autofs_i.h 7.6 KB
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/*
 *  Copyright 1997-1998 Transmeta Corporation - All Rights Reserved
 *  Copyright 2005-2006 Ian Kent <raven@themaw.net>
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 *
 * This file is part of the Linux kernel and is made available under
 * the terms of the GNU General Public License, version 2, or at your
 * option, any later version, incorporated herein by reference.
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 */
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/* Internal header file for autofs */

#include <linux/auto_fs4.h>
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#include <linux/auto_dev-ioctl.h>
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#include <linux/mutex.h>
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#include <linux/spinlock.h>
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#include <linux/list.h>
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#include <linux/completion.h>
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/* This is the range of ioctl() numbers we claim as ours */
#define AUTOFS_IOC_FIRST     AUTOFS_IOC_READY
#define AUTOFS_IOC_COUNT     32

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#define AUTOFS_DEV_IOCTL_IOC_FIRST	(AUTOFS_DEV_IOCTL_VERSION)
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#define AUTOFS_DEV_IOCTL_IOC_COUNT \
	(AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD - AUTOFS_DEV_IOCTL_VERSION_CMD)
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#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/time.h>
#include <linux/string.h>
#include <linux/wait.h>
#include <linux/sched.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <asm/current.h>
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#include <linux/uaccess.h>
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#ifdef pr_fmt
#undef pr_fmt
#endif
#define pr_fmt(fmt) KBUILD_MODNAME ":pid:%d:%s: " fmt, current->pid, __func__
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/*
 * Unified info structure.  This is pointed to by both the dentry and
 * inode structures.  Each file in the filesystem has an instance of this
 * structure.  It holds a reference to the dentry, so dentries are never
 * flushed while the file exists.  All name lookups are dealt with at the
 * dentry level, although the filesystem can interfere in the validation
 * process.  Readdir is implemented by traversing the dentry lists.
 */
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struct autofs_info {
	struct dentry	*dentry;
	struct inode	*inode;

	int		flags;

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	struct completion expire_complete;

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	struct list_head active;
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	int active_count;

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	struct list_head expiring;
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	struct autofs_sb_info *sbi;
	unsigned long last_used;
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	atomic_t count;
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	kuid_t uid;
	kgid_t gid;
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};

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#define AUTOFS_INF_EXPIRING	(1<<0) /* dentry in the process of expiring */
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#define AUTOFS_INF_WANT_EXPIRE	(1<<1) /* the dentry is being considered
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					* for expiry, so RCU_walk is
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					* not permitted.  If it progresses to
					* actual expiry attempt, the flag is
					* not cleared when EXPIRING is set -
					* in that case it gets cleared only
					* when it comes to clearing EXPIRING.
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					*/
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#define AUTOFS_INF_PENDING	(1<<2) /* dentry pending mount */
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struct autofs_wait_queue {
	wait_queue_head_t queue;
	struct autofs_wait_queue *next;
	autofs_wqt_t wait_queue_token;
	/* We use the following to see what we are waiting for */
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	struct qstr name;
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	u32 dev;
	u64 ino;
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	kuid_t uid;
	kgid_t gid;
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	pid_t pid;
	pid_t tgid;
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	/* This is for status reporting upon return */
	int status;
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	unsigned int wait_ctr;
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};

#define AUTOFS_SBI_MAGIC 0x6d4a556d

struct autofs_sb_info {
	u32 magic;
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	int pipefd;
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	struct file *pipe;
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	struct pid *oz_pgrp;
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	int catatonic;
	int version;
	int sub_version;
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	int min_proto;
	int max_proto;
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	unsigned long exp_timeout;
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	unsigned int type;
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	struct super_block *sb;
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	struct mutex wq_mutex;
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	struct mutex pipe_mutex;
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	spinlock_t fs_lock;
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	struct autofs_wait_queue *queues; /* Wait queue pointer */
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	spinlock_t lookup_lock;
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	struct list_head active_list;
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	struct list_head expiring_list;
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	struct rcu_head rcu;
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};

static inline struct autofs_sb_info *autofs4_sbi(struct super_block *sb)
{
	return (struct autofs_sb_info *)(sb->s_fs_info);
}

static inline struct autofs_info *autofs4_dentry_ino(struct dentry *dentry)
{
	return (struct autofs_info *)(dentry->d_fsdata);
}

/* autofs4_oz_mode(): do we see the man behind the curtain?  (The
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 * processes which do manipulations for us in user space sees the raw
 * filesystem without "magic".)
 */
static inline int autofs4_oz_mode(struct autofs_sb_info *sbi)
{
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	return sbi->catatonic || task_pgrp(current) == sbi->oz_pgrp;
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}

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struct inode *autofs4_get_inode(struct super_block *, umode_t);
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void autofs4_free_ino(struct autofs_info *);

/* Expiration */
int is_autofs4_dentry(struct dentry *);
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int autofs4_expire_wait(const struct path *path, int rcu_walk);
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int autofs4_expire_run(struct super_block *, struct vfsmount *,
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		       struct autofs_sb_info *,
		       struct autofs_packet_expire __user *);
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int autofs4_do_expire_multi(struct super_block *sb, struct vfsmount *mnt,
			    struct autofs_sb_info *sbi, int when);
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int autofs4_expire_multi(struct super_block *, struct vfsmount *,
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			 struct autofs_sb_info *, int __user *);
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struct dentry *autofs4_expire_direct(struct super_block *sb,
				     struct vfsmount *mnt,
				     struct autofs_sb_info *sbi, int how);
struct dentry *autofs4_expire_indirect(struct super_block *sb,
				       struct vfsmount *mnt,
				       struct autofs_sb_info *sbi, int how);

/* Device node initialization */

int autofs_dev_ioctl_init(void);
void autofs_dev_ioctl_exit(void);
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/* Operations structures */

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extern const struct inode_operations autofs4_symlink_inode_operations;
extern const struct inode_operations autofs4_dir_inode_operations;
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extern const struct file_operations autofs4_dir_operations;
extern const struct file_operations autofs4_root_operations;
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extern const struct dentry_operations autofs4_dentry_operations;
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/* VFS automount flags management functions */
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static inline void __managed_dentry_set_managed(struct dentry *dentry)
{
	dentry->d_flags |= (DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
}

static inline void managed_dentry_set_managed(struct dentry *dentry)
{
	spin_lock(&dentry->d_lock);
	__managed_dentry_set_managed(dentry);
	spin_unlock(&dentry->d_lock);
}

static inline void __managed_dentry_clear_managed(struct dentry *dentry)
{
	dentry->d_flags &= ~(DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
}

static inline void managed_dentry_clear_managed(struct dentry *dentry)
{
	spin_lock(&dentry->d_lock);
	__managed_dentry_clear_managed(dentry);
	spin_unlock(&dentry->d_lock);
}

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/* Initializing function */

int autofs4_fill_super(struct super_block *, void *, int);
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struct autofs_info *autofs4_new_ino(struct autofs_sb_info *);
void autofs4_clean_ino(struct autofs_info *);
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static inline int autofs_prepare_pipe(struct file *pipe)
{
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	if (!(pipe->f_mode & FMODE_CAN_WRITE))
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		return -EINVAL;
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	if (!S_ISFIFO(file_inode(pipe)->i_mode))
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		return -EINVAL;
	/* We want a packet pipe */
	pipe->f_flags |= O_DIRECT;
	return 0;
}

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/* Queue management functions */

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int autofs4_wait(struct autofs_sb_info *,
		 const struct path *, enum autofs_notify);
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int autofs4_wait_release(struct autofs_sb_info *, autofs_wqt_t, int);
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void autofs4_catatonic_mode(struct autofs_sb_info *);

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static inline u32 autofs4_get_dev(struct autofs_sb_info *sbi)
{
	return new_encode_dev(sbi->sb->s_dev);
}

static inline u64 autofs4_get_ino(struct autofs_sb_info *sbi)
{
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	return d_inode(sbi->sb->s_root)->i_ino;
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}

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static inline void __autofs4_add_expiring(struct dentry *dentry)
{
	struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
	struct autofs_info *ino = autofs4_dentry_ino(dentry);
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	if (ino) {
		if (list_empty(&ino->expiring))
			list_add(&ino->expiring, &sbi->expiring_list);
	}
}

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static inline void autofs4_add_expiring(struct dentry *dentry)
{
	struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
	struct autofs_info *ino = autofs4_dentry_ino(dentry);
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	if (ino) {
		spin_lock(&sbi->lookup_lock);
		if (list_empty(&ino->expiring))
			list_add(&ino->expiring, &sbi->expiring_list);
		spin_unlock(&sbi->lookup_lock);
	}
}

static inline void autofs4_del_expiring(struct dentry *dentry)
{
	struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
	struct autofs_info *ino = autofs4_dentry_ino(dentry);
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	if (ino) {
		spin_lock(&sbi->lookup_lock);
		if (!list_empty(&ino->expiring))
			list_del_init(&ino->expiring);
		spin_unlock(&sbi->lookup_lock);
	}
}

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void autofs4_kill_sb(struct super_block *);