[patch 5/7] vfs: mountinfo: allow using process root
Allow /proc/<pid>/mountinfo to use the root of <pid> to calculate
mountpoints.
- move definition of 'struct proc_mounts' to <linux/mnt_namespace.h>
- add the process's namespace and root to this structure
- pass a pointer to 'struct proc_mounts' into seq_operations
In addition the following cleanups are made:
- use a common open function for /proc/<pid>/{mounts,mountstat}
- surround namespace.c part of these proc files with #ifdef CONFIG_PROC_FS
- make the seq_operations structures const
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Miklos Szeredi
Al Viro
parent
719f5d7f0b
commit
a1a2c409b6
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@ -724,20 +724,21 @@ void save_mount_options(struct super_block *sb, char *options)
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}
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EXPORT_SYMBOL(save_mount_options);
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#ifdef CONFIG_PROC_FS
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/* iterator */
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static void *m_start(struct seq_file *m, loff_t *pos)
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{
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struct mnt_namespace *n = m->private;
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struct proc_mounts *p = m->private;
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down_read(&namespace_sem);
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return seq_list_start(&n->list, *pos);
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return seq_list_start(&p->ns->list, *pos);
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}
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static void *m_next(struct seq_file *m, void *v, loff_t *pos)
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{
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struct mnt_namespace *n = m->private;
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struct proc_mounts *p = m->private;
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return seq_list_next(v, &n->list, pos);
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return seq_list_next(v, &p->ns->list, pos);
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}
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static void m_stop(struct seq_file *m, void *v)
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@ -794,7 +795,7 @@ static int show_vfsmnt(struct seq_file *m, void *v)
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return err;
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}
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struct seq_operations mounts_op = {
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const struct seq_operations mounts_op = {
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.start = m_start,
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.next = m_next,
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.stop = m_stop,
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@ -833,12 +834,13 @@ static int show_vfsstat(struct seq_file *m, void *v)
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return err;
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}
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struct seq_operations mountstats_op = {
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const struct seq_operations mountstats_op = {
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.start = m_start,
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.next = m_next,
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.stop = m_stop,
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.show = show_vfsstat,
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};
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#endif /* CONFIG_PROC_FS */
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/**
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* may_umount_tree - check if a mount tree is busy
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108
fs/proc/base.c
108
fs/proc/base.c
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@ -502,17 +502,14 @@ static const struct inode_operations proc_def_inode_operations = {
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.setattr = proc_setattr,
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};
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extern const struct seq_operations mounts_op;
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struct proc_mounts {
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struct seq_file m;
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int event;
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};
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static int mounts_open(struct inode *inode, struct file *file)
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static int mounts_open_common(struct inode *inode, struct file *file,
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const struct seq_operations *op)
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{
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struct task_struct *task = get_proc_task(inode);
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struct nsproxy *nsp;
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struct mnt_namespace *ns = NULL;
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struct fs_struct *fs = NULL;
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struct path root;
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struct proc_mounts *p;
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int ret = -EINVAL;
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@ -525,40 +522,61 @@ static int mounts_open(struct inode *inode, struct file *file)
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get_mnt_ns(ns);
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}
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rcu_read_unlock();
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if (ns)
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fs = get_fs_struct(task);
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put_task_struct(task);
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}
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if (ns) {
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ret = -ENOMEM;
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p = kmalloc(sizeof(struct proc_mounts), GFP_KERNEL);
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if (p) {
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file->private_data = &p->m;
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ret = seq_open(file, &mounts_op);
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if (!ret) {
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p->m.private = ns;
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p->event = ns->event;
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return 0;
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}
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kfree(p);
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}
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put_mnt_ns(ns);
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}
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if (!ns)
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goto err;
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if (!fs)
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goto err_put_ns;
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read_lock(&fs->lock);
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root = fs->root;
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path_get(&root);
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read_unlock(&fs->lock);
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put_fs_struct(fs);
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ret = -ENOMEM;
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p = kmalloc(sizeof(struct proc_mounts), GFP_KERNEL);
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if (!p)
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goto err_put_path;
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file->private_data = &p->m;
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ret = seq_open(file, op);
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if (ret)
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goto err_free;
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p->m.private = p;
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p->ns = ns;
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p->root = root;
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p->event = ns->event;
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return 0;
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err_free:
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kfree(p);
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err_put_path:
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path_put(&root);
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err_put_ns:
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put_mnt_ns(ns);
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err:
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return ret;
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}
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static int mounts_release(struct inode *inode, struct file *file)
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{
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struct seq_file *m = file->private_data;
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struct mnt_namespace *ns = m->private;
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put_mnt_ns(ns);
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struct proc_mounts *p = file->private_data;
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path_put(&p->root);
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put_mnt_ns(p->ns);
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return seq_release(inode, file);
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}
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static unsigned mounts_poll(struct file *file, poll_table *wait)
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{
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struct proc_mounts *p = file->private_data;
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struct mnt_namespace *ns = p->m.private;
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struct mnt_namespace *ns = p->ns;
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unsigned res = 0;
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poll_wait(file, &ns->poll, wait);
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@ -573,6 +591,11 @@ static unsigned mounts_poll(struct file *file, poll_table *wait)
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return res;
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}
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static int mounts_open(struct inode *inode, struct file *file)
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{
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return mounts_open_common(inode, file, &mounts_op);
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}
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static const struct file_operations proc_mounts_operations = {
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.open = mounts_open,
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.read = seq_read,
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@ -581,38 +604,9 @@ static const struct file_operations proc_mounts_operations = {
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.poll = mounts_poll,
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};
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extern const struct seq_operations mountstats_op;
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static int mountstats_open(struct inode *inode, struct file *file)
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{
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int ret = seq_open(file, &mountstats_op);
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if (!ret) {
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struct seq_file *m = file->private_data;
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struct nsproxy *nsp;
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struct mnt_namespace *mnt_ns = NULL;
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struct task_struct *task = get_proc_task(inode);
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if (task) {
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rcu_read_lock();
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nsp = task_nsproxy(task);
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if (nsp) {
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mnt_ns = nsp->mnt_ns;
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if (mnt_ns)
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get_mnt_ns(mnt_ns);
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}
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rcu_read_unlock();
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put_task_struct(task);
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}
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if (mnt_ns)
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m->private = mnt_ns;
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else {
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seq_release(inode, file);
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ret = -EINVAL;
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}
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}
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return ret;
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return mounts_open_common(inode, file, &mountstats_op);
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}
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static const struct file_operations proc_mountstats_operations = {
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@ -5,6 +5,7 @@
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#include <linux/mount.h>
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#include <linux/sched.h>
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#include <linux/nsproxy.h>
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#include <linux/seq_file.h>
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struct mnt_namespace {
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atomic_t count;
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@ -14,6 +15,13 @@ struct mnt_namespace {
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int event;
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};
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struct proc_mounts {
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struct seq_file m; /* must be the first element */
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struct mnt_namespace *ns;
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struct path root;
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int event;
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};
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extern struct mnt_namespace *copy_mnt_ns(unsigned long, struct mnt_namespace *,
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struct fs_struct *);
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extern void __put_mnt_ns(struct mnt_namespace *ns);
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@ -37,5 +45,8 @@ static inline void get_mnt_ns(struct mnt_namespace *ns)
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atomic_inc(&ns->count);
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}
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extern const struct seq_operations mounts_op;
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extern const struct seq_operations mountstats_op;
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#endif
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#endif
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