lock); |
Ram Pai | 36341f6 | 2005-11-07 17:17:22 -0500 | [diff] [blame] | 453 | for (p = mnt; p; p = next_mnt(p, mnt)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 454 | actual_refs += atomic_read(&p->mnt_count); |
| 455 | minimum_refs += 2; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 456 | } |
| 457 | spin_unlock(&vfsmount_lock); |
| 458 | |
| 459 | if (actual_refs > minimum_refs) |
Ian Kent | e3474a8 | 2006-03-27 01:14:51 -0800 | [diff] [blame] | 460 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 461 | |
Ian Kent | e3474a8 | 2006-03-27 01:14:51 -0800 | [diff] [blame] | 462 | return 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 463 | } |
| 464 | |
| 465 | EXPORT_SYMBOL(may_umount_tree); |
| 466 | |
| 467 | /** |
| 468 | * may_umount - check if a mount point is busy |
| 469 | * @mnt: root of mount |
| 470 | * |
| 471 | * This is called to check if a mount point has any |
| 472 | * open files, pwds, chroots or sub mounts. If the |
| 473 | * mount has sub mounts this will return busy |
| 474 | * regardless of whether the sub mounts are busy. |
| 475 | * |
| 476 | * Doesn't take quota and stuff into account. IOW, in some cases it will |
| 477 | * give false negatives. The main reason why it's here is that we need |
| 478 | * a non-destructive way to look for easily umountable filesystems. |
| 479 | */ |
| 480 | int may_umount(struct vfsmount *mnt) |
| 481 | { |
Ian Kent | e3474a8 | 2006-03-27 01:14:51 -0800 | [diff] [blame] | 482 | int ret = 1; |
Ram Pai | a05964f | 2005-11-07 17:20:17 -0500 | [diff] [blame] | 483 | spin_lock(&vfsmount_lock); |
| 484 | if (propagate_mount_busy(mnt, 2)) |
Ian Kent | e3474a8 | 2006-03-27 01:14:51 -0800 | [diff] [blame] | 485 | ret = 0; |
Ram Pai | a05964f | 2005-11-07 17:20:17 -0500 | [diff] [blame] | 486 | spin_unlock(&vfsmount_lock); |
| 487 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 488 | } |
| 489 | |
| 490 | EXPORT_SYMBOL(may_umount); |
| 491 | |
Ram Pai | b90fa9a | 2005-11-07 17:19:50 -0500 | [diff] [blame] | 492 | void release_mounts(struct list_head *head) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 493 | { |
Ram Pai | 70fbcdf | 2005-11-07 17:17:04 -0500 | [diff] [blame] | 494 | struct vfsmount *mnt; |
Miklos Szeredi | bf066c7 | 2006-01-08 01:03:19 -0800 | [diff] [blame] | 495 | while (!list_empty(head)) { |
Pavel Emelianov | b5e6181 | 2007-05-08 00:30:19 -0700 | [diff] [blame] | 496 | mnt = list_first_entry(head, struct vfsmount, mnt_hash); |
Ram Pai | 70fbcdf | 2005-11-07 17:17:04 -0500 | [diff] [blame] | 497 | list_del_init(&mnt->mnt_hash); |
| 498 | if (mnt->mnt_parent != mnt) { |
| 499 | struct dentry *dentry; |
| 500 | struct vfsmount *m; |
| 501 | spin_lock(&vfsmount_lock); |
| 502 | dentry = mnt->mnt_mountpoint; |
| 503 | m = mnt->mnt_parent; |
| 504 | mnt->mnt_mountpoint = mnt->mnt_root; |
| 505 | mnt->mnt_parent = mnt; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 506 | spin_unlock(&vfsmount_lock); |
Ram Pai | 70fbcdf | 2005-11-07 17:17:04 -0500 | [diff] [blame] | 507 | dput(dentry); |
| 508 | mntput(m); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 509 | } |
| 510 | mntput(mnt); |
Ram Pai | 70fbcdf | 2005-11-07 17:17:04 -0500 | [diff] [blame] | 511 | } |
| 512 | } |
| 513 | |
Ram Pai | a05964f | 2005-11-07 17:20:17 -0500 | [diff] [blame] | 514 | void umount_tree(struct vfsmount *mnt, int propagate, struct list_head *kill) |
Ram Pai | 70fbcdf | 2005-11-07 17:17:04 -0500 | [diff] [blame] | 515 | { |
| 516 | struct vfsmount *p; |
| 517 | |
Akinobu Mita | 1bfba4e | 2006-06-26 00:24:40 -0700 | [diff] [blame] | 518 | for (p = mnt; p; p = next_mnt(p, mnt)) |
| 519 | list_move(&p->mnt_hash, kill); |
Ram Pai | 70fbcdf | 2005-11-07 17:17:04 -0500 | [diff] [blame] | 520 | |
Ram Pai | a05964f | 2005-11-07 17:20:17 -0500 | [diff] [blame] | 521 | if (propagate) |
| 522 | propagate_umount(kill); |
| 523 | |
Ram Pai | 70fbcdf | 2005-11-07 17:17:04 -0500 | [diff] [blame] | 524 | list_for_each_entry(p, kill, mnt_hash) { |
| 525 | list_del_init(&p->mnt_expire); |
| 526 | list_del_init(&p->mnt_list); |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 527 | __touch_mnt_namespace(p->mnt_ns); |
| 528 | p->mnt_ns = NULL; |
Ram Pai | 70fbcdf | 2005-11-07 17:17:04 -0500 | [diff] [blame] | 529 | list_del_init(&p->mnt_child); |
| 530 | if (p->mnt_parent != p) |
Al Viro | f30ac31 | 2006-02-01 07:53:21 -0500 | [diff] [blame] | 531 | p->mnt_mountpoint->d_mounted--; |
Ram Pai | a05964f | 2005-11-07 17:20:17 -0500 | [diff] [blame] | 532 | change_mnt_propagation(p, MS_PRIVATE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 533 | } |
| 534 | } |
| 535 | |
| 536 | static int do_umount(struct vfsmount *mnt, int flags) |
| 537 | { |
Ram Pai | b58fed8 | 2005-11-07 17:16:09 -0500 | [diff] [blame] | 538 | struct super_block *sb = mnt->mnt_sb; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 539 | int retval; |
Ram Pai | 70fbcdf | 2005-11-07 17:17:04 -0500 | [diff] [blame] | 540 | LIST_HEAD(umount_list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 541 | |
| 542 | retval = security_sb_umount(mnt, flags); |
| 543 | if (retval) |
| 544 | return retval; |
| 545 | |
| 546 | /* |
| 547 | * Allow userspace to request a mountpoint be expired rather than |
| 548 | * unmounting unconditionally. Unmount only happens if: |
| 549 | * (1) the mark is already set (the mark is cleared by mntput()) |
| 550 | * (2) the usage count == 1 [parent vfsmount] + 1 [sys_umount] |
| 551 | */ |
| 552 | if (flags & MNT_EXPIRE) { |
| 553 | if (mnt == current->fs->rootmnt || |
| 554 | flags & (MNT_FORCE | MNT_DETACH)) |
| 555 | return -EINVAL; |
| 556 | |
| 557 | if (atomic_read(&mnt->mnt_count) != 2) |
| 558 | return -EBUSY; |
| 559 | |
| 560 | if (!xchg(&mnt->mnt_expiry_mark, 1)) |
| 561 | return -EAGAIN; |
| 562 | } |
| 563 | |
| 564 | /* |
| 565 | * If we may have to abort operations to get out of this |
| 566 | * mount, and they will themselves hold resources we must |
| 567 | * allow the fs to do things. In the Unix tradition of |
| 568 | * 'Gee thats tricky lets do it in userspace' the umount_begin |
| 569 | * might fail to complete on the first run through as other tasks |
| 570 | * must return, and the like. Thats for the mount program to worry |
| 571 | * about for the moment. |
| 572 | */ |
| 573 | |
| 574 | lock_kernel(); |
Trond Myklebust | 8b512d9 | 2006-06-09 09:34:18 -0400 | [diff] [blame] | 575 | if (sb->s_op->umount_begin) |
| 576 | sb->s_op->umount_begin(mnt, flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 577 | unlock_kernel(); |
| 578 | |
| 579 | /* |
| 580 | * No sense to grab the lock for this test, but test itself looks |
| 581 | * somewhat bogus. Suggestions for better replacement? |
| 582 | * Ho-hum... In principle, we might treat that as umount + switch |
| 583 | * to rootfs. GC would eventually take care of the old vfsmount. |
| 584 | * Actually it makes sense, especially if rootfs would contain a |
| 585 | * /reboot - static binary that would close all descriptors and |
| 586 | * call reboot(9). Then init(8) could umount root and exec /reboot. |
| 587 | */ |
| 588 | if (mnt == current->fs->rootmnt && !(flags & MNT_DETACH)) { |
| 589 | /* |
| 590 | * Special case for "unmounting" root ... |
| 591 | * we just try to remount it readonly. |
| 592 | */ |
| 593 | down_write(&sb->s_umount); |
| 594 | if (!(sb->s_flags & MS_RDONLY)) { |
| 595 | lock_kernel(); |
| 596 | DQUOT_OFF(sb); |
| 597 | retval = do_remount_sb(sb, MS_RDONLY, NULL, 0); |
| 598 | unlock_kernel(); |
| 599 | } |
| 600 | up_write(&sb->s_umount); |
| 601 | return retval; |
| 602 | } |
| 603 | |
Ram Pai | 390c684 | 2005-11-07 17:17:51 -0500 | [diff] [blame] | 604 | down_write(&namespace_sem); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 605 | spin_lock(&vfsmount_lock); |
Al Viro | 5addc5d | 2005-11-07 17:15:49 -0500 | [diff] [blame] | 606 | event++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 607 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 608 | retval = -EBUSY; |
Ram Pai | a05964f | 2005-11-07 17:20:17 -0500 | [diff] [blame] | 609 | if (flags & MNT_DETACH || !propagate_mount_busy(mnt, 2)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 610 | if (!list_empty(&mnt->mnt_list)) |
Ram Pai | a05964f | 2005-11-07 17:20:17 -0500 | [diff] [blame] | 611 | umount_tree(mnt, 1, &umount_list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 612 | retval = 0; |
| 613 | } |
| 614 | spin_unlock(&vfsmount_lock); |
| 615 | if (retval) |
| 616 | security_sb_umount_busy(mnt); |
Ram Pai | 390c684 | 2005-11-07 17:17:51 -0500 | [diff] [blame] | 617 | up_write(&namespace_sem); |
Ram Pai | 70fbcdf | 2005-11-07 17:17:04 -0500 | [diff] [blame] | 618 | release_mounts(&umount_list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 619 | return retval; |
| 620 | } |
| 621 | |
| 622 | /* |
| 623 | * Now umount can handle mount points as well as block devices. |
| 624 | * This is important for filesystems which use unnamed block devices. |
| 625 | * |
| 626 | * We now support a flag for forced unmount like the other 'big iron' |
| 627 | * unixes. Our API is identical to OSF/1 to avoid making a mess of AMD |
| 628 | */ |
| 629 | |
| 630 | asmlinkage long sys_umount(char __user * name, int flags) |
| 631 | { |
| 632 | struct nameidata nd; |
| 633 | int retval; |
| 634 | |
| 635 | retval = __user_walk(name, LOOKUP_FOLLOW, &nd); |
| 636 | if (retval) |
| 637 | goto out; |
| 638 | retval = -EINVAL; |
| 639 | if (nd.dentry != nd.mnt->mnt_root) |
| 640 | goto dput_and_out; |
| 641 | if (!check_mnt(nd.mnt)) |
| 642 | goto dput_and_out; |
| 643 | |
| 644 | retval = -EPERM; |
| 645 | if (!capable(CAP_SYS_ADMIN)) |
| 646 | goto dput_and_out; |
| 647 | |
| 648 | retval = do_umount(nd.mnt, flags); |
| 649 | dput_and_out: |
| 650 | path_release_on_umount(&nd); |
| 651 | out: |
| 652 | return retval; |
| 653 | } |
| 654 | |
| 655 | #ifdef __ARCH_WANT_SYS_OLDUMOUNT |
| 656 | |
| 657 | /* |
Ram Pai | b58fed8 | 2005-11-07 17:16:09 -0500 | [diff] [blame] | 658 | * The 2.0 compatible umount. No flags. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 659 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 660 | asmlinkage long sys_oldumount(char __user * name) |
| 661 | { |
Ram Pai | b58fed8 | 2005-11-07 17:16:09 -0500 | [diff] [blame] | 662 | return sys_umount(name, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 663 | } |
| 664 | |
| 665 | #endif |
| 666 | |
| 667 | static int mount_is_safe(struct nameidata *nd) |
| 668 | { |
| 669 | if (capable(CAP_SYS_ADMIN)) |
| 670 | return 0; |
| 671 | return -EPERM; |
| 672 | #ifdef notyet |
| 673 | if (S_ISLNK(nd->dentry->d_inode->i_mode)) |
| 674 | return -EPERM; |
| 675 | if (nd->dentry->d_inode->i_mode & S_ISVTX) { |
| 676 | if (current->uid != nd->dentry->d_inode->i_uid) |
| 677 | return -EPERM; |
| 678 | } |
Christoph Hellwig | e4543ed | 2005-11-08 21:35:04 -0800 | [diff] [blame] | 679 | if (vfs_permission(nd, MAY_WRITE)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 680 | return -EPERM; |
| 681 | return 0; |
| 682 | #endif |
| 683 | } |
| 684 | |
Ram Pai | b58fed8 | 2005-11-07 17:16:09 -0500 | [diff] [blame] | 685 | static int lives_below_in_same_fs(struct dentry *d, struct dentry *dentry) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 686 | { |
| 687 | while (1) { |
| 688 | if (d == dentry) |
| 689 | return 1; |
| 690 | if (d == NULL || d == d->d_parent) |
| 691 | return 0; |
| 692 | d = d->d_parent; |
| 693 | } |
| 694 | } |
| 695 | |
Ram Pai | b90fa9a | 2005-11-07 17:19:50 -0500 | [diff] [blame] | 696 | struct vfsmount *copy_tree(struct vfsmount *mnt, struct dentry *dentry, |
Ram Pai | 36341f6 | 2005-11-07 17:17:22 -0500 | [diff] [blame] | 697 | int flag) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 698 | { |
| 699 | struct vfsmount *res, *p, *q, *r, *s; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 700 | struct nameidata nd; |
| 701 | |
Ram Pai | 9676f0c | 2005-11-07 17:21:20 -0500 | [diff] [blame] | 702 | if (!(flag & CL_COPY_ALL) && IS_MNT_UNBINDABLE(mnt)) |
| 703 | return NULL; |
| 704 | |
Ram Pai | 36341f6 | 2005-11-07 17:17:22 -0500 | [diff] [blame] | 705 | res = q = clone_mnt(mnt, dentry, flag); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 706 | if (!q) |
| 707 | goto Enomem; |
| 708 | q->mnt_mountpoint = mnt->mnt_mountpoint; |
| 709 | |
| 710 | p = mnt; |
Domen Puncer | fdadd65 | 2005-09-10 00:27:07 -0700 | [diff] [blame] | 711 | list_for_each_entry(r, &mnt->mnt_mounts, mnt_child) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 712 | if (!lives_below_in_same_fs(r->mnt_mountpoint, dentry)) |
| 713 | continue; |
| 714 | |
| 715 | for (s = r; s; s = next_mnt(s, r)) { |
Ram Pai | 9676f0c | 2005-11-07 17:21:20 -0500 | [diff] [blame] | 716 | if (!(flag & CL_COPY_ALL) && IS_MNT_UNBINDABLE(s)) { |
| 717 | s = skip_mnt_tree(s); |
| 718 | continue; |
| 719 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 720 | while (p != s->mnt_parent) { |
| 721 | p = p->mnt_parent; |
| 722 | q = q->mnt_parent; |
| 723 | } |
| 724 | p = s; |
| 725 | nd.mnt = q; |
| 726 | nd.dentry = p->mnt_mountpoint; |
Ram Pai | 36341f6 | 2005-11-07 17:17:22 -0500 | [diff] [blame] | 727 | q = clone_mnt(p, p->mnt_root, flag); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 728 | if (!q) |
| 729 | goto Enomem; |
| 730 | spin_lock(&vfsmount_lock); |
| 731 | list_add_tail(&q->mnt_list, &res->mnt_list); |
| 732 | attach_mnt(q, &nd); |
| 733 | spin_unlock(&vfsmount_lock); |
| 734 | } |
| 735 | } |
| 736 | return res; |
Ram Pai | b58fed8 | 2005-11-07 17:16:09 -0500 | [diff] [blame] | 737 | Enomem: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 738 | if (res) { |
Ram Pai | 70fbcdf | 2005-11-07 17:17:04 -0500 | [diff] [blame] | 739 | LIST_HEAD(umount_list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 740 | spin_lock(&vfsmount_lock); |
Ram Pai | a05964f | 2005-11-07 17:20:17 -0500 | [diff] [blame] | 741 | umount_tree(res, 0, &umount_list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 742 | spin_unlock(&vfsmount_lock); |
Ram Pai | 70fbcdf | 2005-11-07 17:17:04 -0500 | [diff] [blame] | 743 | release_mounts(&umount_list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 744 | } |
| 745 | return NULL; |
| 746 | } |
| 747 | |
Ram Pai | b90fa9a | 2005-11-07 17:19:50 -0500 | [diff] [blame] | 748 | /* |
| 749 | * @source_mnt : mount tree to be attached |
Ram Pai | 2144440 | 2005-11-07 17:20:03 -0500 | [diff] [blame] | 750 | * @nd : place the mount tree @source_mnt is attached |
| 751 | * @parent_nd : if non-null, detach the source_mnt from its parent and |
| 752 | * store the parent mount and mountpoint dentry. |
| 753 | * (done when source_mnt is moved) |
Ram Pai | b90fa9a | 2005-11-07 17:19:50 -0500 | [diff] [blame] | 754 | * |
| 755 | * NOTE: in the table below explains the semantics when a source mount |
| 756 | * of a given type is attached to a destination mount of a given type. |
Ram Pai | 9676f0c | 2005-11-07 17:21:20 -0500 | [diff] [blame] | 757 | * --------------------------------------------------------------------------- |
| 758 | * | BIND MOUNT OPERATION | |
| 759 | * |************************************************************************** |
| 760 | * | source-->| shared | private | slave | unbindable | |
| 761 | * | dest | | | | | |
| 762 | * | | | | | | | |
| 763 | * | v | | | | | |
| 764 | * |************************************************************************** |
| 765 | * | shared | shared (++) | shared (+) | shared(+++)| invalid | |
| 766 | * | | | | | | |
| 767 | * |non-shared| shared (+) | private | slave (*) | invalid | |
| 768 | * *************************************************************************** |
Ram Pai | b90fa9a | 2005-11-07 17:19:50 -0500 | [diff] [blame] | 769 | * A bind operation clones the source mount and mounts the clone on the |
| 770 | * destination mount. |
| 771 | * |
| 772 | * (++) the cloned mount is propagated to all the mounts in the propagation |
| 773 | * tree of the destination mount and the cloned mount is added to |
| 774 | * the peer group of the source mount. |
| 775 | * (+) the cloned mount is created under the destination mount and is marked |
| 776 | * as shared. The cloned mount is added to the peer group of the source |
| 777 | * mount. |
Ram Pai | 5afe002 | 2005-11-07 17:21:01 -0500 | [diff] [blame] | 778 | * (+++) the mount is propagated to all the mounts in the propagation tree |
| 779 | * of the destination mount and the cloned mount is made slave |
| 780 | * of the same master as that of the source mount. The cloned mount |
| 781 | * is marked as 'shared and slave'. |
| 782 | * (*) the cloned mount is made a slave of the same master as that of the |
| 783 | * source mount. |
| 784 | * |
Ram Pai | 9676f0c | 2005-11-07 17:21:20 -0500 | [diff] [blame] | 785 | * --------------------------------------------------------------------------- |
| 786 | * | MOVE MOUNT OPERATION | |
| 787 | * |************************************************************************** |
| 788 | * | source-->| shared | private | slave | unbindable | |
| 789 | * | dest | | | | | |
| 790 | * | | | | | | | |
| 791 | * | v | | | | | |
| 792 | * |************************************************************************** |
| 793 | * | shared | shared (+) | shared (+) | shared(+++) | invalid | |
| 794 | * | | | | | | |
| 795 | * |non-shared| shared (+*) | private | slave (*) | unbindable | |
| 796 | * *************************************************************************** |
Ram Pai | 5afe002 | 2005-11-07 17:21:01 -0500 | [diff] [blame] | 797 | * |
| 798 | * (+) the mount is moved to the destination. And is then propagated to |
| 799 | * all the mounts in the propagation tree of the destination mount. |
Ram Pai | 2144440 | 2005-11-07 17:20:03 -0500 | [diff] [blame] | 800 | * (+*) the mount is moved to the destination. |
Ram Pai | 5afe002 | 2005-11-07 17:21:01 -0500 | [diff] [blame] | 801 | * (+++) the mount is moved to the destination and is then propagated to |
| 802 | * all the mounts belonging to the destination mount's propagation tree. |
| 803 | * the mount is marked as 'shared and slave'. |
| 804 | * (*) the mount continues to be a slave at the new location. |
Ram Pai | b90fa9a | 2005-11-07 17:19:50 -0500 | [diff] [blame] | 805 | * |
| 806 | * if the source mount is a tree, the operations explained above is |
| 807 | * applied to each mount in the tree. |
| 808 | * Must be called without spinlocks held, since this function can sleep |
| 809 | * in allocations. |
| 810 | */ |
| 811 | static int attach_recursive_mnt(struct vfsmount *source_mnt, |
Ram Pai | 2144440 | 2005-11-07 17:20:03 -0500 | [diff] [blame] | 812 | struct nameidata *nd, struct nameidata *parent_nd) |
Ram Pai | b90fa9a | 2005-11-07 17:19:50 -0500 | [diff] [blame] | 813 | { |
| 814 | LIST_HEAD(tree_list); |
| 815 | struct vfsmount *dest_mnt = nd->mnt; |
| 816 | struct dentry *dest_dentry = nd->dentry; |
| 817 | struct vfsmount *child, *p; |
| 818 | |
| 819 | if (propagate_mnt(dest_mnt, dest_dentry, source_mnt, &tree_list)) |
| 820 | return -EINVAL; |
| 821 | |
| 822 | if (IS_MNT_SHARED(dest_mnt)) { |
| 823 | for (p = source_mnt; p; p = next_mnt(p, source_mnt)) |
| 824 | set_mnt_shared(p); |
| 825 | } |
| 826 | |
| 827 | spin_lock(&vfsmount_lock); |
Ram Pai | 2144440 | 2005-11-07 17:20:03 -0500 | [diff] [blame] | 828 | if (parent_nd) { |
| 829 | detach_mnt(source_mnt, parent_nd); |
| 830 | attach_mnt(source_mnt, nd); |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 831 | touch_mnt_namespace(current->nsproxy->mnt_ns); |
Ram Pai | 2144440 | 2005-11-07 17:20:03 -0500 | [diff] [blame] | 832 | } else { |
| 833 | mnt_set_mountpoint(dest_mnt, dest_dentry, source_mnt); |
| 834 | commit_tree(source_mnt); |
| 835 | } |
Ram Pai | b90fa9a | 2005-11-07 17:19:50 -0500 | [diff] [blame] | 836 | |
| 837 | list_for_each_entry_safe(child, p, &tree_list, mnt_hash) { |
| 838 | list_del_init(&child->mnt_hash); |
| 839 | commit_tree(child); |
| 840 | } |
| 841 | spin_unlock(&vfsmount_lock); |
| 842 | return 0; |
| 843 | } |
| 844 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 845 | static int graft_tree(struct vfsmount *mnt, struct nameidata *nd) |
| 846 | { |
| 847 | int err; |
| 848 | if (mnt->mnt_sb->s_flags & MS_NOUSER) |
| 849 | return -EINVAL; |
| 850 | |
| 851 | if (S_ISDIR(nd->dentry->d_inode->i_mode) != |
| 852 | S_ISDIR(mnt->mnt_root->d_inode->i_mode)) |
| 853 | return -ENOTDIR; |
| 854 | |
| 855 | err = -ENOENT; |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 856 | mutex_lock(&nd->dentry->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 857 | if (IS_DEADDIR(nd->dentry->d_inode)) |
| 858 | goto out_unlock; |
| 859 | |
| 860 | err = security_sb_check_sb(mnt, nd); |
| 861 | if (err) |
| 862 | goto out_unlock; |
| 863 | |
| 864 | err = -ENOENT; |
Ram Pai | b90fa9a | 2005-11-07 17:19:50 -0500 | [diff] [blame] | 865 | if (IS_ROOT(nd->dentry) || !d_unhashed(nd->dentry)) |
Ram Pai | 2144440 | 2005-11-07 17:20:03 -0500 | [diff] [blame] | 866 | err = attach_recursive_mnt(mnt, nd, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 867 | out_unlock: |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 868 | mutex_unlock(&nd->dentry->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 869 | if (!err) |
| 870 | security_sb_post_addmount(mnt, nd); |
| 871 | return err; |
| 872 | } |
| 873 | |
| 874 | /* |
Ram Pai | 07b2088 | 2005-11-07 17:19:07 -0500 | [diff] [blame] | 875 | * recursively change the type of the mountpoint. |
| 876 | */ |
| 877 | static int do_change_type(struct nameidata *nd, int flag) |
| 878 | { |
| 879 | struct vfsmount *m, *mnt = nd->mnt; |
| 880 | int recurse = flag & MS_REC; |
| 881 | int type = flag & ~MS_REC; |
| 882 | |
Miklos Szeredi | ee6f958 | 2007-05-08 00:30:40 -0700 | [diff] [blame] | 883 | if (!capable(CAP_SYS_ADMIN)) |
| 884 | return -EPERM; |
| 885 | |
Ram Pai | 07b2088 | 2005-11-07 17:19:07 -0500 | [diff] [blame] | 886 | if (nd->dentry != nd->mnt->mnt_root) |
| 887 | return -EINVAL; |
| 888 | |
| 889 | down_write(&namespace_sem); |
| 890 | spin_lock(&vfsmount_lock); |
| 891 | for (m = mnt; m; m = (recurse ? next_mnt(m, mnt) : NULL)) |
| 892 | change_mnt_propagation(m, type); |
| 893 | spin_unlock(&vfsmount_lock); |
| 894 | up_write(&namespace_sem); |
| 895 | return 0; |
| 896 | } |
| 897 | |
| 898 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 899 | * do loopback mount. |
| 900 | */ |
Andrew Morton | eee391a | 2006-05-15 09:44:30 -0700 | [diff] [blame] | 901 | static int do_loopback(struct nameidata *nd, char *old_name, int recurse) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 902 | { |
| 903 | struct nameidata old_nd; |
| 904 | struct vfsmount *mnt = NULL; |
| 905 | int err = mount_is_safe(nd); |
| 906 | if (err) |
| 907 | return err; |
| 908 | if (!old_name || !*old_name) |
| 909 | return -EINVAL; |
| 910 | err = path_lookup(old_name, LOOKUP_FOLLOW, &old_nd); |
| 911 | if (err) |
| 912 | return err; |
| 913 | |
Ram Pai | 390c684 | 2005-11-07 17:17:51 -0500 | [diff] [blame] | 914 | down_write(&namespace_sem); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 915 | err = -EINVAL; |
Ram Pai | 9676f0c | 2005-11-07 17:21:20 -0500 | [diff] [blame] | 916 | if (IS_MNT_UNBINDABLE(old_nd.mnt)) |
| 917 | goto out; |
| 918 | |
Al Viro | ccd48bc | 2005-11-07 17:15:04 -0500 | [diff] [blame] | 919 | if (!check_mnt(nd->mnt) || !check_mnt(old_nd.mnt)) |
| 920 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 921 | |
Al Viro | ccd48bc | 2005-11-07 17:15:04 -0500 | [diff] [blame] | 922 | err = -ENOMEM; |
| 923 | if (recurse) |
Ram Pai | 36341f6 | 2005-11-07 17:17:22 -0500 | [diff] [blame] | 924 | mnt = copy_tree(old_nd.mnt, old_nd.dentry, 0); |
Al Viro | ccd48bc | 2005-11-07 17:15:04 -0500 | [diff] [blame] | 925 | else |
Ram Pai | 36341f6 | 2005-11-07 17:17:22 -0500 | [diff] [blame] | 926 | mnt = clone_mnt(old_nd.mnt, old_nd.dentry, 0); |
Al Viro | ccd48bc | 2005-11-07 17:15:04 -0500 | [diff] [blame] | 927 | |
| 928 | if (!mnt) |
| 929 | goto out; |
| 930 | |
Al Viro | ccd48bc | 2005-11-07 17:15:04 -0500 | [diff] [blame] | 931 | err = graft_tree(mnt, nd); |
| 932 | if (err) { |
Ram Pai | 70fbcdf | 2005-11-07 17:17:04 -0500 | [diff] [blame] | 933 | LIST_HEAD(umount_list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 934 | spin_lock(&vfsmount_lock); |
Ram Pai | a05964f | 2005-11-07 17:20:17 -0500 | [diff] [blame] | 935 | umount_tree(mnt, 0, &umount_list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 936 | spin_unlock(&vfsmount_lock); |
Ram Pai | 70fbcdf | 2005-11-07 17:17:04 -0500 | [diff] [blame] | 937 | release_mounts(&umount_list); |
Ram Pai | 5b83d2c | 2005-11-07 17:16:29 -0500 | [diff] [blame] | 938 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 939 | |
Al Viro | ccd48bc | 2005-11-07 17:15:04 -0500 | [diff] [blame] | 940 | out: |
Ram Pai | 390c684 | 2005-11-07 17:17:51 -0500 | [diff] [blame] | 941 | up_write(&namespace_sem); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 942 | path_release(&old_nd); |
| 943 | return err; |
| 944 | } |
| 945 | |
| 946 | /* |
| 947 | * change filesystem flags. dir should be a physical root of filesystem. |
| 948 | * If you've mounted a non-root directory somewhere and want to do remount |
| 949 | * on it - tough luck. |
| 950 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 951 | static int do_remount(struct nameidata *nd, int flags, int mnt_flags, |
| 952 | void *data) |
| 953 | { |
| 954 | int err; |
Ram Pai | b58fed8 | 2005-11-07 17:16:09 -0500 | [diff] [blame] | 955 | struct super_block *sb = nd->mnt->mnt_sb; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 956 | |
| 957 | if (!capable(CAP_SYS_ADMIN)) |
| 958 | return -EPERM; |
| 959 | |
| 960 | if (!check_mnt(nd->mnt)) |
| 961 | return -EINVAL; |
| 962 | |
| 963 | if (nd->dentry != nd->mnt->mnt_root) |
| 964 | return -EINVAL; |
| 965 | |
| 966 | down_write(&sb->s_umount); |
| 967 | err = do_remount_sb(sb, flags, data, 0); |
| 968 | if (!err) |
Ram Pai | b58fed8 | 2005-11-07 17:16:09 -0500 | [diff] [blame] | 969 | nd->mnt->mnt_flags = mnt_flags; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 970 | up_write(&sb->s_umount); |
| 971 | if (!err) |
| 972 | security_sb_post_remount(nd->mnt, flags, data); |
| 973 | return err; |
| 974 | } |
| 975 | |
Ram Pai | 9676f0c | 2005-11-07 17:21:20 -0500 | [diff] [blame] | 976 | static inline int tree_contains_unbindable(struct vfsmount *mnt) |
| 977 | { |
| 978 | struct vfsmount *p; |
| 979 | for (p = mnt; p; p = next_mnt(p, mnt)) { |
| 980 | if (IS_MNT_UNBINDABLE(p)) |
| 981 | return 1; |
| 982 | } |
| 983 | return 0; |
| 984 | } |
| 985 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 986 | static int do_move_mount(struct nameidata *nd, char *old_name) |
| 987 | { |
| 988 | struct nameidata old_nd, parent_nd; |
| 989 | struct vfsmount *p; |
| 990 | int err = 0; |
| 991 | if (!capable(CAP_SYS_ADMIN)) |
| 992 | return -EPERM; |
| 993 | if (!old_name || !*old_name) |
| 994 | return -EINVAL; |
| 995 | err = path_lookup(old_name, LOOKUP_FOLLOW, &old_nd); |
| 996 | if (err) |
| 997 | return err; |
| 998 | |
Ram Pai | 390c684 | 2005-11-07 17:17:51 -0500 | [diff] [blame] | 999 | down_write(&namespace_sem); |
Ram Pai | b58fed8 | 2005-11-07 17:16:09 -0500 | [diff] [blame] | 1000 | while (d_mountpoint(nd->dentry) && follow_down(&nd->mnt, &nd->dentry)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1001 | ; |
| 1002 | err = -EINVAL; |
| 1003 | if (!check_mnt(nd->mnt) || !check_mnt(old_nd.mnt)) |
| 1004 | goto out; |
| 1005 | |
| 1006 | err = -ENOENT; |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 1007 | mutex_lock(&nd->dentry->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1008 | if (IS_DEADDIR(nd->dentry->d_inode)) |
| 1009 | goto out1; |
| 1010 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1011 | if (!IS_ROOT(nd->dentry) && d_unhashed(nd->dentry)) |
Ram Pai | 2144440 | 2005-11-07 17:20:03 -0500 | [diff] [blame] | 1012 | goto out1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1013 | |
| 1014 | err = -EINVAL; |
| 1015 | if (old_nd.dentry != old_nd.mnt->mnt_root) |
Ram Pai | 2144440 | 2005-11-07 17:20:03 -0500 | [diff] [blame] | 1016 | goto out1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1017 | |
| 1018 | if (old_nd.mnt == old_nd.mnt->mnt_parent) |
Ram Pai | 2144440 | 2005-11-07 17:20:03 -0500 | [diff] [blame] | 1019 | goto out1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1020 | |
| 1021 | if (S_ISDIR(nd->dentry->d_inode->i_mode) != |
| 1022 | S_ISDIR(old_nd.dentry->d_inode->i_mode)) |
Ram Pai | 2144440 | 2005-11-07 17:20:03 -0500 | [diff] [blame] | 1023 | goto out1; |
| 1024 | /* |
| 1025 | * Don't move a mount residing in a shared parent. |
| 1026 | */ |
| 1027 | if (old_nd.mnt->mnt_parent && IS_MNT_SHARED(old_nd.mnt->mnt_parent)) |
| 1028 | goto out1; |
Ram Pai | 9676f0c | 2005-11-07 17:21:20 -0500 | [diff] [blame] | 1029 | /* |
| 1030 | * Don't move a mount tree containing unbindable mounts to a destination |
| 1031 | * mount which is shared. |
| 1032 | */ |
| 1033 | if (IS_MNT_SHARED(nd->mnt) && tree_contains_unbindable(old_nd.mnt)) |
| 1034 | goto out1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1035 | err = -ELOOP; |
Ram Pai | b58fed8 | 2005-11-07 17:16:09 -0500 | [diff] [blame] | 1036 | for (p = nd->mnt; p->mnt_parent != p; p = p->mnt_parent) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1037 | if (p == old_nd.mnt) |
Ram Pai | 2144440 | 2005-11-07 17:20:03 -0500 | [diff] [blame] | 1038 | goto out1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1039 | |
Ram Pai | 2144440 | 2005-11-07 17:20:03 -0500 | [diff] [blame] | 1040 | if ((err = attach_recursive_mnt(old_nd.mnt, nd, &parent_nd))) |
| 1041 | goto out1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1042 | |
Ram Pai | 2144440 | 2005-11-07 17:20:03 -0500 | [diff] [blame] | 1043 | spin_lock(&vfsmount_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1044 | /* if the mount is moved, it should no longer be expire |
| 1045 | * automatically */ |
Miklos Szeredi | 55e700b | 2005-07-07 17:57:30 -0700 | [diff] [blame] | 1046 | list_del_init(&old_nd.mnt->mnt_expire); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1047 | spin_unlock(&vfsmount_lock); |
| 1048 | out1: |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 1049 | mutex_unlock(&nd->dentry->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1050 | out: |
Ram Pai | 390c684 | 2005-11-07 17:17:51 -0500 | [diff] [blame] | 1051 | up_write(&namespace_sem); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1052 | if (!err) |
| 1053 | path_release(&parent_nd); |
| 1054 | path_release(&old_nd); |
| 1055 | return err; |
| 1056 | } |
| 1057 | |
| 1058 | /* |
| 1059 | * create a new mount for userspace and request it to be added into the |
| 1060 | * namespace's tree |
| 1061 | */ |
| 1062 | static int do_new_mount(struct nameidata *nd, char *type, int flags, |
| 1063 | int mnt_flags, char *name, void *data) |
| 1064 | { |
| 1065 | struct vfsmount *mnt; |
| 1066 | |
| 1067 | if (!type || !memchr(type, 0, PAGE_SIZE)) |
| 1068 | return -EINVAL; |
| 1069 | |
| 1070 | /* we need capabilities... */ |
| 1071 | if (!capable(CAP_SYS_ADMIN)) |
| 1072 | return -EPERM; |
| 1073 | |
| 1074 | mnt = do_kern_mount(type, flags, name, data); |
| 1075 | if (IS_ERR(mnt)) |
| 1076 | return PTR_ERR(mnt); |
| 1077 | |
| 1078 | return do_add_mount(mnt, nd, mnt_flags, NULL); |
| 1079 | } |
| 1080 | |
| 1081 | /* |
| 1082 | * add a mount into a namespace's mount tree |
| 1083 | * - provide the option of adding the new mount to an expiration list |
| 1084 | */ |
| 1085 | int do_add_mount(struct vfsmount *newmnt, struct nameidata *nd, |
| 1086 | int mnt_flags, struct list_head *fslist) |
| 1087 | { |
| 1088 | int err; |
| 1089 | |
Ram Pai | 390c684 | 2005-11-07 17:17:51 -0500 | [diff] [blame] | 1090 | down_write(&namespace_sem); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1091 | /* Something was mounted here while we slept */ |
Ram Pai | b58fed8 | 2005-11-07 17:16:09 -0500 | [diff] [blame] | 1092 | while (d_mountpoint(nd->dentry) && follow_down(&nd->mnt, &nd->dentry)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1093 | ; |
| 1094 | err = -EINVAL; |
| 1095 | if (!check_mnt(nd->mnt)) |
| 1096 | goto unlock; |
| 1097 | |
| 1098 | /* Refuse the same filesystem on the same mount point */ |
| 1099 | err = -EBUSY; |
| 1100 | if (nd->mnt->mnt_sb == newmnt->mnt_sb && |
| 1101 | nd->mnt->mnt_root == nd->dentry) |
| 1102 | goto unlock; |
| 1103 | |
| 1104 | err = -EINVAL; |
| 1105 | if (S_ISLNK(newmnt->mnt_root->d_inode->i_mode)) |
| 1106 | goto unlock; |
| 1107 | |
| 1108 | newmnt->mnt_flags = mnt_flags; |
Ram Pai | 5b83d2c | 2005-11-07 17:16:29 -0500 | [diff] [blame] | 1109 | if ((err = graft_tree(newmnt, nd))) |
| 1110 | goto unlock; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1111 | |
Ram Pai | 5b83d2c | 2005-11-07 17:16:29 -0500 | [diff] [blame] | 1112 | if (fslist) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1113 | /* add to the specified expiration list */ |
| 1114 | spin_lock(&vfsmount_lock); |
Miklos Szeredi | 55e700b | 2005-07-07 17:57:30 -0700 | [diff] [blame] | 1115 | list_add_tail(&newmnt->mnt_expire, fslist); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1116 | spin_unlock(&vfsmount_lock); |
| 1117 | } |
Ram Pai | 390c684 | 2005-11-07 17:17:51 -0500 | [diff] [blame] | 1118 | up_write(&namespace_sem); |
Ram Pai | 5b83d2c | 2005-11-07 17:16:29 -0500 | [diff] [blame] | 1119 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1120 | |
| 1121 | unlock: |
Ram Pai | 390c684 | 2005-11-07 17:17:51 -0500 | [diff] [blame] | 1122 | up_write(&namespace_sem); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1123 | mntput(newmnt); |
| 1124 | return err; |
| 1125 | } |
| 1126 | |
| 1127 | EXPORT_SYMBOL_GPL(do_add_mount); |
| 1128 | |
Ram Pai | 70fbcdf | 2005-11-07 17:17:04 -0500 | [diff] [blame] | 1129 | static void expire_mount(struct vfsmount *mnt, struct list_head *mounts, |
| 1130 | struct list_head *umounts) |
Miklos Szeredi | 24ca2af | 2005-07-07 17:57:25 -0700 | [diff] [blame] | 1131 | { |
| 1132 | spin_lock(&vfsmount_lock); |
| 1133 | |
| 1134 | /* |
Miklos Szeredi | ed42c87 | 2005-07-07 17:57:26 -0700 | [diff] [blame] | 1135 | * Check if mount is still attached, if not, let whoever holds it deal |
| 1136 | * with the sucker |
| 1137 | */ |
| 1138 | if (mnt->mnt_parent == mnt) { |
| 1139 | spin_unlock(&vfsmount_lock); |
| 1140 | return; |
| 1141 | } |
| 1142 | |
| 1143 | /* |
Miklos Szeredi | 24ca2af | 2005-07-07 17:57:25 -0700 | [diff] [blame] | 1144 | * Check that it is still dead: the count should now be 2 - as |
| 1145 | * contributed by the vfsmount parent and the mntget above |
| 1146 | */ |
Ram Pai | a05964f | 2005-11-07 17:20:17 -0500 | [diff] [blame] | 1147 | if (!propagate_mount_busy(mnt, 2)) { |
Miklos Szeredi | 24ca2af | 2005-07-07 17:57:25 -0700 | [diff] [blame] | 1148 | /* delete from the namespace */ |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 1149 | touch_mnt_namespace(mnt->mnt_ns); |
Miklos Szeredi | 24ca2af | 2005-07-07 17:57:25 -0700 | [diff] [blame] | 1150 | list_del_init(&mnt->mnt_list); |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 1151 | mnt->mnt_ns = NULL; |
Ram Pai | a05964f | 2005-11-07 17:20:17 -0500 | [diff] [blame] | 1152 | umount_tree(mnt, 1, umounts); |
Miklos Szeredi | 24ca2af | 2005-07-07 17:57:25 -0700 | [diff] [blame] | 1153 | spin_unlock(&vfsmount_lock); |
Miklos Szeredi | 24ca2af | 2005-07-07 17:57:25 -0700 | [diff] [blame] | 1154 | } else { |
| 1155 | /* |
| 1156 | * Someone brought it back to life whilst we didn't have any |
| 1157 | * locks held so return it to the expiration list |
| 1158 | */ |
Miklos Szeredi | 55e700b | 2005-07-07 17:57:30 -0700 | [diff] [blame] | 1159 | list_add_tail(&mnt->mnt_expire, mounts); |
Miklos Szeredi | 24ca2af | 2005-07-07 17:57:25 -0700 | [diff] [blame] | 1160 | spin_unlock(&vfsmount_lock); |
| 1161 | } |
| 1162 | } |
| 1163 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1164 | /* |
Trond Myklebust | 5528f911 | 2006-06-09 09:34:17 -0400 | [diff] [blame] | 1165 | * go through the vfsmounts we've just consigned to the graveyard to |
| 1166 | * - check that they're still dead |
| 1167 | * - delete the vfsmount from the appropriate namespace under lock |
| 1168 | * - dispose of the corpse |
| 1169 | */ |
| 1170 | static void expire_mount_list(struct list_head *graveyard, struct list_head *mounts) |
| 1171 | { |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 1172 | struct mnt_namespace *ns; |
Trond Myklebust | 5528f911 | 2006-06-09 09:34:17 -0400 | [diff] [blame] | 1173 | struct vfsmount *mnt; |
| 1174 | |
| 1175 | while (!list_empty(graveyard)) { |
| 1176 | LIST_HEAD(umounts); |
Pavel Emelianov | b5e6181 | 2007-05-08 00:30:19 -0700 | [diff] [blame] | 1177 | mnt = list_first_entry(graveyard, struct vfsmount, mnt_expire); |
Trond Myklebust | 5528f911 | 2006-06-09 09:34:17 -0400 | [diff] [blame] | 1178 | list_del_init(&mnt->mnt_expire); |
| 1179 | |
| 1180 | /* don't do anything if the namespace is dead - all the |
| 1181 | * vfsmounts from it are going away anyway */ |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 1182 | ns = mnt->mnt_ns; |
| 1183 | if (!ns || !ns->root) |
Trond Myklebust | 5528f911 | 2006-06-09 09:34:17 -0400 | [diff] [blame] | 1184 | continue; |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 1185 | get_mnt_ns(ns); |
Trond Myklebust | 5528f911 | 2006-06-09 09:34:17 -0400 | [diff] [blame] | 1186 | |
| 1187 | spin_unlock(&vfsmount_lock); |
| 1188 | down_write(&namespace_sem); |
| 1189 | expire_mount(mnt, mounts, &umounts); |
| 1190 | up_write(&namespace_sem); |
| 1191 | release_mounts(&umounts); |
| 1192 | mntput(mnt); |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 1193 | put_mnt_ns(ns); |
Trond Myklebust | 5528f911 | 2006-06-09 09:34:17 -0400 | [diff] [blame] | 1194 | spin_lock(&vfsmount_lock); |
| 1195 | } |
| 1196 | } |
| 1197 | |
| 1198 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1199 | * process a list of expirable mountpoints with the intent of discarding any |
| 1200 | * mountpoints that aren't in use and haven't been touched since last we came |
| 1201 | * here |
| 1202 | */ |
| 1203 | void mark_mounts_for_expiry(struct list_head *mounts) |
| 1204 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1205 | struct vfsmount *mnt, *next; |
| 1206 | LIST_HEAD(graveyard); |
| 1207 | |
| 1208 | if (list_empty(mounts)) |
| 1209 | return; |
| 1210 | |
| 1211 | spin_lock(&vfsmount_lock); |
| 1212 | |
| 1213 | /* extract from the expiration list every vfsmount that matches the |
| 1214 | * following criteria: |
| 1215 | * - only referenced by its parent vfsmount |
| 1216 | * - still marked for expiry (marked on the last call here; marks are |
| 1217 | * cleared by mntput()) |
| 1218 | */ |
Miklos Szeredi | 55e700b | 2005-07-07 17:57:30 -0700 | [diff] [blame] | 1219 | list_for_each_entry_safe(mnt, next, mounts, mnt_expire) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1220 | if (!xchg(&mnt->mnt_expiry_mark, 1) || |
| 1221 | atomic_read(&mnt->mnt_count) != 1) |
| 1222 | continue; |
| 1223 | |
| 1224 | mntget(mnt); |
Miklos Szeredi | 55e700b | 2005-07-07 17:57:30 -0700 | [diff] [blame] | 1225 | list_move(&mnt->mnt_expire, &graveyard); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1226 | } |
| 1227 | |
Trond Myklebust | 5528f911 | 2006-06-09 09:34:17 -0400 | [diff] [blame] | 1228 | expire_mount_list(&graveyard, mounts); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1229 | |
| 1230 | spin_unlock(&vfsmount_lock); |
| 1231 | } |
| 1232 | |
| 1233 | EXPORT_SYMBOL_GPL(mark_mounts_for_expiry); |
| 1234 | |
| 1235 | /* |
Trond Myklebust | 5528f911 | 2006-06-09 09:34:17 -0400 | [diff] [blame] | 1236 | * Ripoff of 'select_parent()' |
| 1237 | * |
| 1238 | * search the list of submounts for a given mountpoint, and move any |
| 1239 | * shrinkable submounts to the 'graveyard' list. |
| 1240 | */ |
| 1241 | static int select_submounts(struct vfsmount *parent, struct list_head *graveyard) |
| 1242 | { |
| 1243 | struct vfsmount *this_parent = parent; |
| 1244 | struct list_head *next; |
| 1245 | int found = 0; |
| 1246 | |
| 1247 | repeat: |
| 1248 | next = this_parent->mnt_mounts.next; |
| 1249 | resume: |
| 1250 | while (next != &this_parent->mnt_mounts) { |
| 1251 | struct list_head *tmp = next; |
| 1252 | struct vfsmount *mnt = list_entry(tmp, struct vfsmount, mnt_child); |
| 1253 | |
| 1254 | next = tmp->next; |
| 1255 | if (!(mnt->mnt_flags & MNT_SHRINKABLE)) |
| 1256 | continue; |
| 1257 | /* |
| 1258 | * Descend a level if the d_mounts list is non-empty. |
| 1259 | */ |
| 1260 | if (!list_empty(&mnt->mnt_mounts)) { |
| 1261 | this_parent = mnt; |
| 1262 | goto repeat; |
| 1263 | } |
| 1264 | |
| 1265 | if (!propagate_mount_busy(mnt, 1)) { |
| 1266 | mntget(mnt); |
| 1267 | list_move_tail(&mnt->mnt_expire, graveyard); |
| 1268 | found++; |
| 1269 | } |
| 1270 | } |
| 1271 | /* |
| 1272 | * All done at this level ... ascend and resume the search |
| 1273 | */ |
| 1274 | if (this_parent != parent) { |
| 1275 | next = this_parent->mnt_child.next; |
| 1276 | this_parent = this_parent->mnt_parent; |
| 1277 | goto resume; |
| 1278 | } |
| 1279 | return found; |
| 1280 | } |
| 1281 | |
| 1282 | /* |
| 1283 | * process a list of expirable mountpoints with the intent of discarding any |
| 1284 | * submounts of a specific parent mountpoint |
| 1285 | */ |
| 1286 | void shrink_submounts(struct vfsmount *mountpoint, struct list_head *mounts) |
| 1287 | { |
| 1288 | LIST_HEAD(graveyard); |
| 1289 | int found; |
| 1290 | |
| 1291 | spin_lock(&vfsmount_lock); |
| 1292 | |
| 1293 | /* extract submounts of 'mountpoint' from the expiration list */ |
| 1294 | while ((found = select_submounts(mountpoint, &graveyard)) != 0) |
| 1295 | expire_mount_list(&graveyard, mounts); |
| 1296 | |
| 1297 | spin_unlock(&vfsmount_lock); |
| 1298 | } |
| 1299 | |
| 1300 | EXPORT_SYMBOL_GPL(shrink_submounts); |
| 1301 | |
| 1302 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1303 | * Some copy_from_user() implementations do not return the exact number of |
| 1304 | * bytes remaining to copy on a fault. But copy_mount_options() requires that. |
| 1305 | * Note that this function differs from copy_from_user() in that it will oops |
| 1306 | * on bad values of `to', rather than returning a short copy. |
| 1307 | */ |
Ram Pai | b58fed8 | 2005-11-07 17:16:09 -0500 | [diff] [blame] | 1308 | static long exact_copy_from_user(void *to, const void __user * from, |
| 1309 | unsigned long n) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1310 | { |
| 1311 | char *t = to; |
| 1312 | const char __user *f = from; |
| 1313 | char c; |
| 1314 | |
| 1315 | if (!access_ok(VERIFY_READ, from, n)) |
| 1316 | return n; |
| 1317 | |
| 1318 | while (n) { |
| 1319 | if (__get_user(c, f)) { |
| 1320 | memset(t, 0, n); |
| 1321 | break; |
| 1322 | } |
| 1323 | *t++ = c; |
| 1324 | f++; |
| 1325 | n--; |
| 1326 | } |
| 1327 | return n; |
| 1328 | } |
| 1329 | |
Ram Pai | b58fed8 | 2005-11-07 17:16:09 -0500 | [diff] [blame] | 1330 | int copy_mount_options(const void __user * data, unsigned long *where) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1331 | { |
| 1332 | int i; |
| 1333 | unsigned long page; |
| 1334 | unsigned long size; |
Ram Pai | b58fed8 | 2005-11-07 17:16:09 -0500 | [diff] [blame] | 1335 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1336 | *where = 0; |
| 1337 | if (!data) |
| 1338 | return 0; |
| 1339 | |
| 1340 | if (!(page = __get_free_page(GFP_KERNEL))) |
| 1341 | return -ENOMEM; |
| 1342 | |
| 1343 | /* We only care that *some* data at the address the user |
| 1344 | * gave us is valid. Just in case, we'll zero |
| 1345 | * the remainder of the page. |
| 1346 | */ |
| 1347 | /* copy_from_user cannot cross TASK_SIZE ! */ |
| 1348 | size = TASK_SIZE - (unsigned long)data; |
| 1349 | if (size > PAGE_SIZE) |
| 1350 | size = PAGE_SIZE; |
| 1351 | |
| 1352 | i = size - exact_copy_from_user((void *)page, data, size); |
| 1353 | if (!i) { |
Ram Pai | b58fed8 | 2005-11-07 17:16:09 -0500 | [diff] [blame] | 1354 | free_page(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1355 | return -EFAULT; |
| 1356 | } |
| 1357 | if (i != PAGE_SIZE) |
| 1358 | memset((char *)page + i, 0, PAGE_SIZE - i); |
| 1359 | *where = page; |
| 1360 | return 0; |
| 1361 | } |
| 1362 | |
| 1363 | /* |
| 1364 | * Flags is a 32-bit value that allows up to 31 non-fs dependent flags to |
| 1365 | * be given to the mount() call (ie: read-only, no-dev, no-suid etc). |
| 1366 | * |
| 1367 | * data is a (void *) that can point to any structure up to |
| 1368 | * PAGE_SIZE-1 bytes, which can contain arbitrary fs-dependent |
| 1369 | * information (or be NULL). |
| 1370 | * |
| 1371 | * Pre-0.97 versions of mount() didn't have a flags word. |
| 1372 | * When the flags word was introduced its top half was required |
| 1373 | * to have the magic value 0xC0ED, and this remained so until 2.4.0-test9. |
| 1374 | * Therefore, if this magic number is present, it carries no information |
| 1375 | * and must be discarded. |
| 1376 | */ |
Ram Pai | b58fed8 | 2005-11-07 17:16:09 -0500 | [diff] [blame] | 1377 | long do_mount(char *dev_name, char *dir_name, char *type_page, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1378 | unsigned long flags, void *data_page) |
| 1379 | { |
| 1380 | struct nameidata nd; |
| 1381 | int retval = 0; |
| 1382 | int mnt_flags = 0; |
| 1383 | |
| 1384 | /* Discard magic */ |
| 1385 | if ((flags & MS_MGC_MSK) == MS_MGC_VAL) |
| 1386 | flags &= ~MS_MGC_MSK; |
| 1387 | |
| 1388 | /* Basic sanity checks */ |
| 1389 | |
| 1390 | if (!dir_name || !*dir_name || !memchr(dir_name, 0, PAGE_SIZE)) |
| 1391 | return -EINVAL; |
| 1392 | if (dev_name && !memchr(dev_name, 0, PAGE_SIZE)) |
| 1393 | return -EINVAL; |
| 1394 | |
| 1395 | if (data_page) |
| 1396 | ((char *)data_page)[PAGE_SIZE - 1] = 0; |
| 1397 | |
| 1398 | /* Separate the per-mountpoint flags */ |
| 1399 | if (flags & MS_NOSUID) |
| 1400 | mnt_flags |= MNT_NOSUID; |
| 1401 | if (flags & MS_NODEV) |
| 1402 | mnt_flags |= MNT_NODEV; |
| 1403 | if (flags & MS_NOEXEC) |
| 1404 | mnt_flags |= MNT_NOEXEC; |
Christoph Hellwig | fc33a7b | 2006-01-09 20:52:17 -0800 | [diff] [blame] | 1405 | if (flags & MS_NOATIME) |
| 1406 | mnt_flags |= MNT_NOATIME; |
| 1407 | if (flags & MS_NODIRATIME) |
| 1408 | mnt_flags |= MNT_NODIRATIME; |
Valerie Henson | 47ae32d | 2006-12-13 00:34:34 -0800 | [diff] [blame] | 1409 | if (flags & MS_RELATIME) |
| 1410 | mnt_flags |= MNT_RELATIME; |
Christoph Hellwig | fc33a7b | 2006-01-09 20:52:17 -0800 | [diff] [blame] | 1411 | |
| 1412 | flags &= ~(MS_NOSUID | MS_NOEXEC | MS_NODEV | MS_ACTIVE | |
Valerie Henson | 47ae32d | 2006-12-13 00:34:34 -0800 | [diff] [blame] | 1413 | MS_NOATIME | MS_NODIRATIME | MS_RELATIME); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1414 | |
| 1415 | /* ... and get the mountpoint */ |
| 1416 | retval = path_lookup(dir_name, LOOKUP_FOLLOW, &nd); |
| 1417 | if (retval) |
| 1418 | return retval; |
| 1419 | |
| 1420 | retval = security_sb_mount(dev_name, &nd, type_page, flags, data_page); |
| 1421 | if (retval) |
| 1422 | goto dput_out; |
| 1423 | |
| 1424 | if (flags & MS_REMOUNT) |
| 1425 | retval = do_remount(&nd, flags & ~MS_REMOUNT, mnt_flags, |
| 1426 | data_page); |
| 1427 | else if (flags & MS_BIND) |
Andrew Morton | eee391a | 2006-05-15 09:44:30 -0700 | [diff] [blame] | 1428 | retval = do_loopback(&nd, dev_name, flags & MS_REC); |
Ram Pai | 9676f0c | 2005-11-07 17:21:20 -0500 | [diff] [blame] | 1429 | else if (flags & (MS_SHARED | MS_PRIVATE | MS_SLAVE | MS_UNBINDABLE)) |
Ram Pai | 07b2088 | 2005-11-07 17:19:07 -0500 | [diff] [blame] | 1430 | retval = do_change_type(&nd, flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1431 | else if (flags & MS_MOVE) |
| 1432 | retval = do_move_mount(&nd, dev_name); |
| 1433 | else |
| 1434 | retval = do_new_mount(&nd, type_page, flags, mnt_flags, |
| 1435 | dev_name, data_page); |
| 1436 | dput_out: |
| 1437 | path_release(&nd); |
| 1438 | return retval; |
| 1439 | } |
| 1440 | |
JANAK DESAI | 741a295 | 2006-02-07 12:59:00 -0800 | [diff] [blame] | 1441 | /* |
| 1442 | * Allocate a new namespace structure and populate it with contents |
| 1443 | * copied from the namespace of the passed in task structure. |
| 1444 | */ |
Badari Pulavarty | e3222c4 | 2007-05-08 00:25:21 -0700 | [diff] [blame] | 1445 | static struct mnt_namespace *dup_mnt_ns(struct mnt_namespace *mnt_ns, |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 1446 | struct fs_struct *fs) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1447 | { |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 1448 | struct mnt_namespace *new_ns; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1449 | struct vfsmount *rootmnt = NULL, *pwdmnt = NULL, *altrootmnt = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1450 | struct vfsmount *p, *q; |
| 1451 | |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 1452 | new_ns = kmalloc(sizeof(struct mnt_namespace), GFP_KERNEL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1453 | if (!new_ns) |
Adrian Bunk | f13b835 | 2006-03-15 17:37:32 +0100 | [diff] [blame] | 1454 | return NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1455 | |
| 1456 | atomic_set(&new_ns->count, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1457 | INIT_LIST_HEAD(&new_ns->list); |
Al Viro | 5addc5d | 2005-11-07 17:15:49 -0500 | [diff] [blame] | 1458 | init_waitqueue_head(&new_ns->poll); |
| 1459 | new_ns->event = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1460 | |
Ram Pai | 390c684 | 2005-11-07 17:17:51 -0500 | [diff] [blame] | 1461 | down_write(&namespace_sem); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1462 | /* First pass: copy the tree topology */ |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 1463 | new_ns->root = copy_tree(mnt_ns->root, mnt_ns->root->mnt_root, |
Ram Pai | 9676f0c | 2005-11-07 17:21:20 -0500 | [diff] [blame] | 1464 | CL_COPY_ALL | CL_EXPIRE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1465 | if (!new_ns->root) { |
Ram Pai | 390c684 | 2005-11-07 17:17:51 -0500 | [diff] [blame] | 1466 | up_write(&namespace_sem); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1467 | kfree(new_ns); |
Adrian Bunk | f13b835 | 2006-03-15 17:37:32 +0100 | [diff] [blame] | 1468 | return NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1469 | } |
| 1470 | spin_lock(&vfsmount_lock); |
| 1471 | list_add_tail(&new_ns->list, &new_ns->root->mnt_list); |
| 1472 | spin_unlock(&vfsmount_lock); |
| 1473 | |
| 1474 | /* |
| 1475 | * Second pass: switch the tsk->fs->* elements and mark new vfsmounts |
| 1476 | * as belonging to new namespace. We have already acquired a private |
| 1477 | * fs_struct, so tsk->fs->lock is not needed. |
| 1478 | */ |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 1479 | p = mnt_ns->root; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1480 | q = new_ns->root; |
| 1481 | while (p) { |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 1482 | q->mnt_ns = new_ns; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1483 | if (fs) { |
| 1484 | if (p == fs->rootmnt) { |
| 1485 | rootmnt = p; |
| 1486 | fs->rootmnt = mntget(q); |
| 1487 | } |
| 1488 | if (p == fs->pwdmnt) { |
| 1489 | pwdmnt = p; |
| 1490 | fs->pwdmnt = mntget(q); |
| 1491 | } |
| 1492 | if (p == fs->altrootmnt) { |
| 1493 | altrootmnt = p; |
| 1494 | fs->altrootmnt = mntget(q); |
| 1495 | } |
| 1496 | } |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 1497 | p = next_mnt(p, mnt_ns->root); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1498 | q = next_mnt(q, new_ns->root); |
| 1499 | } |
Ram Pai | 390c684 | 2005-11-07 17:17:51 -0500 | [diff] [blame] | 1500 | up_write(&namespace_sem); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1501 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1502 | if (rootmnt) |
| 1503 | mntput(rootmnt); |
| 1504 | if (pwdmnt) |
| 1505 | mntput(pwdmnt); |
| 1506 | if (altrootmnt) |
| 1507 | mntput(altrootmnt); |
| 1508 | |
JANAK DESAI | 741a295 | 2006-02-07 12:59:00 -0800 | [diff] [blame] | 1509 | return new_ns; |
| 1510 | } |
| 1511 | |
Badari Pulavarty | e3222c4 | 2007-05-08 00:25:21 -0700 | [diff] [blame] | 1512 | struct mnt_namespace *copy_mnt_ns(int flags, struct mnt_namespace *ns, |
| 1513 | struct fs_struct *new_fs) |
JANAK DESAI | 741a295 | 2006-02-07 12:59:00 -0800 | [diff] [blame] | 1514 | { |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 1515 | struct mnt_namespace *new_ns; |
JANAK DESAI | 741a295 | 2006-02-07 12:59:00 -0800 | [diff] [blame] | 1516 | |
Badari Pulavarty | e3222c4 | 2007-05-08 00:25:21 -0700 | [diff] [blame] | 1517 | BUG_ON(!ns); |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 1518 | get_mnt_ns(ns); |
JANAK DESAI | 741a295 | 2006-02-07 12:59:00 -0800 | [diff] [blame] | 1519 | |
| 1520 | if (!(flags & CLONE_NEWNS)) |
Badari Pulavarty | e3222c4 | 2007-05-08 00:25:21 -0700 | [diff] [blame] | 1521 | return ns; |
JANAK DESAI | 741a295 | 2006-02-07 12:59:00 -0800 | [diff] [blame] | 1522 | |
Badari Pulavarty | e3222c4 | 2007-05-08 00:25:21 -0700 | [diff] [blame] | 1523 | new_ns = dup_mnt_ns(ns, new_fs); |
JANAK DESAI | 741a295 | 2006-02-07 12:59:00 -0800 | [diff] [blame] | 1524 | |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 1525 | put_mnt_ns(ns); |
Badari Pulavarty | e3222c4 | 2007-05-08 00:25:21 -0700 | [diff] [blame] | 1526 | return new_ns; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1527 | } |
| 1528 | |
| 1529 | asmlinkage long sys_mount(char __user * dev_name, char __user * dir_name, |
| 1530 | char __user * type, unsigned long flags, |
| 1531 | void __user * data) |
| 1532 | { |
| 1533 | int retval; |
| 1534 | unsigned long data_page; |
| 1535 | unsigned long type_page; |
| 1536 | unsigned long dev_page; |
| 1537 | char *dir_page; |
| 1538 | |
Ram Pai | b58fed8 | 2005-11-07 17:16:09 -0500 | [diff] [blame] | 1539 | retval = copy_mount_options(type, &type_page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1540 | if (retval < 0) |
| 1541 | return retval; |
| 1542 | |
| 1543 | dir_page = getname(dir_name); |
| 1544 | retval = PTR_ERR(dir_page); |
| 1545 | if (IS_ERR(dir_page)) |
| 1546 | goto out1; |
| 1547 | |
Ram Pai | b58fed8 | 2005-11-07 17:16:09 -0500 | [diff] [blame] | 1548 | retval = copy_mount_options(dev_name, &dev_page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1549 | if (retval < 0) |
| 1550 | goto out2; |
| 1551 | |
Ram Pai | b58fed8 | 2005-11-07 17:16:09 -0500 | [diff] [blame] | 1552 | retval = copy_mount_options(data, &data_page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1553 | if (retval < 0) |
| 1554 | goto out3; |
| 1555 | |
| 1556 | lock_kernel(); |
Ram Pai | b58fed8 | 2005-11-07 17:16:09 -0500 | [diff] [blame] | 1557 | retval = do_mount((char *)dev_page, dir_page, (char *)type_page, |
| 1558 | flags, (void *)data_page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1559 | unlock_kernel(); |
| 1560 | free_page(data_page); |
| 1561 | |
| 1562 | out3: |
| 1563 | free_page(dev_page); |
| 1564 | out2: |
| 1565 | putname(dir_page); |
| 1566 | out1: |
| 1567 | free_page(type_page); |
| 1568 | return retval; |
| 1569 | } |
| 1570 | |
| 1571 | /* |
| 1572 | * Replace the fs->{rootmnt,root} with {mnt,dentry}. Put the old values. |
| 1573 | * It can block. Requires the big lock held. |
| 1574 | */ |
| 1575 | void set_fs_root(struct fs_struct *fs, struct vfsmount *mnt, |
| 1576 | struct dentry *dentry) |
| 1577 | { |
| 1578 | struct dentry *old_root; |
| 1579 | struct vfsmount *old_rootmnt; |
| 1580 | write_lock(&fs->lock); |
| 1581 | old_root = fs->root; |
| 1582 | old_rootmnt = fs->rootmnt; |
| 1583 | fs->rootmnt = mntget(mnt); |
| 1584 | fs->root = dget(dentry); |
| 1585 | write_unlock(&fs->lock); |
| 1586 | if (old_root) { |
| 1587 | dput(old_root); |
| 1588 | mntput(old_rootmnt); |
| 1589 | } |
| 1590 | } |
| 1591 | |
| 1592 | /* |
| 1593 | * Replace the fs->{pwdmnt,pwd} with {mnt,dentry}. Put the old values. |
| 1594 | * It can block. Requires the big lock held. |
| 1595 | */ |
| 1596 | void set_fs_pwd(struct fs_struct *fs, struct vfsmount *mnt, |
| 1597 | struct dentry *dentry) |
| 1598 | { |
| 1599 | struct dentry *old_pwd; |
| 1600 | struct vfsmount *old_pwdmnt; |
| 1601 | |
| 1602 | write_lock(&fs->lock); |
| 1603 | old_pwd = fs->pwd; |
| 1604 | old_pwdmnt = fs->pwdmnt; |
| 1605 | fs->pwdmnt = mntget(mnt); |
| 1606 | fs->pwd = dget(dentry); |
| 1607 | write_unlock(&fs->lock); |
| 1608 | |
| 1609 | if (old_pwd) { |
| 1610 | dput(old_pwd); |
| 1611 | mntput(old_pwdmnt); |
| 1612 | } |
| 1613 | } |
| 1614 | |
| 1615 | static void chroot_fs_refs(struct nameidata *old_nd, struct nameidata *new_nd) |
| 1616 | { |
| 1617 | struct task_struct *g, *p; |
| 1618 | struct fs_struct *fs; |
| 1619 | |
| 1620 | read_lock(&tasklist_lock); |
| 1621 | do_each_thread(g, p) { |
| 1622 | task_lock(p); |
| 1623 | fs = p->fs; |
| 1624 | if (fs) { |
| 1625 | atomic_inc(&fs->count); |
| 1626 | task_unlock(p); |
Ram Pai | b58fed8 | 2005-11-07 17:16:09 -0500 | [diff] [blame] | 1627 | if (fs->root == old_nd->dentry |
| 1628 | && fs->rootmnt == old_nd->mnt) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1629 | set_fs_root(fs, new_nd->mnt, new_nd->dentry); |
Ram Pai | b58fed8 | 2005-11-07 17:16:09 -0500 | [diff] [blame] | 1630 | if (fs->pwd == old_nd->dentry |
| 1631 | && fs->pwdmnt == old_nd->mnt) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1632 | set_fs_pwd(fs, new_nd->mnt, new_nd->dentry); |
| 1633 | put_fs_struct(fs); |
| 1634 | } else |
| 1635 | task_unlock(p); |
| 1636 | } while_each_thread(g, p); |
| 1637 | read_unlock(&tasklist_lock); |
| 1638 | } |
| 1639 | |
| 1640 | /* |
| 1641 | * pivot_root Semantics: |
| 1642 | * Moves the root file system of the current process to the directory put_old, |
| 1643 | * makes new_root as the new root file system of the current process, and sets |
| 1644 | * root/cwd of all processes which had them on the current root to new_root. |
| 1645 | * |
| 1646 | * Restrictions: |
| 1647 | * The new_root and put_old must be directories, and must not be on the |
| 1648 | * same file system as the current process root. The put_old must be |
| 1649 | * underneath new_root, i.e. adding a non-zero number of /.. to the string |
| 1650 | * pointed to by put_old must yield the same directory as new_root. No other |
| 1651 | * file system may be mounted on put_old. After all, new_root is a mountpoint. |
| 1652 | * |
Neil Brown | 4a0d11f | 2006-01-08 01:03:18 -0800 | [diff] [blame] | 1653 | * Also, the current root cannot be on the 'rootfs' (initial ramfs) filesystem. |
| 1654 | * See Documentation/filesystems/ramfs-rootfs-initramfs.txt for alternatives |
| 1655 | * in this situation. |
| 1656 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1657 | * Notes: |
| 1658 | * - we don't move root/cwd if they are not at the root (reason: if something |
| 1659 | * cared enough to change them, it's probably wrong to force them elsewhere) |
| 1660 | * - it's okay to pick a root that isn't the root of a file system, e.g. |
| 1661 | * /nfs/my_root where /nfs is the mount point. It must be a mountpoint, |
| 1662 | * though, so you may need to say mount --bind /nfs/my_root /nfs/my_root |
| 1663 | * first. |
| 1664 | */ |
Ram Pai | b58fed8 | 2005-11-07 17:16:09 -0500 | [diff] [blame] | 1665 | asmlinkage long sys_pivot_root(const char __user * new_root, |
| 1666 | const char __user * put_old) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1667 | { |
| 1668 | struct vfsmount *tmp; |
| 1669 | struct nameidata new_nd, old_nd, parent_nd, root_parent, user_nd; |
| 1670 | int error; |
| 1671 | |
| 1672 | if (!capable(CAP_SYS_ADMIN)) |
| 1673 | return -EPERM; |
| 1674 | |
| 1675 | lock_kernel(); |
| 1676 | |
Ram Pai | b58fed8 | 2005-11-07 17:16:09 -0500 | [diff] [blame] | 1677 | error = __user_walk(new_root, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, |
| 1678 | &new_nd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1679 | if (error) |
| 1680 | goto out0; |
| 1681 | error = -EINVAL; |
| 1682 | if (!check_mnt(new_nd.mnt)) |
| 1683 | goto out1; |
| 1684 | |
Ram Pai | b58fed8 | 2005-11-07 17:16:09 -0500 | [diff] [blame] | 1685 | error = __user_walk(put_old, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &old_nd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1686 | if (error) |
| 1687 | goto out1; |
| 1688 | |
| 1689 | error = security_sb_pivotroot(&old_nd, &new_nd); |
| 1690 | if (error) { |
| 1691 | path_release(&old_nd); |
| 1692 | goto out1; |
| 1693 | } |
| 1694 | |
| 1695 | read_lock(¤t->fs->lock); |
| 1696 | user_nd.mnt = mntget(current->fs->rootmnt); |
| 1697 | user_nd.dentry = dget(current->fs->root); |
| 1698 | read_unlock(¤t->fs->lock); |
Ram Pai | 390c684 | 2005-11-07 17:17:51 -0500 | [diff] [blame] | 1699 | down_write(&namespace_sem); |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 1700 | mutex_lock(&old_nd.dentry->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1701 | error = -EINVAL; |
Ram Pai | 2144440 | 2005-11-07 17:20:03 -0500 | [diff] [blame] | 1702 | if (IS_MNT_SHARED(old_nd.mnt) || |
| 1703 | IS_MNT_SHARED(new_nd.mnt->mnt_parent) || |
| 1704 | IS_MNT_SHARED(user_nd.mnt->mnt_parent)) |
| 1705 | goto out2; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1706 | if (!check_mnt(user_nd.mnt)) |
| 1707 | goto out2; |
| 1708 | error = -ENOENT; |
| 1709 | if (IS_DEADDIR(new_nd.dentry->d_inode)) |
| 1710 | goto out2; |
| 1711 | if (d_unhashed(new_nd.dentry) && !IS_ROOT(new_nd.dentry)) |
| 1712 | goto out2; |
| 1713 | if (d_unhashed(old_nd.dentry) && !IS_ROOT(old_nd.dentry)) |
| 1714 | goto out2; |
| 1715 | error = -EBUSY; |
| 1716 | if (new_nd.mnt == user_nd.mnt || old_nd.mnt == user_nd.mnt) |
| 1717 | goto out2; /* loop, on the same file system */ |
| 1718 | error = -EINVAL; |
| 1719 | if (user_nd.mnt->mnt_root != user_nd.dentry) |
| 1720 | goto out2; /* not a mountpoint */ |
Miklos Szeredi | 0bb6fcc | 2005-09-06 15:19:36 -0700 | [diff] [blame] | 1721 | if (user_nd.mnt->mnt_parent == user_nd.mnt) |
| 1722 | goto out2; /* not attached */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1723 | if (new_nd.mnt->mnt_root != new_nd.dentry) |
| 1724 | goto out2; /* not a mountpoint */ |
Miklos Szeredi | 0bb6fcc | 2005-09-06 15:19:36 -0700 | [diff] [blame] | 1725 | if (new_nd.mnt->mnt_parent == new_nd.mnt) |
| 1726 | goto out2; /* not attached */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1727 | tmp = old_nd.mnt; /* make sure we can reach put_old from new_root */ |
| 1728 | spin_lock(&vfsmount_lock); |
| 1729 | if (tmp != new_nd.mnt) { |
| 1730 | for (;;) { |
| 1731 | if (tmp->mnt_parent == tmp) |
| 1732 | goto out3; /* already mounted on put_old */ |
| 1733 | if (tmp->mnt_parent == new_nd.mnt) |
| 1734 | break; |
| 1735 | tmp = tmp->mnt_parent; |
| 1736 | } |
| 1737 | if (!is_subdir(tmp->mnt_mountpoint, new_nd.dentry)) |
| 1738 | goto out3; |
| 1739 | } else if (!is_subdir(old_nd.dentry, new_nd.dentry)) |
| 1740 | goto out3; |
| 1741 | detach_mnt(new_nd.mnt, &parent_nd); |
| 1742 | detach_mnt(user_nd.mnt, &root_parent); |
| 1743 | attach_mnt(user_nd.mnt, &old_nd); /* mount old root on put_old */ |
| 1744 | attach_mnt(new_nd.mnt, &root_parent); /* mount new_root on / */ |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 1745 | touch_mnt_namespace(current->nsproxy->mnt_ns); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1746 | spin_unlock(&vfsmount_lock); |
| 1747 | chroot_fs_refs(&user_nd, &new_nd); |
| 1748 | security_sb_post_pivotroot(&user_nd, &new_nd); |
| 1749 | error = 0; |
| 1750 | path_release(&root_parent); |
| 1751 | path_release(&parent_nd); |
| 1752 | out2: |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 1753 | mutex_unlock(&old_nd.dentry->d_inode->i_mutex); |
Ram Pai | 390c684 | 2005-11-07 17:17:51 -0500 | [diff] [blame] | 1754 | up_write(&namespace_sem); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1755 | path_release(&user_nd); |
| 1756 | path_release(&old_nd); |
| 1757 | out1: |
| 1758 | path_release(&new_nd); |
| 1759 | out0: |
| 1760 | unlock_kernel(); |
| 1761 | return error; |
| 1762 | out3: |
| 1763 | spin_unlock(&vfsmount_lock); |
| 1764 | goto out2; |
| 1765 | } |
| 1766 | |
| 1767 | static void __init init_mount_tree(void) |
| 1768 | { |
| 1769 | struct vfsmount *mnt; |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 1770 | struct mnt_namespace *ns; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1771 | |
| 1772 | mnt = do_kern_mount("rootfs", 0, "rootfs", NULL); |
| 1773 | if (IS_ERR(mnt)) |
| 1774 | panic("Can't create rootfs"); |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 1775 | ns = kmalloc(sizeof(*ns), GFP_KERNEL); |
| 1776 | if (!ns) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1777 | panic("Can't allocate initial namespace"); |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 1778 | atomic_set(&ns->count, 1); |
| 1779 | INIT_LIST_HEAD(&ns->list); |
| 1780 | init_waitqueue_head(&ns->poll); |
| 1781 | ns->event = 0; |
| 1782 | list_add(&mnt->mnt_list, &ns->list); |
| 1783 | ns->root = mnt; |
| 1784 | mnt->mnt_ns = ns; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1785 | |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 1786 | init_task.nsproxy->mnt_ns = ns; |
| 1787 | get_mnt_ns(ns); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1788 | |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 1789 | set_fs_pwd(current->fs, ns->root, ns->root->mnt_root); |
| 1790 | set_fs_root(current->fs, ns->root, ns->root->mnt_root); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1791 | } |
| 1792 | |
| 1793 | void __init mnt_init(unsigned long mempages) |
| 1794 | { |
| 1795 | struct list_head *d; |
| 1796 | unsigned int nr_hash; |
| 1797 | int i; |
Randy Dunlap | 15a67dd | 2006-09-29 01:58:57 -0700 | [diff] [blame] | 1798 | int err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1799 | |
Ram Pai | 390c684 | 2005-11-07 17:17:51 -0500 | [diff] [blame] | 1800 | init_rwsem(&namespace_sem); |
| 1801 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1802 | mnt_cache = kmem_cache_create("mnt_cache", sizeof(struct vfsmount), |
Ram Pai | b58fed8 | 2005-11-07 17:16:09 -0500 | [diff] [blame] | 1803 | 0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1804 | |
Ram Pai | b58fed8 | 2005-11-07 17:16:09 -0500 | [diff] [blame] | 1805 | mount_hashtable = (struct list_head *)__get_free_page(GFP_ATOMIC); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1806 | |
| 1807 | if (!mount_hashtable) |
| 1808 | panic("Failed to allocate mount hash table\n"); |
| 1809 | |
| 1810 | /* |
| 1811 | * Find the power-of-two list-heads that can fit into the allocation.. |
| 1812 | * We don't guarantee that "sizeof(struct list_head)" is necessarily |
| 1813 | * a power-of-two. |
| 1814 | */ |
| 1815 | nr_hash = PAGE_SIZE / sizeof(struct list_head); |
| 1816 | hash_bits = 0; |
| 1817 | do { |
| 1818 | hash_bits++; |
| 1819 | } while ((nr_hash >> hash_bits) != 0); |
| 1820 | hash_bits--; |
| 1821 | |
| 1822 | /* |
| 1823 | * Re-calculate the actual number of entries and the mask |
| 1824 | * from the number of bits we can fit. |
| 1825 | */ |
| 1826 | nr_hash = 1UL << hash_bits; |
Ram Pai | b58fed8 | 2005-11-07 17:16:09 -0500 | [diff] [blame] | 1827 | hash_mask = nr_hash - 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1828 | |
| 1829 | printk("Mount-cache hash table entries: %d\n", nr_hash); |
| 1830 | |
| 1831 | /* And initialize the newly allocated array */ |
| 1832 | d = mount_hashtable; |
| 1833 | i = nr_hash; |
| 1834 | do { |
| 1835 | INIT_LIST_HEAD(d); |
| 1836 | d++; |
| 1837 | i--; |
| 1838 | } while (i); |
Randy Dunlap | 15a67dd | 2006-09-29 01:58:57 -0700 | [diff] [blame] | 1839 | err = sysfs_init(); |
| 1840 | if (err) |
| 1841 | printk(KERN_WARNING "%s: sysfs_init error: %d\n", |
| 1842 | __FUNCTION__, err); |
| 1843 | err = subsystem_register(&fs_subsys); |
| 1844 | if (err) |
| 1845 | printk(KERN_WARNING "%s: subsystem_register error: %d\n", |
| 1846 | __FUNCTION__, err); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1847 | init_rootfs(); |
| 1848 | init_mount_tree(); |
| 1849 | } |
| 1850 | |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 1851 | void __put_mnt_ns(struct mnt_namespace *ns) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1852 | { |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 1853 | struct vfsmount *root = ns->root; |
Ram Pai | 70fbcdf | 2005-11-07 17:17:04 -0500 | [diff] [blame] | 1854 | LIST_HEAD(umount_list); |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 1855 | ns->root = NULL; |
Miklos Szeredi | 1ce88cf | 2005-07-07 17:57:24 -0700 | [diff] [blame] | 1856 | spin_unlock(&vfsmount_lock); |
Ram Pai | 390c684 | 2005-11-07 17:17:51 -0500 | [diff] [blame] | 1857 | down_write(&namespace_sem); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1858 | spin_lock(&vfsmount_lock); |
Ram Pai | a05964f | 2005-11-07 17:20:17 -0500 | [diff] [blame] | 1859 | umount_tree(root, 0, &umount_list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1860 | spin_unlock(&vfsmount_lock); |
Ram Pai | 390c684 | 2005-11-07 17:17:51 -0500 | [diff] [blame] | 1861 | up_write(&namespace_sem); |
Ram Pai | 70fbcdf | 2005-11-07 17:17:04 -0500 | [diff] [blame] | 1862 | release_mounts(&umount_list); |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 1863 | kfree(ns); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1864 | } |