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> |
Al Viro | d10577a | 2011-12-07 13:06:11 -0500 | [diff] [blame] | 12 | #include <linux/export.h> |
Randy Dunlap | 16f7e0f | 2006-01-11 12:17:46 -0800 | [diff] [blame] | 13 | #include <linux/capability.h> |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 14 | #include <linux/mnt_namespace.h> |
Eric W. Biederman | 771b137 | 2012-07-26 21:08:32 -0700 | [diff] [blame] | 15 | #include <linux/user_namespace.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 16 | #include <linux/namei.h> |
| 17 | #include <linux/security.h> |
Miklos Szeredi | 73cd49e | 2008-03-26 22:11:34 +0100 | [diff] [blame] | 18 | #include <linux/idr.h> |
Rob Landley | 57f150a | 2013-09-11 14:26:10 -0700 | [diff] [blame] | 19 | #include <linux/init.h> /* init_rootfs */ |
Al Viro | d10577a | 2011-12-07 13:06:11 -0500 | [diff] [blame] | 20 | #include <linux/fs_struct.h> /* get_fs_root et.al. */ |
| 21 | #include <linux/fsnotify.h> /* fsnotify_vfsmount_delete */ |
| 22 | #include <linux/uaccess.h> |
David Howells | 0bb80f2 | 2013-04-12 01:50:06 +0100 | [diff] [blame] | 23 | #include <linux/proc_ns.h> |
Linus Torvalds | 20b4fb4 | 2013-05-01 17:51:54 -0700 | [diff] [blame] | 24 | #include <linux/magic.h> |
Al Viro | 0818bf2 | 2014-02-28 13:46:44 -0500 | [diff] [blame] | 25 | #include <linux/bootmem.h> |
Al Viro | 9ea459e | 2014-08-08 13:08:20 -0400 | [diff] [blame] | 26 | #include <linux/task_work.h> |
Ram Pai | 07b2088 | 2005-11-07 17:19:07 -0500 | [diff] [blame] | 27 | #include "pnode.h" |
Adrian Bunk | 948730b | 2007-07-15 23:41:25 -0700 | [diff] [blame] | 28 | #include "internal.h" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 29 | |
Al Viro | 0818bf2 | 2014-02-28 13:46:44 -0500 | [diff] [blame] | 30 | static unsigned int m_hash_mask __read_mostly; |
| 31 | static unsigned int m_hash_shift __read_mostly; |
| 32 | static unsigned int mp_hash_mask __read_mostly; |
| 33 | static unsigned int mp_hash_shift __read_mostly; |
| 34 | |
| 35 | static __initdata unsigned long mhash_entries; |
| 36 | static int __init set_mhash_entries(char *str) |
| 37 | { |
| 38 | if (!str) |
| 39 | return 0; |
| 40 | mhash_entries = simple_strtoul(str, &str, 0); |
| 41 | return 1; |
| 42 | } |
| 43 | __setup("mhash_entries=", set_mhash_entries); |
| 44 | |
| 45 | static __initdata unsigned long mphash_entries; |
| 46 | static int __init set_mphash_entries(char *str) |
| 47 | { |
| 48 | if (!str) |
| 49 | return 0; |
| 50 | mphash_entries = simple_strtoul(str, &str, 0); |
| 51 | return 1; |
| 52 | } |
| 53 | __setup("mphash_entries=", set_mphash_entries); |
Eric Dumazet | 13f14b4 | 2008-02-06 01:37:57 -0800 | [diff] [blame] | 54 | |
Al Viro | c7999c3 | 2014-02-27 14:40:10 -0500 | [diff] [blame] | 55 | static u64 event; |
Miklos Szeredi | 73cd49e | 2008-03-26 22:11:34 +0100 | [diff] [blame] | 56 | static DEFINE_IDA(mnt_id_ida); |
Miklos Szeredi | 719f5d7 | 2008-03-27 13:06:23 +0100 | [diff] [blame] | 57 | static DEFINE_IDA(mnt_group_ida); |
Nick Piggin | 99b7db7 | 2010-08-18 04:37:39 +1000 | [diff] [blame] | 58 | static DEFINE_SPINLOCK(mnt_id_lock); |
Al Viro | f21f622 | 2009-06-24 03:12:00 -0400 | [diff] [blame] | 59 | static int mnt_id_start = 0; |
| 60 | static int mnt_group_start = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 61 | |
Al Viro | 38129a1 | 2014-03-20 21:10:51 -0400 | [diff] [blame] | 62 | static struct hlist_head *mount_hashtable __read_mostly; |
Al Viro | 0818bf2 | 2014-02-28 13:46:44 -0500 | [diff] [blame] | 63 | static struct hlist_head *mountpoint_hashtable __read_mostly; |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 64 | static struct kmem_cache *mnt_cache __read_mostly; |
Al Viro | 59aa0da | 2013-09-16 21:34:53 -0400 | [diff] [blame] | 65 | static DECLARE_RWSEM(namespace_sem); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 66 | |
Miklos Szeredi | f87fd4c | 2006-01-16 22:14:23 -0800 | [diff] [blame] | 67 | /* /sys/fs */ |
Greg Kroah-Hartman | 00d2666 | 2007-10-29 14:17:23 -0600 | [diff] [blame] | 68 | struct kobject *fs_kobj; |
| 69 | EXPORT_SYMBOL_GPL(fs_kobj); |
Miklos Szeredi | f87fd4c | 2006-01-16 22:14:23 -0800 | [diff] [blame] | 70 | |
Nick Piggin | 99b7db7 | 2010-08-18 04:37:39 +1000 | [diff] [blame] | 71 | /* |
| 72 | * vfsmount lock may be taken for read to prevent changes to the |
| 73 | * vfsmount hash, ie. during mountpoint lookups or walking back |
| 74 | * up the tree. |
| 75 | * |
| 76 | * It should be taken for write in all cases where the vfsmount |
| 77 | * tree or hash is modified or when a vfsmount structure is modified. |
| 78 | */ |
Al Viro | 48a066e | 2013-09-29 22:06:07 -0400 | [diff] [blame] | 79 | __cacheline_aligned_in_smp DEFINE_SEQLOCK(mount_lock); |
Nick Piggin | 99b7db7 | 2010-08-18 04:37:39 +1000 | [diff] [blame] | 80 | |
Al Viro | 38129a1 | 2014-03-20 21:10:51 -0400 | [diff] [blame] | 81 | static inline struct hlist_head *m_hash(struct vfsmount *mnt, struct dentry *dentry) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 82 | { |
Ram Pai | b58fed8 | 2005-11-07 17:16:09 -0500 | [diff] [blame] | 83 | unsigned long tmp = ((unsigned long)mnt / L1_CACHE_BYTES); |
| 84 | tmp += ((unsigned long)dentry / L1_CACHE_BYTES); |
Al Viro | 0818bf2 | 2014-02-28 13:46:44 -0500 | [diff] [blame] | 85 | tmp = tmp + (tmp >> m_hash_shift); |
| 86 | return &mount_hashtable[tmp & m_hash_mask]; |
| 87 | } |
| 88 | |
| 89 | static inline struct hlist_head *mp_hash(struct dentry *dentry) |
| 90 | { |
| 91 | unsigned long tmp = ((unsigned long)dentry / L1_CACHE_BYTES); |
| 92 | tmp = tmp + (tmp >> mp_hash_shift); |
| 93 | return &mountpoint_hashtable[tmp & mp_hash_mask]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 94 | } |
| 95 | |
Nick Piggin | 99b7db7 | 2010-08-18 04:37:39 +1000 | [diff] [blame] | 96 | /* |
| 97 | * allocation is serialized by namespace_sem, but we need the spinlock to |
| 98 | * serialize with freeing. |
| 99 | */ |
Al Viro | b105e27 | 2011-11-24 20:38:33 -0500 | [diff] [blame] | 100 | static int mnt_alloc_id(struct mount *mnt) |
Miklos Szeredi | 73cd49e | 2008-03-26 22:11:34 +0100 | [diff] [blame] | 101 | { |
| 102 | int res; |
| 103 | |
| 104 | retry: |
| 105 | ida_pre_get(&mnt_id_ida, GFP_KERNEL); |
Nick Piggin | 99b7db7 | 2010-08-18 04:37:39 +1000 | [diff] [blame] | 106 | spin_lock(&mnt_id_lock); |
Al Viro | 15169fe | 2011-11-25 00:50:41 -0500 | [diff] [blame] | 107 | res = ida_get_new_above(&mnt_id_ida, mnt_id_start, &mnt->mnt_id); |
Al Viro | f21f622 | 2009-06-24 03:12:00 -0400 | [diff] [blame] | 108 | if (!res) |
Al Viro | 15169fe | 2011-11-25 00:50:41 -0500 | [diff] [blame] | 109 | mnt_id_start = mnt->mnt_id + 1; |
Nick Piggin | 99b7db7 | 2010-08-18 04:37:39 +1000 | [diff] [blame] | 110 | spin_unlock(&mnt_id_lock); |
Miklos Szeredi | 73cd49e | 2008-03-26 22:11:34 +0100 | [diff] [blame] | 111 | if (res == -EAGAIN) |
| 112 | goto retry; |
| 113 | |
| 114 | return res; |
| 115 | } |
| 116 | |
Al Viro | b105e27 | 2011-11-24 20:38:33 -0500 | [diff] [blame] | 117 | static void mnt_free_id(struct mount *mnt) |
Miklos Szeredi | 73cd49e | 2008-03-26 22:11:34 +0100 | [diff] [blame] | 118 | { |
Al Viro | 15169fe | 2011-11-25 00:50:41 -0500 | [diff] [blame] | 119 | int id = mnt->mnt_id; |
Nick Piggin | 99b7db7 | 2010-08-18 04:37:39 +1000 | [diff] [blame] | 120 | spin_lock(&mnt_id_lock); |
Al Viro | f21f622 | 2009-06-24 03:12:00 -0400 | [diff] [blame] | 121 | ida_remove(&mnt_id_ida, id); |
| 122 | if (mnt_id_start > id) |
| 123 | mnt_id_start = id; |
Nick Piggin | 99b7db7 | 2010-08-18 04:37:39 +1000 | [diff] [blame] | 124 | spin_unlock(&mnt_id_lock); |
Miklos Szeredi | 73cd49e | 2008-03-26 22:11:34 +0100 | [diff] [blame] | 125 | } |
| 126 | |
Miklos Szeredi | 719f5d7 | 2008-03-27 13:06:23 +0100 | [diff] [blame] | 127 | /* |
| 128 | * Allocate a new peer group ID |
| 129 | * |
| 130 | * mnt_group_ida is protected by namespace_sem |
| 131 | */ |
Al Viro | 4b8b21f | 2011-11-24 19:54:23 -0500 | [diff] [blame] | 132 | static int mnt_alloc_group_id(struct mount *mnt) |
Miklos Szeredi | 719f5d7 | 2008-03-27 13:06:23 +0100 | [diff] [blame] | 133 | { |
Al Viro | f21f622 | 2009-06-24 03:12:00 -0400 | [diff] [blame] | 134 | int res; |
| 135 | |
Miklos Szeredi | 719f5d7 | 2008-03-27 13:06:23 +0100 | [diff] [blame] | 136 | if (!ida_pre_get(&mnt_group_ida, GFP_KERNEL)) |
| 137 | return -ENOMEM; |
| 138 | |
Al Viro | f21f622 | 2009-06-24 03:12:00 -0400 | [diff] [blame] | 139 | res = ida_get_new_above(&mnt_group_ida, |
| 140 | mnt_group_start, |
Al Viro | 15169fe | 2011-11-25 00:50:41 -0500 | [diff] [blame] | 141 | &mnt->mnt_group_id); |
Al Viro | f21f622 | 2009-06-24 03:12:00 -0400 | [diff] [blame] | 142 | if (!res) |
Al Viro | 15169fe | 2011-11-25 00:50:41 -0500 | [diff] [blame] | 143 | mnt_group_start = mnt->mnt_group_id + 1; |
Al Viro | f21f622 | 2009-06-24 03:12:00 -0400 | [diff] [blame] | 144 | |
| 145 | return res; |
Miklos Szeredi | 719f5d7 | 2008-03-27 13:06:23 +0100 | [diff] [blame] | 146 | } |
| 147 | |
| 148 | /* |
| 149 | * Release a peer group ID |
| 150 | */ |
Al Viro | 4b8b21f | 2011-11-24 19:54:23 -0500 | [diff] [blame] | 151 | void mnt_release_group_id(struct mount *mnt) |
Miklos Szeredi | 719f5d7 | 2008-03-27 13:06:23 +0100 | [diff] [blame] | 152 | { |
Al Viro | 15169fe | 2011-11-25 00:50:41 -0500 | [diff] [blame] | 153 | int id = mnt->mnt_group_id; |
Al Viro | f21f622 | 2009-06-24 03:12:00 -0400 | [diff] [blame] | 154 | ida_remove(&mnt_group_ida, id); |
| 155 | if (mnt_group_start > id) |
| 156 | mnt_group_start = id; |
Al Viro | 15169fe | 2011-11-25 00:50:41 -0500 | [diff] [blame] | 157 | mnt->mnt_group_id = 0; |
Miklos Szeredi | 719f5d7 | 2008-03-27 13:06:23 +0100 | [diff] [blame] | 158 | } |
| 159 | |
Nick Piggin | b3e19d9 | 2011-01-07 17:50:11 +1100 | [diff] [blame] | 160 | /* |
| 161 | * vfsmount lock must be held for read |
| 162 | */ |
Al Viro | 83adc75 | 2011-11-24 22:37:54 -0500 | [diff] [blame] | 163 | static inline void mnt_add_count(struct mount *mnt, int n) |
Nick Piggin | b3e19d9 | 2011-01-07 17:50:11 +1100 | [diff] [blame] | 164 | { |
| 165 | #ifdef CONFIG_SMP |
Al Viro | 68e8a9f | 2011-11-24 22:53:09 -0500 | [diff] [blame] | 166 | this_cpu_add(mnt->mnt_pcp->mnt_count, n); |
Nick Piggin | b3e19d9 | 2011-01-07 17:50:11 +1100 | [diff] [blame] | 167 | #else |
| 168 | preempt_disable(); |
Al Viro | 68e8a9f | 2011-11-24 22:53:09 -0500 | [diff] [blame] | 169 | mnt->mnt_count += n; |
Nick Piggin | b3e19d9 | 2011-01-07 17:50:11 +1100 | [diff] [blame] | 170 | preempt_enable(); |
| 171 | #endif |
| 172 | } |
| 173 | |
Nick Piggin | b3e19d9 | 2011-01-07 17:50:11 +1100 | [diff] [blame] | 174 | /* |
| 175 | * vfsmount lock must be held for write |
| 176 | */ |
Al Viro | 83adc75 | 2011-11-24 22:37:54 -0500 | [diff] [blame] | 177 | unsigned int mnt_get_count(struct mount *mnt) |
Nick Piggin | b3e19d9 | 2011-01-07 17:50:11 +1100 | [diff] [blame] | 178 | { |
| 179 | #ifdef CONFIG_SMP |
Al Viro | f03c659 | 2011-01-14 22:30:21 -0500 | [diff] [blame] | 180 | unsigned int count = 0; |
Nick Piggin | b3e19d9 | 2011-01-07 17:50:11 +1100 | [diff] [blame] | 181 | int cpu; |
| 182 | |
| 183 | for_each_possible_cpu(cpu) { |
Al Viro | 68e8a9f | 2011-11-24 22:53:09 -0500 | [diff] [blame] | 184 | count += per_cpu_ptr(mnt->mnt_pcp, cpu)->mnt_count; |
Nick Piggin | b3e19d9 | 2011-01-07 17:50:11 +1100 | [diff] [blame] | 185 | } |
| 186 | |
| 187 | return count; |
| 188 | #else |
Al Viro | 68e8a9f | 2011-11-24 22:53:09 -0500 | [diff] [blame] | 189 | return mnt->mnt_count; |
Nick Piggin | b3e19d9 | 2011-01-07 17:50:11 +1100 | [diff] [blame] | 190 | #endif |
| 191 | } |
| 192 | |
Al Viro | 87b95ce | 2015-01-10 19:01:08 -0500 | [diff] [blame] | 193 | static void drop_mountpoint(struct fs_pin *p) |
| 194 | { |
| 195 | struct mount *m = container_of(p, struct mount, mnt_umount); |
| 196 | dput(m->mnt_ex_mountpoint); |
| 197 | pin_remove(p); |
| 198 | mntput(&m->mnt); |
| 199 | } |
| 200 | |
Al Viro | b105e27 | 2011-11-24 20:38:33 -0500 | [diff] [blame] | 201 | static struct mount *alloc_vfsmnt(const char *name) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 202 | { |
Al Viro | c63181e | 2011-11-25 02:35:16 -0500 | [diff] [blame] | 203 | struct mount *mnt = kmem_cache_zalloc(mnt_cache, GFP_KERNEL); |
| 204 | if (mnt) { |
Miklos Szeredi | 73cd49e | 2008-03-26 22:11:34 +0100 | [diff] [blame] | 205 | int err; |
| 206 | |
Al Viro | c63181e | 2011-11-25 02:35:16 -0500 | [diff] [blame] | 207 | err = mnt_alloc_id(mnt); |
Li Zefan | 88b3878 | 2008-07-21 18:06:36 +0800 | [diff] [blame] | 208 | if (err) |
| 209 | goto out_free_cache; |
| 210 | |
| 211 | if (name) { |
Andrzej Hajda | fcc139a | 2015-02-13 14:36:41 -0800 | [diff] [blame] | 212 | mnt->mnt_devname = kstrdup_const(name, GFP_KERNEL); |
Al Viro | c63181e | 2011-11-25 02:35:16 -0500 | [diff] [blame] | 213 | if (!mnt->mnt_devname) |
Li Zefan | 88b3878 | 2008-07-21 18:06:36 +0800 | [diff] [blame] | 214 | goto out_free_id; |
Miklos Szeredi | 73cd49e | 2008-03-26 22:11:34 +0100 | [diff] [blame] | 215 | } |
| 216 | |
Nick Piggin | b3e19d9 | 2011-01-07 17:50:11 +1100 | [diff] [blame] | 217 | #ifdef CONFIG_SMP |
Al Viro | c63181e | 2011-11-25 02:35:16 -0500 | [diff] [blame] | 218 | mnt->mnt_pcp = alloc_percpu(struct mnt_pcp); |
| 219 | if (!mnt->mnt_pcp) |
Nick Piggin | b3e19d9 | 2011-01-07 17:50:11 +1100 | [diff] [blame] | 220 | goto out_free_devname; |
| 221 | |
Al Viro | c63181e | 2011-11-25 02:35:16 -0500 | [diff] [blame] | 222 | this_cpu_add(mnt->mnt_pcp->mnt_count, 1); |
Nick Piggin | b3e19d9 | 2011-01-07 17:50:11 +1100 | [diff] [blame] | 223 | #else |
Al Viro | c63181e | 2011-11-25 02:35:16 -0500 | [diff] [blame] | 224 | mnt->mnt_count = 1; |
| 225 | mnt->mnt_writers = 0; |
Nick Piggin | b3e19d9 | 2011-01-07 17:50:11 +1100 | [diff] [blame] | 226 | #endif |
| 227 | |
Al Viro | 38129a1 | 2014-03-20 21:10:51 -0400 | [diff] [blame] | 228 | INIT_HLIST_NODE(&mnt->mnt_hash); |
Al Viro | c63181e | 2011-11-25 02:35:16 -0500 | [diff] [blame] | 229 | INIT_LIST_HEAD(&mnt->mnt_child); |
| 230 | INIT_LIST_HEAD(&mnt->mnt_mounts); |
| 231 | INIT_LIST_HEAD(&mnt->mnt_list); |
| 232 | INIT_LIST_HEAD(&mnt->mnt_expire); |
| 233 | INIT_LIST_HEAD(&mnt->mnt_share); |
| 234 | INIT_LIST_HEAD(&mnt->mnt_slave_list); |
| 235 | INIT_LIST_HEAD(&mnt->mnt_slave); |
Eric W. Biederman | 0a5eb7c | 2013-09-22 19:37:01 -0700 | [diff] [blame] | 236 | INIT_HLIST_NODE(&mnt->mnt_mp_list); |
Andreas Gruenbacher | 2504c5d | 2009-12-17 21:24:27 -0500 | [diff] [blame] | 237 | #ifdef CONFIG_FSNOTIFY |
| 238 | INIT_HLIST_HEAD(&mnt->mnt_fsnotify_marks); |
| 239 | #endif |
Al Viro | 87b95ce | 2015-01-10 19:01:08 -0500 | [diff] [blame] | 240 | init_fs_pin(&mnt->mnt_umount, drop_mountpoint); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 241 | } |
Al Viro | c63181e | 2011-11-25 02:35:16 -0500 | [diff] [blame] | 242 | return mnt; |
Li Zefan | 88b3878 | 2008-07-21 18:06:36 +0800 | [diff] [blame] | 243 | |
npiggin@suse.de | d3ef3d7 | 2009-04-26 20:25:54 +1000 | [diff] [blame] | 244 | #ifdef CONFIG_SMP |
| 245 | out_free_devname: |
Andrzej Hajda | fcc139a | 2015-02-13 14:36:41 -0800 | [diff] [blame] | 246 | kfree_const(mnt->mnt_devname); |
npiggin@suse.de | d3ef3d7 | 2009-04-26 20:25:54 +1000 | [diff] [blame] | 247 | #endif |
Li Zefan | 88b3878 | 2008-07-21 18:06:36 +0800 | [diff] [blame] | 248 | out_free_id: |
Al Viro | c63181e | 2011-11-25 02:35:16 -0500 | [diff] [blame] | 249 | mnt_free_id(mnt); |
Li Zefan | 88b3878 | 2008-07-21 18:06:36 +0800 | [diff] [blame] | 250 | out_free_cache: |
Al Viro | c63181e | 2011-11-25 02:35:16 -0500 | [diff] [blame] | 251 | kmem_cache_free(mnt_cache, mnt); |
Li Zefan | 88b3878 | 2008-07-21 18:06:36 +0800 | [diff] [blame] | 252 | return NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 253 | } |
| 254 | |
Dave Hansen | 8366025 | 2008-02-15 14:37:30 -0800 | [diff] [blame] | 255 | /* |
| 256 | * Most r/o checks on a fs are for operations that take |
| 257 | * discrete amounts of time, like a write() or unlink(). |
| 258 | * We must keep track of when those operations start |
| 259 | * (for permission checks) and when they end, so that |
| 260 | * we can determine when writes are able to occur to |
| 261 | * a filesystem. |
| 262 | */ |
Dave Hansen | 3d73363 | 2008-02-15 14:37:59 -0800 | [diff] [blame] | 263 | /* |
| 264 | * __mnt_is_readonly: check whether a mount is read-only |
| 265 | * @mnt: the mount to check for its write status |
| 266 | * |
| 267 | * This shouldn't be used directly ouside of the VFS. |
| 268 | * It does not guarantee that the filesystem will stay |
| 269 | * r/w, just that it is right *now*. This can not and |
| 270 | * should not be used in place of IS_RDONLY(inode). |
| 271 | * mnt_want/drop_write() will _keep_ the filesystem |
| 272 | * r/w. |
| 273 | */ |
| 274 | int __mnt_is_readonly(struct vfsmount *mnt) |
| 275 | { |
Dave Hansen | 2e4b7fc | 2008-02-15 14:38:00 -0800 | [diff] [blame] | 276 | if (mnt->mnt_flags & MNT_READONLY) |
| 277 | return 1; |
| 278 | if (mnt->mnt_sb->s_flags & MS_RDONLY) |
| 279 | return 1; |
| 280 | return 0; |
Dave Hansen | 3d73363 | 2008-02-15 14:37:59 -0800 | [diff] [blame] | 281 | } |
| 282 | EXPORT_SYMBOL_GPL(__mnt_is_readonly); |
| 283 | |
Al Viro | 83adc75 | 2011-11-24 22:37:54 -0500 | [diff] [blame] | 284 | static inline void mnt_inc_writers(struct mount *mnt) |
Dave Hansen | 3d73363 | 2008-02-15 14:37:59 -0800 | [diff] [blame] | 285 | { |
npiggin@suse.de | d3ef3d7 | 2009-04-26 20:25:54 +1000 | [diff] [blame] | 286 | #ifdef CONFIG_SMP |
Al Viro | 68e8a9f | 2011-11-24 22:53:09 -0500 | [diff] [blame] | 287 | this_cpu_inc(mnt->mnt_pcp->mnt_writers); |
npiggin@suse.de | d3ef3d7 | 2009-04-26 20:25:54 +1000 | [diff] [blame] | 288 | #else |
Al Viro | 68e8a9f | 2011-11-24 22:53:09 -0500 | [diff] [blame] | 289 | mnt->mnt_writers++; |
npiggin@suse.de | d3ef3d7 | 2009-04-26 20:25:54 +1000 | [diff] [blame] | 290 | #endif |
Dave Hansen | 3d73363 | 2008-02-15 14:37:59 -0800 | [diff] [blame] | 291 | } |
Dave Hansen | 3d73363 | 2008-02-15 14:37:59 -0800 | [diff] [blame] | 292 | |
Al Viro | 83adc75 | 2011-11-24 22:37:54 -0500 | [diff] [blame] | 293 | static inline void mnt_dec_writers(struct mount *mnt) |
Dave Hansen | 3d73363 | 2008-02-15 14:37:59 -0800 | [diff] [blame] | 294 | { |
npiggin@suse.de | d3ef3d7 | 2009-04-26 20:25:54 +1000 | [diff] [blame] | 295 | #ifdef CONFIG_SMP |
Al Viro | 68e8a9f | 2011-11-24 22:53:09 -0500 | [diff] [blame] | 296 | this_cpu_dec(mnt->mnt_pcp->mnt_writers); |
npiggin@suse.de | d3ef3d7 | 2009-04-26 20:25:54 +1000 | [diff] [blame] | 297 | #else |
Al Viro | 68e8a9f | 2011-11-24 22:53:09 -0500 | [diff] [blame] | 298 | mnt->mnt_writers--; |
npiggin@suse.de | d3ef3d7 | 2009-04-26 20:25:54 +1000 | [diff] [blame] | 299 | #endif |
| 300 | } |
| 301 | |
Al Viro | 83adc75 | 2011-11-24 22:37:54 -0500 | [diff] [blame] | 302 | static unsigned int mnt_get_writers(struct mount *mnt) |
npiggin@suse.de | d3ef3d7 | 2009-04-26 20:25:54 +1000 | [diff] [blame] | 303 | { |
| 304 | #ifdef CONFIG_SMP |
| 305 | unsigned int count = 0; |
Dave Hansen | 3d73363 | 2008-02-15 14:37:59 -0800 | [diff] [blame] | 306 | int cpu; |
Dave Hansen | 3d73363 | 2008-02-15 14:37:59 -0800 | [diff] [blame] | 307 | |
| 308 | for_each_possible_cpu(cpu) { |
Al Viro | 68e8a9f | 2011-11-24 22:53:09 -0500 | [diff] [blame] | 309 | count += per_cpu_ptr(mnt->mnt_pcp, cpu)->mnt_writers; |
Dave Hansen | 3d73363 | 2008-02-15 14:37:59 -0800 | [diff] [blame] | 310 | } |
Dave Hansen | 3d73363 | 2008-02-15 14:37:59 -0800 | [diff] [blame] | 311 | |
npiggin@suse.de | d3ef3d7 | 2009-04-26 20:25:54 +1000 | [diff] [blame] | 312 | return count; |
| 313 | #else |
| 314 | return mnt->mnt_writers; |
| 315 | #endif |
Dave Hansen | 3d73363 | 2008-02-15 14:37:59 -0800 | [diff] [blame] | 316 | } |
| 317 | |
Miklos Szeredi | 4ed5e82 | 2011-11-21 12:11:31 +0100 | [diff] [blame] | 318 | static int mnt_is_readonly(struct vfsmount *mnt) |
| 319 | { |
| 320 | if (mnt->mnt_sb->s_readonly_remount) |
| 321 | return 1; |
| 322 | /* Order wrt setting s_flags/s_readonly_remount in do_remount() */ |
| 323 | smp_rmb(); |
| 324 | return __mnt_is_readonly(mnt); |
| 325 | } |
| 326 | |
Dave Hansen | 3d73363 | 2008-02-15 14:37:59 -0800 | [diff] [blame] | 327 | /* |
Jan Kara | eb04c28 | 2012-06-12 16:20:35 +0200 | [diff] [blame] | 328 | * Most r/o & frozen checks on a fs are for operations that take discrete |
| 329 | * amounts of time, like a write() or unlink(). We must keep track of when |
| 330 | * those operations start (for permission checks) and when they end, so that we |
| 331 | * can determine when writes are able to occur to a filesystem. |
Dave Hansen | 3d73363 | 2008-02-15 14:37:59 -0800 | [diff] [blame] | 332 | */ |
Dave Hansen | 8366025 | 2008-02-15 14:37:30 -0800 | [diff] [blame] | 333 | /** |
Jan Kara | eb04c28 | 2012-06-12 16:20:35 +0200 | [diff] [blame] | 334 | * __mnt_want_write - get write access to a mount without freeze protection |
Al Viro | 83adc75 | 2011-11-24 22:37:54 -0500 | [diff] [blame] | 335 | * @m: the mount on which to take a write |
Dave Hansen | 8366025 | 2008-02-15 14:37:30 -0800 | [diff] [blame] | 336 | * |
Jan Kara | eb04c28 | 2012-06-12 16:20:35 +0200 | [diff] [blame] | 337 | * This tells the low-level filesystem that a write is about to be performed to |
| 338 | * it, and makes sure that writes are allowed (mnt it read-write) before |
| 339 | * returning success. This operation does not protect against filesystem being |
| 340 | * frozen. When the write operation is finished, __mnt_drop_write() must be |
| 341 | * called. This is effectively a refcount. |
Dave Hansen | 8366025 | 2008-02-15 14:37:30 -0800 | [diff] [blame] | 342 | */ |
Jan Kara | eb04c28 | 2012-06-12 16:20:35 +0200 | [diff] [blame] | 343 | int __mnt_want_write(struct vfsmount *m) |
Dave Hansen | 8366025 | 2008-02-15 14:37:30 -0800 | [diff] [blame] | 344 | { |
Al Viro | 83adc75 | 2011-11-24 22:37:54 -0500 | [diff] [blame] | 345 | struct mount *mnt = real_mount(m); |
Dave Hansen | 3d73363 | 2008-02-15 14:37:59 -0800 | [diff] [blame] | 346 | int ret = 0; |
Dave Hansen | 3d73363 | 2008-02-15 14:37:59 -0800 | [diff] [blame] | 347 | |
npiggin@suse.de | d3ef3d7 | 2009-04-26 20:25:54 +1000 | [diff] [blame] | 348 | preempt_disable(); |
Nick Piggin | c6653a8 | 2011-01-07 17:50:10 +1100 | [diff] [blame] | 349 | mnt_inc_writers(mnt); |
npiggin@suse.de | d3ef3d7 | 2009-04-26 20:25:54 +1000 | [diff] [blame] | 350 | /* |
Nick Piggin | c6653a8 | 2011-01-07 17:50:10 +1100 | [diff] [blame] | 351 | * The store to mnt_inc_writers must be visible before we pass |
npiggin@suse.de | d3ef3d7 | 2009-04-26 20:25:54 +1000 | [diff] [blame] | 352 | * MNT_WRITE_HOLD loop below, so that the slowpath can see our |
| 353 | * incremented count after it has set MNT_WRITE_HOLD. |
| 354 | */ |
| 355 | smp_mb(); |
Miao Xie | 1e75529 | 2012-11-16 17:23:50 +0800 | [diff] [blame] | 356 | while (ACCESS_ONCE(mnt->mnt.mnt_flags) & MNT_WRITE_HOLD) |
npiggin@suse.de | d3ef3d7 | 2009-04-26 20:25:54 +1000 | [diff] [blame] | 357 | cpu_relax(); |
| 358 | /* |
| 359 | * After the slowpath clears MNT_WRITE_HOLD, mnt_is_readonly will |
| 360 | * be set to match its requirements. So we must not load that until |
| 361 | * MNT_WRITE_HOLD is cleared. |
| 362 | */ |
| 363 | smp_rmb(); |
Miklos Szeredi | 4ed5e82 | 2011-11-21 12:11:31 +0100 | [diff] [blame] | 364 | if (mnt_is_readonly(m)) { |
Nick Piggin | c6653a8 | 2011-01-07 17:50:10 +1100 | [diff] [blame] | 365 | mnt_dec_writers(mnt); |
Dave Hansen | 3d73363 | 2008-02-15 14:37:59 -0800 | [diff] [blame] | 366 | ret = -EROFS; |
Dave Hansen | 3d73363 | 2008-02-15 14:37:59 -0800 | [diff] [blame] | 367 | } |
npiggin@suse.de | d3ef3d7 | 2009-04-26 20:25:54 +1000 | [diff] [blame] | 368 | preempt_enable(); |
Jan Kara | eb04c28 | 2012-06-12 16:20:35 +0200 | [diff] [blame] | 369 | |
| 370 | return ret; |
| 371 | } |
| 372 | |
| 373 | /** |
| 374 | * mnt_want_write - get write access to a mount |
| 375 | * @m: the mount on which to take a write |
| 376 | * |
| 377 | * This tells the low-level filesystem that a write is about to be performed to |
| 378 | * it, and makes sure that writes are allowed (mount is read-write, filesystem |
| 379 | * is not frozen) before returning success. When the write operation is |
| 380 | * finished, mnt_drop_write() must be called. This is effectively a refcount. |
| 381 | */ |
| 382 | int mnt_want_write(struct vfsmount *m) |
| 383 | { |
| 384 | int ret; |
| 385 | |
| 386 | sb_start_write(m->mnt_sb); |
| 387 | ret = __mnt_want_write(m); |
| 388 | if (ret) |
| 389 | sb_end_write(m->mnt_sb); |
Dave Hansen | 3d73363 | 2008-02-15 14:37:59 -0800 | [diff] [blame] | 390 | return ret; |
Dave Hansen | 8366025 | 2008-02-15 14:37:30 -0800 | [diff] [blame] | 391 | } |
| 392 | EXPORT_SYMBOL_GPL(mnt_want_write); |
| 393 | |
| 394 | /** |
npiggin@suse.de | 96029c4 | 2009-04-26 20:25:55 +1000 | [diff] [blame] | 395 | * mnt_clone_write - get write access to a mount |
| 396 | * @mnt: the mount on which to take a write |
| 397 | * |
| 398 | * This is effectively like mnt_want_write, except |
| 399 | * it must only be used to take an extra write reference |
| 400 | * on a mountpoint that we already know has a write reference |
| 401 | * on it. This allows some optimisation. |
| 402 | * |
| 403 | * After finished, mnt_drop_write must be called as usual to |
| 404 | * drop the reference. |
| 405 | */ |
| 406 | int mnt_clone_write(struct vfsmount *mnt) |
| 407 | { |
| 408 | /* superblock may be r/o */ |
| 409 | if (__mnt_is_readonly(mnt)) |
| 410 | return -EROFS; |
| 411 | preempt_disable(); |
Al Viro | 83adc75 | 2011-11-24 22:37:54 -0500 | [diff] [blame] | 412 | mnt_inc_writers(real_mount(mnt)); |
npiggin@suse.de | 96029c4 | 2009-04-26 20:25:55 +1000 | [diff] [blame] | 413 | preempt_enable(); |
| 414 | return 0; |
| 415 | } |
| 416 | EXPORT_SYMBOL_GPL(mnt_clone_write); |
| 417 | |
| 418 | /** |
Jan Kara | eb04c28 | 2012-06-12 16:20:35 +0200 | [diff] [blame] | 419 | * __mnt_want_write_file - get write access to a file's mount |
| 420 | * @file: the file who's mount on which to take a write |
| 421 | * |
| 422 | * This is like __mnt_want_write, but it takes a file and can |
| 423 | * do some optimisations if the file is open for write already |
| 424 | */ |
| 425 | int __mnt_want_write_file(struct file *file) |
| 426 | { |
Al Viro | 83f936c | 2014-03-14 12:02:47 -0400 | [diff] [blame] | 427 | if (!(file->f_mode & FMODE_WRITER)) |
Jan Kara | eb04c28 | 2012-06-12 16:20:35 +0200 | [diff] [blame] | 428 | return __mnt_want_write(file->f_path.mnt); |
| 429 | else |
| 430 | return mnt_clone_write(file->f_path.mnt); |
| 431 | } |
| 432 | |
| 433 | /** |
npiggin@suse.de | 96029c4 | 2009-04-26 20:25:55 +1000 | [diff] [blame] | 434 | * mnt_want_write_file - get write access to a file's mount |
| 435 | * @file: the file who's mount on which to take a write |
| 436 | * |
| 437 | * This is like mnt_want_write, but it takes a file and can |
| 438 | * do some optimisations if the file is open for write already |
| 439 | */ |
| 440 | int mnt_want_write_file(struct file *file) |
| 441 | { |
Jan Kara | eb04c28 | 2012-06-12 16:20:35 +0200 | [diff] [blame] | 442 | int ret; |
| 443 | |
| 444 | sb_start_write(file->f_path.mnt->mnt_sb); |
| 445 | ret = __mnt_want_write_file(file); |
| 446 | if (ret) |
| 447 | sb_end_write(file->f_path.mnt->mnt_sb); |
| 448 | return ret; |
npiggin@suse.de | 96029c4 | 2009-04-26 20:25:55 +1000 | [diff] [blame] | 449 | } |
| 450 | EXPORT_SYMBOL_GPL(mnt_want_write_file); |
| 451 | |
| 452 | /** |
Jan Kara | eb04c28 | 2012-06-12 16:20:35 +0200 | [diff] [blame] | 453 | * __mnt_drop_write - give up write access to a mount |
Dave Hansen | 8366025 | 2008-02-15 14:37:30 -0800 | [diff] [blame] | 454 | * @mnt: the mount on which to give up write access |
| 455 | * |
| 456 | * Tells the low-level filesystem that we are done |
| 457 | * performing writes to it. Must be matched with |
Jan Kara | eb04c28 | 2012-06-12 16:20:35 +0200 | [diff] [blame] | 458 | * __mnt_want_write() call above. |
Dave Hansen | 8366025 | 2008-02-15 14:37:30 -0800 | [diff] [blame] | 459 | */ |
Jan Kara | eb04c28 | 2012-06-12 16:20:35 +0200 | [diff] [blame] | 460 | void __mnt_drop_write(struct vfsmount *mnt) |
Dave Hansen | 8366025 | 2008-02-15 14:37:30 -0800 | [diff] [blame] | 461 | { |
npiggin@suse.de | d3ef3d7 | 2009-04-26 20:25:54 +1000 | [diff] [blame] | 462 | preempt_disable(); |
Al Viro | 83adc75 | 2011-11-24 22:37:54 -0500 | [diff] [blame] | 463 | mnt_dec_writers(real_mount(mnt)); |
npiggin@suse.de | d3ef3d7 | 2009-04-26 20:25:54 +1000 | [diff] [blame] | 464 | preempt_enable(); |
Dave Hansen | 8366025 | 2008-02-15 14:37:30 -0800 | [diff] [blame] | 465 | } |
Jan Kara | eb04c28 | 2012-06-12 16:20:35 +0200 | [diff] [blame] | 466 | |
| 467 | /** |
| 468 | * mnt_drop_write - give up write access to a mount |
| 469 | * @mnt: the mount on which to give up write access |
| 470 | * |
| 471 | * Tells the low-level filesystem that we are done performing writes to it and |
| 472 | * also allows filesystem to be frozen again. Must be matched with |
| 473 | * mnt_want_write() call above. |
| 474 | */ |
| 475 | void mnt_drop_write(struct vfsmount *mnt) |
| 476 | { |
| 477 | __mnt_drop_write(mnt); |
| 478 | sb_end_write(mnt->mnt_sb); |
| 479 | } |
Dave Hansen | 8366025 | 2008-02-15 14:37:30 -0800 | [diff] [blame] | 480 | EXPORT_SYMBOL_GPL(mnt_drop_write); |
| 481 | |
Jan Kara | eb04c28 | 2012-06-12 16:20:35 +0200 | [diff] [blame] | 482 | void __mnt_drop_write_file(struct file *file) |
| 483 | { |
| 484 | __mnt_drop_write(file->f_path.mnt); |
| 485 | } |
| 486 | |
Al Viro | 2a79f17 | 2011-12-09 08:06:57 -0500 | [diff] [blame] | 487 | void mnt_drop_write_file(struct file *file) |
| 488 | { |
| 489 | mnt_drop_write(file->f_path.mnt); |
| 490 | } |
| 491 | EXPORT_SYMBOL(mnt_drop_write_file); |
| 492 | |
Al Viro | 83adc75 | 2011-11-24 22:37:54 -0500 | [diff] [blame] | 493 | static int mnt_make_readonly(struct mount *mnt) |
Dave Hansen | 8366025 | 2008-02-15 14:37:30 -0800 | [diff] [blame] | 494 | { |
Dave Hansen | 3d73363 | 2008-02-15 14:37:59 -0800 | [diff] [blame] | 495 | int ret = 0; |
| 496 | |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 497 | lock_mount_hash(); |
Al Viro | 83adc75 | 2011-11-24 22:37:54 -0500 | [diff] [blame] | 498 | mnt->mnt.mnt_flags |= MNT_WRITE_HOLD; |
npiggin@suse.de | d3ef3d7 | 2009-04-26 20:25:54 +1000 | [diff] [blame] | 499 | /* |
| 500 | * After storing MNT_WRITE_HOLD, we'll read the counters. This store |
| 501 | * should be visible before we do. |
| 502 | */ |
| 503 | smp_mb(); |
| 504 | |
| 505 | /* |
| 506 | * With writers on hold, if this value is zero, then there are |
| 507 | * definitely no active writers (although held writers may subsequently |
| 508 | * increment the count, they'll have to wait, and decrement it after |
| 509 | * seeing MNT_READONLY). |
| 510 | * |
| 511 | * It is OK to have counter incremented on one CPU and decremented on |
| 512 | * another: the sum will add up correctly. The danger would be when we |
| 513 | * sum up each counter, if we read a counter before it is incremented, |
| 514 | * but then read another CPU's count which it has been subsequently |
| 515 | * decremented from -- we would see more decrements than we should. |
| 516 | * MNT_WRITE_HOLD protects against this scenario, because |
| 517 | * mnt_want_write first increments count, then smp_mb, then spins on |
| 518 | * MNT_WRITE_HOLD, so it can't be decremented by another CPU while |
| 519 | * we're counting up here. |
| 520 | */ |
Nick Piggin | c6653a8 | 2011-01-07 17:50:10 +1100 | [diff] [blame] | 521 | if (mnt_get_writers(mnt) > 0) |
npiggin@suse.de | d3ef3d7 | 2009-04-26 20:25:54 +1000 | [diff] [blame] | 522 | ret = -EBUSY; |
| 523 | else |
Al Viro | 83adc75 | 2011-11-24 22:37:54 -0500 | [diff] [blame] | 524 | mnt->mnt.mnt_flags |= MNT_READONLY; |
npiggin@suse.de | d3ef3d7 | 2009-04-26 20:25:54 +1000 | [diff] [blame] | 525 | /* |
| 526 | * MNT_READONLY must become visible before ~MNT_WRITE_HOLD, so writers |
| 527 | * that become unheld will see MNT_READONLY. |
| 528 | */ |
| 529 | smp_wmb(); |
Al Viro | 83adc75 | 2011-11-24 22:37:54 -0500 | [diff] [blame] | 530 | mnt->mnt.mnt_flags &= ~MNT_WRITE_HOLD; |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 531 | unlock_mount_hash(); |
Dave Hansen | 3d73363 | 2008-02-15 14:37:59 -0800 | [diff] [blame] | 532 | return ret; |
Dave Hansen | 8366025 | 2008-02-15 14:37:30 -0800 | [diff] [blame] | 533 | } |
Dave Hansen | 8366025 | 2008-02-15 14:37:30 -0800 | [diff] [blame] | 534 | |
Al Viro | 83adc75 | 2011-11-24 22:37:54 -0500 | [diff] [blame] | 535 | static void __mnt_unmake_readonly(struct mount *mnt) |
Dave Hansen | 2e4b7fc | 2008-02-15 14:38:00 -0800 | [diff] [blame] | 536 | { |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 537 | lock_mount_hash(); |
Al Viro | 83adc75 | 2011-11-24 22:37:54 -0500 | [diff] [blame] | 538 | mnt->mnt.mnt_flags &= ~MNT_READONLY; |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 539 | unlock_mount_hash(); |
Dave Hansen | 2e4b7fc | 2008-02-15 14:38:00 -0800 | [diff] [blame] | 540 | } |
| 541 | |
Miklos Szeredi | 4ed5e82 | 2011-11-21 12:11:31 +0100 | [diff] [blame] | 542 | int sb_prepare_remount_readonly(struct super_block *sb) |
| 543 | { |
| 544 | struct mount *mnt; |
| 545 | int err = 0; |
| 546 | |
Miklos Szeredi | 8e8b879 | 2011-11-21 12:11:33 +0100 | [diff] [blame] | 547 | /* Racy optimization. Recheck the counter under MNT_WRITE_HOLD */ |
| 548 | if (atomic_long_read(&sb->s_remove_count)) |
| 549 | return -EBUSY; |
| 550 | |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 551 | lock_mount_hash(); |
Miklos Szeredi | 4ed5e82 | 2011-11-21 12:11:31 +0100 | [diff] [blame] | 552 | list_for_each_entry(mnt, &sb->s_mounts, mnt_instance) { |
| 553 | if (!(mnt->mnt.mnt_flags & MNT_READONLY)) { |
| 554 | mnt->mnt.mnt_flags |= MNT_WRITE_HOLD; |
| 555 | smp_mb(); |
| 556 | if (mnt_get_writers(mnt) > 0) { |
| 557 | err = -EBUSY; |
| 558 | break; |
| 559 | } |
| 560 | } |
| 561 | } |
Miklos Szeredi | 8e8b879 | 2011-11-21 12:11:33 +0100 | [diff] [blame] | 562 | if (!err && atomic_long_read(&sb->s_remove_count)) |
| 563 | err = -EBUSY; |
| 564 | |
Miklos Szeredi | 4ed5e82 | 2011-11-21 12:11:31 +0100 | [diff] [blame] | 565 | if (!err) { |
| 566 | sb->s_readonly_remount = 1; |
| 567 | smp_wmb(); |
| 568 | } |
| 569 | list_for_each_entry(mnt, &sb->s_mounts, mnt_instance) { |
| 570 | if (mnt->mnt.mnt_flags & MNT_WRITE_HOLD) |
| 571 | mnt->mnt.mnt_flags &= ~MNT_WRITE_HOLD; |
| 572 | } |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 573 | unlock_mount_hash(); |
Miklos Szeredi | 4ed5e82 | 2011-11-21 12:11:31 +0100 | [diff] [blame] | 574 | |
| 575 | return err; |
| 576 | } |
| 577 | |
Al Viro | b105e27 | 2011-11-24 20:38:33 -0500 | [diff] [blame] | 578 | static void free_vfsmnt(struct mount *mnt) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 579 | { |
Andrzej Hajda | fcc139a | 2015-02-13 14:36:41 -0800 | [diff] [blame] | 580 | kfree_const(mnt->mnt_devname); |
npiggin@suse.de | d3ef3d7 | 2009-04-26 20:25:54 +1000 | [diff] [blame] | 581 | #ifdef CONFIG_SMP |
Al Viro | 68e8a9f | 2011-11-24 22:53:09 -0500 | [diff] [blame] | 582 | free_percpu(mnt->mnt_pcp); |
npiggin@suse.de | d3ef3d7 | 2009-04-26 20:25:54 +1000 | [diff] [blame] | 583 | #endif |
Al Viro | b105e27 | 2011-11-24 20:38:33 -0500 | [diff] [blame] | 584 | kmem_cache_free(mnt_cache, mnt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 585 | } |
| 586 | |
David Howells | 8ffcb32 | 2014-01-24 12:17:54 +0000 | [diff] [blame] | 587 | static void delayed_free_vfsmnt(struct rcu_head *head) |
| 588 | { |
| 589 | free_vfsmnt(container_of(head, struct mount, mnt_rcu)); |
| 590 | } |
| 591 | |
Al Viro | 48a066e | 2013-09-29 22:06:07 -0400 | [diff] [blame] | 592 | /* call under rcu_read_lock */ |
| 593 | bool legitimize_mnt(struct vfsmount *bastard, unsigned seq) |
| 594 | { |
| 595 | struct mount *mnt; |
| 596 | if (read_seqretry(&mount_lock, seq)) |
| 597 | return false; |
| 598 | if (bastard == NULL) |
| 599 | return true; |
| 600 | mnt = real_mount(bastard); |
| 601 | mnt_add_count(mnt, 1); |
| 602 | if (likely(!read_seqretry(&mount_lock, seq))) |
| 603 | return true; |
| 604 | if (bastard->mnt_flags & MNT_SYNC_UMOUNT) { |
| 605 | mnt_add_count(mnt, -1); |
| 606 | return false; |
| 607 | } |
| 608 | rcu_read_unlock(); |
| 609 | mntput(bastard); |
| 610 | rcu_read_lock(); |
| 611 | return false; |
| 612 | } |
| 613 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 614 | /* |
Al Viro | 474279d | 2013-10-01 16:11:26 -0400 | [diff] [blame] | 615 | * find the first mount at @dentry on vfsmount @mnt. |
Al Viro | 48a066e | 2013-09-29 22:06:07 -0400 | [diff] [blame] | 616 | * call under rcu_read_lock() |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 617 | */ |
Al Viro | 474279d | 2013-10-01 16:11:26 -0400 | [diff] [blame] | 618 | struct mount *__lookup_mnt(struct vfsmount *mnt, struct dentry *dentry) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 619 | { |
Al Viro | 38129a1 | 2014-03-20 21:10:51 -0400 | [diff] [blame] | 620 | struct hlist_head *head = m_hash(mnt, dentry); |
Al Viro | 474279d | 2013-10-01 16:11:26 -0400 | [diff] [blame] | 621 | struct mount *p; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 622 | |
Al Viro | 38129a1 | 2014-03-20 21:10:51 -0400 | [diff] [blame] | 623 | hlist_for_each_entry_rcu(p, head, mnt_hash) |
Al Viro | 474279d | 2013-10-01 16:11:26 -0400 | [diff] [blame] | 624 | if (&p->mnt_parent->mnt == mnt && p->mnt_mountpoint == dentry) |
| 625 | return p; |
| 626 | return NULL; |
| 627 | } |
| 628 | |
| 629 | /* |
| 630 | * find the last mount at @dentry on vfsmount @mnt. |
Al Viro | 48a066e | 2013-09-29 22:06:07 -0400 | [diff] [blame] | 631 | * mount_lock must be held. |
Al Viro | 474279d | 2013-10-01 16:11:26 -0400 | [diff] [blame] | 632 | */ |
| 633 | struct mount *__lookup_mnt_last(struct vfsmount *mnt, struct dentry *dentry) |
| 634 | { |
Eric W. Biederman | 411a938 | 2014-12-22 19:12:07 -0600 | [diff] [blame] | 635 | struct mount *p, *res = NULL; |
| 636 | p = __lookup_mnt(mnt, dentry); |
Al Viro | 38129a1 | 2014-03-20 21:10:51 -0400 | [diff] [blame] | 637 | if (!p) |
| 638 | goto out; |
Eric W. Biederman | 411a938 | 2014-12-22 19:12:07 -0600 | [diff] [blame] | 639 | if (!(p->mnt.mnt_flags & MNT_UMOUNT)) |
| 640 | res = p; |
Al Viro | 38129a1 | 2014-03-20 21:10:51 -0400 | [diff] [blame] | 641 | hlist_for_each_entry_continue(p, mnt_hash) { |
Al Viro | 1d6a32a | 2014-03-20 20:34:43 -0400 | [diff] [blame] | 642 | if (&p->mnt_parent->mnt != mnt || p->mnt_mountpoint != dentry) |
| 643 | break; |
Eric W. Biederman | 411a938 | 2014-12-22 19:12:07 -0600 | [diff] [blame] | 644 | if (!(p->mnt.mnt_flags & MNT_UMOUNT)) |
| 645 | res = p; |
Al Viro | 1d6a32a | 2014-03-20 20:34:43 -0400 | [diff] [blame] | 646 | } |
Al Viro | 38129a1 | 2014-03-20 21:10:51 -0400 | [diff] [blame] | 647 | out: |
Al Viro | 1d6a32a | 2014-03-20 20:34:43 -0400 | [diff] [blame] | 648 | return res; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 649 | } |
| 650 | |
Ram Pai | a05964f | 2005-11-07 17:20:17 -0500 | [diff] [blame] | 651 | /* |
David Howells | f015f126 | 2012-06-25 12:55:28 +0100 | [diff] [blame] | 652 | * lookup_mnt - Return the first child mount mounted at path |
| 653 | * |
| 654 | * "First" means first mounted chronologically. If you create the |
| 655 | * following mounts: |
| 656 | * |
| 657 | * mount /dev/sda1 /mnt |
| 658 | * mount /dev/sda2 /mnt |
| 659 | * mount /dev/sda3 /mnt |
| 660 | * |
| 661 | * Then lookup_mnt() on the base /mnt dentry in the root mount will |
| 662 | * return successively the root dentry and vfsmount of /dev/sda1, then |
| 663 | * /dev/sda2, then /dev/sda3, then NULL. |
| 664 | * |
| 665 | * lookup_mnt takes a reference to the found vfsmount. |
Ram Pai | a05964f | 2005-11-07 17:20:17 -0500 | [diff] [blame] | 666 | */ |
Al Viro | 1c755af | 2009-04-18 14:06:57 -0400 | [diff] [blame] | 667 | struct vfsmount *lookup_mnt(struct path *path) |
Ram Pai | a05964f | 2005-11-07 17:20:17 -0500 | [diff] [blame] | 668 | { |
Al Viro | c710536 | 2011-11-24 18:22:03 -0500 | [diff] [blame] | 669 | struct mount *child_mnt; |
Al Viro | 48a066e | 2013-09-29 22:06:07 -0400 | [diff] [blame] | 670 | struct vfsmount *m; |
| 671 | unsigned seq; |
Nick Piggin | 99b7db7 | 2010-08-18 04:37:39 +1000 | [diff] [blame] | 672 | |
Al Viro | 48a066e | 2013-09-29 22:06:07 -0400 | [diff] [blame] | 673 | rcu_read_lock(); |
| 674 | do { |
| 675 | seq = read_seqbegin(&mount_lock); |
| 676 | child_mnt = __lookup_mnt(path->mnt, path->dentry); |
| 677 | m = child_mnt ? &child_mnt->mnt : NULL; |
| 678 | } while (!legitimize_mnt(m, seq)); |
| 679 | rcu_read_unlock(); |
| 680 | return m; |
Ram Pai | a05964f | 2005-11-07 17:20:17 -0500 | [diff] [blame] | 681 | } |
| 682 | |
Eric W. Biederman | 7af1364 | 2013-10-04 19:15:13 -0700 | [diff] [blame] | 683 | /* |
| 684 | * __is_local_mountpoint - Test to see if dentry is a mountpoint in the |
| 685 | * current mount namespace. |
| 686 | * |
| 687 | * The common case is dentries are not mountpoints at all and that |
| 688 | * test is handled inline. For the slow case when we are actually |
| 689 | * dealing with a mountpoint of some kind, walk through all of the |
| 690 | * mounts in the current mount namespace and test to see if the dentry |
| 691 | * is a mountpoint. |
| 692 | * |
| 693 | * The mount_hashtable is not usable in the context because we |
| 694 | * need to identify all mounts that may be in the current mount |
| 695 | * namespace not just a mount that happens to have some specified |
| 696 | * parent mount. |
| 697 | */ |
| 698 | bool __is_local_mountpoint(struct dentry *dentry) |
| 699 | { |
| 700 | struct mnt_namespace *ns = current->nsproxy->mnt_ns; |
| 701 | struct mount *mnt; |
| 702 | bool is_covered = false; |
| 703 | |
| 704 | if (!d_mountpoint(dentry)) |
| 705 | goto out; |
| 706 | |
| 707 | down_read(&namespace_sem); |
| 708 | list_for_each_entry(mnt, &ns->list, mnt_list) { |
| 709 | is_covered = (mnt->mnt_mountpoint == dentry); |
| 710 | if (is_covered) |
| 711 | break; |
| 712 | } |
| 713 | up_read(&namespace_sem); |
| 714 | out: |
| 715 | return is_covered; |
| 716 | } |
| 717 | |
Eric W. Biederman | e2dfa93 | 2014-02-24 17:32:34 -0800 | [diff] [blame] | 718 | static struct mountpoint *lookup_mountpoint(struct dentry *dentry) |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 719 | { |
Al Viro | 0818bf2 | 2014-02-28 13:46:44 -0500 | [diff] [blame] | 720 | struct hlist_head *chain = mp_hash(dentry); |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 721 | struct mountpoint *mp; |
| 722 | |
Al Viro | 0818bf2 | 2014-02-28 13:46:44 -0500 | [diff] [blame] | 723 | hlist_for_each_entry(mp, chain, m_hash) { |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 724 | if (mp->m_dentry == dentry) { |
| 725 | /* might be worth a WARN_ON() */ |
| 726 | if (d_unlinked(dentry)) |
| 727 | return ERR_PTR(-ENOENT); |
| 728 | mp->m_count++; |
| 729 | return mp; |
| 730 | } |
| 731 | } |
Eric W. Biederman | e2dfa93 | 2014-02-24 17:32:34 -0800 | [diff] [blame] | 732 | return NULL; |
| 733 | } |
| 734 | |
| 735 | static struct mountpoint *new_mountpoint(struct dentry *dentry) |
| 736 | { |
| 737 | struct hlist_head *chain = mp_hash(dentry); |
| 738 | struct mountpoint *mp; |
| 739 | int ret; |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 740 | |
| 741 | mp = kmalloc(sizeof(struct mountpoint), GFP_KERNEL); |
| 742 | if (!mp) |
| 743 | return ERR_PTR(-ENOMEM); |
| 744 | |
Miklos Szeredi | eed8100 | 2013-09-05 14:39:11 +0200 | [diff] [blame] | 745 | ret = d_set_mounted(dentry); |
| 746 | if (ret) { |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 747 | kfree(mp); |
Miklos Szeredi | eed8100 | 2013-09-05 14:39:11 +0200 | [diff] [blame] | 748 | return ERR_PTR(ret); |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 749 | } |
Miklos Szeredi | eed8100 | 2013-09-05 14:39:11 +0200 | [diff] [blame] | 750 | |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 751 | mp->m_dentry = dentry; |
| 752 | mp->m_count = 1; |
Al Viro | 0818bf2 | 2014-02-28 13:46:44 -0500 | [diff] [blame] | 753 | hlist_add_head(&mp->m_hash, chain); |
Eric W. Biederman | 0a5eb7c | 2013-09-22 19:37:01 -0700 | [diff] [blame] | 754 | INIT_HLIST_HEAD(&mp->m_list); |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 755 | return mp; |
| 756 | } |
| 757 | |
| 758 | static void put_mountpoint(struct mountpoint *mp) |
| 759 | { |
| 760 | if (!--mp->m_count) { |
| 761 | struct dentry *dentry = mp->m_dentry; |
Eric W. Biederman | 0a5eb7c | 2013-09-22 19:37:01 -0700 | [diff] [blame] | 762 | BUG_ON(!hlist_empty(&mp->m_list)); |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 763 | spin_lock(&dentry->d_lock); |
| 764 | dentry->d_flags &= ~DCACHE_MOUNTED; |
| 765 | spin_unlock(&dentry->d_lock); |
Al Viro | 0818bf2 | 2014-02-28 13:46:44 -0500 | [diff] [blame] | 766 | hlist_del(&mp->m_hash); |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 767 | kfree(mp); |
| 768 | } |
| 769 | } |
| 770 | |
Al Viro | 143c8c9 | 2011-11-25 00:46:35 -0500 | [diff] [blame] | 771 | static inline int check_mnt(struct mount *mnt) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 772 | { |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 773 | return mnt->mnt_ns == current->nsproxy->mnt_ns; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 774 | } |
| 775 | |
Nick Piggin | 99b7db7 | 2010-08-18 04:37:39 +1000 | [diff] [blame] | 776 | /* |
| 777 | * vfsmount lock must be held for write |
| 778 | */ |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 779 | static void touch_mnt_namespace(struct mnt_namespace *ns) |
Al Viro | 5addc5d | 2005-11-07 17:15:49 -0500 | [diff] [blame] | 780 | { |
| 781 | if (ns) { |
| 782 | ns->event = ++event; |
| 783 | wake_up_interruptible(&ns->poll); |
| 784 | } |
| 785 | } |
| 786 | |
Nick Piggin | 99b7db7 | 2010-08-18 04:37:39 +1000 | [diff] [blame] | 787 | /* |
| 788 | * vfsmount lock must be held for write |
| 789 | */ |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 790 | static void __touch_mnt_namespace(struct mnt_namespace *ns) |
Al Viro | 5addc5d | 2005-11-07 17:15:49 -0500 | [diff] [blame] | 791 | { |
| 792 | if (ns && ns->event != event) { |
| 793 | ns->event = event; |
| 794 | wake_up_interruptible(&ns->poll); |
| 795 | } |
| 796 | } |
| 797 | |
Nick Piggin | 99b7db7 | 2010-08-18 04:37:39 +1000 | [diff] [blame] | 798 | /* |
| 799 | * vfsmount lock must be held for write |
| 800 | */ |
Eric W. Biederman | 7bdb11d | 2014-12-29 13:03:41 -0600 | [diff] [blame] | 801 | static void unhash_mnt(struct mount *mnt) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 802 | { |
Al Viro | 0714a53 | 2011-11-24 22:19:58 -0500 | [diff] [blame] | 803 | mnt->mnt_parent = mnt; |
Al Viro | a73324d | 2011-11-24 22:25:07 -0500 | [diff] [blame] | 804 | mnt->mnt_mountpoint = mnt->mnt.mnt_root; |
Al Viro | 6b41d53 | 2011-11-24 23:24:33 -0500 | [diff] [blame] | 805 | list_del_init(&mnt->mnt_child); |
Al Viro | 38129a1 | 2014-03-20 21:10:51 -0400 | [diff] [blame] | 806 | hlist_del_init_rcu(&mnt->mnt_hash); |
Eric W. Biederman | 0a5eb7c | 2013-09-22 19:37:01 -0700 | [diff] [blame] | 807 | hlist_del_init(&mnt->mnt_mp_list); |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 808 | put_mountpoint(mnt->mnt_mp); |
| 809 | mnt->mnt_mp = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 810 | } |
| 811 | |
Nick Piggin | 99b7db7 | 2010-08-18 04:37:39 +1000 | [diff] [blame] | 812 | /* |
| 813 | * vfsmount lock must be held for write |
| 814 | */ |
Eric W. Biederman | 7bdb11d | 2014-12-29 13:03:41 -0600 | [diff] [blame] | 815 | static void detach_mnt(struct mount *mnt, struct path *old_path) |
| 816 | { |
| 817 | old_path->dentry = mnt->mnt_mountpoint; |
| 818 | old_path->mnt = &mnt->mnt_parent->mnt; |
| 819 | unhash_mnt(mnt); |
| 820 | } |
| 821 | |
| 822 | /* |
| 823 | * vfsmount lock must be held for write |
| 824 | */ |
Eric W. Biederman | 6a46c57 | 2015-01-15 22:58:33 -0600 | [diff] [blame] | 825 | static void umount_mnt(struct mount *mnt) |
| 826 | { |
| 827 | /* old mountpoint will be dropped when we can do that */ |
| 828 | mnt->mnt_ex_mountpoint = mnt->mnt_mountpoint; |
| 829 | unhash_mnt(mnt); |
| 830 | } |
| 831 | |
| 832 | /* |
| 833 | * vfsmount lock must be held for write |
| 834 | */ |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 835 | void mnt_set_mountpoint(struct mount *mnt, |
| 836 | struct mountpoint *mp, |
Al Viro | 44d964d6 | 2011-11-24 21:28:22 -0500 | [diff] [blame] | 837 | struct mount *child_mnt) |
Ram Pai | b90fa9a | 2005-11-07 17:19:50 -0500 | [diff] [blame] | 838 | { |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 839 | mp->m_count++; |
Al Viro | 3a2393d | 2011-11-25 03:19:09 -0500 | [diff] [blame] | 840 | mnt_add_count(mnt, 1); /* essentially, that's mntget */ |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 841 | child_mnt->mnt_mountpoint = dget(mp->m_dentry); |
Al Viro | 3a2393d | 2011-11-25 03:19:09 -0500 | [diff] [blame] | 842 | child_mnt->mnt_parent = mnt; |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 843 | child_mnt->mnt_mp = mp; |
Eric W. Biederman | 0a5eb7c | 2013-09-22 19:37:01 -0700 | [diff] [blame] | 844 | hlist_add_head(&child_mnt->mnt_mp_list, &mp->m_list); |
Ram Pai | b90fa9a | 2005-11-07 17:19:50 -0500 | [diff] [blame] | 845 | } |
| 846 | |
Nick Piggin | 99b7db7 | 2010-08-18 04:37:39 +1000 | [diff] [blame] | 847 | /* |
| 848 | * vfsmount lock must be held for write |
| 849 | */ |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 850 | static void attach_mnt(struct mount *mnt, |
| 851 | struct mount *parent, |
| 852 | struct mountpoint *mp) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 853 | { |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 854 | mnt_set_mountpoint(parent, mp, mnt); |
Al Viro | 38129a1 | 2014-03-20 21:10:51 -0400 | [diff] [blame] | 855 | hlist_add_head_rcu(&mnt->mnt_hash, m_hash(&parent->mnt, mp->m_dentry)); |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 856 | list_add_tail(&mnt->mnt_child, &parent->mnt_mounts); |
Ram Pai | b90fa9a | 2005-11-07 17:19:50 -0500 | [diff] [blame] | 857 | } |
| 858 | |
Al Viro | 12a5b52 | 2014-08-10 03:44:55 -0400 | [diff] [blame] | 859 | static void attach_shadowed(struct mount *mnt, |
| 860 | struct mount *parent, |
| 861 | struct mount *shadows) |
| 862 | { |
| 863 | if (shadows) { |
Linus Torvalds | f6f9933 | 2014-08-11 11:44:11 -0700 | [diff] [blame] | 864 | hlist_add_behind_rcu(&mnt->mnt_hash, &shadows->mnt_hash); |
Al Viro | 12a5b52 | 2014-08-10 03:44:55 -0400 | [diff] [blame] | 865 | list_add(&mnt->mnt_child, &shadows->mnt_child); |
| 866 | } else { |
| 867 | hlist_add_head_rcu(&mnt->mnt_hash, |
| 868 | m_hash(&parent->mnt, mnt->mnt_mountpoint)); |
| 869 | list_add_tail(&mnt->mnt_child, &parent->mnt_mounts); |
| 870 | } |
| 871 | } |
| 872 | |
Ram Pai | b90fa9a | 2005-11-07 17:19:50 -0500 | [diff] [blame] | 873 | /* |
Nick Piggin | 99b7db7 | 2010-08-18 04:37:39 +1000 | [diff] [blame] | 874 | * vfsmount lock must be held for write |
Ram Pai | b90fa9a | 2005-11-07 17:19:50 -0500 | [diff] [blame] | 875 | */ |
Al Viro | 1d6a32a | 2014-03-20 20:34:43 -0400 | [diff] [blame] | 876 | static void commit_tree(struct mount *mnt, struct mount *shadows) |
Ram Pai | b90fa9a | 2005-11-07 17:19:50 -0500 | [diff] [blame] | 877 | { |
Al Viro | 0714a53 | 2011-11-24 22:19:58 -0500 | [diff] [blame] | 878 | struct mount *parent = mnt->mnt_parent; |
Al Viro | 83adc75 | 2011-11-24 22:37:54 -0500 | [diff] [blame] | 879 | struct mount *m; |
Ram Pai | b90fa9a | 2005-11-07 17:19:50 -0500 | [diff] [blame] | 880 | LIST_HEAD(head); |
Al Viro | 143c8c9 | 2011-11-25 00:46:35 -0500 | [diff] [blame] | 881 | struct mnt_namespace *n = parent->mnt_ns; |
Ram Pai | b90fa9a | 2005-11-07 17:19:50 -0500 | [diff] [blame] | 882 | |
Al Viro | 0714a53 | 2011-11-24 22:19:58 -0500 | [diff] [blame] | 883 | BUG_ON(parent == mnt); |
Ram Pai | b90fa9a | 2005-11-07 17:19:50 -0500 | [diff] [blame] | 884 | |
Al Viro | 1a4eeaf | 2011-11-25 02:19:55 -0500 | [diff] [blame] | 885 | list_add_tail(&head, &mnt->mnt_list); |
Al Viro | f7a99c5 | 2012-06-09 00:59:08 -0400 | [diff] [blame] | 886 | list_for_each_entry(m, &head, mnt_list) |
Al Viro | 143c8c9 | 2011-11-25 00:46:35 -0500 | [diff] [blame] | 887 | m->mnt_ns = n; |
Al Viro | f03c659 | 2011-01-14 22:30:21 -0500 | [diff] [blame] | 888 | |
Ram Pai | b90fa9a | 2005-11-07 17:19:50 -0500 | [diff] [blame] | 889 | list_splice(&head, n->list.prev); |
| 890 | |
Al Viro | 12a5b52 | 2014-08-10 03:44:55 -0400 | [diff] [blame] | 891 | attach_shadowed(mnt, parent, shadows); |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 892 | touch_mnt_namespace(n); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 893 | } |
| 894 | |
Al Viro | 909b0a8 | 2011-11-25 03:06:56 -0500 | [diff] [blame] | 895 | static struct mount *next_mnt(struct mount *p, struct mount *root) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 896 | { |
Al Viro | 6b41d53 | 2011-11-24 23:24:33 -0500 | [diff] [blame] | 897 | struct list_head *next = p->mnt_mounts.next; |
| 898 | if (next == &p->mnt_mounts) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 899 | while (1) { |
Al Viro | 909b0a8 | 2011-11-25 03:06:56 -0500 | [diff] [blame] | 900 | if (p == root) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 901 | return NULL; |
Al Viro | 6b41d53 | 2011-11-24 23:24:33 -0500 | [diff] [blame] | 902 | next = p->mnt_child.next; |
| 903 | if (next != &p->mnt_parent->mnt_mounts) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 904 | break; |
Al Viro | 0714a53 | 2011-11-24 22:19:58 -0500 | [diff] [blame] | 905 | p = p->mnt_parent; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 906 | } |
| 907 | } |
Al Viro | 6b41d53 | 2011-11-24 23:24:33 -0500 | [diff] [blame] | 908 | return list_entry(next, struct mount, mnt_child); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 909 | } |
| 910 | |
Al Viro | 315fc83 | 2011-11-24 18:57:30 -0500 | [diff] [blame] | 911 | static struct mount *skip_mnt_tree(struct mount *p) |
Ram Pai | 9676f0c | 2005-11-07 17:21:20 -0500 | [diff] [blame] | 912 | { |
Al Viro | 6b41d53 | 2011-11-24 23:24:33 -0500 | [diff] [blame] | 913 | struct list_head *prev = p->mnt_mounts.prev; |
| 914 | while (prev != &p->mnt_mounts) { |
| 915 | p = list_entry(prev, struct mount, mnt_child); |
| 916 | prev = p->mnt_mounts.prev; |
Ram Pai | 9676f0c | 2005-11-07 17:21:20 -0500 | [diff] [blame] | 917 | } |
| 918 | return p; |
| 919 | } |
| 920 | |
Al Viro | 9d412a4 | 2011-03-17 22:08:28 -0400 | [diff] [blame] | 921 | struct vfsmount * |
| 922 | vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void *data) |
| 923 | { |
Al Viro | b105e27 | 2011-11-24 20:38:33 -0500 | [diff] [blame] | 924 | struct mount *mnt; |
Al Viro | 9d412a4 | 2011-03-17 22:08:28 -0400 | [diff] [blame] | 925 | struct dentry *root; |
| 926 | |
| 927 | if (!type) |
| 928 | return ERR_PTR(-ENODEV); |
| 929 | |
| 930 | mnt = alloc_vfsmnt(name); |
| 931 | if (!mnt) |
| 932 | return ERR_PTR(-ENOMEM); |
| 933 | |
| 934 | if (flags & MS_KERNMOUNT) |
Al Viro | b105e27 | 2011-11-24 20:38:33 -0500 | [diff] [blame] | 935 | mnt->mnt.mnt_flags = MNT_INTERNAL; |
Al Viro | 9d412a4 | 2011-03-17 22:08:28 -0400 | [diff] [blame] | 936 | |
| 937 | root = mount_fs(type, flags, name, data); |
| 938 | if (IS_ERR(root)) { |
David Howells | 8ffcb32 | 2014-01-24 12:17:54 +0000 | [diff] [blame] | 939 | mnt_free_id(mnt); |
Al Viro | 9d412a4 | 2011-03-17 22:08:28 -0400 | [diff] [blame] | 940 | free_vfsmnt(mnt); |
| 941 | return ERR_CAST(root); |
| 942 | } |
| 943 | |
Al Viro | b105e27 | 2011-11-24 20:38:33 -0500 | [diff] [blame] | 944 | mnt->mnt.mnt_root = root; |
| 945 | mnt->mnt.mnt_sb = root->d_sb; |
Al Viro | a73324d | 2011-11-24 22:25:07 -0500 | [diff] [blame] | 946 | mnt->mnt_mountpoint = mnt->mnt.mnt_root; |
Al Viro | 0714a53 | 2011-11-24 22:19:58 -0500 | [diff] [blame] | 947 | mnt->mnt_parent = mnt; |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 948 | lock_mount_hash(); |
Miklos Szeredi | 39f7c4d | 2011-11-21 12:11:30 +0100 | [diff] [blame] | 949 | list_add_tail(&mnt->mnt_instance, &root->d_sb->s_mounts); |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 950 | unlock_mount_hash(); |
Al Viro | b105e27 | 2011-11-24 20:38:33 -0500 | [diff] [blame] | 951 | return &mnt->mnt; |
Al Viro | 9d412a4 | 2011-03-17 22:08:28 -0400 | [diff] [blame] | 952 | } |
| 953 | EXPORT_SYMBOL_GPL(vfs_kern_mount); |
| 954 | |
Al Viro | 87129cc | 2011-11-24 21:24:27 -0500 | [diff] [blame] | 955 | static struct mount *clone_mnt(struct mount *old, struct dentry *root, |
Ram Pai | 36341f6 | 2005-11-07 17:17:22 -0500 | [diff] [blame] | 956 | int flag) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 957 | { |
Al Viro | 87129cc | 2011-11-24 21:24:27 -0500 | [diff] [blame] | 958 | struct super_block *sb = old->mnt.mnt_sb; |
David Howells | be34d1a | 2012-06-25 12:55:18 +0100 | [diff] [blame] | 959 | struct mount *mnt; |
| 960 | int err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 961 | |
David Howells | be34d1a | 2012-06-25 12:55:18 +0100 | [diff] [blame] | 962 | mnt = alloc_vfsmnt(old->mnt_devname); |
| 963 | if (!mnt) |
| 964 | return ERR_PTR(-ENOMEM); |
Miklos Szeredi | 719f5d7 | 2008-03-27 13:06:23 +0100 | [diff] [blame] | 965 | |
Eric W. Biederman | 7a472ef | 2012-07-31 13:13:04 -0700 | [diff] [blame] | 966 | if (flag & (CL_SLAVE | CL_PRIVATE | CL_SHARED_TO_SLAVE)) |
David Howells | be34d1a | 2012-06-25 12:55:18 +0100 | [diff] [blame] | 967 | mnt->mnt_group_id = 0; /* not a peer of original */ |
| 968 | else |
| 969 | mnt->mnt_group_id = old->mnt_group_id; |
Miklos Szeredi | 719f5d7 | 2008-03-27 13:06:23 +0100 | [diff] [blame] | 970 | |
David Howells | be34d1a | 2012-06-25 12:55:18 +0100 | [diff] [blame] | 971 | if ((flag & CL_MAKE_SHARED) && !mnt->mnt_group_id) { |
| 972 | err = mnt_alloc_group_id(mnt); |
| 973 | if (err) |
| 974 | goto out_free; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 975 | } |
David Howells | be34d1a | 2012-06-25 12:55:18 +0100 | [diff] [blame] | 976 | |
Al Viro | f2ebb3a | 2014-02-27 09:35:45 -0500 | [diff] [blame] | 977 | mnt->mnt.mnt_flags = old->mnt.mnt_flags & ~(MNT_WRITE_HOLD|MNT_MARKED); |
Eric W. Biederman | 132c94e | 2013-03-22 04:08:05 -0700 | [diff] [blame] | 978 | /* Don't allow unprivileged users to change mount flags */ |
Eric W. Biederman | 9566d67 | 2014-07-28 17:26:07 -0700 | [diff] [blame] | 979 | if (flag & CL_UNPRIVILEGED) { |
| 980 | mnt->mnt.mnt_flags |= MNT_LOCK_ATIME; |
| 981 | |
| 982 | if (mnt->mnt.mnt_flags & MNT_READONLY) |
| 983 | mnt->mnt.mnt_flags |= MNT_LOCK_READONLY; |
| 984 | |
| 985 | if (mnt->mnt.mnt_flags & MNT_NODEV) |
| 986 | mnt->mnt.mnt_flags |= MNT_LOCK_NODEV; |
| 987 | |
| 988 | if (mnt->mnt.mnt_flags & MNT_NOSUID) |
| 989 | mnt->mnt.mnt_flags |= MNT_LOCK_NOSUID; |
| 990 | |
| 991 | if (mnt->mnt.mnt_flags & MNT_NOEXEC) |
| 992 | mnt->mnt.mnt_flags |= MNT_LOCK_NOEXEC; |
| 993 | } |
Eric W. Biederman | 132c94e | 2013-03-22 04:08:05 -0700 | [diff] [blame] | 994 | |
Eric W. Biederman | 5ff9d8a | 2013-03-29 21:04:39 -0700 | [diff] [blame] | 995 | /* Don't allow unprivileged users to reveal what is under a mount */ |
Eric W. Biederman | 381cacb | 2014-10-07 17:11:46 -0700 | [diff] [blame] | 996 | if ((flag & CL_UNPRIVILEGED) && |
| 997 | (!(flag & CL_EXPIRE) || list_empty(&old->mnt_expire))) |
Eric W. Biederman | 5ff9d8a | 2013-03-29 21:04:39 -0700 | [diff] [blame] | 998 | mnt->mnt.mnt_flags |= MNT_LOCKED; |
| 999 | |
David Howells | be34d1a | 2012-06-25 12:55:18 +0100 | [diff] [blame] | 1000 | atomic_inc(&sb->s_active); |
| 1001 | mnt->mnt.mnt_sb = sb; |
| 1002 | mnt->mnt.mnt_root = dget(root); |
| 1003 | mnt->mnt_mountpoint = mnt->mnt.mnt_root; |
| 1004 | mnt->mnt_parent = mnt; |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 1005 | lock_mount_hash(); |
David Howells | be34d1a | 2012-06-25 12:55:18 +0100 | [diff] [blame] | 1006 | list_add_tail(&mnt->mnt_instance, &sb->s_mounts); |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 1007 | unlock_mount_hash(); |
David Howells | be34d1a | 2012-06-25 12:55:18 +0100 | [diff] [blame] | 1008 | |
Eric W. Biederman | 7a472ef | 2012-07-31 13:13:04 -0700 | [diff] [blame] | 1009 | if ((flag & CL_SLAVE) || |
| 1010 | ((flag & CL_SHARED_TO_SLAVE) && IS_MNT_SHARED(old))) { |
David Howells | be34d1a | 2012-06-25 12:55:18 +0100 | [diff] [blame] | 1011 | list_add(&mnt->mnt_slave, &old->mnt_slave_list); |
| 1012 | mnt->mnt_master = old; |
| 1013 | CLEAR_MNT_SHARED(mnt); |
| 1014 | } else if (!(flag & CL_PRIVATE)) { |
| 1015 | if ((flag & CL_MAKE_SHARED) || IS_MNT_SHARED(old)) |
| 1016 | list_add(&mnt->mnt_share, &old->mnt_share); |
| 1017 | if (IS_MNT_SLAVE(old)) |
| 1018 | list_add(&mnt->mnt_slave, &old->mnt_slave); |
| 1019 | mnt->mnt_master = old->mnt_master; |
| 1020 | } |
| 1021 | if (flag & CL_MAKE_SHARED) |
| 1022 | set_mnt_shared(mnt); |
| 1023 | |
| 1024 | /* stick the duplicate mount on the same expiry list |
| 1025 | * as the original if that was on one */ |
| 1026 | if (flag & CL_EXPIRE) { |
| 1027 | if (!list_empty(&old->mnt_expire)) |
| 1028 | list_add(&mnt->mnt_expire, &old->mnt_expire); |
| 1029 | } |
| 1030 | |
Al Viro | cb338d0 | 2011-11-24 20:55:08 -0500 | [diff] [blame] | 1031 | return mnt; |
Miklos Szeredi | 719f5d7 | 2008-03-27 13:06:23 +0100 | [diff] [blame] | 1032 | |
| 1033 | out_free: |
David Howells | 8ffcb32 | 2014-01-24 12:17:54 +0000 | [diff] [blame] | 1034 | mnt_free_id(mnt); |
Miklos Szeredi | 719f5d7 | 2008-03-27 13:06:23 +0100 | [diff] [blame] | 1035 | free_vfsmnt(mnt); |
David Howells | be34d1a | 2012-06-25 12:55:18 +0100 | [diff] [blame] | 1036 | return ERR_PTR(err); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1037 | } |
| 1038 | |
Al Viro | 9ea459e | 2014-08-08 13:08:20 -0400 | [diff] [blame] | 1039 | static void cleanup_mnt(struct mount *mnt) |
| 1040 | { |
| 1041 | /* |
| 1042 | * This probably indicates that somebody messed |
| 1043 | * up a mnt_want/drop_write() pair. If this |
| 1044 | * happens, the filesystem was probably unable |
| 1045 | * to make r/w->r/o transitions. |
| 1046 | */ |
| 1047 | /* |
| 1048 | * The locking used to deal with mnt_count decrement provides barriers, |
| 1049 | * so mnt_get_writers() below is safe. |
| 1050 | */ |
| 1051 | WARN_ON(mnt_get_writers(mnt)); |
| 1052 | if (unlikely(mnt->mnt_pins.first)) |
| 1053 | mnt_pin_kill(mnt); |
| 1054 | fsnotify_vfsmount_delete(&mnt->mnt); |
| 1055 | dput(mnt->mnt.mnt_root); |
| 1056 | deactivate_super(mnt->mnt.mnt_sb); |
| 1057 | mnt_free_id(mnt); |
| 1058 | call_rcu(&mnt->mnt_rcu, delayed_free_vfsmnt); |
| 1059 | } |
| 1060 | |
| 1061 | static void __cleanup_mnt(struct rcu_head *head) |
| 1062 | { |
| 1063 | cleanup_mnt(container_of(head, struct mount, mnt_rcu)); |
| 1064 | } |
| 1065 | |
| 1066 | static LLIST_HEAD(delayed_mntput_list); |
| 1067 | static void delayed_mntput(struct work_struct *unused) |
| 1068 | { |
| 1069 | struct llist_node *node = llist_del_all(&delayed_mntput_list); |
| 1070 | struct llist_node *next; |
| 1071 | |
| 1072 | for (; node; node = next) { |
| 1073 | next = llist_next(node); |
| 1074 | cleanup_mnt(llist_entry(node, struct mount, mnt_llist)); |
| 1075 | } |
| 1076 | } |
| 1077 | static DECLARE_DELAYED_WORK(delayed_mntput_work, delayed_mntput); |
| 1078 | |
Al Viro | 900148d | 2011-11-25 00:33:11 -0500 | [diff] [blame] | 1079 | static void mntput_no_expire(struct mount *mnt) |
Al Viro | 7b7b1ac | 2005-11-07 17:13:39 -0500 | [diff] [blame] | 1080 | { |
Al Viro | 48a066e | 2013-09-29 22:06:07 -0400 | [diff] [blame] | 1081 | rcu_read_lock(); |
| 1082 | mnt_add_count(mnt, -1); |
| 1083 | if (likely(mnt->mnt_ns)) { /* shouldn't be the last one */ |
| 1084 | rcu_read_unlock(); |
Al Viro | f03c659 | 2011-01-14 22:30:21 -0500 | [diff] [blame] | 1085 | return; |
Nick Piggin | b3e19d9 | 2011-01-07 17:50:11 +1100 | [diff] [blame] | 1086 | } |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 1087 | lock_mount_hash(); |
Nick Piggin | b3e19d9 | 2011-01-07 17:50:11 +1100 | [diff] [blame] | 1088 | if (mnt_get_count(mnt)) { |
Al Viro | 48a066e | 2013-09-29 22:06:07 -0400 | [diff] [blame] | 1089 | rcu_read_unlock(); |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 1090 | unlock_mount_hash(); |
Nick Piggin | b3e19d9 | 2011-01-07 17:50:11 +1100 | [diff] [blame] | 1091 | return; |
| 1092 | } |
Al Viro | 48a066e | 2013-09-29 22:06:07 -0400 | [diff] [blame] | 1093 | if (unlikely(mnt->mnt.mnt_flags & MNT_DOOMED)) { |
| 1094 | rcu_read_unlock(); |
| 1095 | unlock_mount_hash(); |
| 1096 | return; |
| 1097 | } |
| 1098 | mnt->mnt.mnt_flags |= MNT_DOOMED; |
| 1099 | rcu_read_unlock(); |
Andi Kleen | 962830d | 2012-05-08 13:32:02 +0930 | [diff] [blame] | 1100 | |
Miklos Szeredi | 39f7c4d | 2011-11-21 12:11:30 +0100 | [diff] [blame] | 1101 | list_del(&mnt->mnt_instance); |
Eric W. Biederman | ce07d89 | 2014-12-23 21:37:03 -0600 | [diff] [blame] | 1102 | |
| 1103 | if (unlikely(!list_empty(&mnt->mnt_mounts))) { |
| 1104 | struct mount *p, *tmp; |
| 1105 | list_for_each_entry_safe(p, tmp, &mnt->mnt_mounts, mnt_child) { |
| 1106 | umount_mnt(p); |
| 1107 | } |
| 1108 | } |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 1109 | unlock_mount_hash(); |
Al Viro | 649a795 | 2013-09-28 12:41:25 -0400 | [diff] [blame] | 1110 | |
Al Viro | 9ea459e | 2014-08-08 13:08:20 -0400 | [diff] [blame] | 1111 | if (likely(!(mnt->mnt.mnt_flags & MNT_INTERNAL))) { |
| 1112 | struct task_struct *task = current; |
| 1113 | if (likely(!(task->flags & PF_KTHREAD))) { |
| 1114 | init_task_work(&mnt->mnt_rcu, __cleanup_mnt); |
| 1115 | if (!task_work_add(task, &mnt->mnt_rcu, true)) |
| 1116 | return; |
| 1117 | } |
| 1118 | if (llist_add(&mnt->mnt_llist, &delayed_mntput_list)) |
| 1119 | schedule_delayed_work(&delayed_mntput_work, 1); |
| 1120 | return; |
| 1121 | } |
| 1122 | cleanup_mnt(mnt); |
Al Viro | 7b7b1ac | 2005-11-07 17:13:39 -0500 | [diff] [blame] | 1123 | } |
Nick Piggin | b3e19d9 | 2011-01-07 17:50:11 +1100 | [diff] [blame] | 1124 | |
| 1125 | void mntput(struct vfsmount *mnt) |
| 1126 | { |
| 1127 | if (mnt) { |
Al Viro | 863d684 | 2011-11-25 00:57:42 -0500 | [diff] [blame] | 1128 | struct mount *m = real_mount(mnt); |
Nick Piggin | b3e19d9 | 2011-01-07 17:50:11 +1100 | [diff] [blame] | 1129 | /* avoid cacheline pingpong, hope gcc doesn't get "smart" */ |
Al Viro | 863d684 | 2011-11-25 00:57:42 -0500 | [diff] [blame] | 1130 | if (unlikely(m->mnt_expiry_mark)) |
| 1131 | m->mnt_expiry_mark = 0; |
| 1132 | mntput_no_expire(m); |
Nick Piggin | b3e19d9 | 2011-01-07 17:50:11 +1100 | [diff] [blame] | 1133 | } |
| 1134 | } |
| 1135 | EXPORT_SYMBOL(mntput); |
| 1136 | |
| 1137 | struct vfsmount *mntget(struct vfsmount *mnt) |
| 1138 | { |
| 1139 | if (mnt) |
Al Viro | 83adc75 | 2011-11-24 22:37:54 -0500 | [diff] [blame] | 1140 | mnt_add_count(real_mount(mnt), 1); |
Nick Piggin | b3e19d9 | 2011-01-07 17:50:11 +1100 | [diff] [blame] | 1141 | return mnt; |
| 1142 | } |
| 1143 | EXPORT_SYMBOL(mntget); |
| 1144 | |
Al Viro | 3064c35 | 2014-08-07 09:12:31 -0400 | [diff] [blame] | 1145 | struct vfsmount *mnt_clone_internal(struct path *path) |
Al Viro | 7b7b1ac | 2005-11-07 17:13:39 -0500 | [diff] [blame] | 1146 | { |
Al Viro | 3064c35 | 2014-08-07 09:12:31 -0400 | [diff] [blame] | 1147 | struct mount *p; |
| 1148 | p = clone_mnt(real_mount(path->mnt), path->dentry, CL_PRIVATE); |
| 1149 | if (IS_ERR(p)) |
| 1150 | return ERR_CAST(p); |
| 1151 | p->mnt.mnt_flags |= MNT_INTERNAL; |
| 1152 | return &p->mnt; |
Al Viro | 7b7b1ac | 2005-11-07 17:13:39 -0500 | [diff] [blame] | 1153 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1154 | |
Miklos Szeredi | b3b304a | 2008-02-08 04:21:35 -0800 | [diff] [blame] | 1155 | static inline void mangle(struct seq_file *m, const char *s) |
| 1156 | { |
| 1157 | seq_escape(m, s, " \t\n\\"); |
| 1158 | } |
| 1159 | |
| 1160 | /* |
| 1161 | * Simple .show_options callback for filesystems which don't want to |
| 1162 | * implement more complex mount option showing. |
| 1163 | * |
| 1164 | * See also save_mount_options(). |
| 1165 | */ |
Al Viro | 34c80b1 | 2011-12-08 21:32:45 -0500 | [diff] [blame] | 1166 | int generic_show_options(struct seq_file *m, struct dentry *root) |
Miklos Szeredi | b3b304a | 2008-02-08 04:21:35 -0800 | [diff] [blame] | 1167 | { |
Al Viro | 2a32ceb | 2009-05-08 16:05:57 -0400 | [diff] [blame] | 1168 | const char *options; |
| 1169 | |
| 1170 | rcu_read_lock(); |
Al Viro | 34c80b1 | 2011-12-08 21:32:45 -0500 | [diff] [blame] | 1171 | options = rcu_dereference(root->d_sb->s_options); |
Miklos Szeredi | b3b304a | 2008-02-08 04:21:35 -0800 | [diff] [blame] | 1172 | |
| 1173 | if (options != NULL && options[0]) { |
| 1174 | seq_putc(m, ','); |
| 1175 | mangle(m, options); |
| 1176 | } |
Al Viro | 2a32ceb | 2009-05-08 16:05:57 -0400 | [diff] [blame] | 1177 | rcu_read_unlock(); |
Miklos Szeredi | b3b304a | 2008-02-08 04:21:35 -0800 | [diff] [blame] | 1178 | |
| 1179 | return 0; |
| 1180 | } |
| 1181 | EXPORT_SYMBOL(generic_show_options); |
| 1182 | |
| 1183 | /* |
| 1184 | * If filesystem uses generic_show_options(), this function should be |
| 1185 | * called from the fill_super() callback. |
| 1186 | * |
| 1187 | * The .remount_fs callback usually needs to be handled in a special |
| 1188 | * way, to make sure, that previous options are not overwritten if the |
| 1189 | * remount fails. |
| 1190 | * |
| 1191 | * Also note, that if the filesystem's .remount_fs function doesn't |
| 1192 | * reset all options to their default value, but changes only newly |
| 1193 | * given options, then the displayed options will not reflect reality |
| 1194 | * any more. |
| 1195 | */ |
| 1196 | void save_mount_options(struct super_block *sb, char *options) |
| 1197 | { |
Al Viro | 2a32ceb | 2009-05-08 16:05:57 -0400 | [diff] [blame] | 1198 | BUG_ON(sb->s_options); |
| 1199 | rcu_assign_pointer(sb->s_options, kstrdup(options, GFP_KERNEL)); |
Miklos Szeredi | b3b304a | 2008-02-08 04:21:35 -0800 | [diff] [blame] | 1200 | } |
| 1201 | EXPORT_SYMBOL(save_mount_options); |
| 1202 | |
Al Viro | 2a32ceb | 2009-05-08 16:05:57 -0400 | [diff] [blame] | 1203 | void replace_mount_options(struct super_block *sb, char *options) |
| 1204 | { |
| 1205 | char *old = sb->s_options; |
| 1206 | rcu_assign_pointer(sb->s_options, options); |
| 1207 | if (old) { |
| 1208 | synchronize_rcu(); |
| 1209 | kfree(old); |
| 1210 | } |
| 1211 | } |
| 1212 | EXPORT_SYMBOL(replace_mount_options); |
| 1213 | |
Miklos Szeredi | a1a2c40 | 2008-03-27 13:06:24 +0100 | [diff] [blame] | 1214 | #ifdef CONFIG_PROC_FS |
Al Viro | 0226f49 | 2011-12-06 12:21:54 -0500 | [diff] [blame] | 1215 | /* iterator; we want it to have access to namespace_sem, thus here... */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1216 | static void *m_start(struct seq_file *m, loff_t *pos) |
| 1217 | { |
Al Viro | 6ce6e24 | 2012-06-09 01:16:59 -0400 | [diff] [blame] | 1218 | struct proc_mounts *p = proc_mounts(m); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1219 | |
Ram Pai | 390c684 | 2005-11-07 17:17:51 -0500 | [diff] [blame] | 1220 | down_read(&namespace_sem); |
Al Viro | c7999c3 | 2014-02-27 14:40:10 -0500 | [diff] [blame] | 1221 | if (p->cached_event == p->ns->event) { |
| 1222 | void *v = p->cached_mount; |
| 1223 | if (*pos == p->cached_index) |
| 1224 | return v; |
| 1225 | if (*pos == p->cached_index + 1) { |
| 1226 | v = seq_list_next(v, &p->ns->list, &p->cached_index); |
| 1227 | return p->cached_mount = v; |
| 1228 | } |
| 1229 | } |
| 1230 | |
| 1231 | p->cached_event = p->ns->event; |
| 1232 | p->cached_mount = seq_list_start(&p->ns->list, *pos); |
| 1233 | p->cached_index = *pos; |
| 1234 | return p->cached_mount; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1235 | } |
| 1236 | |
| 1237 | static void *m_next(struct seq_file *m, void *v, loff_t *pos) |
| 1238 | { |
Al Viro | 6ce6e24 | 2012-06-09 01:16:59 -0400 | [diff] [blame] | 1239 | struct proc_mounts *p = proc_mounts(m); |
Pavel Emelianov | b0765fb | 2007-07-15 23:39:55 -0700 | [diff] [blame] | 1240 | |
Al Viro | c7999c3 | 2014-02-27 14:40:10 -0500 | [diff] [blame] | 1241 | p->cached_mount = seq_list_next(v, &p->ns->list, pos); |
| 1242 | p->cached_index = *pos; |
| 1243 | return p->cached_mount; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1244 | } |
| 1245 | |
| 1246 | static void m_stop(struct seq_file *m, void *v) |
| 1247 | { |
Ram Pai | 390c684 | 2005-11-07 17:17:51 -0500 | [diff] [blame] | 1248 | up_read(&namespace_sem); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1249 | } |
| 1250 | |
Al Viro | 0226f49 | 2011-12-06 12:21:54 -0500 | [diff] [blame] | 1251 | static int m_show(struct seq_file *m, void *v) |
Al Viro | 9f5596a | 2010-02-05 00:40:25 -0500 | [diff] [blame] | 1252 | { |
Al Viro | 6ce6e24 | 2012-06-09 01:16:59 -0400 | [diff] [blame] | 1253 | struct proc_mounts *p = proc_mounts(m); |
Al Viro | 1a4eeaf | 2011-11-25 02:19:55 -0500 | [diff] [blame] | 1254 | struct mount *r = list_entry(v, struct mount, mnt_list); |
Al Viro | 0226f49 | 2011-12-06 12:21:54 -0500 | [diff] [blame] | 1255 | return p->show(m, &r->mnt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1256 | } |
| 1257 | |
Miklos Szeredi | a1a2c40 | 2008-03-27 13:06:24 +0100 | [diff] [blame] | 1258 | const struct seq_operations mounts_op = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1259 | .start = m_start, |
| 1260 | .next = m_next, |
| 1261 | .stop = m_stop, |
Al Viro | 0226f49 | 2011-12-06 12:21:54 -0500 | [diff] [blame] | 1262 | .show = m_show, |
Chuck Lever | b4629fe | 2006-03-20 13:44:12 -0500 | [diff] [blame] | 1263 | }; |
Miklos Szeredi | a1a2c40 | 2008-03-27 13:06:24 +0100 | [diff] [blame] | 1264 | #endif /* CONFIG_PROC_FS */ |
Chuck Lever | b4629fe | 2006-03-20 13:44:12 -0500 | [diff] [blame] | 1265 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1266 | /** |
| 1267 | * may_umount_tree - check if a mount tree is busy |
| 1268 | * @mnt: root of mount tree |
| 1269 | * |
| 1270 | * This is called to check if a tree of mounts has any |
| 1271 | * open files, pwds, chroots or sub mounts that are |
| 1272 | * busy. |
| 1273 | */ |
Al Viro | 909b0a8 | 2011-11-25 03:06:56 -0500 | [diff] [blame] | 1274 | int may_umount_tree(struct vfsmount *m) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1275 | { |
Al Viro | 909b0a8 | 2011-11-25 03:06:56 -0500 | [diff] [blame] | 1276 | struct mount *mnt = real_mount(m); |
Ram Pai | 36341f6 | 2005-11-07 17:17:22 -0500 | [diff] [blame] | 1277 | int actual_refs = 0; |
| 1278 | int minimum_refs = 0; |
Al Viro | 315fc83 | 2011-11-24 18:57:30 -0500 | [diff] [blame] | 1279 | struct mount *p; |
Al Viro | 909b0a8 | 2011-11-25 03:06:56 -0500 | [diff] [blame] | 1280 | BUG_ON(!m); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1281 | |
Nick Piggin | b3e19d9 | 2011-01-07 17:50:11 +1100 | [diff] [blame] | 1282 | /* write lock needed for mnt_get_count */ |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 1283 | lock_mount_hash(); |
Al Viro | 909b0a8 | 2011-11-25 03:06:56 -0500 | [diff] [blame] | 1284 | for (p = mnt; p; p = next_mnt(p, mnt)) { |
Al Viro | 83adc75 | 2011-11-24 22:37:54 -0500 | [diff] [blame] | 1285 | actual_refs += mnt_get_count(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1286 | minimum_refs += 2; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1287 | } |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 1288 | unlock_mount_hash(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1289 | |
| 1290 | if (actual_refs > minimum_refs) |
Ian Kent | e3474a8 | 2006-03-27 01:14:51 -0800 | [diff] [blame] | 1291 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1292 | |
Ian Kent | e3474a8 | 2006-03-27 01:14:51 -0800 | [diff] [blame] | 1293 | return 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1294 | } |
| 1295 | |
| 1296 | EXPORT_SYMBOL(may_umount_tree); |
| 1297 | |
| 1298 | /** |
| 1299 | * may_umount - check if a mount point is busy |
| 1300 | * @mnt: root of mount |
| 1301 | * |
| 1302 | * This is called to check if a mount point has any |
| 1303 | * open files, pwds, chroots or sub mounts. If the |
| 1304 | * mount has sub mounts this will return busy |
| 1305 | * regardless of whether the sub mounts are busy. |
| 1306 | * |
| 1307 | * Doesn't take quota and stuff into account. IOW, in some cases it will |
| 1308 | * give false negatives. The main reason why it's here is that we need |
| 1309 | * a non-destructive way to look for easily umountable filesystems. |
| 1310 | */ |
| 1311 | int may_umount(struct vfsmount *mnt) |
| 1312 | { |
Ian Kent | e3474a8 | 2006-03-27 01:14:51 -0800 | [diff] [blame] | 1313 | int ret = 1; |
Al Viro | 8ad08d8 | 2010-01-16 12:56:08 -0500 | [diff] [blame] | 1314 | down_read(&namespace_sem); |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 1315 | lock_mount_hash(); |
Al Viro | 1ab5973 | 2011-11-24 21:35:16 -0500 | [diff] [blame] | 1316 | if (propagate_mount_busy(real_mount(mnt), 2)) |
Ian Kent | e3474a8 | 2006-03-27 01:14:51 -0800 | [diff] [blame] | 1317 | ret = 0; |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 1318 | unlock_mount_hash(); |
Al Viro | 8ad08d8 | 2010-01-16 12:56:08 -0500 | [diff] [blame] | 1319 | up_read(&namespace_sem); |
Ram Pai | a05964f | 2005-11-07 17:20:17 -0500 | [diff] [blame] | 1320 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1321 | } |
| 1322 | |
| 1323 | EXPORT_SYMBOL(may_umount); |
| 1324 | |
Al Viro | 38129a1 | 2014-03-20 21:10:51 -0400 | [diff] [blame] | 1325 | static HLIST_HEAD(unmounted); /* protected by namespace_sem */ |
Al Viro | e3197d8 | 2013-03-16 14:35:16 -0400 | [diff] [blame] | 1326 | |
Al Viro | 97216be | 2013-03-16 15:12:40 -0400 | [diff] [blame] | 1327 | static void namespace_unlock(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1328 | { |
Eric W. Biederman | a3b3c56 | 2015-04-02 20:33:53 -0500 | [diff] [blame] | 1329 | struct hlist_head head; |
Al Viro | 97216be | 2013-03-16 15:12:40 -0400 | [diff] [blame] | 1330 | |
Eric W. Biederman | a3b3c56 | 2015-04-02 20:33:53 -0500 | [diff] [blame] | 1331 | hlist_move_list(&unmounted, &head); |
Al Viro | 97216be | 2013-03-16 15:12:40 -0400 | [diff] [blame] | 1332 | |
Al Viro | 97216be | 2013-03-16 15:12:40 -0400 | [diff] [blame] | 1333 | up_write(&namespace_sem); |
| 1334 | |
Eric W. Biederman | a3b3c56 | 2015-04-02 20:33:53 -0500 | [diff] [blame] | 1335 | if (likely(hlist_empty(&head))) |
| 1336 | return; |
| 1337 | |
Al Viro | 48a066e | 2013-09-29 22:06:07 -0400 | [diff] [blame] | 1338 | synchronize_rcu(); |
| 1339 | |
Al Viro | 87b95ce | 2015-01-10 19:01:08 -0500 | [diff] [blame] | 1340 | group_pin_kill(&head); |
Ram Pai | 70fbcdf | 2005-11-07 17:17:04 -0500 | [diff] [blame] | 1341 | } |
| 1342 | |
Al Viro | 97216be | 2013-03-16 15:12:40 -0400 | [diff] [blame] | 1343 | static inline void namespace_lock(void) |
Al Viro | e3197d8 | 2013-03-16 14:35:16 -0400 | [diff] [blame] | 1344 | { |
Al Viro | 97216be | 2013-03-16 15:12:40 -0400 | [diff] [blame] | 1345 | down_write(&namespace_sem); |
Al Viro | e3197d8 | 2013-03-16 14:35:16 -0400 | [diff] [blame] | 1346 | } |
| 1347 | |
Eric W. Biederman | e819f15 | 2014-12-24 07:20:01 -0600 | [diff] [blame] | 1348 | enum umount_tree_flags { |
| 1349 | UMOUNT_SYNC = 1, |
| 1350 | UMOUNT_PROPAGATE = 2, |
Eric W. Biederman | e0c9c0a | 2015-04-01 18:30:06 -0500 | [diff] [blame] | 1351 | UMOUNT_CONNECTED = 4, |
Eric W. Biederman | e819f15 | 2014-12-24 07:20:01 -0600 | [diff] [blame] | 1352 | }; |
Nick Piggin | 99b7db7 | 2010-08-18 04:37:39 +1000 | [diff] [blame] | 1353 | /* |
Al Viro | 48a066e | 2013-09-29 22:06:07 -0400 | [diff] [blame] | 1354 | * mount_lock must be held |
Nick Piggin | 99b7db7 | 2010-08-18 04:37:39 +1000 | [diff] [blame] | 1355 | * namespace_sem must be held for write |
| 1356 | */ |
Eric W. Biederman | e819f15 | 2014-12-24 07:20:01 -0600 | [diff] [blame] | 1357 | static void umount_tree(struct mount *mnt, enum umount_tree_flags how) |
Ram Pai | 70fbcdf | 2005-11-07 17:17:04 -0500 | [diff] [blame] | 1358 | { |
Eric W. Biederman | c003b26 | 2014-12-18 13:10:48 -0600 | [diff] [blame] | 1359 | LIST_HEAD(tmp_list); |
Al Viro | 315fc83 | 2011-11-24 18:57:30 -0500 | [diff] [blame] | 1360 | struct mount *p; |
Ram Pai | 70fbcdf | 2005-11-07 17:17:04 -0500 | [diff] [blame] | 1361 | |
Eric W. Biederman | 5d88457 | 2015-01-03 05:39:35 -0600 | [diff] [blame] | 1362 | if (how & UMOUNT_PROPAGATE) |
| 1363 | propagate_mount_unlock(mnt); |
| 1364 | |
Eric W. Biederman | c003b26 | 2014-12-18 13:10:48 -0600 | [diff] [blame] | 1365 | /* Gather the mounts to umount */ |
Eric W. Biederman | 590ce4b | 2014-12-22 18:30:08 -0600 | [diff] [blame] | 1366 | for (p = mnt; p; p = next_mnt(p, mnt)) { |
| 1367 | p->mnt.mnt_flags |= MNT_UMOUNT; |
Eric W. Biederman | c003b26 | 2014-12-18 13:10:48 -0600 | [diff] [blame] | 1368 | list_move(&p->mnt_list, &tmp_list); |
Eric W. Biederman | 590ce4b | 2014-12-22 18:30:08 -0600 | [diff] [blame] | 1369 | } |
Eric W. Biederman | c003b26 | 2014-12-18 13:10:48 -0600 | [diff] [blame] | 1370 | |
Eric W. Biederman | 411a938 | 2014-12-22 19:12:07 -0600 | [diff] [blame] | 1371 | /* Hide the mounts from mnt_mounts */ |
Eric W. Biederman | c003b26 | 2014-12-18 13:10:48 -0600 | [diff] [blame] | 1372 | list_for_each_entry(p, &tmp_list, mnt_list) { |
Eric W. Biederman | c003b26 | 2014-12-18 13:10:48 -0600 | [diff] [blame] | 1373 | list_del_init(&p->mnt_child); |
Al Viro | 38129a1 | 2014-03-20 21:10:51 -0400 | [diff] [blame] | 1374 | } |
Ram Pai | 70fbcdf | 2005-11-07 17:17:04 -0500 | [diff] [blame] | 1375 | |
Eric W. Biederman | c003b26 | 2014-12-18 13:10:48 -0600 | [diff] [blame] | 1376 | /* Add propogated mounts to the tmp_list */ |
Eric W. Biederman | e819f15 | 2014-12-24 07:20:01 -0600 | [diff] [blame] | 1377 | if (how & UMOUNT_PROPAGATE) |
Al Viro | 7b8a53f | 2011-01-15 20:08:44 -0500 | [diff] [blame] | 1378 | propagate_umount(&tmp_list); |
Ram Pai | a05964f | 2005-11-07 17:20:17 -0500 | [diff] [blame] | 1379 | |
Eric W. Biederman | c003b26 | 2014-12-18 13:10:48 -0600 | [diff] [blame] | 1380 | while (!list_empty(&tmp_list)) { |
Eric W. Biederman | ce07d89 | 2014-12-23 21:37:03 -0600 | [diff] [blame] | 1381 | bool disconnect; |
Eric W. Biederman | c003b26 | 2014-12-18 13:10:48 -0600 | [diff] [blame] | 1382 | p = list_first_entry(&tmp_list, struct mount, mnt_list); |
Al Viro | 6776db3d | 2011-11-25 00:22:05 -0500 | [diff] [blame] | 1383 | list_del_init(&p->mnt_expire); |
Al Viro | 1a4eeaf | 2011-11-25 02:19:55 -0500 | [diff] [blame] | 1384 | list_del_init(&p->mnt_list); |
Al Viro | 143c8c9 | 2011-11-25 00:46:35 -0500 | [diff] [blame] | 1385 | __touch_mnt_namespace(p->mnt_ns); |
| 1386 | p->mnt_ns = NULL; |
Eric W. Biederman | e819f15 | 2014-12-24 07:20:01 -0600 | [diff] [blame] | 1387 | if (how & UMOUNT_SYNC) |
Al Viro | 48a066e | 2013-09-29 22:06:07 -0400 | [diff] [blame] | 1388 | p->mnt.mnt_flags |= MNT_SYNC_UMOUNT; |
Al Viro | 87b95ce | 2015-01-10 19:01:08 -0500 | [diff] [blame] | 1389 | |
Eric W. Biederman | e0c9c0a | 2015-04-01 18:30:06 -0500 | [diff] [blame] | 1390 | disconnect = !(((how & UMOUNT_CONNECTED) && |
| 1391 | mnt_has_parent(p) && |
| 1392 | (p->mnt_parent->mnt.mnt_flags & MNT_UMOUNT)) || |
| 1393 | IS_MNT_LOCKED_AND_LAZY(p)); |
Eric W. Biederman | ce07d89 | 2014-12-23 21:37:03 -0600 | [diff] [blame] | 1394 | |
| 1395 | pin_insert_group(&p->mnt_umount, &p->mnt_parent->mnt, |
| 1396 | disconnect ? &unmounted : NULL); |
Al Viro | 676da58 | 2011-11-24 21:47:05 -0500 | [diff] [blame] | 1397 | if (mnt_has_parent(p)) { |
Al Viro | 81b6b06 | 2014-08-30 18:32:05 -0400 | [diff] [blame] | 1398 | mnt_add_count(p->mnt_parent, -1); |
Eric W. Biederman | ce07d89 | 2014-12-23 21:37:03 -0600 | [diff] [blame] | 1399 | if (!disconnect) { |
| 1400 | /* Don't forget about p */ |
| 1401 | list_add_tail(&p->mnt_child, &p->mnt_parent->mnt_mounts); |
| 1402 | } else { |
| 1403 | umount_mnt(p); |
| 1404 | } |
Al Viro | 7c4b93d | 2008-03-21 23:59:49 -0400 | [diff] [blame] | 1405 | } |
Al Viro | 0f0afb1 | 2011-11-24 20:43:10 -0500 | [diff] [blame] | 1406 | change_mnt_propagation(p, MS_PRIVATE); |
Al Viro | 38129a1 | 2014-03-20 21:10:51 -0400 | [diff] [blame] | 1407 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1408 | } |
| 1409 | |
Al Viro | b54b9be | 2013-03-16 14:39:34 -0400 | [diff] [blame] | 1410 | static void shrink_submounts(struct mount *mnt); |
Al Viro | c35038b | 2008-03-22 00:46:23 -0400 | [diff] [blame] | 1411 | |
Al Viro | 1ab5973 | 2011-11-24 21:35:16 -0500 | [diff] [blame] | 1412 | static int do_umount(struct mount *mnt, int flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1413 | { |
Al Viro | 1ab5973 | 2011-11-24 21:35:16 -0500 | [diff] [blame] | 1414 | struct super_block *sb = mnt->mnt.mnt_sb; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1415 | int retval; |
| 1416 | |
Al Viro | 1ab5973 | 2011-11-24 21:35:16 -0500 | [diff] [blame] | 1417 | retval = security_sb_umount(&mnt->mnt, flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1418 | if (retval) |
| 1419 | return retval; |
| 1420 | |
| 1421 | /* |
| 1422 | * Allow userspace to request a mountpoint be expired rather than |
| 1423 | * unmounting unconditionally. Unmount only happens if: |
| 1424 | * (1) the mark is already set (the mark is cleared by mntput()) |
| 1425 | * (2) the usage count == 1 [parent vfsmount] + 1 [sys_umount] |
| 1426 | */ |
| 1427 | if (flags & MNT_EXPIRE) { |
Al Viro | 1ab5973 | 2011-11-24 21:35:16 -0500 | [diff] [blame] | 1428 | if (&mnt->mnt == current->fs->root.mnt || |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1429 | flags & (MNT_FORCE | MNT_DETACH)) |
| 1430 | return -EINVAL; |
| 1431 | |
Nick Piggin | b3e19d9 | 2011-01-07 17:50:11 +1100 | [diff] [blame] | 1432 | /* |
| 1433 | * probably don't strictly need the lock here if we examined |
| 1434 | * all race cases, but it's a slowpath. |
| 1435 | */ |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 1436 | lock_mount_hash(); |
Al Viro | 83adc75 | 2011-11-24 22:37:54 -0500 | [diff] [blame] | 1437 | if (mnt_get_count(mnt) != 2) { |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 1438 | unlock_mount_hash(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1439 | return -EBUSY; |
Nick Piggin | b3e19d9 | 2011-01-07 17:50:11 +1100 | [diff] [blame] | 1440 | } |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 1441 | unlock_mount_hash(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1442 | |
Al Viro | 863d684 | 2011-11-25 00:57:42 -0500 | [diff] [blame] | 1443 | if (!xchg(&mnt->mnt_expiry_mark, 1)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1444 | return -EAGAIN; |
| 1445 | } |
| 1446 | |
| 1447 | /* |
| 1448 | * If we may have to abort operations to get out of this |
| 1449 | * mount, and they will themselves hold resources we must |
| 1450 | * allow the fs to do things. In the Unix tradition of |
| 1451 | * 'Gee thats tricky lets do it in userspace' the umount_begin |
| 1452 | * might fail to complete on the first run through as other tasks |
| 1453 | * must return, and the like. Thats for the mount program to worry |
| 1454 | * about for the moment. |
| 1455 | */ |
| 1456 | |
Al Viro | 42faad9 | 2008-04-24 07:21:56 -0400 | [diff] [blame] | 1457 | if (flags & MNT_FORCE && sb->s_op->umount_begin) { |
Al Viro | 42faad9 | 2008-04-24 07:21:56 -0400 | [diff] [blame] | 1458 | sb->s_op->umount_begin(sb); |
Al Viro | 42faad9 | 2008-04-24 07:21:56 -0400 | [diff] [blame] | 1459 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1460 | |
| 1461 | /* |
| 1462 | * No sense to grab the lock for this test, but test itself looks |
| 1463 | * somewhat bogus. Suggestions for better replacement? |
| 1464 | * Ho-hum... In principle, we might treat that as umount + switch |
| 1465 | * to rootfs. GC would eventually take care of the old vfsmount. |
| 1466 | * Actually it makes sense, especially if rootfs would contain a |
| 1467 | * /reboot - static binary that would close all descriptors and |
| 1468 | * call reboot(9). Then init(8) could umount root and exec /reboot. |
| 1469 | */ |
Al Viro | 1ab5973 | 2011-11-24 21:35:16 -0500 | [diff] [blame] | 1470 | if (&mnt->mnt == current->fs->root.mnt && !(flags & MNT_DETACH)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1471 | /* |
| 1472 | * Special case for "unmounting" root ... |
| 1473 | * we just try to remount it readonly. |
| 1474 | */ |
Andy Lutomirski | a1480dc | 2014-10-08 12:32:47 -0700 | [diff] [blame] | 1475 | if (!capable(CAP_SYS_ADMIN)) |
| 1476 | return -EPERM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1477 | down_write(&sb->s_umount); |
Al Viro | 4aa98cf | 2009-05-08 13:36:58 -0400 | [diff] [blame] | 1478 | if (!(sb->s_flags & MS_RDONLY)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1479 | retval = do_remount_sb(sb, MS_RDONLY, NULL, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1480 | up_write(&sb->s_umount); |
| 1481 | return retval; |
| 1482 | } |
| 1483 | |
Al Viro | 97216be | 2013-03-16 15:12:40 -0400 | [diff] [blame] | 1484 | namespace_lock(); |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 1485 | lock_mount_hash(); |
Al Viro | 5addc5d | 2005-11-07 17:15:49 -0500 | [diff] [blame] | 1486 | event++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1487 | |
Al Viro | 48a066e | 2013-09-29 22:06:07 -0400 | [diff] [blame] | 1488 | if (flags & MNT_DETACH) { |
Al Viro | 1a4eeaf | 2011-11-25 02:19:55 -0500 | [diff] [blame] | 1489 | if (!list_empty(&mnt->mnt_list)) |
Eric W. Biederman | e819f15 | 2014-12-24 07:20:01 -0600 | [diff] [blame] | 1490 | umount_tree(mnt, UMOUNT_PROPAGATE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1491 | retval = 0; |
Al Viro | 48a066e | 2013-09-29 22:06:07 -0400 | [diff] [blame] | 1492 | } else { |
| 1493 | shrink_submounts(mnt); |
| 1494 | retval = -EBUSY; |
| 1495 | if (!propagate_mount_busy(mnt, 2)) { |
| 1496 | if (!list_empty(&mnt->mnt_list)) |
Eric W. Biederman | e819f15 | 2014-12-24 07:20:01 -0600 | [diff] [blame] | 1497 | umount_tree(mnt, UMOUNT_PROPAGATE|UMOUNT_SYNC); |
Al Viro | 48a066e | 2013-09-29 22:06:07 -0400 | [diff] [blame] | 1498 | retval = 0; |
| 1499 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1500 | } |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 1501 | unlock_mount_hash(); |
Al Viro | e3197d8 | 2013-03-16 14:35:16 -0400 | [diff] [blame] | 1502 | namespace_unlock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1503 | return retval; |
| 1504 | } |
| 1505 | |
Eric W. Biederman | 80b5dce | 2013-10-03 01:31:18 -0700 | [diff] [blame] | 1506 | /* |
| 1507 | * __detach_mounts - lazily unmount all mounts on the specified dentry |
| 1508 | * |
| 1509 | * During unlink, rmdir, and d_drop it is possible to loose the path |
| 1510 | * to an existing mountpoint, and wind up leaking the mount. |
| 1511 | * detach_mounts allows lazily unmounting those mounts instead of |
| 1512 | * leaking them. |
| 1513 | * |
| 1514 | * The caller may hold dentry->d_inode->i_mutex. |
| 1515 | */ |
| 1516 | void __detach_mounts(struct dentry *dentry) |
| 1517 | { |
| 1518 | struct mountpoint *mp; |
| 1519 | struct mount *mnt; |
| 1520 | |
| 1521 | namespace_lock(); |
| 1522 | mp = lookup_mountpoint(dentry); |
Eric W. Biederman | f53e579 | 2015-01-19 11:48:45 -0600 | [diff] [blame] | 1523 | if (IS_ERR_OR_NULL(mp)) |
Eric W. Biederman | 80b5dce | 2013-10-03 01:31:18 -0700 | [diff] [blame] | 1524 | goto out_unlock; |
| 1525 | |
| 1526 | lock_mount_hash(); |
| 1527 | while (!hlist_empty(&mp->m_list)) { |
| 1528 | mnt = hlist_entry(mp->m_list.first, struct mount, mnt_mp_list); |
Eric W. Biederman | ce07d89 | 2014-12-23 21:37:03 -0600 | [diff] [blame] | 1529 | if (mnt->mnt.mnt_flags & MNT_UMOUNT) { |
| 1530 | struct mount *p, *tmp; |
| 1531 | list_for_each_entry_safe(p, tmp, &mnt->mnt_mounts, mnt_child) { |
| 1532 | hlist_add_head(&p->mnt_umount.s_list, &unmounted); |
| 1533 | umount_mnt(p); |
| 1534 | } |
| 1535 | } |
Eric W. Biederman | e0c9c0a | 2015-04-01 18:30:06 -0500 | [diff] [blame] | 1536 | else umount_tree(mnt, UMOUNT_CONNECTED); |
Eric W. Biederman | 80b5dce | 2013-10-03 01:31:18 -0700 | [diff] [blame] | 1537 | } |
| 1538 | unlock_mount_hash(); |
| 1539 | put_mountpoint(mp); |
| 1540 | out_unlock: |
| 1541 | namespace_unlock(); |
| 1542 | } |
| 1543 | |
Al Viro | 9b40bc9 | 2013-02-22 22:45:42 -0500 | [diff] [blame] | 1544 | /* |
| 1545 | * Is the caller allowed to modify his namespace? |
| 1546 | */ |
| 1547 | static inline bool may_mount(void) |
| 1548 | { |
| 1549 | return ns_capable(current->nsproxy->mnt_ns->user_ns, CAP_SYS_ADMIN); |
| 1550 | } |
| 1551 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1552 | /* |
| 1553 | * Now umount can handle mount points as well as block devices. |
| 1554 | * This is important for filesystems which use unnamed block devices. |
| 1555 | * |
| 1556 | * We now support a flag for forced unmount like the other 'big iron' |
| 1557 | * unixes. Our API is identical to OSF/1 to avoid making a mess of AMD |
| 1558 | */ |
| 1559 | |
Heiko Carstens | bdc480e | 2009-01-14 14:14:12 +0100 | [diff] [blame] | 1560 | SYSCALL_DEFINE2(umount, char __user *, name, int, flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1561 | { |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 1562 | struct path path; |
Al Viro | 900148d | 2011-11-25 00:33:11 -0500 | [diff] [blame] | 1563 | struct mount *mnt; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1564 | int retval; |
Miklos Szeredi | db1f05b | 2010-02-10 12:15:53 +0100 | [diff] [blame] | 1565 | int lookup_flags = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1566 | |
Miklos Szeredi | db1f05b | 2010-02-10 12:15:53 +0100 | [diff] [blame] | 1567 | if (flags & ~(MNT_FORCE | MNT_DETACH | MNT_EXPIRE | UMOUNT_NOFOLLOW)) |
| 1568 | return -EINVAL; |
| 1569 | |
Al Viro | 9b40bc9 | 2013-02-22 22:45:42 -0500 | [diff] [blame] | 1570 | if (!may_mount()) |
| 1571 | return -EPERM; |
| 1572 | |
Miklos Szeredi | db1f05b | 2010-02-10 12:15:53 +0100 | [diff] [blame] | 1573 | if (!(flags & UMOUNT_NOFOLLOW)) |
| 1574 | lookup_flags |= LOOKUP_FOLLOW; |
| 1575 | |
Al Viro | 197df04 | 2013-09-08 14:03:27 -0400 | [diff] [blame] | 1576 | retval = user_path_mountpoint_at(AT_FDCWD, name, lookup_flags, &path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1577 | if (retval) |
| 1578 | goto out; |
Al Viro | 900148d | 2011-11-25 00:33:11 -0500 | [diff] [blame] | 1579 | mnt = real_mount(path.mnt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1580 | retval = -EINVAL; |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 1581 | if (path.dentry != path.mnt->mnt_root) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1582 | goto dput_and_out; |
Al Viro | 143c8c9 | 2011-11-25 00:46:35 -0500 | [diff] [blame] | 1583 | if (!check_mnt(mnt)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1584 | goto dput_and_out; |
Eric W. Biederman | 5ff9d8a | 2013-03-29 21:04:39 -0700 | [diff] [blame] | 1585 | if (mnt->mnt.mnt_flags & MNT_LOCKED) |
| 1586 | goto dput_and_out; |
Eric W. Biederman | b2f5d4d | 2014-10-04 14:44:03 -0700 | [diff] [blame] | 1587 | retval = -EPERM; |
| 1588 | if (flags & MNT_FORCE && !capable(CAP_SYS_ADMIN)) |
| 1589 | goto dput_and_out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1590 | |
Al Viro | 900148d | 2011-11-25 00:33:11 -0500 | [diff] [blame] | 1591 | retval = do_umount(mnt, flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1592 | dput_and_out: |
Jan Blunck | 429731b | 2008-02-14 19:34:31 -0800 | [diff] [blame] | 1593 | /* we mustn't call path_put() as that would clear mnt_expiry_mark */ |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 1594 | dput(path.dentry); |
Al Viro | 900148d | 2011-11-25 00:33:11 -0500 | [diff] [blame] | 1595 | mntput_no_expire(mnt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1596 | out: |
| 1597 | return retval; |
| 1598 | } |
| 1599 | |
| 1600 | #ifdef __ARCH_WANT_SYS_OLDUMOUNT |
| 1601 | |
| 1602 | /* |
Ram Pai | b58fed8 | 2005-11-07 17:16:09 -0500 | [diff] [blame] | 1603 | * The 2.0 compatible umount. No flags. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1604 | */ |
Heiko Carstens | bdc480e | 2009-01-14 14:14:12 +0100 | [diff] [blame] | 1605 | SYSCALL_DEFINE1(oldumount, char __user *, name) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1606 | { |
Ram Pai | b58fed8 | 2005-11-07 17:16:09 -0500 | [diff] [blame] | 1607 | return sys_umount(name, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1608 | } |
| 1609 | |
| 1610 | #endif |
| 1611 | |
Eric W. Biederman | 4ce5d2b | 2013-03-30 01:35:18 -0700 | [diff] [blame] | 1612 | static bool is_mnt_ns_file(struct dentry *dentry) |
Eric W. Biederman | 8823c07 | 2010-03-07 18:49:36 -0800 | [diff] [blame] | 1613 | { |
Eric W. Biederman | 4ce5d2b | 2013-03-30 01:35:18 -0700 | [diff] [blame] | 1614 | /* Is this a proxy for a mount namespace? */ |
Al Viro | e149ed2 | 2014-11-01 10:57:28 -0400 | [diff] [blame] | 1615 | return dentry->d_op == &ns_dentry_operations && |
| 1616 | dentry->d_fsdata == &mntns_operations; |
Eric W. Biederman | 4ce5d2b | 2013-03-30 01:35:18 -0700 | [diff] [blame] | 1617 | } |
| 1618 | |
Al Viro | 58be2825 | 2014-11-01 00:00:23 -0400 | [diff] [blame] | 1619 | struct mnt_namespace *to_mnt_ns(struct ns_common *ns) |
| 1620 | { |
| 1621 | return container_of(ns, struct mnt_namespace, ns); |
| 1622 | } |
| 1623 | |
Eric W. Biederman | 4ce5d2b | 2013-03-30 01:35:18 -0700 | [diff] [blame] | 1624 | static bool mnt_ns_loop(struct dentry *dentry) |
| 1625 | { |
| 1626 | /* Could bind mounting the mount namespace inode cause a |
| 1627 | * mount namespace loop? |
| 1628 | */ |
| 1629 | struct mnt_namespace *mnt_ns; |
| 1630 | if (!is_mnt_ns_file(dentry)) |
| 1631 | return false; |
| 1632 | |
Al Viro | f77c801 | 2014-11-01 03:13:17 -0400 | [diff] [blame] | 1633 | mnt_ns = to_mnt_ns(get_proc_ns(dentry->d_inode)); |
Eric W. Biederman | 8823c07 | 2010-03-07 18:49:36 -0800 | [diff] [blame] | 1634 | return current->nsproxy->mnt_ns->seq >= mnt_ns->seq; |
| 1635 | } |
| 1636 | |
Al Viro | 87129cc | 2011-11-24 21:24:27 -0500 | [diff] [blame] | 1637 | struct mount *copy_tree(struct mount *mnt, struct dentry *dentry, |
Ram Pai | 36341f6 | 2005-11-07 17:17:22 -0500 | [diff] [blame] | 1638 | int flag) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1639 | { |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 1640 | struct mount *res, *p, *q, *r, *parent; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1641 | |
Eric W. Biederman | 4ce5d2b | 2013-03-30 01:35:18 -0700 | [diff] [blame] | 1642 | if (!(flag & CL_COPY_UNBINDABLE) && IS_MNT_UNBINDABLE(mnt)) |
| 1643 | return ERR_PTR(-EINVAL); |
| 1644 | |
| 1645 | if (!(flag & CL_COPY_MNT_NS_FILE) && is_mnt_ns_file(dentry)) |
David Howells | be34d1a | 2012-06-25 12:55:18 +0100 | [diff] [blame] | 1646 | return ERR_PTR(-EINVAL); |
Ram Pai | 9676f0c | 2005-11-07 17:21:20 -0500 | [diff] [blame] | 1647 | |
Ram Pai | 36341f6 | 2005-11-07 17:17:22 -0500 | [diff] [blame] | 1648 | res = q = clone_mnt(mnt, dentry, flag); |
David Howells | be34d1a | 2012-06-25 12:55:18 +0100 | [diff] [blame] | 1649 | if (IS_ERR(q)) |
| 1650 | return q; |
| 1651 | |
Al Viro | a73324d | 2011-11-24 22:25:07 -0500 | [diff] [blame] | 1652 | q->mnt_mountpoint = mnt->mnt_mountpoint; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1653 | |
| 1654 | p = mnt; |
Al Viro | 6b41d53 | 2011-11-24 23:24:33 -0500 | [diff] [blame] | 1655 | list_for_each_entry(r, &mnt->mnt_mounts, mnt_child) { |
Al Viro | 315fc83 | 2011-11-24 18:57:30 -0500 | [diff] [blame] | 1656 | struct mount *s; |
Jan Blunck | 7ec02ef | 2008-04-29 00:59:40 -0700 | [diff] [blame] | 1657 | if (!is_subdir(r->mnt_mountpoint, dentry)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1658 | continue; |
| 1659 | |
Al Viro | 909b0a8 | 2011-11-25 03:06:56 -0500 | [diff] [blame] | 1660 | for (s = r; s; s = next_mnt(s, r)) { |
Al Viro | 12a5b52 | 2014-08-10 03:44:55 -0400 | [diff] [blame] | 1661 | struct mount *t = NULL; |
Eric W. Biederman | 4ce5d2b | 2013-03-30 01:35:18 -0700 | [diff] [blame] | 1662 | if (!(flag & CL_COPY_UNBINDABLE) && |
| 1663 | IS_MNT_UNBINDABLE(s)) { |
| 1664 | s = skip_mnt_tree(s); |
| 1665 | continue; |
| 1666 | } |
| 1667 | if (!(flag & CL_COPY_MNT_NS_FILE) && |
| 1668 | is_mnt_ns_file(s->mnt.mnt_root)) { |
Ram Pai | 9676f0c | 2005-11-07 17:21:20 -0500 | [diff] [blame] | 1669 | s = skip_mnt_tree(s); |
| 1670 | continue; |
| 1671 | } |
Al Viro | 0714a53 | 2011-11-24 22:19:58 -0500 | [diff] [blame] | 1672 | while (p != s->mnt_parent) { |
| 1673 | p = p->mnt_parent; |
| 1674 | q = q->mnt_parent; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1675 | } |
Al Viro | 87129cc | 2011-11-24 21:24:27 -0500 | [diff] [blame] | 1676 | p = s; |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 1677 | parent = q; |
Al Viro | 87129cc | 2011-11-24 21:24:27 -0500 | [diff] [blame] | 1678 | q = clone_mnt(p, p->mnt.mnt_root, flag); |
David Howells | be34d1a | 2012-06-25 12:55:18 +0100 | [diff] [blame] | 1679 | if (IS_ERR(q)) |
| 1680 | goto out; |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 1681 | lock_mount_hash(); |
Al Viro | 1a4eeaf | 2011-11-25 02:19:55 -0500 | [diff] [blame] | 1682 | list_add_tail(&q->mnt_list, &res->mnt_list); |
Al Viro | 12a5b52 | 2014-08-10 03:44:55 -0400 | [diff] [blame] | 1683 | mnt_set_mountpoint(parent, p->mnt_mp, q); |
| 1684 | if (!list_empty(&parent->mnt_mounts)) { |
| 1685 | t = list_last_entry(&parent->mnt_mounts, |
| 1686 | struct mount, mnt_child); |
| 1687 | if (t->mnt_mp != p->mnt_mp) |
| 1688 | t = NULL; |
| 1689 | } |
| 1690 | attach_shadowed(q, parent, t); |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 1691 | unlock_mount_hash(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1692 | } |
| 1693 | } |
| 1694 | return res; |
David Howells | be34d1a | 2012-06-25 12:55:18 +0100 | [diff] [blame] | 1695 | out: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1696 | if (res) { |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 1697 | lock_mount_hash(); |
Eric W. Biederman | e819f15 | 2014-12-24 07:20:01 -0600 | [diff] [blame] | 1698 | umount_tree(res, UMOUNT_SYNC); |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 1699 | unlock_mount_hash(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1700 | } |
David Howells | be34d1a | 2012-06-25 12:55:18 +0100 | [diff] [blame] | 1701 | return q; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1702 | } |
| 1703 | |
David Howells | be34d1a | 2012-06-25 12:55:18 +0100 | [diff] [blame] | 1704 | /* Caller should check returned pointer for errors */ |
| 1705 | |
Al Viro | 589ff87 | 2009-04-18 03:28:19 -0400 | [diff] [blame] | 1706 | struct vfsmount *collect_mounts(struct path *path) |
Al Viro | 8aec080 | 2007-06-07 12:20:32 -0400 | [diff] [blame] | 1707 | { |
Al Viro | cb338d0 | 2011-11-24 20:55:08 -0500 | [diff] [blame] | 1708 | struct mount *tree; |
Al Viro | 97216be | 2013-03-16 15:12:40 -0400 | [diff] [blame] | 1709 | namespace_lock(); |
Eric W. Biederman | cd4a401 | 2015-01-07 14:28:26 -0600 | [diff] [blame] | 1710 | if (!check_mnt(real_mount(path->mnt))) |
| 1711 | tree = ERR_PTR(-EINVAL); |
| 1712 | else |
| 1713 | tree = copy_tree(real_mount(path->mnt), path->dentry, |
| 1714 | CL_COPY_ALL | CL_PRIVATE); |
Al Viro | 328e6d9 | 2013-03-16 14:49:45 -0400 | [diff] [blame] | 1715 | namespace_unlock(); |
David Howells | be34d1a | 2012-06-25 12:55:18 +0100 | [diff] [blame] | 1716 | if (IS_ERR(tree)) |
Dan Carpenter | 52e220d | 2013-08-14 12:44:39 +0300 | [diff] [blame] | 1717 | return ERR_CAST(tree); |
David Howells | be34d1a | 2012-06-25 12:55:18 +0100 | [diff] [blame] | 1718 | return &tree->mnt; |
Al Viro | 8aec080 | 2007-06-07 12:20:32 -0400 | [diff] [blame] | 1719 | } |
| 1720 | |
| 1721 | void drop_collected_mounts(struct vfsmount *mnt) |
| 1722 | { |
Al Viro | 97216be | 2013-03-16 15:12:40 -0400 | [diff] [blame] | 1723 | namespace_lock(); |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 1724 | lock_mount_hash(); |
Eric W. Biederman | e819f15 | 2014-12-24 07:20:01 -0600 | [diff] [blame] | 1725 | umount_tree(real_mount(mnt), UMOUNT_SYNC); |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 1726 | unlock_mount_hash(); |
Al Viro | 3ab6abe | 2013-03-16 14:42:19 -0400 | [diff] [blame] | 1727 | namespace_unlock(); |
Al Viro | 8aec080 | 2007-06-07 12:20:32 -0400 | [diff] [blame] | 1728 | } |
| 1729 | |
Miklos Szeredi | c771d68 | 2014-10-24 00:14:36 +0200 | [diff] [blame] | 1730 | /** |
| 1731 | * clone_private_mount - create a private clone of a path |
| 1732 | * |
| 1733 | * This creates a new vfsmount, which will be the clone of @path. The new will |
| 1734 | * not be attached anywhere in the namespace and will be private (i.e. changes |
| 1735 | * to the originating mount won't be propagated into this). |
| 1736 | * |
| 1737 | * Release with mntput(). |
| 1738 | */ |
| 1739 | struct vfsmount *clone_private_mount(struct path *path) |
| 1740 | { |
| 1741 | struct mount *old_mnt = real_mount(path->mnt); |
| 1742 | struct mount *new_mnt; |
| 1743 | |
| 1744 | if (IS_MNT_UNBINDABLE(old_mnt)) |
| 1745 | return ERR_PTR(-EINVAL); |
| 1746 | |
| 1747 | down_read(&namespace_sem); |
| 1748 | new_mnt = clone_mnt(old_mnt, path->dentry, CL_PRIVATE); |
| 1749 | up_read(&namespace_sem); |
| 1750 | if (IS_ERR(new_mnt)) |
| 1751 | return ERR_CAST(new_mnt); |
| 1752 | |
| 1753 | return &new_mnt->mnt; |
| 1754 | } |
| 1755 | EXPORT_SYMBOL_GPL(clone_private_mount); |
| 1756 | |
Al Viro | 1f70713 | 2010-01-30 22:51:25 -0500 | [diff] [blame] | 1757 | int iterate_mounts(int (*f)(struct vfsmount *, void *), void *arg, |
| 1758 | struct vfsmount *root) |
| 1759 | { |
Al Viro | 1a4eeaf | 2011-11-25 02:19:55 -0500 | [diff] [blame] | 1760 | struct mount *mnt; |
Al Viro | 1f70713 | 2010-01-30 22:51:25 -0500 | [diff] [blame] | 1761 | int res = f(root, arg); |
| 1762 | if (res) |
| 1763 | return res; |
Al Viro | 1a4eeaf | 2011-11-25 02:19:55 -0500 | [diff] [blame] | 1764 | list_for_each_entry(mnt, &real_mount(root)->mnt_list, mnt_list) { |
| 1765 | res = f(&mnt->mnt, arg); |
Al Viro | 1f70713 | 2010-01-30 22:51:25 -0500 | [diff] [blame] | 1766 | if (res) |
| 1767 | return res; |
| 1768 | } |
| 1769 | return 0; |
| 1770 | } |
| 1771 | |
Al Viro | 4b8b21f | 2011-11-24 19:54:23 -0500 | [diff] [blame] | 1772 | static void cleanup_group_ids(struct mount *mnt, struct mount *end) |
Miklos Szeredi | 719f5d7 | 2008-03-27 13:06:23 +0100 | [diff] [blame] | 1773 | { |
Al Viro | 315fc83 | 2011-11-24 18:57:30 -0500 | [diff] [blame] | 1774 | struct mount *p; |
Miklos Szeredi | 719f5d7 | 2008-03-27 13:06:23 +0100 | [diff] [blame] | 1775 | |
Al Viro | 909b0a8 | 2011-11-25 03:06:56 -0500 | [diff] [blame] | 1776 | for (p = mnt; p != end; p = next_mnt(p, mnt)) { |
Al Viro | fc7be13 | 2011-11-25 01:05:37 -0500 | [diff] [blame] | 1777 | if (p->mnt_group_id && !IS_MNT_SHARED(p)) |
Al Viro | 4b8b21f | 2011-11-24 19:54:23 -0500 | [diff] [blame] | 1778 | mnt_release_group_id(p); |
Miklos Szeredi | 719f5d7 | 2008-03-27 13:06:23 +0100 | [diff] [blame] | 1779 | } |
| 1780 | } |
| 1781 | |
Al Viro | 4b8b21f | 2011-11-24 19:54:23 -0500 | [diff] [blame] | 1782 | static int invent_group_ids(struct mount *mnt, bool recurse) |
Miklos Szeredi | 719f5d7 | 2008-03-27 13:06:23 +0100 | [diff] [blame] | 1783 | { |
Al Viro | 315fc83 | 2011-11-24 18:57:30 -0500 | [diff] [blame] | 1784 | struct mount *p; |
Miklos Szeredi | 719f5d7 | 2008-03-27 13:06:23 +0100 | [diff] [blame] | 1785 | |
Al Viro | 909b0a8 | 2011-11-25 03:06:56 -0500 | [diff] [blame] | 1786 | for (p = mnt; p; p = recurse ? next_mnt(p, mnt) : NULL) { |
Al Viro | fc7be13 | 2011-11-25 01:05:37 -0500 | [diff] [blame] | 1787 | if (!p->mnt_group_id && !IS_MNT_SHARED(p)) { |
Al Viro | 4b8b21f | 2011-11-24 19:54:23 -0500 | [diff] [blame] | 1788 | int err = mnt_alloc_group_id(p); |
Miklos Szeredi | 719f5d7 | 2008-03-27 13:06:23 +0100 | [diff] [blame] | 1789 | if (err) { |
Al Viro | 4b8b21f | 2011-11-24 19:54:23 -0500 | [diff] [blame] | 1790 | cleanup_group_ids(mnt, p); |
Miklos Szeredi | 719f5d7 | 2008-03-27 13:06:23 +0100 | [diff] [blame] | 1791 | return err; |
| 1792 | } |
| 1793 | } |
| 1794 | } |
| 1795 | |
| 1796 | return 0; |
| 1797 | } |
| 1798 | |
Ram Pai | b90fa9a | 2005-11-07 17:19:50 -0500 | [diff] [blame] | 1799 | /* |
| 1800 | * @source_mnt : mount tree to be attached |
Ram Pai | 2144440 | 2005-11-07 17:20:03 -0500 | [diff] [blame] | 1801 | * @nd : place the mount tree @source_mnt is attached |
| 1802 | * @parent_nd : if non-null, detach the source_mnt from its parent and |
| 1803 | * store the parent mount and mountpoint dentry. |
| 1804 | * (done when source_mnt is moved) |
Ram Pai | b90fa9a | 2005-11-07 17:19:50 -0500 | [diff] [blame] | 1805 | * |
| 1806 | * NOTE: in the table below explains the semantics when a source mount |
| 1807 | * 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] | 1808 | * --------------------------------------------------------------------------- |
| 1809 | * | BIND MOUNT OPERATION | |
| 1810 | * |************************************************************************** |
| 1811 | * | source-->| shared | private | slave | unbindable | |
| 1812 | * | dest | | | | | |
| 1813 | * | | | | | | | |
| 1814 | * | v | | | | | |
| 1815 | * |************************************************************************** |
| 1816 | * | shared | shared (++) | shared (+) | shared(+++)| invalid | |
| 1817 | * | | | | | | |
| 1818 | * |non-shared| shared (+) | private | slave (*) | invalid | |
| 1819 | * *************************************************************************** |
Ram Pai | b90fa9a | 2005-11-07 17:19:50 -0500 | [diff] [blame] | 1820 | * A bind operation clones the source mount and mounts the clone on the |
| 1821 | * destination mount. |
| 1822 | * |
| 1823 | * (++) the cloned mount is propagated to all the mounts in the propagation |
| 1824 | * tree of the destination mount and the cloned mount is added to |
| 1825 | * the peer group of the source mount. |
| 1826 | * (+) the cloned mount is created under the destination mount and is marked |
| 1827 | * as shared. The cloned mount is added to the peer group of the source |
| 1828 | * mount. |
Ram Pai | 5afe002 | 2005-11-07 17:21:01 -0500 | [diff] [blame] | 1829 | * (+++) the mount is propagated to all the mounts in the propagation tree |
| 1830 | * of the destination mount and the cloned mount is made slave |
| 1831 | * of the same master as that of the source mount. The cloned mount |
| 1832 | * is marked as 'shared and slave'. |
| 1833 | * (*) the cloned mount is made a slave of the same master as that of the |
| 1834 | * source mount. |
| 1835 | * |
Ram Pai | 9676f0c | 2005-11-07 17:21:20 -0500 | [diff] [blame] | 1836 | * --------------------------------------------------------------------------- |
| 1837 | * | MOVE MOUNT OPERATION | |
| 1838 | * |************************************************************************** |
| 1839 | * | source-->| shared | private | slave | unbindable | |
| 1840 | * | dest | | | | | |
| 1841 | * | | | | | | | |
| 1842 | * | v | | | | | |
| 1843 | * |************************************************************************** |
| 1844 | * | shared | shared (+) | shared (+) | shared(+++) | invalid | |
| 1845 | * | | | | | | |
| 1846 | * |non-shared| shared (+*) | private | slave (*) | unbindable | |
| 1847 | * *************************************************************************** |
Ram Pai | 5afe002 | 2005-11-07 17:21:01 -0500 | [diff] [blame] | 1848 | * |
| 1849 | * (+) the mount is moved to the destination. And is then propagated to |
| 1850 | * all the mounts in the propagation tree of the destination mount. |
Ram Pai | 2144440 | 2005-11-07 17:20:03 -0500 | [diff] [blame] | 1851 | * (+*) the mount is moved to the destination. |
Ram Pai | 5afe002 | 2005-11-07 17:21:01 -0500 | [diff] [blame] | 1852 | * (+++) the mount is moved to the destination and is then propagated to |
| 1853 | * all the mounts belonging to the destination mount's propagation tree. |
| 1854 | * the mount is marked as 'shared and slave'. |
| 1855 | * (*) the mount continues to be a slave at the new location. |
Ram Pai | b90fa9a | 2005-11-07 17:19:50 -0500 | [diff] [blame] | 1856 | * |
| 1857 | * if the source mount is a tree, the operations explained above is |
| 1858 | * applied to each mount in the tree. |
| 1859 | * Must be called without spinlocks held, since this function can sleep |
| 1860 | * in allocations. |
| 1861 | */ |
Al Viro | 0fb54e5 | 2011-11-24 19:59:16 -0500 | [diff] [blame] | 1862 | static int attach_recursive_mnt(struct mount *source_mnt, |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 1863 | struct mount *dest_mnt, |
| 1864 | struct mountpoint *dest_mp, |
| 1865 | struct path *parent_path) |
Ram Pai | b90fa9a | 2005-11-07 17:19:50 -0500 | [diff] [blame] | 1866 | { |
Al Viro | 38129a1 | 2014-03-20 21:10:51 -0400 | [diff] [blame] | 1867 | HLIST_HEAD(tree_list); |
Al Viro | 315fc83 | 2011-11-24 18:57:30 -0500 | [diff] [blame] | 1868 | struct mount *child, *p; |
Al Viro | 38129a1 | 2014-03-20 21:10:51 -0400 | [diff] [blame] | 1869 | struct hlist_node *n; |
Miklos Szeredi | 719f5d7 | 2008-03-27 13:06:23 +0100 | [diff] [blame] | 1870 | int err; |
Ram Pai | b90fa9a | 2005-11-07 17:19:50 -0500 | [diff] [blame] | 1871 | |
Al Viro | fc7be13 | 2011-11-25 01:05:37 -0500 | [diff] [blame] | 1872 | if (IS_MNT_SHARED(dest_mnt)) { |
Al Viro | 0fb54e5 | 2011-11-24 19:59:16 -0500 | [diff] [blame] | 1873 | err = invent_group_ids(source_mnt, true); |
Miklos Szeredi | 719f5d7 | 2008-03-27 13:06:23 +0100 | [diff] [blame] | 1874 | if (err) |
| 1875 | goto out; |
Al Viro | 0b1b901 | 2014-03-21 10:14:08 -0400 | [diff] [blame] | 1876 | err = propagate_mnt(dest_mnt, dest_mp, source_mnt, &tree_list); |
Al Viro | f2ebb3a | 2014-02-27 09:35:45 -0500 | [diff] [blame] | 1877 | lock_mount_hash(); |
Al Viro | 0b1b901 | 2014-03-21 10:14:08 -0400 | [diff] [blame] | 1878 | if (err) |
| 1879 | goto out_cleanup_ids; |
Al Viro | 909b0a8 | 2011-11-25 03:06:56 -0500 | [diff] [blame] | 1880 | for (p = source_mnt; p; p = next_mnt(p, source_mnt)) |
Al Viro | 0f0afb1 | 2011-11-24 20:43:10 -0500 | [diff] [blame] | 1881 | set_mnt_shared(p); |
Al Viro | 0b1b901 | 2014-03-21 10:14:08 -0400 | [diff] [blame] | 1882 | } else { |
| 1883 | lock_mount_hash(); |
Ram Pai | b90fa9a | 2005-11-07 17:19:50 -0500 | [diff] [blame] | 1884 | } |
Al Viro | 1a39068 | 2008-03-21 20:48:19 -0400 | [diff] [blame] | 1885 | if (parent_path) { |
Al Viro | 0fb54e5 | 2011-11-24 19:59:16 -0500 | [diff] [blame] | 1886 | detach_mnt(source_mnt, parent_path); |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 1887 | attach_mnt(source_mnt, dest_mnt, dest_mp); |
Al Viro | 143c8c9 | 2011-11-25 00:46:35 -0500 | [diff] [blame] | 1888 | touch_mnt_namespace(source_mnt->mnt_ns); |
Ram Pai | 2144440 | 2005-11-07 17:20:03 -0500 | [diff] [blame] | 1889 | } else { |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 1890 | mnt_set_mountpoint(dest_mnt, dest_mp, source_mnt); |
Al Viro | 1d6a32a | 2014-03-20 20:34:43 -0400 | [diff] [blame] | 1891 | commit_tree(source_mnt, NULL); |
Ram Pai | 2144440 | 2005-11-07 17:20:03 -0500 | [diff] [blame] | 1892 | } |
Ram Pai | b90fa9a | 2005-11-07 17:19:50 -0500 | [diff] [blame] | 1893 | |
Al Viro | 38129a1 | 2014-03-20 21:10:51 -0400 | [diff] [blame] | 1894 | hlist_for_each_entry_safe(child, n, &tree_list, mnt_hash) { |
Al Viro | 1d6a32a | 2014-03-20 20:34:43 -0400 | [diff] [blame] | 1895 | struct mount *q; |
Al Viro | 38129a1 | 2014-03-20 21:10:51 -0400 | [diff] [blame] | 1896 | hlist_del_init(&child->mnt_hash); |
Al Viro | 1d6a32a | 2014-03-20 20:34:43 -0400 | [diff] [blame] | 1897 | q = __lookup_mnt_last(&child->mnt_parent->mnt, |
| 1898 | child->mnt_mountpoint); |
| 1899 | commit_tree(child, q); |
Ram Pai | b90fa9a | 2005-11-07 17:19:50 -0500 | [diff] [blame] | 1900 | } |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 1901 | unlock_mount_hash(); |
Nick Piggin | 99b7db7 | 2010-08-18 04:37:39 +1000 | [diff] [blame] | 1902 | |
Ram Pai | b90fa9a | 2005-11-07 17:19:50 -0500 | [diff] [blame] | 1903 | return 0; |
Miklos Szeredi | 719f5d7 | 2008-03-27 13:06:23 +0100 | [diff] [blame] | 1904 | |
| 1905 | out_cleanup_ids: |
Al Viro | f2ebb3a | 2014-02-27 09:35:45 -0500 | [diff] [blame] | 1906 | while (!hlist_empty(&tree_list)) { |
| 1907 | child = hlist_entry(tree_list.first, struct mount, mnt_hash); |
Eric W. Biederman | e819f15 | 2014-12-24 07:20:01 -0600 | [diff] [blame] | 1908 | umount_tree(child, UMOUNT_SYNC); |
Al Viro | f2ebb3a | 2014-02-27 09:35:45 -0500 | [diff] [blame] | 1909 | } |
| 1910 | unlock_mount_hash(); |
Al Viro | 0b1b901 | 2014-03-21 10:14:08 -0400 | [diff] [blame] | 1911 | cleanup_group_ids(source_mnt, NULL); |
Miklos Szeredi | 719f5d7 | 2008-03-27 13:06:23 +0100 | [diff] [blame] | 1912 | out: |
| 1913 | return err; |
Ram Pai | b90fa9a | 2005-11-07 17:19:50 -0500 | [diff] [blame] | 1914 | } |
| 1915 | |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 1916 | static struct mountpoint *lock_mount(struct path *path) |
Al Viro | b12cea9 | 2011-03-18 08:55:38 -0400 | [diff] [blame] | 1917 | { |
| 1918 | struct vfsmount *mnt; |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 1919 | struct dentry *dentry = path->dentry; |
Al Viro | b12cea9 | 2011-03-18 08:55:38 -0400 | [diff] [blame] | 1920 | retry: |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 1921 | mutex_lock(&dentry->d_inode->i_mutex); |
| 1922 | if (unlikely(cant_mount(dentry))) { |
| 1923 | mutex_unlock(&dentry->d_inode->i_mutex); |
| 1924 | return ERR_PTR(-ENOENT); |
Al Viro | b12cea9 | 2011-03-18 08:55:38 -0400 | [diff] [blame] | 1925 | } |
Al Viro | 97216be | 2013-03-16 15:12:40 -0400 | [diff] [blame] | 1926 | namespace_lock(); |
Al Viro | b12cea9 | 2011-03-18 08:55:38 -0400 | [diff] [blame] | 1927 | mnt = lookup_mnt(path); |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 1928 | if (likely(!mnt)) { |
Eric W. Biederman | e2dfa93 | 2014-02-24 17:32:34 -0800 | [diff] [blame] | 1929 | struct mountpoint *mp = lookup_mountpoint(dentry); |
| 1930 | if (!mp) |
| 1931 | mp = new_mountpoint(dentry); |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 1932 | if (IS_ERR(mp)) { |
Al Viro | 97216be | 2013-03-16 15:12:40 -0400 | [diff] [blame] | 1933 | namespace_unlock(); |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 1934 | mutex_unlock(&dentry->d_inode->i_mutex); |
| 1935 | return mp; |
| 1936 | } |
| 1937 | return mp; |
| 1938 | } |
Al Viro | 97216be | 2013-03-16 15:12:40 -0400 | [diff] [blame] | 1939 | namespace_unlock(); |
Al Viro | b12cea9 | 2011-03-18 08:55:38 -0400 | [diff] [blame] | 1940 | mutex_unlock(&path->dentry->d_inode->i_mutex); |
| 1941 | path_put(path); |
| 1942 | path->mnt = mnt; |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 1943 | dentry = path->dentry = dget(mnt->mnt_root); |
Al Viro | b12cea9 | 2011-03-18 08:55:38 -0400 | [diff] [blame] | 1944 | goto retry; |
| 1945 | } |
| 1946 | |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 1947 | static void unlock_mount(struct mountpoint *where) |
Al Viro | b12cea9 | 2011-03-18 08:55:38 -0400 | [diff] [blame] | 1948 | { |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 1949 | struct dentry *dentry = where->m_dentry; |
| 1950 | put_mountpoint(where); |
Al Viro | 328e6d9 | 2013-03-16 14:49:45 -0400 | [diff] [blame] | 1951 | namespace_unlock(); |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 1952 | mutex_unlock(&dentry->d_inode->i_mutex); |
Al Viro | b12cea9 | 2011-03-18 08:55:38 -0400 | [diff] [blame] | 1953 | } |
| 1954 | |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 1955 | static int graft_tree(struct mount *mnt, struct mount *p, struct mountpoint *mp) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1956 | { |
Al Viro | 95bc5f2 | 2011-11-25 00:30:56 -0500 | [diff] [blame] | 1957 | if (mnt->mnt.mnt_sb->s_flags & MS_NOUSER) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1958 | return -EINVAL; |
| 1959 | |
David Howells | e36cb0b | 2015-01-29 12:02:35 +0000 | [diff] [blame] | 1960 | if (d_is_dir(mp->m_dentry) != |
| 1961 | d_is_dir(mnt->mnt.mnt_root)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1962 | return -ENOTDIR; |
| 1963 | |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 1964 | return attach_recursive_mnt(mnt, p, mp, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1965 | } |
| 1966 | |
| 1967 | /* |
Valerie Aurora | 7a2e8a8 | 2010-08-26 11:07:22 -0700 | [diff] [blame] | 1968 | * Sanity check the flags to change_mnt_propagation. |
| 1969 | */ |
| 1970 | |
| 1971 | static int flags_to_propagation_type(int flags) |
| 1972 | { |
Roman Borisov | 7c6e984 | 2011-05-25 16:26:48 -0700 | [diff] [blame] | 1973 | int type = flags & ~(MS_REC | MS_SILENT); |
Valerie Aurora | 7a2e8a8 | 2010-08-26 11:07:22 -0700 | [diff] [blame] | 1974 | |
| 1975 | /* Fail if any non-propagation flags are set */ |
| 1976 | if (type & ~(MS_SHARED | MS_PRIVATE | MS_SLAVE | MS_UNBINDABLE)) |
| 1977 | return 0; |
| 1978 | /* Only one propagation flag should be set */ |
| 1979 | if (!is_power_of_2(type)) |
| 1980 | return 0; |
| 1981 | return type; |
| 1982 | } |
| 1983 | |
| 1984 | /* |
Ram Pai | 07b2088 | 2005-11-07 17:19:07 -0500 | [diff] [blame] | 1985 | * recursively change the type of the mountpoint. |
| 1986 | */ |
Al Viro | 0a0d8a4 | 2008-08-02 00:55:27 -0400 | [diff] [blame] | 1987 | static int do_change_type(struct path *path, int flag) |
Ram Pai | 07b2088 | 2005-11-07 17:19:07 -0500 | [diff] [blame] | 1988 | { |
Al Viro | 315fc83 | 2011-11-24 18:57:30 -0500 | [diff] [blame] | 1989 | struct mount *m; |
Al Viro | 4b8b21f | 2011-11-24 19:54:23 -0500 | [diff] [blame] | 1990 | struct mount *mnt = real_mount(path->mnt); |
Ram Pai | 07b2088 | 2005-11-07 17:19:07 -0500 | [diff] [blame] | 1991 | int recurse = flag & MS_REC; |
Valerie Aurora | 7a2e8a8 | 2010-08-26 11:07:22 -0700 | [diff] [blame] | 1992 | int type; |
Miklos Szeredi | 719f5d7 | 2008-03-27 13:06:23 +0100 | [diff] [blame] | 1993 | int err = 0; |
Ram Pai | 07b2088 | 2005-11-07 17:19:07 -0500 | [diff] [blame] | 1994 | |
Al Viro | 2d92ab3 | 2008-08-02 00:51:11 -0400 | [diff] [blame] | 1995 | if (path->dentry != path->mnt->mnt_root) |
Ram Pai | 07b2088 | 2005-11-07 17:19:07 -0500 | [diff] [blame] | 1996 | return -EINVAL; |
| 1997 | |
Valerie Aurora | 7a2e8a8 | 2010-08-26 11:07:22 -0700 | [diff] [blame] | 1998 | type = flags_to_propagation_type(flag); |
| 1999 | if (!type) |
| 2000 | return -EINVAL; |
| 2001 | |
Al Viro | 97216be | 2013-03-16 15:12:40 -0400 | [diff] [blame] | 2002 | namespace_lock(); |
Miklos Szeredi | 719f5d7 | 2008-03-27 13:06:23 +0100 | [diff] [blame] | 2003 | if (type == MS_SHARED) { |
| 2004 | err = invent_group_ids(mnt, recurse); |
| 2005 | if (err) |
| 2006 | goto out_unlock; |
| 2007 | } |
| 2008 | |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 2009 | lock_mount_hash(); |
Al Viro | 909b0a8 | 2011-11-25 03:06:56 -0500 | [diff] [blame] | 2010 | for (m = mnt; m; m = (recurse ? next_mnt(m, mnt) : NULL)) |
Al Viro | 0f0afb1 | 2011-11-24 20:43:10 -0500 | [diff] [blame] | 2011 | change_mnt_propagation(m, type); |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 2012 | unlock_mount_hash(); |
Miklos Szeredi | 719f5d7 | 2008-03-27 13:06:23 +0100 | [diff] [blame] | 2013 | |
| 2014 | out_unlock: |
Al Viro | 97216be | 2013-03-16 15:12:40 -0400 | [diff] [blame] | 2015 | namespace_unlock(); |
Miklos Szeredi | 719f5d7 | 2008-03-27 13:06:23 +0100 | [diff] [blame] | 2016 | return err; |
Ram Pai | 07b2088 | 2005-11-07 17:19:07 -0500 | [diff] [blame] | 2017 | } |
| 2018 | |
Eric W. Biederman | 5ff9d8a | 2013-03-29 21:04:39 -0700 | [diff] [blame] | 2019 | static bool has_locked_children(struct mount *mnt, struct dentry *dentry) |
| 2020 | { |
| 2021 | struct mount *child; |
| 2022 | list_for_each_entry(child, &mnt->mnt_mounts, mnt_child) { |
| 2023 | if (!is_subdir(child->mnt_mountpoint, dentry)) |
| 2024 | continue; |
| 2025 | |
| 2026 | if (child->mnt.mnt_flags & MNT_LOCKED) |
| 2027 | return true; |
| 2028 | } |
| 2029 | return false; |
| 2030 | } |
| 2031 | |
Ram Pai | 07b2088 | 2005-11-07 17:19:07 -0500 | [diff] [blame] | 2032 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2033 | * do loopback mount. |
| 2034 | */ |
Al Viro | 808d4e3 | 2012-10-11 11:42:01 -0400 | [diff] [blame] | 2035 | static int do_loopback(struct path *path, const char *old_name, |
Eric Sandeen | 2dafe1c | 2008-02-08 04:22:12 -0800 | [diff] [blame] | 2036 | int recurse) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2037 | { |
Al Viro | 2d92ab3 | 2008-08-02 00:51:11 -0400 | [diff] [blame] | 2038 | struct path old_path; |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 2039 | struct mount *mnt = NULL, *old, *parent; |
| 2040 | struct mountpoint *mp; |
Al Viro | 57eccb8 | 2013-02-22 22:49:10 -0500 | [diff] [blame] | 2041 | int err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2042 | if (!old_name || !*old_name) |
| 2043 | return -EINVAL; |
Trond Myklebust | 815d405 | 2011-09-26 20:36:09 -0400 | [diff] [blame] | 2044 | err = kern_path(old_name, LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT, &old_path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2045 | if (err) |
| 2046 | return err; |
| 2047 | |
Eric W. Biederman | 8823c07 | 2010-03-07 18:49:36 -0800 | [diff] [blame] | 2048 | err = -EINVAL; |
Eric W. Biederman | 4ce5d2b | 2013-03-30 01:35:18 -0700 | [diff] [blame] | 2049 | if (mnt_ns_loop(old_path.dentry)) |
Eric W. Biederman | 8823c07 | 2010-03-07 18:49:36 -0800 | [diff] [blame] | 2050 | goto out; |
| 2051 | |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 2052 | mp = lock_mount(path); |
| 2053 | err = PTR_ERR(mp); |
| 2054 | if (IS_ERR(mp)) |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 2055 | goto out; |
Ram Pai | 9676f0c | 2005-11-07 17:21:20 -0500 | [diff] [blame] | 2056 | |
Al Viro | 87129cc | 2011-11-24 21:24:27 -0500 | [diff] [blame] | 2057 | old = real_mount(old_path.mnt); |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 2058 | parent = real_mount(path->mnt); |
Al Viro | 87129cc | 2011-11-24 21:24:27 -0500 | [diff] [blame] | 2059 | |
Al Viro | b12cea9 | 2011-03-18 08:55:38 -0400 | [diff] [blame] | 2060 | err = -EINVAL; |
Al Viro | fc7be13 | 2011-11-25 01:05:37 -0500 | [diff] [blame] | 2061 | if (IS_MNT_UNBINDABLE(old)) |
Al Viro | b12cea9 | 2011-03-18 08:55:38 -0400 | [diff] [blame] | 2062 | goto out2; |
| 2063 | |
Al Viro | e149ed2 | 2014-11-01 10:57:28 -0400 | [diff] [blame] | 2064 | if (!check_mnt(parent)) |
| 2065 | goto out2; |
| 2066 | |
| 2067 | if (!check_mnt(old) && old_path.dentry->d_op != &ns_dentry_operations) |
Al Viro | b12cea9 | 2011-03-18 08:55:38 -0400 | [diff] [blame] | 2068 | goto out2; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2069 | |
Eric W. Biederman | 5ff9d8a | 2013-03-29 21:04:39 -0700 | [diff] [blame] | 2070 | if (!recurse && has_locked_children(old, old_path.dentry)) |
| 2071 | goto out2; |
| 2072 | |
Al Viro | ccd48bc | 2005-11-07 17:15:04 -0500 | [diff] [blame] | 2073 | if (recurse) |
Eric W. Biederman | 4ce5d2b | 2013-03-30 01:35:18 -0700 | [diff] [blame] | 2074 | mnt = copy_tree(old, old_path.dentry, CL_COPY_MNT_NS_FILE); |
Al Viro | ccd48bc | 2005-11-07 17:15:04 -0500 | [diff] [blame] | 2075 | else |
Al Viro | 87129cc | 2011-11-24 21:24:27 -0500 | [diff] [blame] | 2076 | mnt = clone_mnt(old, old_path.dentry, 0); |
Al Viro | ccd48bc | 2005-11-07 17:15:04 -0500 | [diff] [blame] | 2077 | |
David Howells | be34d1a | 2012-06-25 12:55:18 +0100 | [diff] [blame] | 2078 | if (IS_ERR(mnt)) { |
| 2079 | err = PTR_ERR(mnt); |
Andrey Vagin | e9c5d8a | 2013-04-09 17:33:29 +0400 | [diff] [blame] | 2080 | goto out2; |
David Howells | be34d1a | 2012-06-25 12:55:18 +0100 | [diff] [blame] | 2081 | } |
Al Viro | ccd48bc | 2005-11-07 17:15:04 -0500 | [diff] [blame] | 2082 | |
Eric W. Biederman | 5ff9d8a | 2013-03-29 21:04:39 -0700 | [diff] [blame] | 2083 | mnt->mnt.mnt_flags &= ~MNT_LOCKED; |
| 2084 | |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 2085 | err = graft_tree(mnt, parent, mp); |
Al Viro | ccd48bc | 2005-11-07 17:15:04 -0500 | [diff] [blame] | 2086 | if (err) { |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 2087 | lock_mount_hash(); |
Eric W. Biederman | e819f15 | 2014-12-24 07:20:01 -0600 | [diff] [blame] | 2088 | umount_tree(mnt, UMOUNT_SYNC); |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 2089 | unlock_mount_hash(); |
Ram Pai | 5b83d2c5c | 2005-11-07 17:16:29 -0500 | [diff] [blame] | 2090 | } |
Al Viro | b12cea9 | 2011-03-18 08:55:38 -0400 | [diff] [blame] | 2091 | out2: |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 2092 | unlock_mount(mp); |
Al Viro | ccd48bc | 2005-11-07 17:15:04 -0500 | [diff] [blame] | 2093 | out: |
Al Viro | 2d92ab3 | 2008-08-02 00:51:11 -0400 | [diff] [blame] | 2094 | path_put(&old_path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2095 | return err; |
| 2096 | } |
| 2097 | |
Dave Hansen | 2e4b7fc | 2008-02-15 14:38:00 -0800 | [diff] [blame] | 2098 | static int change_mount_flags(struct vfsmount *mnt, int ms_flags) |
| 2099 | { |
| 2100 | int error = 0; |
| 2101 | int readonly_request = 0; |
| 2102 | |
| 2103 | if (ms_flags & MS_RDONLY) |
| 2104 | readonly_request = 1; |
| 2105 | if (readonly_request == __mnt_is_readonly(mnt)) |
| 2106 | return 0; |
| 2107 | |
| 2108 | if (readonly_request) |
Al Viro | 83adc75 | 2011-11-24 22:37:54 -0500 | [diff] [blame] | 2109 | error = mnt_make_readonly(real_mount(mnt)); |
Dave Hansen | 2e4b7fc | 2008-02-15 14:38:00 -0800 | [diff] [blame] | 2110 | else |
Al Viro | 83adc75 | 2011-11-24 22:37:54 -0500 | [diff] [blame] | 2111 | __mnt_unmake_readonly(real_mount(mnt)); |
Dave Hansen | 2e4b7fc | 2008-02-15 14:38:00 -0800 | [diff] [blame] | 2112 | return error; |
| 2113 | } |
| 2114 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2115 | /* |
| 2116 | * change filesystem flags. dir should be a physical root of filesystem. |
| 2117 | * If you've mounted a non-root directory somewhere and want to do remount |
| 2118 | * on it - tough luck. |
| 2119 | */ |
Al Viro | 0a0d8a4 | 2008-08-02 00:55:27 -0400 | [diff] [blame] | 2120 | static int do_remount(struct path *path, int flags, int mnt_flags, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2121 | void *data) |
| 2122 | { |
| 2123 | int err; |
Al Viro | 2d92ab3 | 2008-08-02 00:51:11 -0400 | [diff] [blame] | 2124 | struct super_block *sb = path->mnt->mnt_sb; |
Al Viro | 143c8c9 | 2011-11-25 00:46:35 -0500 | [diff] [blame] | 2125 | struct mount *mnt = real_mount(path->mnt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2126 | |
Al Viro | 143c8c9 | 2011-11-25 00:46:35 -0500 | [diff] [blame] | 2127 | if (!check_mnt(mnt)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2128 | return -EINVAL; |
| 2129 | |
Al Viro | 2d92ab3 | 2008-08-02 00:51:11 -0400 | [diff] [blame] | 2130 | if (path->dentry != path->mnt->mnt_root) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2131 | return -EINVAL; |
| 2132 | |
Eric W. Biederman | 07b6455 | 2014-07-28 17:10:56 -0700 | [diff] [blame] | 2133 | /* Don't allow changing of locked mnt flags. |
| 2134 | * |
| 2135 | * No locks need to be held here while testing the various |
| 2136 | * MNT_LOCK flags because those flags can never be cleared |
| 2137 | * once they are set. |
| 2138 | */ |
| 2139 | if ((mnt->mnt.mnt_flags & MNT_LOCK_READONLY) && |
| 2140 | !(mnt_flags & MNT_READONLY)) { |
| 2141 | return -EPERM; |
| 2142 | } |
Eric W. Biederman | 9566d67 | 2014-07-28 17:26:07 -0700 | [diff] [blame] | 2143 | if ((mnt->mnt.mnt_flags & MNT_LOCK_NODEV) && |
| 2144 | !(mnt_flags & MNT_NODEV)) { |
Eric W. Biederman | 3e18664 | 2014-08-13 01:33:38 -0700 | [diff] [blame] | 2145 | /* Was the nodev implicitly added in mount? */ |
| 2146 | if ((mnt->mnt_ns->user_ns != &init_user_ns) && |
| 2147 | !(sb->s_type->fs_flags & FS_USERNS_DEV_MOUNT)) { |
| 2148 | mnt_flags |= MNT_NODEV; |
| 2149 | } else { |
| 2150 | return -EPERM; |
| 2151 | } |
Eric W. Biederman | 9566d67 | 2014-07-28 17:26:07 -0700 | [diff] [blame] | 2152 | } |
| 2153 | if ((mnt->mnt.mnt_flags & MNT_LOCK_NOSUID) && |
| 2154 | !(mnt_flags & MNT_NOSUID)) { |
| 2155 | return -EPERM; |
| 2156 | } |
| 2157 | if ((mnt->mnt.mnt_flags & MNT_LOCK_NOEXEC) && |
| 2158 | !(mnt_flags & MNT_NOEXEC)) { |
| 2159 | return -EPERM; |
| 2160 | } |
| 2161 | if ((mnt->mnt.mnt_flags & MNT_LOCK_ATIME) && |
| 2162 | ((mnt->mnt.mnt_flags & MNT_ATIME_MASK) != (mnt_flags & MNT_ATIME_MASK))) { |
| 2163 | return -EPERM; |
| 2164 | } |
| 2165 | |
Eric Paris | ff36fe2 | 2011-03-03 16:09:14 -0500 | [diff] [blame] | 2166 | err = security_sb_remount(sb, data); |
| 2167 | if (err) |
| 2168 | return err; |
| 2169 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2170 | down_write(&sb->s_umount); |
Dave Hansen | 2e4b7fc | 2008-02-15 14:38:00 -0800 | [diff] [blame] | 2171 | if (flags & MS_BIND) |
Al Viro | 2d92ab3 | 2008-08-02 00:51:11 -0400 | [diff] [blame] | 2172 | err = change_mount_flags(path->mnt, flags); |
Al Viro | 57eccb8 | 2013-02-22 22:49:10 -0500 | [diff] [blame] | 2173 | else if (!capable(CAP_SYS_ADMIN)) |
| 2174 | err = -EPERM; |
Al Viro | 4aa98cf | 2009-05-08 13:36:58 -0400 | [diff] [blame] | 2175 | else |
Dave Hansen | 2e4b7fc | 2008-02-15 14:38:00 -0800 | [diff] [blame] | 2176 | err = do_remount_sb(sb, flags, data, 0); |
Al Viro | 7b43a79 | 2010-01-16 13:01:26 -0500 | [diff] [blame] | 2177 | if (!err) { |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 2178 | lock_mount_hash(); |
Eric W. Biederman | a6138db | 2014-07-28 16:26:53 -0700 | [diff] [blame] | 2179 | mnt_flags |= mnt->mnt.mnt_flags & ~MNT_USER_SETTABLE_MASK; |
Al Viro | 143c8c9 | 2011-11-25 00:46:35 -0500 | [diff] [blame] | 2180 | mnt->mnt.mnt_flags = mnt_flags; |
Al Viro | 143c8c9 | 2011-11-25 00:46:35 -0500 | [diff] [blame] | 2181 | touch_mnt_namespace(mnt->mnt_ns); |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 2182 | unlock_mount_hash(); |
Dan Williams | 0e55a7c | 2008-09-26 19:01:20 -0700 | [diff] [blame] | 2183 | } |
Al Viro | 6339dab | 2013-09-16 22:41:01 -0400 | [diff] [blame] | 2184 | up_write(&sb->s_umount); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2185 | return err; |
| 2186 | } |
| 2187 | |
Al Viro | cbbe362 | 2011-11-24 20:01:19 -0500 | [diff] [blame] | 2188 | static inline int tree_contains_unbindable(struct mount *mnt) |
Ram Pai | 9676f0c | 2005-11-07 17:21:20 -0500 | [diff] [blame] | 2189 | { |
Al Viro | 315fc83 | 2011-11-24 18:57:30 -0500 | [diff] [blame] | 2190 | struct mount *p; |
Al Viro | 909b0a8 | 2011-11-25 03:06:56 -0500 | [diff] [blame] | 2191 | for (p = mnt; p; p = next_mnt(p, mnt)) { |
Al Viro | fc7be13 | 2011-11-25 01:05:37 -0500 | [diff] [blame] | 2192 | if (IS_MNT_UNBINDABLE(p)) |
Ram Pai | 9676f0c | 2005-11-07 17:21:20 -0500 | [diff] [blame] | 2193 | return 1; |
| 2194 | } |
| 2195 | return 0; |
| 2196 | } |
| 2197 | |
Al Viro | 808d4e3 | 2012-10-11 11:42:01 -0400 | [diff] [blame] | 2198 | static int do_move_mount(struct path *path, const char *old_name) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2199 | { |
Al Viro | 2d92ab3 | 2008-08-02 00:51:11 -0400 | [diff] [blame] | 2200 | struct path old_path, parent_path; |
Al Viro | 676da58 | 2011-11-24 21:47:05 -0500 | [diff] [blame] | 2201 | struct mount *p; |
Al Viro | 0fb54e5 | 2011-11-24 19:59:16 -0500 | [diff] [blame] | 2202 | struct mount *old; |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 2203 | struct mountpoint *mp; |
Al Viro | 57eccb8 | 2013-02-22 22:49:10 -0500 | [diff] [blame] | 2204 | int err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2205 | if (!old_name || !*old_name) |
| 2206 | return -EINVAL; |
Al Viro | 2d92ab3 | 2008-08-02 00:51:11 -0400 | [diff] [blame] | 2207 | err = kern_path(old_name, LOOKUP_FOLLOW, &old_path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2208 | if (err) |
| 2209 | return err; |
| 2210 | |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 2211 | mp = lock_mount(path); |
| 2212 | err = PTR_ERR(mp); |
| 2213 | if (IS_ERR(mp)) |
David Howells | cc53ce5 | 2011-01-14 18:45:26 +0000 | [diff] [blame] | 2214 | goto out; |
| 2215 | |
Al Viro | 143c8c9 | 2011-11-25 00:46:35 -0500 | [diff] [blame] | 2216 | old = real_mount(old_path.mnt); |
Al Viro | fc7be13 | 2011-11-25 01:05:37 -0500 | [diff] [blame] | 2217 | p = real_mount(path->mnt); |
Al Viro | 143c8c9 | 2011-11-25 00:46:35 -0500 | [diff] [blame] | 2218 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2219 | err = -EINVAL; |
Al Viro | fc7be13 | 2011-11-25 01:05:37 -0500 | [diff] [blame] | 2220 | if (!check_mnt(p) || !check_mnt(old)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2221 | goto out1; |
| 2222 | |
Eric W. Biederman | 5ff9d8a | 2013-03-29 21:04:39 -0700 | [diff] [blame] | 2223 | if (old->mnt.mnt_flags & MNT_LOCKED) |
| 2224 | goto out1; |
| 2225 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2226 | err = -EINVAL; |
Al Viro | 2d92ab3 | 2008-08-02 00:51:11 -0400 | [diff] [blame] | 2227 | if (old_path.dentry != old_path.mnt->mnt_root) |
Ram Pai | 2144440 | 2005-11-07 17:20:03 -0500 | [diff] [blame] | 2228 | goto out1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2229 | |
Al Viro | 676da58 | 2011-11-24 21:47:05 -0500 | [diff] [blame] | 2230 | if (!mnt_has_parent(old)) |
Ram Pai | 2144440 | 2005-11-07 17:20:03 -0500 | [diff] [blame] | 2231 | goto out1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2232 | |
David Howells | e36cb0b | 2015-01-29 12:02:35 +0000 | [diff] [blame] | 2233 | if (d_is_dir(path->dentry) != |
| 2234 | d_is_dir(old_path.dentry)) |
Ram Pai | 2144440 | 2005-11-07 17:20:03 -0500 | [diff] [blame] | 2235 | goto out1; |
| 2236 | /* |
| 2237 | * Don't move a mount residing in a shared parent. |
| 2238 | */ |
Al Viro | fc7be13 | 2011-11-25 01:05:37 -0500 | [diff] [blame] | 2239 | if (IS_MNT_SHARED(old->mnt_parent)) |
Ram Pai | 2144440 | 2005-11-07 17:20:03 -0500 | [diff] [blame] | 2240 | goto out1; |
Ram Pai | 9676f0c | 2005-11-07 17:21:20 -0500 | [diff] [blame] | 2241 | /* |
| 2242 | * Don't move a mount tree containing unbindable mounts to a destination |
| 2243 | * mount which is shared. |
| 2244 | */ |
Al Viro | fc7be13 | 2011-11-25 01:05:37 -0500 | [diff] [blame] | 2245 | if (IS_MNT_SHARED(p) && tree_contains_unbindable(old)) |
Ram Pai | 9676f0c | 2005-11-07 17:21:20 -0500 | [diff] [blame] | 2246 | goto out1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2247 | err = -ELOOP; |
Al Viro | fc7be13 | 2011-11-25 01:05:37 -0500 | [diff] [blame] | 2248 | for (; mnt_has_parent(p); p = p->mnt_parent) |
Al Viro | 676da58 | 2011-11-24 21:47:05 -0500 | [diff] [blame] | 2249 | if (p == old) |
Ram Pai | 2144440 | 2005-11-07 17:20:03 -0500 | [diff] [blame] | 2250 | goto out1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2251 | |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 2252 | err = attach_recursive_mnt(old, real_mount(path->mnt), mp, &parent_path); |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 2253 | if (err) |
Ram Pai | 2144440 | 2005-11-07 17:20:03 -0500 | [diff] [blame] | 2254 | goto out1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2255 | |
| 2256 | /* if the mount is moved, it should no longer be expire |
| 2257 | * automatically */ |
Al Viro | 6776db3d | 2011-11-25 00:22:05 -0500 | [diff] [blame] | 2258 | list_del_init(&old->mnt_expire); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2259 | out1: |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 2260 | unlock_mount(mp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2261 | out: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2262 | if (!err) |
Al Viro | 1a39068 | 2008-03-21 20:48:19 -0400 | [diff] [blame] | 2263 | path_put(&parent_path); |
Al Viro | 2d92ab3 | 2008-08-02 00:51:11 -0400 | [diff] [blame] | 2264 | path_put(&old_path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2265 | return err; |
| 2266 | } |
| 2267 | |
Al Viro | 9d412a4 | 2011-03-17 22:08:28 -0400 | [diff] [blame] | 2268 | static struct vfsmount *fs_set_subtype(struct vfsmount *mnt, const char *fstype) |
| 2269 | { |
| 2270 | int err; |
| 2271 | const char *subtype = strchr(fstype, '.'); |
| 2272 | if (subtype) { |
| 2273 | subtype++; |
| 2274 | err = -EINVAL; |
| 2275 | if (!subtype[0]) |
| 2276 | goto err; |
| 2277 | } else |
| 2278 | subtype = ""; |
| 2279 | |
| 2280 | mnt->mnt_sb->s_subtype = kstrdup(subtype, GFP_KERNEL); |
| 2281 | err = -ENOMEM; |
| 2282 | if (!mnt->mnt_sb->s_subtype) |
| 2283 | goto err; |
| 2284 | return mnt; |
| 2285 | |
| 2286 | err: |
| 2287 | mntput(mnt); |
| 2288 | return ERR_PTR(err); |
| 2289 | } |
| 2290 | |
Al Viro | 9d412a4 | 2011-03-17 22:08:28 -0400 | [diff] [blame] | 2291 | /* |
| 2292 | * add a mount into a namespace's mount tree |
| 2293 | */ |
Al Viro | 95bc5f2 | 2011-11-25 00:30:56 -0500 | [diff] [blame] | 2294 | static int do_add_mount(struct mount *newmnt, struct path *path, int mnt_flags) |
Al Viro | 9d412a4 | 2011-03-17 22:08:28 -0400 | [diff] [blame] | 2295 | { |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 2296 | struct mountpoint *mp; |
| 2297 | struct mount *parent; |
Al Viro | 9d412a4 | 2011-03-17 22:08:28 -0400 | [diff] [blame] | 2298 | int err; |
| 2299 | |
Al Viro | f2ebb3a | 2014-02-27 09:35:45 -0500 | [diff] [blame] | 2300 | mnt_flags &= ~MNT_INTERNAL_FLAGS; |
Al Viro | 9d412a4 | 2011-03-17 22:08:28 -0400 | [diff] [blame] | 2301 | |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 2302 | mp = lock_mount(path); |
| 2303 | if (IS_ERR(mp)) |
| 2304 | return PTR_ERR(mp); |
Al Viro | 9d412a4 | 2011-03-17 22:08:28 -0400 | [diff] [blame] | 2305 | |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 2306 | parent = real_mount(path->mnt); |
Al Viro | 9d412a4 | 2011-03-17 22:08:28 -0400 | [diff] [blame] | 2307 | err = -EINVAL; |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 2308 | if (unlikely(!check_mnt(parent))) { |
Al Viro | 156cacb | 2012-09-21 08:19:02 -0400 | [diff] [blame] | 2309 | /* that's acceptable only for automounts done in private ns */ |
| 2310 | if (!(mnt_flags & MNT_SHRINKABLE)) |
| 2311 | goto unlock; |
| 2312 | /* ... and for those we'd better have mountpoint still alive */ |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 2313 | if (!parent->mnt_ns) |
Al Viro | 156cacb | 2012-09-21 08:19:02 -0400 | [diff] [blame] | 2314 | goto unlock; |
| 2315 | } |
Al Viro | 9d412a4 | 2011-03-17 22:08:28 -0400 | [diff] [blame] | 2316 | |
| 2317 | /* Refuse the same filesystem on the same mount point */ |
| 2318 | err = -EBUSY; |
Al Viro | 95bc5f2 | 2011-11-25 00:30:56 -0500 | [diff] [blame] | 2319 | if (path->mnt->mnt_sb == newmnt->mnt.mnt_sb && |
Al Viro | 9d412a4 | 2011-03-17 22:08:28 -0400 | [diff] [blame] | 2320 | path->mnt->mnt_root == path->dentry) |
| 2321 | goto unlock; |
| 2322 | |
| 2323 | err = -EINVAL; |
David Howells | e36cb0b | 2015-01-29 12:02:35 +0000 | [diff] [blame] | 2324 | if (d_is_symlink(newmnt->mnt.mnt_root)) |
Al Viro | 9d412a4 | 2011-03-17 22:08:28 -0400 | [diff] [blame] | 2325 | goto unlock; |
| 2326 | |
Al Viro | 95bc5f2 | 2011-11-25 00:30:56 -0500 | [diff] [blame] | 2327 | newmnt->mnt.mnt_flags = mnt_flags; |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 2328 | err = graft_tree(newmnt, parent, mp); |
Al Viro | 9d412a4 | 2011-03-17 22:08:28 -0400 | [diff] [blame] | 2329 | |
| 2330 | unlock: |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 2331 | unlock_mount(mp); |
Al Viro | 9d412a4 | 2011-03-17 22:08:28 -0400 | [diff] [blame] | 2332 | return err; |
| 2333 | } |
Al Viro | b1e75df | 2011-01-17 01:47:59 -0500 | [diff] [blame] | 2334 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2335 | /* |
| 2336 | * create a new mount for userspace and request it to be added into the |
| 2337 | * namespace's tree |
| 2338 | */ |
Eric W. Biederman | 0c55cfc | 2012-07-26 21:42:03 -0700 | [diff] [blame] | 2339 | static int do_new_mount(struct path *path, const char *fstype, int flags, |
Al Viro | 808d4e3 | 2012-10-11 11:42:01 -0400 | [diff] [blame] | 2340 | int mnt_flags, const char *name, void *data) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2341 | { |
Eric W. Biederman | 0c55cfc | 2012-07-26 21:42:03 -0700 | [diff] [blame] | 2342 | struct file_system_type *type; |
Al Viro | 9b40bc9 | 2013-02-22 22:45:42 -0500 | [diff] [blame] | 2343 | struct user_namespace *user_ns = current->nsproxy->mnt_ns->user_ns; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2344 | struct vfsmount *mnt; |
Al Viro | 15f9a3f | 2011-01-17 01:41:58 -0500 | [diff] [blame] | 2345 | int err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2346 | |
Eric W. Biederman | 0c55cfc | 2012-07-26 21:42:03 -0700 | [diff] [blame] | 2347 | if (!fstype) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2348 | return -EINVAL; |
| 2349 | |
Eric W. Biederman | 0c55cfc | 2012-07-26 21:42:03 -0700 | [diff] [blame] | 2350 | type = get_fs_type(fstype); |
| 2351 | if (!type) |
| 2352 | return -ENODEV; |
| 2353 | |
| 2354 | if (user_ns != &init_user_ns) { |
| 2355 | if (!(type->fs_flags & FS_USERNS_MOUNT)) { |
| 2356 | put_filesystem(type); |
| 2357 | return -EPERM; |
| 2358 | } |
| 2359 | /* Only in special cases allow devices from mounts |
| 2360 | * created outside the initial user namespace. |
| 2361 | */ |
| 2362 | if (!(type->fs_flags & FS_USERNS_DEV_MOUNT)) { |
| 2363 | flags |= MS_NODEV; |
Eric W. Biederman | 9566d67 | 2014-07-28 17:26:07 -0700 | [diff] [blame] | 2364 | mnt_flags |= MNT_NODEV | MNT_LOCK_NODEV; |
Eric W. Biederman | 0c55cfc | 2012-07-26 21:42:03 -0700 | [diff] [blame] | 2365 | } |
| 2366 | } |
| 2367 | |
| 2368 | mnt = vfs_kern_mount(type, flags, name, data); |
| 2369 | if (!IS_ERR(mnt) && (type->fs_flags & FS_HAS_SUBTYPE) && |
| 2370 | !mnt->mnt_sb->s_subtype) |
| 2371 | mnt = fs_set_subtype(mnt, fstype); |
| 2372 | |
| 2373 | put_filesystem(type); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2374 | if (IS_ERR(mnt)) |
| 2375 | return PTR_ERR(mnt); |
| 2376 | |
Al Viro | 95bc5f2 | 2011-11-25 00:30:56 -0500 | [diff] [blame] | 2377 | err = do_add_mount(real_mount(mnt), path, mnt_flags); |
Al Viro | 15f9a3f | 2011-01-17 01:41:58 -0500 | [diff] [blame] | 2378 | if (err) |
| 2379 | mntput(mnt); |
| 2380 | return err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2381 | } |
| 2382 | |
Al Viro | 19a167a | 2011-01-17 01:35:23 -0500 | [diff] [blame] | 2383 | int finish_automount(struct vfsmount *m, struct path *path) |
| 2384 | { |
Al Viro | 6776db3d | 2011-11-25 00:22:05 -0500 | [diff] [blame] | 2385 | struct mount *mnt = real_mount(m); |
Al Viro | 19a167a | 2011-01-17 01:35:23 -0500 | [diff] [blame] | 2386 | int err; |
| 2387 | /* The new mount record should have at least 2 refs to prevent it being |
| 2388 | * expired before we get a chance to add it |
| 2389 | */ |
Al Viro | 6776db3d | 2011-11-25 00:22:05 -0500 | [diff] [blame] | 2390 | BUG_ON(mnt_get_count(mnt) < 2); |
Al Viro | 19a167a | 2011-01-17 01:35:23 -0500 | [diff] [blame] | 2391 | |
| 2392 | if (m->mnt_sb == path->mnt->mnt_sb && |
| 2393 | m->mnt_root == path->dentry) { |
Al Viro | b1e75df | 2011-01-17 01:47:59 -0500 | [diff] [blame] | 2394 | err = -ELOOP; |
| 2395 | goto fail; |
Al Viro | 19a167a | 2011-01-17 01:35:23 -0500 | [diff] [blame] | 2396 | } |
| 2397 | |
Al Viro | 95bc5f2 | 2011-11-25 00:30:56 -0500 | [diff] [blame] | 2398 | err = do_add_mount(mnt, path, path->mnt->mnt_flags | MNT_SHRINKABLE); |
Al Viro | b1e75df | 2011-01-17 01:47:59 -0500 | [diff] [blame] | 2399 | if (!err) |
| 2400 | return 0; |
| 2401 | fail: |
| 2402 | /* remove m from any expiration list it may be on */ |
Al Viro | 6776db3d | 2011-11-25 00:22:05 -0500 | [diff] [blame] | 2403 | if (!list_empty(&mnt->mnt_expire)) { |
Al Viro | 97216be | 2013-03-16 15:12:40 -0400 | [diff] [blame] | 2404 | namespace_lock(); |
Al Viro | 6776db3d | 2011-11-25 00:22:05 -0500 | [diff] [blame] | 2405 | list_del_init(&mnt->mnt_expire); |
Al Viro | 97216be | 2013-03-16 15:12:40 -0400 | [diff] [blame] | 2406 | namespace_unlock(); |
Al Viro | 19a167a | 2011-01-17 01:35:23 -0500 | [diff] [blame] | 2407 | } |
Al Viro | b1e75df | 2011-01-17 01:47:59 -0500 | [diff] [blame] | 2408 | mntput(m); |
| 2409 | mntput(m); |
Al Viro | 19a167a | 2011-01-17 01:35:23 -0500 | [diff] [blame] | 2410 | return err; |
| 2411 | } |
| 2412 | |
David Howells | ea5b778 | 2011-01-14 19:10:03 +0000 | [diff] [blame] | 2413 | /** |
| 2414 | * mnt_set_expiry - Put a mount on an expiration list |
| 2415 | * @mnt: The mount to list. |
| 2416 | * @expiry_list: The list to add the mount to. |
| 2417 | */ |
| 2418 | void mnt_set_expiry(struct vfsmount *mnt, struct list_head *expiry_list) |
| 2419 | { |
Al Viro | 97216be | 2013-03-16 15:12:40 -0400 | [diff] [blame] | 2420 | namespace_lock(); |
David Howells | ea5b778 | 2011-01-14 19:10:03 +0000 | [diff] [blame] | 2421 | |
Al Viro | 6776db3d | 2011-11-25 00:22:05 -0500 | [diff] [blame] | 2422 | list_add_tail(&real_mount(mnt)->mnt_expire, expiry_list); |
David Howells | ea5b778 | 2011-01-14 19:10:03 +0000 | [diff] [blame] | 2423 | |
Al Viro | 97216be | 2013-03-16 15:12:40 -0400 | [diff] [blame] | 2424 | namespace_unlock(); |
David Howells | ea5b778 | 2011-01-14 19:10:03 +0000 | [diff] [blame] | 2425 | } |
| 2426 | EXPORT_SYMBOL(mnt_set_expiry); |
| 2427 | |
| 2428 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2429 | * process a list of expirable mountpoints with the intent of discarding any |
| 2430 | * mountpoints that aren't in use and haven't been touched since last we came |
| 2431 | * here |
| 2432 | */ |
| 2433 | void mark_mounts_for_expiry(struct list_head *mounts) |
| 2434 | { |
Al Viro | 761d5c3 | 2011-11-24 21:07:43 -0500 | [diff] [blame] | 2435 | struct mount *mnt, *next; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2436 | LIST_HEAD(graveyard); |
| 2437 | |
| 2438 | if (list_empty(mounts)) |
| 2439 | return; |
| 2440 | |
Al Viro | 97216be | 2013-03-16 15:12:40 -0400 | [diff] [blame] | 2441 | namespace_lock(); |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 2442 | lock_mount_hash(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2443 | |
| 2444 | /* extract from the expiration list every vfsmount that matches the |
| 2445 | * following criteria: |
| 2446 | * - only referenced by its parent vfsmount |
| 2447 | * - still marked for expiry (marked on the last call here; marks are |
| 2448 | * cleared by mntput()) |
| 2449 | */ |
Al Viro | 6776db3d | 2011-11-25 00:22:05 -0500 | [diff] [blame] | 2450 | list_for_each_entry_safe(mnt, next, mounts, mnt_expire) { |
Al Viro | 863d684 | 2011-11-25 00:57:42 -0500 | [diff] [blame] | 2451 | if (!xchg(&mnt->mnt_expiry_mark, 1) || |
Al Viro | 1ab5973 | 2011-11-24 21:35:16 -0500 | [diff] [blame] | 2452 | propagate_mount_busy(mnt, 1)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2453 | continue; |
Al Viro | 6776db3d | 2011-11-25 00:22:05 -0500 | [diff] [blame] | 2454 | list_move(&mnt->mnt_expire, &graveyard); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2455 | } |
Al Viro | bcc5c7d | 2008-03-22 00:21:53 -0400 | [diff] [blame] | 2456 | while (!list_empty(&graveyard)) { |
Al Viro | 6776db3d | 2011-11-25 00:22:05 -0500 | [diff] [blame] | 2457 | mnt = list_first_entry(&graveyard, struct mount, mnt_expire); |
Al Viro | 143c8c9 | 2011-11-25 00:46:35 -0500 | [diff] [blame] | 2458 | touch_mnt_namespace(mnt->mnt_ns); |
Eric W. Biederman | e819f15 | 2014-12-24 07:20:01 -0600 | [diff] [blame] | 2459 | umount_tree(mnt, UMOUNT_PROPAGATE|UMOUNT_SYNC); |
Al Viro | bcc5c7d | 2008-03-22 00:21:53 -0400 | [diff] [blame] | 2460 | } |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 2461 | unlock_mount_hash(); |
Al Viro | 3ab6abe | 2013-03-16 14:42:19 -0400 | [diff] [blame] | 2462 | namespace_unlock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2463 | } |
| 2464 | |
| 2465 | EXPORT_SYMBOL_GPL(mark_mounts_for_expiry); |
| 2466 | |
| 2467 | /* |
Trond Myklebust | 5528f911 | 2006-06-09 09:34:17 -0400 | [diff] [blame] | 2468 | * Ripoff of 'select_parent()' |
| 2469 | * |
| 2470 | * search the list of submounts for a given mountpoint, and move any |
| 2471 | * shrinkable submounts to the 'graveyard' list. |
| 2472 | */ |
Al Viro | 692afc3 | 2011-11-24 21:15:14 -0500 | [diff] [blame] | 2473 | static int select_submounts(struct mount *parent, struct list_head *graveyard) |
Trond Myklebust | 5528f911 | 2006-06-09 09:34:17 -0400 | [diff] [blame] | 2474 | { |
Al Viro | 692afc3 | 2011-11-24 21:15:14 -0500 | [diff] [blame] | 2475 | struct mount *this_parent = parent; |
Trond Myklebust | 5528f911 | 2006-06-09 09:34:17 -0400 | [diff] [blame] | 2476 | struct list_head *next; |
| 2477 | int found = 0; |
| 2478 | |
| 2479 | repeat: |
Al Viro | 6b41d53 | 2011-11-24 23:24:33 -0500 | [diff] [blame] | 2480 | next = this_parent->mnt_mounts.next; |
Trond Myklebust | 5528f911 | 2006-06-09 09:34:17 -0400 | [diff] [blame] | 2481 | resume: |
Al Viro | 6b41d53 | 2011-11-24 23:24:33 -0500 | [diff] [blame] | 2482 | while (next != &this_parent->mnt_mounts) { |
Trond Myklebust | 5528f911 | 2006-06-09 09:34:17 -0400 | [diff] [blame] | 2483 | struct list_head *tmp = next; |
Al Viro | 6b41d53 | 2011-11-24 23:24:33 -0500 | [diff] [blame] | 2484 | struct mount *mnt = list_entry(tmp, struct mount, mnt_child); |
Trond Myklebust | 5528f911 | 2006-06-09 09:34:17 -0400 | [diff] [blame] | 2485 | |
| 2486 | next = tmp->next; |
Al Viro | 692afc3 | 2011-11-24 21:15:14 -0500 | [diff] [blame] | 2487 | if (!(mnt->mnt.mnt_flags & MNT_SHRINKABLE)) |
Trond Myklebust | 5528f911 | 2006-06-09 09:34:17 -0400 | [diff] [blame] | 2488 | continue; |
| 2489 | /* |
| 2490 | * Descend a level if the d_mounts list is non-empty. |
| 2491 | */ |
Al Viro | 6b41d53 | 2011-11-24 23:24:33 -0500 | [diff] [blame] | 2492 | if (!list_empty(&mnt->mnt_mounts)) { |
Trond Myklebust | 5528f911 | 2006-06-09 09:34:17 -0400 | [diff] [blame] | 2493 | this_parent = mnt; |
| 2494 | goto repeat; |
| 2495 | } |
| 2496 | |
Al Viro | 1ab5973 | 2011-11-24 21:35:16 -0500 | [diff] [blame] | 2497 | if (!propagate_mount_busy(mnt, 1)) { |
Al Viro | 6776db3d | 2011-11-25 00:22:05 -0500 | [diff] [blame] | 2498 | list_move_tail(&mnt->mnt_expire, graveyard); |
Trond Myklebust | 5528f911 | 2006-06-09 09:34:17 -0400 | [diff] [blame] | 2499 | found++; |
| 2500 | } |
| 2501 | } |
| 2502 | /* |
| 2503 | * All done at this level ... ascend and resume the search |
| 2504 | */ |
| 2505 | if (this_parent != parent) { |
Al Viro | 6b41d53 | 2011-11-24 23:24:33 -0500 | [diff] [blame] | 2506 | next = this_parent->mnt_child.next; |
Al Viro | 0714a53 | 2011-11-24 22:19:58 -0500 | [diff] [blame] | 2507 | this_parent = this_parent->mnt_parent; |
Trond Myklebust | 5528f911 | 2006-06-09 09:34:17 -0400 | [diff] [blame] | 2508 | goto resume; |
| 2509 | } |
| 2510 | return found; |
| 2511 | } |
| 2512 | |
| 2513 | /* |
| 2514 | * process a list of expirable mountpoints with the intent of discarding any |
| 2515 | * submounts of a specific parent mountpoint |
Nick Piggin | 99b7db7 | 2010-08-18 04:37:39 +1000 | [diff] [blame] | 2516 | * |
Al Viro | 48a066e | 2013-09-29 22:06:07 -0400 | [diff] [blame] | 2517 | * mount_lock must be held for write |
Trond Myklebust | 5528f911 | 2006-06-09 09:34:17 -0400 | [diff] [blame] | 2518 | */ |
Al Viro | b54b9be | 2013-03-16 14:39:34 -0400 | [diff] [blame] | 2519 | static void shrink_submounts(struct mount *mnt) |
Trond Myklebust | 5528f911 | 2006-06-09 09:34:17 -0400 | [diff] [blame] | 2520 | { |
| 2521 | LIST_HEAD(graveyard); |
Al Viro | 761d5c3 | 2011-11-24 21:07:43 -0500 | [diff] [blame] | 2522 | struct mount *m; |
Trond Myklebust | 5528f911 | 2006-06-09 09:34:17 -0400 | [diff] [blame] | 2523 | |
Trond Myklebust | 5528f911 | 2006-06-09 09:34:17 -0400 | [diff] [blame] | 2524 | /* extract submounts of 'mountpoint' from the expiration list */ |
Al Viro | c35038b | 2008-03-22 00:46:23 -0400 | [diff] [blame] | 2525 | while (select_submounts(mnt, &graveyard)) { |
Al Viro | bcc5c7d | 2008-03-22 00:21:53 -0400 | [diff] [blame] | 2526 | while (!list_empty(&graveyard)) { |
Al Viro | 761d5c3 | 2011-11-24 21:07:43 -0500 | [diff] [blame] | 2527 | m = list_first_entry(&graveyard, struct mount, |
Al Viro | 6776db3d | 2011-11-25 00:22:05 -0500 | [diff] [blame] | 2528 | mnt_expire); |
Al Viro | 143c8c9 | 2011-11-25 00:46:35 -0500 | [diff] [blame] | 2529 | touch_mnt_namespace(m->mnt_ns); |
Eric W. Biederman | e819f15 | 2014-12-24 07:20:01 -0600 | [diff] [blame] | 2530 | umount_tree(m, UMOUNT_PROPAGATE|UMOUNT_SYNC); |
Al Viro | bcc5c7d | 2008-03-22 00:21:53 -0400 | [diff] [blame] | 2531 | } |
| 2532 | } |
Trond Myklebust | 5528f911 | 2006-06-09 09:34:17 -0400 | [diff] [blame] | 2533 | } |
| 2534 | |
Trond Myklebust | 5528f911 | 2006-06-09 09:34:17 -0400 | [diff] [blame] | 2535 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2536 | * Some copy_from_user() implementations do not return the exact number of |
| 2537 | * bytes remaining to copy on a fault. But copy_mount_options() requires that. |
| 2538 | * Note that this function differs from copy_from_user() in that it will oops |
| 2539 | * on bad values of `to', rather than returning a short copy. |
| 2540 | */ |
Ram Pai | b58fed8 | 2005-11-07 17:16:09 -0500 | [diff] [blame] | 2541 | static long exact_copy_from_user(void *to, const void __user * from, |
| 2542 | unsigned long n) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2543 | { |
| 2544 | char *t = to; |
| 2545 | const char __user *f = from; |
| 2546 | char c; |
| 2547 | |
| 2548 | if (!access_ok(VERIFY_READ, from, n)) |
| 2549 | return n; |
| 2550 | |
| 2551 | while (n) { |
| 2552 | if (__get_user(c, f)) { |
| 2553 | memset(t, 0, n); |
| 2554 | break; |
| 2555 | } |
| 2556 | *t++ = c; |
| 2557 | f++; |
| 2558 | n--; |
| 2559 | } |
| 2560 | return n; |
| 2561 | } |
| 2562 | |
Ram Pai | b58fed8 | 2005-11-07 17:16:09 -0500 | [diff] [blame] | 2563 | int copy_mount_options(const void __user * data, unsigned long *where) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2564 | { |
| 2565 | int i; |
| 2566 | unsigned long page; |
| 2567 | unsigned long size; |
Ram Pai | b58fed8 | 2005-11-07 17:16:09 -0500 | [diff] [blame] | 2568 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2569 | *where = 0; |
| 2570 | if (!data) |
| 2571 | return 0; |
| 2572 | |
| 2573 | if (!(page = __get_free_page(GFP_KERNEL))) |
| 2574 | return -ENOMEM; |
| 2575 | |
| 2576 | /* We only care that *some* data at the address the user |
| 2577 | * gave us is valid. Just in case, we'll zero |
| 2578 | * the remainder of the page. |
| 2579 | */ |
| 2580 | /* copy_from_user cannot cross TASK_SIZE ! */ |
| 2581 | size = TASK_SIZE - (unsigned long)data; |
| 2582 | if (size > PAGE_SIZE) |
| 2583 | size = PAGE_SIZE; |
| 2584 | |
| 2585 | i = size - exact_copy_from_user((void *)page, data, size); |
| 2586 | if (!i) { |
Ram Pai | b58fed8 | 2005-11-07 17:16:09 -0500 | [diff] [blame] | 2587 | free_page(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2588 | return -EFAULT; |
| 2589 | } |
| 2590 | if (i != PAGE_SIZE) |
| 2591 | memset((char *)page + i, 0, PAGE_SIZE - i); |
| 2592 | *where = page; |
| 2593 | return 0; |
| 2594 | } |
| 2595 | |
Tim Gardner | b8850d1 | 2014-08-28 11:26:03 -0600 | [diff] [blame] | 2596 | char *copy_mount_string(const void __user *data) |
Vegard Nossum | eca6f53 | 2009-09-18 13:05:45 -0700 | [diff] [blame] | 2597 | { |
Tim Gardner | b8850d1 | 2014-08-28 11:26:03 -0600 | [diff] [blame] | 2598 | return data ? strndup_user(data, PAGE_SIZE) : NULL; |
Vegard Nossum | eca6f53 | 2009-09-18 13:05:45 -0700 | [diff] [blame] | 2599 | } |
| 2600 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2601 | /* |
| 2602 | * Flags is a 32-bit value that allows up to 31 non-fs dependent flags to |
| 2603 | * be given to the mount() call (ie: read-only, no-dev, no-suid etc). |
| 2604 | * |
| 2605 | * data is a (void *) that can point to any structure up to |
| 2606 | * PAGE_SIZE-1 bytes, which can contain arbitrary fs-dependent |
| 2607 | * information (or be NULL). |
| 2608 | * |
| 2609 | * Pre-0.97 versions of mount() didn't have a flags word. |
| 2610 | * When the flags word was introduced its top half was required |
| 2611 | * to have the magic value 0xC0ED, and this remained so until 2.4.0-test9. |
| 2612 | * Therefore, if this magic number is present, it carries no information |
| 2613 | * and must be discarded. |
| 2614 | */ |
Seunghun Lee | 5e6123f | 2014-09-14 22:15:10 +0900 | [diff] [blame] | 2615 | long do_mount(const char *dev_name, const char __user *dir_name, |
Al Viro | 808d4e3 | 2012-10-11 11:42:01 -0400 | [diff] [blame] | 2616 | const char *type_page, unsigned long flags, void *data_page) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2617 | { |
Al Viro | 2d92ab3 | 2008-08-02 00:51:11 -0400 | [diff] [blame] | 2618 | struct path path; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2619 | int retval = 0; |
| 2620 | int mnt_flags = 0; |
| 2621 | |
| 2622 | /* Discard magic */ |
| 2623 | if ((flags & MS_MGC_MSK) == MS_MGC_VAL) |
| 2624 | flags &= ~MS_MGC_MSK; |
| 2625 | |
| 2626 | /* Basic sanity checks */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2627 | if (data_page) |
| 2628 | ((char *)data_page)[PAGE_SIZE - 1] = 0; |
| 2629 | |
Tetsuo Handa | a27ab9f2 | 2009-10-04 21:49:49 +0900 | [diff] [blame] | 2630 | /* ... and get the mountpoint */ |
Seunghun Lee | 5e6123f | 2014-09-14 22:15:10 +0900 | [diff] [blame] | 2631 | retval = user_path(dir_name, &path); |
Tetsuo Handa | a27ab9f2 | 2009-10-04 21:49:49 +0900 | [diff] [blame] | 2632 | if (retval) |
| 2633 | return retval; |
| 2634 | |
| 2635 | retval = security_sb_mount(dev_name, &path, |
| 2636 | type_page, flags, data_page); |
Al Viro | 0d5cadb | 2013-05-04 14:40:51 -0400 | [diff] [blame] | 2637 | if (!retval && !may_mount()) |
| 2638 | retval = -EPERM; |
Tetsuo Handa | a27ab9f2 | 2009-10-04 21:49:49 +0900 | [diff] [blame] | 2639 | if (retval) |
| 2640 | goto dput_out; |
| 2641 | |
Andi Kleen | 613cbe3 | 2009-04-19 18:40:43 +0200 | [diff] [blame] | 2642 | /* Default to relatime unless overriden */ |
| 2643 | if (!(flags & MS_NOATIME)) |
| 2644 | mnt_flags |= MNT_RELATIME; |
Matthew Garrett | 0a1c01c | 2009-03-26 17:53:14 +0000 | [diff] [blame] | 2645 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2646 | /* Separate the per-mountpoint flags */ |
| 2647 | if (flags & MS_NOSUID) |
| 2648 | mnt_flags |= MNT_NOSUID; |
| 2649 | if (flags & MS_NODEV) |
| 2650 | mnt_flags |= MNT_NODEV; |
| 2651 | if (flags & MS_NOEXEC) |
| 2652 | mnt_flags |= MNT_NOEXEC; |
Christoph Hellwig | fc33a7b | 2006-01-09 20:52:17 -0800 | [diff] [blame] | 2653 | if (flags & MS_NOATIME) |
| 2654 | mnt_flags |= MNT_NOATIME; |
| 2655 | if (flags & MS_NODIRATIME) |
| 2656 | mnt_flags |= MNT_NODIRATIME; |
Matthew Garrett | d0adde5 | 2009-03-26 17:49:56 +0000 | [diff] [blame] | 2657 | if (flags & MS_STRICTATIME) |
| 2658 | mnt_flags &= ~(MNT_RELATIME | MNT_NOATIME); |
Dave Hansen | 2e4b7fc | 2008-02-15 14:38:00 -0800 | [diff] [blame] | 2659 | if (flags & MS_RDONLY) |
| 2660 | mnt_flags |= MNT_READONLY; |
Christoph Hellwig | fc33a7b | 2006-01-09 20:52:17 -0800 | [diff] [blame] | 2661 | |
Eric W. Biederman | ffbc6f0 | 2014-07-28 17:36:04 -0700 | [diff] [blame] | 2662 | /* The default atime for remount is preservation */ |
| 2663 | if ((flags & MS_REMOUNT) && |
| 2664 | ((flags & (MS_NOATIME | MS_NODIRATIME | MS_RELATIME | |
| 2665 | MS_STRICTATIME)) == 0)) { |
| 2666 | mnt_flags &= ~MNT_ATIME_MASK; |
| 2667 | mnt_flags |= path.mnt->mnt_flags & MNT_ATIME_MASK; |
| 2668 | } |
| 2669 | |
Al Viro | 7a4dec5 | 2010-08-09 12:05:43 -0400 | [diff] [blame] | 2670 | flags &= ~(MS_NOSUID | MS_NOEXEC | MS_NODEV | MS_ACTIVE | MS_BORN | |
Matthew Garrett | d0adde5 | 2009-03-26 17:49:56 +0000 | [diff] [blame] | 2671 | MS_NOATIME | MS_NODIRATIME | MS_RELATIME| MS_KERNMOUNT | |
| 2672 | MS_STRICTATIME); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2673 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2674 | if (flags & MS_REMOUNT) |
Al Viro | 2d92ab3 | 2008-08-02 00:51:11 -0400 | [diff] [blame] | 2675 | retval = do_remount(&path, flags & ~MS_REMOUNT, mnt_flags, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2676 | data_page); |
| 2677 | else if (flags & MS_BIND) |
Al Viro | 2d92ab3 | 2008-08-02 00:51:11 -0400 | [diff] [blame] | 2678 | retval = do_loopback(&path, dev_name, flags & MS_REC); |
Ram Pai | 9676f0c | 2005-11-07 17:21:20 -0500 | [diff] [blame] | 2679 | else if (flags & (MS_SHARED | MS_PRIVATE | MS_SLAVE | MS_UNBINDABLE)) |
Al Viro | 2d92ab3 | 2008-08-02 00:51:11 -0400 | [diff] [blame] | 2680 | retval = do_change_type(&path, flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2681 | else if (flags & MS_MOVE) |
Al Viro | 2d92ab3 | 2008-08-02 00:51:11 -0400 | [diff] [blame] | 2682 | retval = do_move_mount(&path, dev_name); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2683 | else |
Al Viro | 2d92ab3 | 2008-08-02 00:51:11 -0400 | [diff] [blame] | 2684 | retval = do_new_mount(&path, type_page, flags, mnt_flags, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2685 | dev_name, data_page); |
| 2686 | dput_out: |
Al Viro | 2d92ab3 | 2008-08-02 00:51:11 -0400 | [diff] [blame] | 2687 | path_put(&path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2688 | return retval; |
| 2689 | } |
| 2690 | |
Eric W. Biederman | 771b137 | 2012-07-26 21:08:32 -0700 | [diff] [blame] | 2691 | static void free_mnt_ns(struct mnt_namespace *ns) |
| 2692 | { |
Al Viro | 6344c43 | 2014-11-01 00:45:45 -0400 | [diff] [blame] | 2693 | ns_free_inum(&ns->ns); |
Eric W. Biederman | 771b137 | 2012-07-26 21:08:32 -0700 | [diff] [blame] | 2694 | put_user_ns(ns->user_ns); |
| 2695 | kfree(ns); |
| 2696 | } |
| 2697 | |
Eric W. Biederman | 8823c07 | 2010-03-07 18:49:36 -0800 | [diff] [blame] | 2698 | /* |
| 2699 | * Assign a sequence number so we can detect when we attempt to bind |
| 2700 | * mount a reference to an older mount namespace into the current |
| 2701 | * mount namespace, preventing reference counting loops. A 64bit |
| 2702 | * number incrementing at 10Ghz will take 12,427 years to wrap which |
| 2703 | * is effectively never, so we can ignore the possibility. |
| 2704 | */ |
| 2705 | static atomic64_t mnt_ns_seq = ATOMIC64_INIT(1); |
| 2706 | |
Eric W. Biederman | 771b137 | 2012-07-26 21:08:32 -0700 | [diff] [blame] | 2707 | static struct mnt_namespace *alloc_mnt_ns(struct user_namespace *user_ns) |
Trond Myklebust | cf8d2c1 | 2009-06-22 15:09:13 -0400 | [diff] [blame] | 2708 | { |
| 2709 | struct mnt_namespace *new_ns; |
Eric W. Biederman | 98f842e | 2011-06-15 10:21:48 -0700 | [diff] [blame] | 2710 | int ret; |
Trond Myklebust | cf8d2c1 | 2009-06-22 15:09:13 -0400 | [diff] [blame] | 2711 | |
| 2712 | new_ns = kmalloc(sizeof(struct mnt_namespace), GFP_KERNEL); |
| 2713 | if (!new_ns) |
| 2714 | return ERR_PTR(-ENOMEM); |
Al Viro | 6344c43 | 2014-11-01 00:45:45 -0400 | [diff] [blame] | 2715 | ret = ns_alloc_inum(&new_ns->ns); |
Eric W. Biederman | 98f842e | 2011-06-15 10:21:48 -0700 | [diff] [blame] | 2716 | if (ret) { |
| 2717 | kfree(new_ns); |
| 2718 | return ERR_PTR(ret); |
| 2719 | } |
Al Viro | 33c4294 | 2014-11-01 02:32:53 -0400 | [diff] [blame] | 2720 | new_ns->ns.ops = &mntns_operations; |
Eric W. Biederman | 8823c07 | 2010-03-07 18:49:36 -0800 | [diff] [blame] | 2721 | new_ns->seq = atomic64_add_return(1, &mnt_ns_seq); |
Trond Myklebust | cf8d2c1 | 2009-06-22 15:09:13 -0400 | [diff] [blame] | 2722 | atomic_set(&new_ns->count, 1); |
| 2723 | new_ns->root = NULL; |
| 2724 | INIT_LIST_HEAD(&new_ns->list); |
| 2725 | init_waitqueue_head(&new_ns->poll); |
| 2726 | new_ns->event = 0; |
Eric W. Biederman | 771b137 | 2012-07-26 21:08:32 -0700 | [diff] [blame] | 2727 | new_ns->user_ns = get_user_ns(user_ns); |
Trond Myklebust | cf8d2c1 | 2009-06-22 15:09:13 -0400 | [diff] [blame] | 2728 | return new_ns; |
| 2729 | } |
| 2730 | |
Al Viro | 9559f68 | 2013-09-28 20:47:57 -0400 | [diff] [blame] | 2731 | struct mnt_namespace *copy_mnt_ns(unsigned long flags, struct mnt_namespace *ns, |
| 2732 | struct user_namespace *user_ns, struct fs_struct *new_fs) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2733 | { |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 2734 | struct mnt_namespace *new_ns; |
Al Viro | 7f2da1e | 2008-05-10 20:44:54 -0400 | [diff] [blame] | 2735 | struct vfsmount *rootmnt = NULL, *pwdmnt = NULL; |
Al Viro | 315fc83 | 2011-11-24 18:57:30 -0500 | [diff] [blame] | 2736 | struct mount *p, *q; |
Al Viro | 9559f68 | 2013-09-28 20:47:57 -0400 | [diff] [blame] | 2737 | struct mount *old; |
Al Viro | cb338d0 | 2011-11-24 20:55:08 -0500 | [diff] [blame] | 2738 | struct mount *new; |
Eric W. Biederman | 7a472ef | 2012-07-31 13:13:04 -0700 | [diff] [blame] | 2739 | int copy_flags; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2740 | |
Al Viro | 9559f68 | 2013-09-28 20:47:57 -0400 | [diff] [blame] | 2741 | BUG_ON(!ns); |
| 2742 | |
| 2743 | if (likely(!(flags & CLONE_NEWNS))) { |
| 2744 | get_mnt_ns(ns); |
| 2745 | return ns; |
| 2746 | } |
| 2747 | |
| 2748 | old = ns->root; |
| 2749 | |
Eric W. Biederman | 771b137 | 2012-07-26 21:08:32 -0700 | [diff] [blame] | 2750 | new_ns = alloc_mnt_ns(user_ns); |
Trond Myklebust | cf8d2c1 | 2009-06-22 15:09:13 -0400 | [diff] [blame] | 2751 | if (IS_ERR(new_ns)) |
| 2752 | return new_ns; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2753 | |
Al Viro | 97216be | 2013-03-16 15:12:40 -0400 | [diff] [blame] | 2754 | namespace_lock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2755 | /* First pass: copy the tree topology */ |
Eric W. Biederman | 4ce5d2b | 2013-03-30 01:35:18 -0700 | [diff] [blame] | 2756 | copy_flags = CL_COPY_UNBINDABLE | CL_EXPIRE; |
Al Viro | 9559f68 | 2013-09-28 20:47:57 -0400 | [diff] [blame] | 2757 | if (user_ns != ns->user_ns) |
Eric W. Biederman | 132c94e | 2013-03-22 04:08:05 -0700 | [diff] [blame] | 2758 | copy_flags |= CL_SHARED_TO_SLAVE | CL_UNPRIVILEGED; |
Eric W. Biederman | 7a472ef | 2012-07-31 13:13:04 -0700 | [diff] [blame] | 2759 | new = copy_tree(old, old->mnt.mnt_root, copy_flags); |
David Howells | be34d1a | 2012-06-25 12:55:18 +0100 | [diff] [blame] | 2760 | if (IS_ERR(new)) { |
Al Viro | 328e6d9 | 2013-03-16 14:49:45 -0400 | [diff] [blame] | 2761 | namespace_unlock(); |
Eric W. Biederman | 771b137 | 2012-07-26 21:08:32 -0700 | [diff] [blame] | 2762 | free_mnt_ns(new_ns); |
David Howells | be34d1a | 2012-06-25 12:55:18 +0100 | [diff] [blame] | 2763 | return ERR_CAST(new); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2764 | } |
Al Viro | be08d6d | 2011-12-06 13:32:36 -0500 | [diff] [blame] | 2765 | new_ns->root = new; |
Al Viro | 1a4eeaf | 2011-11-25 02:19:55 -0500 | [diff] [blame] | 2766 | list_add_tail(&new_ns->list, &new->mnt_list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2767 | |
| 2768 | /* |
| 2769 | * Second pass: switch the tsk->fs->* elements and mark new vfsmounts |
| 2770 | * as belonging to new namespace. We have already acquired a private |
| 2771 | * fs_struct, so tsk->fs->lock is not needed. |
| 2772 | */ |
Al Viro | 909b0a8 | 2011-11-25 03:06:56 -0500 | [diff] [blame] | 2773 | p = old; |
Al Viro | cb338d0 | 2011-11-24 20:55:08 -0500 | [diff] [blame] | 2774 | q = new; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2775 | while (p) { |
Al Viro | 143c8c9 | 2011-11-25 00:46:35 -0500 | [diff] [blame] | 2776 | q->mnt_ns = new_ns; |
Al Viro | 9559f68 | 2013-09-28 20:47:57 -0400 | [diff] [blame] | 2777 | if (new_fs) { |
| 2778 | if (&p->mnt == new_fs->root.mnt) { |
| 2779 | new_fs->root.mnt = mntget(&q->mnt); |
Al Viro | 315fc83 | 2011-11-24 18:57:30 -0500 | [diff] [blame] | 2780 | rootmnt = &p->mnt; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2781 | } |
Al Viro | 9559f68 | 2013-09-28 20:47:57 -0400 | [diff] [blame] | 2782 | if (&p->mnt == new_fs->pwd.mnt) { |
| 2783 | new_fs->pwd.mnt = mntget(&q->mnt); |
Al Viro | 315fc83 | 2011-11-24 18:57:30 -0500 | [diff] [blame] | 2784 | pwdmnt = &p->mnt; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2785 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2786 | } |
Al Viro | 909b0a8 | 2011-11-25 03:06:56 -0500 | [diff] [blame] | 2787 | p = next_mnt(p, old); |
| 2788 | q = next_mnt(q, new); |
Eric W. Biederman | 4ce5d2b | 2013-03-30 01:35:18 -0700 | [diff] [blame] | 2789 | if (!q) |
| 2790 | break; |
| 2791 | while (p->mnt.mnt_root != q->mnt.mnt_root) |
| 2792 | p = next_mnt(p, old); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2793 | } |
Al Viro | 328e6d9 | 2013-03-16 14:49:45 -0400 | [diff] [blame] | 2794 | namespace_unlock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2795 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2796 | if (rootmnt) |
Al Viro | f03c659 | 2011-01-14 22:30:21 -0500 | [diff] [blame] | 2797 | mntput(rootmnt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2798 | if (pwdmnt) |
Al Viro | f03c659 | 2011-01-14 22:30:21 -0500 | [diff] [blame] | 2799 | mntput(pwdmnt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2800 | |
JANAK DESAI | 741a295 | 2006-02-07 12:59:00 -0800 | [diff] [blame] | 2801 | return new_ns; |
| 2802 | } |
| 2803 | |
Trond Myklebust | cf8d2c1 | 2009-06-22 15:09:13 -0400 | [diff] [blame] | 2804 | /** |
| 2805 | * create_mnt_ns - creates a private namespace and adds a root filesystem |
| 2806 | * @mnt: pointer to the new root filesystem mountpoint |
| 2807 | */ |
Al Viro | 1a4eeaf | 2011-11-25 02:19:55 -0500 | [diff] [blame] | 2808 | static struct mnt_namespace *create_mnt_ns(struct vfsmount *m) |
Trond Myklebust | cf8d2c1 | 2009-06-22 15:09:13 -0400 | [diff] [blame] | 2809 | { |
Eric W. Biederman | 771b137 | 2012-07-26 21:08:32 -0700 | [diff] [blame] | 2810 | struct mnt_namespace *new_ns = alloc_mnt_ns(&init_user_ns); |
Trond Myklebust | cf8d2c1 | 2009-06-22 15:09:13 -0400 | [diff] [blame] | 2811 | if (!IS_ERR(new_ns)) { |
Al Viro | 1a4eeaf | 2011-11-25 02:19:55 -0500 | [diff] [blame] | 2812 | struct mount *mnt = real_mount(m); |
| 2813 | mnt->mnt_ns = new_ns; |
Al Viro | be08d6d | 2011-12-06 13:32:36 -0500 | [diff] [blame] | 2814 | new_ns->root = mnt; |
Al Viro | b1983cd | 2013-05-04 15:18:53 -0400 | [diff] [blame] | 2815 | list_add(&mnt->mnt_list, &new_ns->list); |
Al Viro | c133449 | 2011-11-16 16:12:14 -0500 | [diff] [blame] | 2816 | } else { |
Al Viro | 1a4eeaf | 2011-11-25 02:19:55 -0500 | [diff] [blame] | 2817 | mntput(m); |
Trond Myklebust | cf8d2c1 | 2009-06-22 15:09:13 -0400 | [diff] [blame] | 2818 | } |
| 2819 | return new_ns; |
| 2820 | } |
Trond Myklebust | cf8d2c1 | 2009-06-22 15:09:13 -0400 | [diff] [blame] | 2821 | |
Al Viro | ea441d1 | 2011-11-16 21:43:59 -0500 | [diff] [blame] | 2822 | struct dentry *mount_subtree(struct vfsmount *mnt, const char *name) |
| 2823 | { |
| 2824 | struct mnt_namespace *ns; |
Al Viro | d31da0f | 2011-11-22 12:31:21 -0500 | [diff] [blame] | 2825 | struct super_block *s; |
Al Viro | ea441d1 | 2011-11-16 21:43:59 -0500 | [diff] [blame] | 2826 | struct path path; |
| 2827 | int err; |
| 2828 | |
| 2829 | ns = create_mnt_ns(mnt); |
| 2830 | if (IS_ERR(ns)) |
| 2831 | return ERR_CAST(ns); |
| 2832 | |
| 2833 | err = vfs_path_lookup(mnt->mnt_root, mnt, |
| 2834 | name, LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT, &path); |
| 2835 | |
| 2836 | put_mnt_ns(ns); |
| 2837 | |
| 2838 | if (err) |
| 2839 | return ERR_PTR(err); |
| 2840 | |
| 2841 | /* trade a vfsmount reference for active sb one */ |
Al Viro | d31da0f | 2011-11-22 12:31:21 -0500 | [diff] [blame] | 2842 | s = path.mnt->mnt_sb; |
| 2843 | atomic_inc(&s->s_active); |
Al Viro | ea441d1 | 2011-11-16 21:43:59 -0500 | [diff] [blame] | 2844 | mntput(path.mnt); |
| 2845 | /* lock the sucker */ |
Al Viro | d31da0f | 2011-11-22 12:31:21 -0500 | [diff] [blame] | 2846 | down_write(&s->s_umount); |
Al Viro | ea441d1 | 2011-11-16 21:43:59 -0500 | [diff] [blame] | 2847 | /* ... and return the root of (sub)tree on it */ |
| 2848 | return path.dentry; |
| 2849 | } |
| 2850 | EXPORT_SYMBOL(mount_subtree); |
| 2851 | |
Heiko Carstens | bdc480e | 2009-01-14 14:14:12 +0100 | [diff] [blame] | 2852 | SYSCALL_DEFINE5(mount, char __user *, dev_name, char __user *, dir_name, |
| 2853 | char __user *, type, unsigned long, flags, void __user *, data) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2854 | { |
Vegard Nossum | eca6f53 | 2009-09-18 13:05:45 -0700 | [diff] [blame] | 2855 | int ret; |
| 2856 | char *kernel_type; |
Vegard Nossum | eca6f53 | 2009-09-18 13:05:45 -0700 | [diff] [blame] | 2857 | char *kernel_dev; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2858 | unsigned long data_page; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2859 | |
Tim Gardner | b8850d1 | 2014-08-28 11:26:03 -0600 | [diff] [blame] | 2860 | kernel_type = copy_mount_string(type); |
| 2861 | ret = PTR_ERR(kernel_type); |
| 2862 | if (IS_ERR(kernel_type)) |
Vegard Nossum | eca6f53 | 2009-09-18 13:05:45 -0700 | [diff] [blame] | 2863 | goto out_type; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2864 | |
Tim Gardner | b8850d1 | 2014-08-28 11:26:03 -0600 | [diff] [blame] | 2865 | kernel_dev = copy_mount_string(dev_name); |
| 2866 | ret = PTR_ERR(kernel_dev); |
| 2867 | if (IS_ERR(kernel_dev)) |
Vegard Nossum | eca6f53 | 2009-09-18 13:05:45 -0700 | [diff] [blame] | 2868 | goto out_dev; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2869 | |
Vegard Nossum | eca6f53 | 2009-09-18 13:05:45 -0700 | [diff] [blame] | 2870 | ret = copy_mount_options(data, &data_page); |
| 2871 | if (ret < 0) |
| 2872 | goto out_data; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2873 | |
Seunghun Lee | 5e6123f | 2014-09-14 22:15:10 +0900 | [diff] [blame] | 2874 | ret = do_mount(kernel_dev, dir_name, kernel_type, flags, |
Vegard Nossum | eca6f53 | 2009-09-18 13:05:45 -0700 | [diff] [blame] | 2875 | (void *) data_page); |
| 2876 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2877 | free_page(data_page); |
Vegard Nossum | eca6f53 | 2009-09-18 13:05:45 -0700 | [diff] [blame] | 2878 | out_data: |
| 2879 | kfree(kernel_dev); |
| 2880 | out_dev: |
Vegard Nossum | eca6f53 | 2009-09-18 13:05:45 -0700 | [diff] [blame] | 2881 | kfree(kernel_type); |
| 2882 | out_type: |
| 2883 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2884 | } |
| 2885 | |
| 2886 | /* |
Al Viro | afac7cb | 2011-11-23 19:34:49 -0500 | [diff] [blame] | 2887 | * Return true if path is reachable from root |
| 2888 | * |
Al Viro | 48a066e | 2013-09-29 22:06:07 -0400 | [diff] [blame] | 2889 | * namespace_sem or mount_lock is held |
Al Viro | afac7cb | 2011-11-23 19:34:49 -0500 | [diff] [blame] | 2890 | */ |
Al Viro | 643822b | 2011-11-24 22:00:28 -0500 | [diff] [blame] | 2891 | bool is_path_reachable(struct mount *mnt, struct dentry *dentry, |
Al Viro | afac7cb | 2011-11-23 19:34:49 -0500 | [diff] [blame] | 2892 | const struct path *root) |
| 2893 | { |
Al Viro | 643822b | 2011-11-24 22:00:28 -0500 | [diff] [blame] | 2894 | while (&mnt->mnt != root->mnt && mnt_has_parent(mnt)) { |
Al Viro | a73324d | 2011-11-24 22:25:07 -0500 | [diff] [blame] | 2895 | dentry = mnt->mnt_mountpoint; |
Al Viro | 0714a53 | 2011-11-24 22:19:58 -0500 | [diff] [blame] | 2896 | mnt = mnt->mnt_parent; |
Al Viro | afac7cb | 2011-11-23 19:34:49 -0500 | [diff] [blame] | 2897 | } |
Al Viro | 643822b | 2011-11-24 22:00:28 -0500 | [diff] [blame] | 2898 | return &mnt->mnt == root->mnt && is_subdir(dentry, root->dentry); |
Al Viro | afac7cb | 2011-11-23 19:34:49 -0500 | [diff] [blame] | 2899 | } |
| 2900 | |
| 2901 | int path_is_under(struct path *path1, struct path *path2) |
| 2902 | { |
| 2903 | int res; |
Al Viro | 48a066e | 2013-09-29 22:06:07 -0400 | [diff] [blame] | 2904 | read_seqlock_excl(&mount_lock); |
Al Viro | 643822b | 2011-11-24 22:00:28 -0500 | [diff] [blame] | 2905 | res = is_path_reachable(real_mount(path1->mnt), path1->dentry, path2); |
Al Viro | 48a066e | 2013-09-29 22:06:07 -0400 | [diff] [blame] | 2906 | read_sequnlock_excl(&mount_lock); |
Al Viro | afac7cb | 2011-11-23 19:34:49 -0500 | [diff] [blame] | 2907 | return res; |
| 2908 | } |
| 2909 | EXPORT_SYMBOL(path_is_under); |
| 2910 | |
| 2911 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2912 | * pivot_root Semantics: |
| 2913 | * Moves the root file system of the current process to the directory put_old, |
| 2914 | * makes new_root as the new root file system of the current process, and sets |
| 2915 | * root/cwd of all processes which had them on the current root to new_root. |
| 2916 | * |
| 2917 | * Restrictions: |
| 2918 | * The new_root and put_old must be directories, and must not be on the |
| 2919 | * same file system as the current process root. The put_old must be |
| 2920 | * underneath new_root, i.e. adding a non-zero number of /.. to the string |
| 2921 | * pointed to by put_old must yield the same directory as new_root. No other |
| 2922 | * file system may be mounted on put_old. After all, new_root is a mountpoint. |
| 2923 | * |
Neil Brown | 4a0d11f | 2006-01-08 01:03:18 -0800 | [diff] [blame] | 2924 | * Also, the current root cannot be on the 'rootfs' (initial ramfs) filesystem. |
| 2925 | * See Documentation/filesystems/ramfs-rootfs-initramfs.txt for alternatives |
| 2926 | * in this situation. |
| 2927 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2928 | * Notes: |
| 2929 | * - we don't move root/cwd if they are not at the root (reason: if something |
| 2930 | * cared enough to change them, it's probably wrong to force them elsewhere) |
| 2931 | * - it's okay to pick a root that isn't the root of a file system, e.g. |
| 2932 | * /nfs/my_root where /nfs is the mount point. It must be a mountpoint, |
| 2933 | * though, so you may need to say mount --bind /nfs/my_root /nfs/my_root |
| 2934 | * first. |
| 2935 | */ |
Heiko Carstens | 3480b25 | 2009-01-14 14:14:16 +0100 | [diff] [blame] | 2936 | SYSCALL_DEFINE2(pivot_root, const char __user *, new_root, |
| 2937 | const char __user *, put_old) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2938 | { |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 2939 | struct path new, old, parent_path, root_parent, root; |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 2940 | struct mount *new_mnt, *root_mnt, *old_mnt; |
| 2941 | struct mountpoint *old_mp, *root_mp; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2942 | int error; |
| 2943 | |
Al Viro | 9b40bc9 | 2013-02-22 22:45:42 -0500 | [diff] [blame] | 2944 | if (!may_mount()) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2945 | return -EPERM; |
| 2946 | |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 2947 | error = user_path_dir(new_root, &new); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2948 | if (error) |
| 2949 | goto out0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2950 | |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 2951 | error = user_path_dir(put_old, &old); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2952 | if (error) |
| 2953 | goto out1; |
| 2954 | |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 2955 | error = security_sb_pivotroot(&old, &new); |
Al Viro | b12cea9 | 2011-03-18 08:55:38 -0400 | [diff] [blame] | 2956 | if (error) |
| 2957 | goto out2; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2958 | |
Miklos Szeredi | f7ad3c6 | 2010-08-10 11:41:36 +0200 | [diff] [blame] | 2959 | get_fs_root(current->fs, &root); |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 2960 | old_mp = lock_mount(&old); |
| 2961 | error = PTR_ERR(old_mp); |
| 2962 | if (IS_ERR(old_mp)) |
Al Viro | b12cea9 | 2011-03-18 08:55:38 -0400 | [diff] [blame] | 2963 | goto out3; |
| 2964 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2965 | error = -EINVAL; |
Al Viro | 419148d | 2011-11-24 19:41:16 -0500 | [diff] [blame] | 2966 | new_mnt = real_mount(new.mnt); |
| 2967 | root_mnt = real_mount(root.mnt); |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 2968 | old_mnt = real_mount(old.mnt); |
| 2969 | if (IS_MNT_SHARED(old_mnt) || |
Al Viro | fc7be13 | 2011-11-25 01:05:37 -0500 | [diff] [blame] | 2970 | IS_MNT_SHARED(new_mnt->mnt_parent) || |
| 2971 | IS_MNT_SHARED(root_mnt->mnt_parent)) |
Al Viro | b12cea9 | 2011-03-18 08:55:38 -0400 | [diff] [blame] | 2972 | goto out4; |
Al Viro | 143c8c9 | 2011-11-25 00:46:35 -0500 | [diff] [blame] | 2973 | if (!check_mnt(root_mnt) || !check_mnt(new_mnt)) |
Al Viro | b12cea9 | 2011-03-18 08:55:38 -0400 | [diff] [blame] | 2974 | goto out4; |
Eric W. Biederman | 5ff9d8a | 2013-03-29 21:04:39 -0700 | [diff] [blame] | 2975 | if (new_mnt->mnt.mnt_flags & MNT_LOCKED) |
| 2976 | goto out4; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2977 | error = -ENOENT; |
Alexey Dobriyan | f3da392 | 2009-05-04 03:32:03 +0400 | [diff] [blame] | 2978 | if (d_unlinked(new.dentry)) |
Al Viro | b12cea9 | 2011-03-18 08:55:38 -0400 | [diff] [blame] | 2979 | goto out4; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2980 | error = -EBUSY; |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 2981 | if (new_mnt == root_mnt || old_mnt == root_mnt) |
Al Viro | b12cea9 | 2011-03-18 08:55:38 -0400 | [diff] [blame] | 2982 | goto out4; /* loop, on the same file system */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2983 | error = -EINVAL; |
Al Viro | 8c3ee42 | 2008-03-22 18:00:39 -0400 | [diff] [blame] | 2984 | if (root.mnt->mnt_root != root.dentry) |
Al Viro | b12cea9 | 2011-03-18 08:55:38 -0400 | [diff] [blame] | 2985 | goto out4; /* not a mountpoint */ |
Al Viro | 676da58 | 2011-11-24 21:47:05 -0500 | [diff] [blame] | 2986 | if (!mnt_has_parent(root_mnt)) |
Al Viro | b12cea9 | 2011-03-18 08:55:38 -0400 | [diff] [blame] | 2987 | goto out4; /* not attached */ |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 2988 | root_mp = root_mnt->mnt_mp; |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 2989 | if (new.mnt->mnt_root != new.dentry) |
Al Viro | b12cea9 | 2011-03-18 08:55:38 -0400 | [diff] [blame] | 2990 | goto out4; /* not a mountpoint */ |
Al Viro | 676da58 | 2011-11-24 21:47:05 -0500 | [diff] [blame] | 2991 | if (!mnt_has_parent(new_mnt)) |
Al Viro | b12cea9 | 2011-03-18 08:55:38 -0400 | [diff] [blame] | 2992 | goto out4; /* not attached */ |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 2993 | /* make sure we can reach put_old from new_root */ |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 2994 | if (!is_path_reachable(old_mnt, old.dentry, &new)) |
Al Viro | b12cea9 | 2011-03-18 08:55:38 -0400 | [diff] [blame] | 2995 | goto out4; |
Eric W. Biederman | 0d08260 | 2014-10-08 10:42:27 -0700 | [diff] [blame] | 2996 | /* make certain new is below the root */ |
| 2997 | if (!is_path_reachable(new_mnt, new.dentry, &root)) |
| 2998 | goto out4; |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 2999 | root_mp->m_count++; /* pin it so it won't go away */ |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 3000 | lock_mount_hash(); |
Al Viro | 419148d | 2011-11-24 19:41:16 -0500 | [diff] [blame] | 3001 | detach_mnt(new_mnt, &parent_path); |
| 3002 | detach_mnt(root_mnt, &root_parent); |
Eric W. Biederman | 5ff9d8a | 2013-03-29 21:04:39 -0700 | [diff] [blame] | 3003 | if (root_mnt->mnt.mnt_flags & MNT_LOCKED) { |
| 3004 | new_mnt->mnt.mnt_flags |= MNT_LOCKED; |
| 3005 | root_mnt->mnt.mnt_flags &= ~MNT_LOCKED; |
| 3006 | } |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 3007 | /* mount old root on put_old */ |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 3008 | attach_mnt(root_mnt, old_mnt, old_mp); |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 3009 | /* mount new_root on / */ |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 3010 | attach_mnt(new_mnt, real_mount(root_parent.mnt), root_mp); |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 3011 | touch_mnt_namespace(current->nsproxy->mnt_ns); |
Eric W. Biederman | 4fed655 | 2014-10-08 10:42:57 -0700 | [diff] [blame] | 3012 | /* A moved mount should not expire automatically */ |
| 3013 | list_del_init(&new_mnt->mnt_expire); |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 3014 | unlock_mount_hash(); |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 3015 | chroot_fs_refs(&root, &new); |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 3016 | put_mountpoint(root_mp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3017 | error = 0; |
Al Viro | b12cea9 | 2011-03-18 08:55:38 -0400 | [diff] [blame] | 3018 | out4: |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 3019 | unlock_mount(old_mp); |
Al Viro | b12cea9 | 2011-03-18 08:55:38 -0400 | [diff] [blame] | 3020 | if (!error) { |
| 3021 | path_put(&root_parent); |
| 3022 | path_put(&parent_path); |
| 3023 | } |
| 3024 | out3: |
Al Viro | 8c3ee42 | 2008-03-22 18:00:39 -0400 | [diff] [blame] | 3025 | path_put(&root); |
Al Viro | b12cea9 | 2011-03-18 08:55:38 -0400 | [diff] [blame] | 3026 | out2: |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 3027 | path_put(&old); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3028 | out1: |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 3029 | path_put(&new); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3030 | out0: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3031 | return error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3032 | } |
| 3033 | |
| 3034 | static void __init init_mount_tree(void) |
| 3035 | { |
| 3036 | struct vfsmount *mnt; |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 3037 | struct mnt_namespace *ns; |
Jan Blunck | ac748a0 | 2008-02-14 19:34:39 -0800 | [diff] [blame] | 3038 | struct path root; |
Eric W. Biederman | 0c55cfc | 2012-07-26 21:42:03 -0700 | [diff] [blame] | 3039 | struct file_system_type *type; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3040 | |
Eric W. Biederman | 0c55cfc | 2012-07-26 21:42:03 -0700 | [diff] [blame] | 3041 | type = get_fs_type("rootfs"); |
| 3042 | if (!type) |
| 3043 | panic("Can't find rootfs type"); |
| 3044 | mnt = vfs_kern_mount(type, 0, "rootfs", NULL); |
| 3045 | put_filesystem(type); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3046 | if (IS_ERR(mnt)) |
| 3047 | panic("Can't create rootfs"); |
Nick Piggin | b3e19d9 | 2011-01-07 17:50:11 +1100 | [diff] [blame] | 3048 | |
Trond Myklebust | 3b22edc | 2009-06-23 17:29:49 -0400 | [diff] [blame] | 3049 | ns = create_mnt_ns(mnt); |
| 3050 | if (IS_ERR(ns)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3051 | panic("Can't allocate initial namespace"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3052 | |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 3053 | init_task.nsproxy->mnt_ns = ns; |
| 3054 | get_mnt_ns(ns); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3055 | |
Al Viro | be08d6d | 2011-12-06 13:32:36 -0500 | [diff] [blame] | 3056 | root.mnt = mnt; |
| 3057 | root.dentry = mnt->mnt_root; |
Eric W. Biederman | da362b0 | 2014-10-07 12:19:53 -0700 | [diff] [blame] | 3058 | mnt->mnt_flags |= MNT_LOCKED; |
Jan Blunck | ac748a0 | 2008-02-14 19:34:39 -0800 | [diff] [blame] | 3059 | |
| 3060 | set_fs_pwd(current->fs, &root); |
| 3061 | set_fs_root(current->fs, &root); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3062 | } |
| 3063 | |
Denis Cheng | 74bf17c | 2007-10-16 23:26:30 -0700 | [diff] [blame] | 3064 | void __init mnt_init(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3065 | { |
Eric Dumazet | 13f14b4 | 2008-02-06 01:37:57 -0800 | [diff] [blame] | 3066 | unsigned u; |
Randy Dunlap | 15a67dd | 2006-09-29 01:58:57 -0700 | [diff] [blame] | 3067 | int err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3068 | |
Al Viro | 7d6fec4 | 2011-11-23 12:14:10 -0500 | [diff] [blame] | 3069 | mnt_cache = kmem_cache_create("mnt_cache", sizeof(struct mount), |
Paul Mundt | 20c2df8 | 2007-07-20 10:11:58 +0900 | [diff] [blame] | 3070 | 0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3071 | |
Al Viro | 0818bf2 | 2014-02-28 13:46:44 -0500 | [diff] [blame] | 3072 | mount_hashtable = alloc_large_system_hash("Mount-cache", |
Al Viro | 38129a1 | 2014-03-20 21:10:51 -0400 | [diff] [blame] | 3073 | sizeof(struct hlist_head), |
Al Viro | 0818bf2 | 2014-02-28 13:46:44 -0500 | [diff] [blame] | 3074 | mhash_entries, 19, |
| 3075 | 0, |
| 3076 | &m_hash_shift, &m_hash_mask, 0, 0); |
| 3077 | mountpoint_hashtable = alloc_large_system_hash("Mountpoint-cache", |
| 3078 | sizeof(struct hlist_head), |
| 3079 | mphash_entries, 19, |
| 3080 | 0, |
| 3081 | &mp_hash_shift, &mp_hash_mask, 0, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3082 | |
Al Viro | 84d1719 | 2013-03-15 10:53:28 -0400 | [diff] [blame] | 3083 | if (!mount_hashtable || !mountpoint_hashtable) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3084 | panic("Failed to allocate mount hash table\n"); |
| 3085 | |
Al Viro | 0818bf2 | 2014-02-28 13:46:44 -0500 | [diff] [blame] | 3086 | for (u = 0; u <= m_hash_mask; u++) |
Al Viro | 38129a1 | 2014-03-20 21:10:51 -0400 | [diff] [blame] | 3087 | INIT_HLIST_HEAD(&mount_hashtable[u]); |
Al Viro | 0818bf2 | 2014-02-28 13:46:44 -0500 | [diff] [blame] | 3088 | for (u = 0; u <= mp_hash_mask; u++) |
| 3089 | INIT_HLIST_HEAD(&mountpoint_hashtable[u]); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3090 | |
Tejun Heo | 4b93dc9 | 2013-11-28 14:54:43 -0500 | [diff] [blame] | 3091 | kernfs_init(); |
| 3092 | |
Randy Dunlap | 15a67dd | 2006-09-29 01:58:57 -0700 | [diff] [blame] | 3093 | err = sysfs_init(); |
| 3094 | if (err) |
| 3095 | printk(KERN_WARNING "%s: sysfs_init error: %d\n", |
Harvey Harrison | 8e24eea | 2008-04-30 00:55:09 -0700 | [diff] [blame] | 3096 | __func__, err); |
Greg Kroah-Hartman | 00d2666 | 2007-10-29 14:17:23 -0600 | [diff] [blame] | 3097 | fs_kobj = kobject_create_and_add("fs", NULL); |
| 3098 | if (!fs_kobj) |
Harvey Harrison | 8e24eea | 2008-04-30 00:55:09 -0700 | [diff] [blame] | 3099 | printk(KERN_WARNING "%s: kobj create error\n", __func__); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3100 | init_rootfs(); |
| 3101 | init_mount_tree(); |
| 3102 | } |
| 3103 | |
Trond Myklebust | 616511d | 2009-06-22 15:09:13 -0400 | [diff] [blame] | 3104 | void put_mnt_ns(struct mnt_namespace *ns) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3105 | { |
Al Viro | d498b25 | 2010-02-05 02:21:06 -0500 | [diff] [blame] | 3106 | if (!atomic_dec_and_test(&ns->count)) |
Trond Myklebust | 616511d | 2009-06-22 15:09:13 -0400 | [diff] [blame] | 3107 | return; |
Al Viro | 7b00ed6 | 2013-09-16 21:19:20 -0400 | [diff] [blame] | 3108 | drop_collected_mounts(&ns->root->mnt); |
Eric W. Biederman | 771b137 | 2012-07-26 21:08:32 -0700 | [diff] [blame] | 3109 | free_mnt_ns(ns); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3110 | } |
Al Viro | 9d412a4 | 2011-03-17 22:08:28 -0400 | [diff] [blame] | 3111 | |
| 3112 | struct vfsmount *kern_mount_data(struct file_system_type *type, void *data) |
| 3113 | { |
Tim Chen | 423e0ab | 2011-07-19 09:32:38 -0700 | [diff] [blame] | 3114 | struct vfsmount *mnt; |
| 3115 | mnt = vfs_kern_mount(type, MS_KERNMOUNT, type->name, data); |
| 3116 | if (!IS_ERR(mnt)) { |
| 3117 | /* |
| 3118 | * it is a longterm mount, don't release mnt until |
| 3119 | * we unmount before file sys is unregistered |
| 3120 | */ |
Al Viro | f7a99c5 | 2012-06-09 00:59:08 -0400 | [diff] [blame] | 3121 | real_mount(mnt)->mnt_ns = MNT_NS_INTERNAL; |
Tim Chen | 423e0ab | 2011-07-19 09:32:38 -0700 | [diff] [blame] | 3122 | } |
| 3123 | return mnt; |
Al Viro | 9d412a4 | 2011-03-17 22:08:28 -0400 | [diff] [blame] | 3124 | } |
| 3125 | EXPORT_SYMBOL_GPL(kern_mount_data); |
Tim Chen | 423e0ab | 2011-07-19 09:32:38 -0700 | [diff] [blame] | 3126 | |
| 3127 | void kern_unmount(struct vfsmount *mnt) |
| 3128 | { |
| 3129 | /* release long term mount so mount point can be released */ |
| 3130 | if (!IS_ERR_OR_NULL(mnt)) { |
Al Viro | f7a99c5 | 2012-06-09 00:59:08 -0400 | [diff] [blame] | 3131 | real_mount(mnt)->mnt_ns = NULL; |
Al Viro | 48a066e | 2013-09-29 22:06:07 -0400 | [diff] [blame] | 3132 | synchronize_rcu(); /* yecchhh... */ |
Tim Chen | 423e0ab | 2011-07-19 09:32:38 -0700 | [diff] [blame] | 3133 | mntput(mnt); |
| 3134 | } |
| 3135 | } |
| 3136 | EXPORT_SYMBOL(kern_unmount); |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 3137 | |
| 3138 | bool our_mnt(struct vfsmount *mnt) |
| 3139 | { |
Al Viro | 143c8c9 | 2011-11-25 00:46:35 -0500 | [diff] [blame] | 3140 | return check_mnt(real_mount(mnt)); |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 3141 | } |
Eric W. Biederman | 8823c07 | 2010-03-07 18:49:36 -0800 | [diff] [blame] | 3142 | |
Eric W. Biederman | 3151527 | 2013-03-15 01:45:51 -0700 | [diff] [blame] | 3143 | bool current_chrooted(void) |
| 3144 | { |
| 3145 | /* Does the current process have a non-standard root */ |
| 3146 | struct path ns_root; |
| 3147 | struct path fs_root; |
| 3148 | bool chrooted; |
| 3149 | |
| 3150 | /* Find the namespace root */ |
| 3151 | ns_root.mnt = ¤t->nsproxy->mnt_ns->root->mnt; |
| 3152 | ns_root.dentry = ns_root.mnt->mnt_root; |
| 3153 | path_get(&ns_root); |
| 3154 | while (d_mountpoint(ns_root.dentry) && follow_down_one(&ns_root)) |
| 3155 | ; |
| 3156 | |
| 3157 | get_fs_root(current->fs, &fs_root); |
| 3158 | |
| 3159 | chrooted = !path_equal(&fs_root, &ns_root); |
| 3160 | |
| 3161 | path_put(&fs_root); |
| 3162 | path_put(&ns_root); |
| 3163 | |
| 3164 | return chrooted; |
| 3165 | } |
| 3166 | |
Eric W. Biederman | e51db73 | 2013-03-30 19:57:41 -0700 | [diff] [blame] | 3167 | bool fs_fully_visible(struct file_system_type *type) |
Eric W. Biederman | 87a8ebd | 2013-03-24 14:28:27 -0700 | [diff] [blame] | 3168 | { |
| 3169 | struct mnt_namespace *ns = current->nsproxy->mnt_ns; |
| 3170 | struct mount *mnt; |
Eric W. Biederman | e51db73 | 2013-03-30 19:57:41 -0700 | [diff] [blame] | 3171 | bool visible = false; |
Eric W. Biederman | 87a8ebd | 2013-03-24 14:28:27 -0700 | [diff] [blame] | 3172 | |
Eric W. Biederman | e51db73 | 2013-03-30 19:57:41 -0700 | [diff] [blame] | 3173 | if (unlikely(!ns)) |
| 3174 | return false; |
| 3175 | |
Al Viro | 44bb438 | 2013-09-16 21:37:36 -0400 | [diff] [blame] | 3176 | down_read(&namespace_sem); |
Eric W. Biederman | 87a8ebd | 2013-03-24 14:28:27 -0700 | [diff] [blame] | 3177 | list_for_each_entry(mnt, &ns->list, mnt_list) { |
Eric W. Biederman | e51db73 | 2013-03-30 19:57:41 -0700 | [diff] [blame] | 3178 | struct mount *child; |
| 3179 | if (mnt->mnt.mnt_sb->s_type != type) |
| 3180 | continue; |
| 3181 | |
| 3182 | /* This mount is not fully visible if there are any child mounts |
| 3183 | * that cover anything except for empty directories. |
| 3184 | */ |
| 3185 | list_for_each_entry(child, &mnt->mnt_mounts, mnt_child) { |
| 3186 | struct inode *inode = child->mnt_mountpoint->d_inode; |
| 3187 | if (!S_ISDIR(inode->i_mode)) |
| 3188 | goto next; |
Eric W. Biederman | 41301ae | 2013-11-14 21:22:25 -0800 | [diff] [blame] | 3189 | if (inode->i_nlink > 2) |
Eric W. Biederman | e51db73 | 2013-03-30 19:57:41 -0700 | [diff] [blame] | 3190 | goto next; |
Eric W. Biederman | 87a8ebd | 2013-03-24 14:28:27 -0700 | [diff] [blame] | 3191 | } |
Eric W. Biederman | e51db73 | 2013-03-30 19:57:41 -0700 | [diff] [blame] | 3192 | visible = true; |
| 3193 | goto found; |
| 3194 | next: ; |
Eric W. Biederman | 87a8ebd | 2013-03-24 14:28:27 -0700 | [diff] [blame] | 3195 | } |
Eric W. Biederman | e51db73 | 2013-03-30 19:57:41 -0700 | [diff] [blame] | 3196 | found: |
Al Viro | 44bb438 | 2013-09-16 21:37:36 -0400 | [diff] [blame] | 3197 | up_read(&namespace_sem); |
Eric W. Biederman | e51db73 | 2013-03-30 19:57:41 -0700 | [diff] [blame] | 3198 | return visible; |
Eric W. Biederman | 87a8ebd | 2013-03-24 14:28:27 -0700 | [diff] [blame] | 3199 | } |
| 3200 | |
Al Viro | 6496452 | 2014-11-01 00:37:32 -0400 | [diff] [blame] | 3201 | static struct ns_common *mntns_get(struct task_struct *task) |
Eric W. Biederman | 8823c07 | 2010-03-07 18:49:36 -0800 | [diff] [blame] | 3202 | { |
Al Viro | 58be2825 | 2014-11-01 00:00:23 -0400 | [diff] [blame] | 3203 | struct ns_common *ns = NULL; |
Eric W. Biederman | 8823c07 | 2010-03-07 18:49:36 -0800 | [diff] [blame] | 3204 | struct nsproxy *nsproxy; |
| 3205 | |
Eric W. Biederman | 728dba3 | 2014-02-03 19:13:49 -0800 | [diff] [blame] | 3206 | task_lock(task); |
| 3207 | nsproxy = task->nsproxy; |
Eric W. Biederman | 8823c07 | 2010-03-07 18:49:36 -0800 | [diff] [blame] | 3208 | if (nsproxy) { |
Al Viro | 58be2825 | 2014-11-01 00:00:23 -0400 | [diff] [blame] | 3209 | ns = &nsproxy->mnt_ns->ns; |
| 3210 | get_mnt_ns(to_mnt_ns(ns)); |
Eric W. Biederman | 8823c07 | 2010-03-07 18:49:36 -0800 | [diff] [blame] | 3211 | } |
Eric W. Biederman | 728dba3 | 2014-02-03 19:13:49 -0800 | [diff] [blame] | 3212 | task_unlock(task); |
Eric W. Biederman | 8823c07 | 2010-03-07 18:49:36 -0800 | [diff] [blame] | 3213 | |
| 3214 | return ns; |
| 3215 | } |
| 3216 | |
Al Viro | 6496452 | 2014-11-01 00:37:32 -0400 | [diff] [blame] | 3217 | static void mntns_put(struct ns_common *ns) |
Eric W. Biederman | 8823c07 | 2010-03-07 18:49:36 -0800 | [diff] [blame] | 3218 | { |
Al Viro | 58be2825 | 2014-11-01 00:00:23 -0400 | [diff] [blame] | 3219 | put_mnt_ns(to_mnt_ns(ns)); |
Eric W. Biederman | 8823c07 | 2010-03-07 18:49:36 -0800 | [diff] [blame] | 3220 | } |
| 3221 | |
Al Viro | 6496452 | 2014-11-01 00:37:32 -0400 | [diff] [blame] | 3222 | static int mntns_install(struct nsproxy *nsproxy, struct ns_common *ns) |
Eric W. Biederman | 8823c07 | 2010-03-07 18:49:36 -0800 | [diff] [blame] | 3223 | { |
| 3224 | struct fs_struct *fs = current->fs; |
Al Viro | 58be2825 | 2014-11-01 00:00:23 -0400 | [diff] [blame] | 3225 | struct mnt_namespace *mnt_ns = to_mnt_ns(ns); |
Eric W. Biederman | 8823c07 | 2010-03-07 18:49:36 -0800 | [diff] [blame] | 3226 | struct path root; |
| 3227 | |
Eric W. Biederman | 0c55cfc | 2012-07-26 21:42:03 -0700 | [diff] [blame] | 3228 | if (!ns_capable(mnt_ns->user_ns, CAP_SYS_ADMIN) || |
Eric W. Biederman | c7b96ac | 2013-03-20 12:49:49 -0700 | [diff] [blame] | 3229 | !ns_capable(current_user_ns(), CAP_SYS_CHROOT) || |
| 3230 | !ns_capable(current_user_ns(), CAP_SYS_ADMIN)) |
Zhao Hongjiang | ae11e0f | 2012-09-13 16:38:03 +0800 | [diff] [blame] | 3231 | return -EPERM; |
Eric W. Biederman | 8823c07 | 2010-03-07 18:49:36 -0800 | [diff] [blame] | 3232 | |
| 3233 | if (fs->users != 1) |
| 3234 | return -EINVAL; |
| 3235 | |
| 3236 | get_mnt_ns(mnt_ns); |
| 3237 | put_mnt_ns(nsproxy->mnt_ns); |
| 3238 | nsproxy->mnt_ns = mnt_ns; |
| 3239 | |
| 3240 | /* Find the root */ |
| 3241 | root.mnt = &mnt_ns->root->mnt; |
| 3242 | root.dentry = mnt_ns->root->mnt.mnt_root; |
| 3243 | path_get(&root); |
| 3244 | while(d_mountpoint(root.dentry) && follow_down_one(&root)) |
| 3245 | ; |
| 3246 | |
| 3247 | /* Update the pwd and root */ |
| 3248 | set_fs_pwd(fs, &root); |
| 3249 | set_fs_root(fs, &root); |
| 3250 | |
| 3251 | path_put(&root); |
| 3252 | return 0; |
| 3253 | } |
| 3254 | |
| 3255 | const struct proc_ns_operations mntns_operations = { |
| 3256 | .name = "mnt", |
| 3257 | .type = CLONE_NEWNS, |
| 3258 | .get = mntns_get, |
| 3259 | .put = mntns_put, |
| 3260 | .install = mntns_install, |
| 3261 | }; |