kernel-ark/include/linux/mnt_namespace.h
Ram Pai 2d4d4864ac [patch 6/7] vfs: mountinfo: add /proc/<pid>/mountinfo
[mszeredi@suse.cz] rewrite and split big patch into managable chunks

/proc/mounts in its current form lacks important information:

 - propagation state
 - root of mount for bind mounts
 - the st_dev value used within the filesystem
 - identifier for each mount and it's parent

It also suffers from the following problems:

 - not easily extendable
 - ambiguity of mountpoints within a chrooted environment
 - doesn't distinguish between filesystem dependent and independent options
 - doesn't distinguish between per mount and per super block options

This patch introduces /proc/<pid>/mountinfo which attempts to address
all these deficiencies.

Code shared between /proc/<pid>/mounts and /proc/<pid>/mountinfo is
extracted into separate functions.

Thanks to Al Viro for the help in getting the design right.

Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-04-23 00:05:03 -04:00

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1.1 KiB
C

#ifndef _NAMESPACE_H_
#define _NAMESPACE_H_
#ifdef __KERNEL__
#include <linux/mount.h>
#include <linux/sched.h>
#include <linux/nsproxy.h>
#include <linux/seq_file.h>
struct mnt_namespace {
atomic_t count;
struct vfsmount * root;
struct list_head list;
wait_queue_head_t poll;
int event;
};
struct proc_mounts {
struct seq_file m; /* must be the first element */
struct mnt_namespace *ns;
struct path root;
int event;
};
extern struct mnt_namespace *copy_mnt_ns(unsigned long, struct mnt_namespace *,
struct fs_struct *);
extern void __put_mnt_ns(struct mnt_namespace *ns);
static inline void put_mnt_ns(struct mnt_namespace *ns)
{
if (atomic_dec_and_lock(&ns->count, &vfsmount_lock))
/* releases vfsmount_lock */
__put_mnt_ns(ns);
}
static inline void exit_mnt_ns(struct task_struct *p)
{
struct mnt_namespace *ns = p->nsproxy->mnt_ns;
if (ns)
put_mnt_ns(ns);
}
static inline void get_mnt_ns(struct mnt_namespace *ns)
{
atomic_inc(&ns->count);
}
extern const struct seq_operations mounts_op;
extern const struct seq_operations mountinfo_op;
extern const struct seq_operations mountstats_op;
#endif
#endif