![Ian Kent](/assets/img/avatar_default.png)
For tree mount maps, a call to chdir or chroot, to a directory above the moint point directories at a certain time during the expire results in the expire incorrectly thinking the tree is not busy. This patch adds a check to see if the filesystem above the tree mount points is busy and also locks the filesystem during the tree mount expire to prevent the race. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
205 lines
5.6 KiB
C
205 lines
5.6 KiB
C
/* -*- c -*- ------------------------------------------------------------- *
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*
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* linux/fs/autofs/autofs_i.h
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*
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* Copyright 1997-1998 Transmeta Corporation - All Rights Reserved
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*
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* This file is part of the Linux kernel and is made available under
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* the terms of the GNU General Public License, version 2, or at your
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* option, any later version, incorporated herein by reference.
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*
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* ----------------------------------------------------------------------- */
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/* Internal header file for autofs */
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#include <linux/auto_fs4.h>
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#include <linux/list.h>
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/* This is the range of ioctl() numbers we claim as ours */
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#define AUTOFS_IOC_FIRST AUTOFS_IOC_READY
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#define AUTOFS_IOC_COUNT 32
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/time.h>
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#include <linux/string.h>
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#include <linux/wait.h>
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#include <linux/sched.h>
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#include <linux/mount.h>
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#include <linux/namei.h>
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#include <asm/current.h>
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#include <asm/uaccess.h>
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/* #define DEBUG */
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#ifdef DEBUG
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#define DPRINTK(fmt,args...) do { printk(KERN_DEBUG "pid %d: %s: " fmt "\n" , current->pid , __FUNCTION__ , ##args); } while(0)
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#else
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#define DPRINTK(fmt,args...) do {} while(0)
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#endif
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#define AUTOFS_SUPER_MAGIC 0x0187
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/*
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* If the daemon returns a negative response (AUTOFS_IOC_FAIL) then the
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* kernel will keep the negative response cached for up to the time given
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* here, although the time can be shorter if the kernel throws the dcache
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* entry away. This probably should be settable from user space.
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*/
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#define AUTOFS_NEGATIVE_TIMEOUT (60*HZ) /* 1 minute */
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/* Unified info structure. This is pointed to by both the dentry and
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inode structures. Each file in the filesystem has an instance of this
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structure. It holds a reference to the dentry, so dentries are never
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flushed while the file exists. All name lookups are dealt with at the
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dentry level, although the filesystem can interfere in the validation
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process. Readdir is implemented by traversing the dentry lists. */
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struct autofs_info {
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struct dentry *dentry;
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struct inode *inode;
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int flags;
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struct autofs_sb_info *sbi;
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unsigned long last_used;
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mode_t mode;
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size_t size;
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void (*free)(struct autofs_info *);
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union {
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const char *symlink;
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} u;
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};
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#define AUTOFS_INF_EXPIRING (1<<0) /* dentry is in the process of expiring */
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struct autofs_wait_queue {
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wait_queue_head_t queue;
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struct autofs_wait_queue *next;
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autofs_wqt_t wait_queue_token;
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/* We use the following to see what we are waiting for */
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int hash;
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int len;
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char *name;
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/* This is for status reporting upon return */
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int status;
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atomic_t notified;
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atomic_t wait_ctr;
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};
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#define AUTOFS_SBI_MAGIC 0x6d4a556d
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struct autofs_sb_info {
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u32 magic;
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struct file *pipe;
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pid_t oz_pgrp;
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int catatonic;
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int version;
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int sub_version;
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unsigned long exp_timeout;
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int reghost_enabled;
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int needs_reghost;
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struct super_block *sb;
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struct semaphore wq_sem;
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spinlock_t fs_lock;
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struct autofs_wait_queue *queues; /* Wait queue pointer */
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};
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static inline struct autofs_sb_info *autofs4_sbi(struct super_block *sb)
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{
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return (struct autofs_sb_info *)(sb->s_fs_info);
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}
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static inline struct autofs_info *autofs4_dentry_ino(struct dentry *dentry)
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{
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return (struct autofs_info *)(dentry->d_fsdata);
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}
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/* 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
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filesystem without "magic".) */
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static inline int autofs4_oz_mode(struct autofs_sb_info *sbi) {
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return sbi->catatonic || process_group(current) == sbi->oz_pgrp;
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}
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/* Does a dentry have some pending activity? */
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static inline int autofs4_ispending(struct dentry *dentry)
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{
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struct autofs_info *inf = autofs4_dentry_ino(dentry);
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int pending = 0;
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if (dentry->d_flags & DCACHE_AUTOFS_PENDING)
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return 1;
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if (inf) {
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spin_lock(&inf->sbi->fs_lock);
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pending = inf->flags & AUTOFS_INF_EXPIRING;
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spin_unlock(&inf->sbi->fs_lock);
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}
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return pending;
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}
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static inline void autofs4_copy_atime(struct file *src, struct file *dst)
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{
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dst->f_dentry->d_inode->i_atime = src->f_dentry->d_inode->i_atime;
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return;
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}
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struct inode *autofs4_get_inode(struct super_block *, struct autofs_info *);
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void autofs4_free_ino(struct autofs_info *);
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/* Expiration */
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int is_autofs4_dentry(struct dentry *);
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int autofs4_expire_run(struct super_block *, struct vfsmount *,
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struct autofs_sb_info *,
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struct autofs_packet_expire __user *);
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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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/* Operations structures */
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extern struct inode_operations autofs4_symlink_inode_operations;
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extern struct inode_operations autofs4_dir_inode_operations;
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extern struct inode_operations autofs4_root_inode_operations;
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extern struct file_operations autofs4_dir_operations;
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extern struct file_operations autofs4_root_operations;
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/* Initializing function */
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int autofs4_fill_super(struct super_block *, void *, int);
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struct autofs_info *autofs4_init_ino(struct autofs_info *, struct autofs_sb_info *sbi, mode_t mode);
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/* Queue management functions */
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enum autofs_notify
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{
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NFY_NONE,
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NFY_MOUNT,
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NFY_EXPIRE
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};
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int autofs4_wait(struct autofs_sb_info *,struct dentry *, 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 int simple_positive(struct dentry *dentry)
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{
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return dentry->d_inode && !d_unhashed(dentry);
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}
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static inline int simple_empty_nolock(struct dentry *dentry)
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{
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struct dentry *child;
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int ret = 0;
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list_for_each_entry(child, &dentry->d_subdirs, d_child)
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if (simple_positive(child))
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goto out;
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ret = 1;
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out:
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return ret;
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}
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