582 lines
15 KiB
C
582 lines
15 KiB
C
/* -*- linux-c -*- --------------------------------------------------------- *
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*
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* linux/fs/autofs/root.c
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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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#include <linux/capability.h>
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#include <linux/errno.h>
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#include <linux/stat.h>
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#include <linux/slab.h>
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#include <linux/param.h>
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#include <linux/time.h>
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#include <linux/smp_lock.h>
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#include "autofs_i.h"
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static int autofs_root_readdir(struct file *,void *,filldir_t);
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static struct dentry *autofs_root_lookup(struct inode *,struct dentry *, struct nameidata *);
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static int autofs_root_symlink(struct inode *,struct dentry *,const char *);
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static int autofs_root_unlink(struct inode *,struct dentry *);
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static int autofs_root_rmdir(struct inode *,struct dentry *);
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static int autofs_root_mkdir(struct inode *,struct dentry *,int);
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static int autofs_root_ioctl(struct inode *, struct file *,unsigned int,unsigned long);
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const struct file_operations autofs_root_operations = {
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.read = generic_read_dir,
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.readdir = autofs_root_readdir,
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.ioctl = autofs_root_ioctl,
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};
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const struct inode_operations autofs_root_inode_operations = {
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.lookup = autofs_root_lookup,
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.unlink = autofs_root_unlink,
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.symlink = autofs_root_symlink,
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.mkdir = autofs_root_mkdir,
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.rmdir = autofs_root_rmdir,
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};
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static int autofs_root_readdir(struct file *filp, void *dirent, filldir_t filldir)
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{
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struct autofs_dir_ent *ent = NULL;
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struct autofs_dirhash *dirhash;
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struct autofs_sb_info *sbi;
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struct inode * inode = filp->f_path.dentry->d_inode;
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off_t onr, nr;
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lock_kernel();
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sbi = autofs_sbi(inode->i_sb);
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dirhash = &sbi->dirhash;
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nr = filp->f_pos;
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switch(nr)
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{
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case 0:
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if (filldir(dirent, ".", 1, nr, inode->i_ino, DT_DIR) < 0)
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goto out;
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filp->f_pos = ++nr;
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/* fall through */
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case 1:
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if (filldir(dirent, "..", 2, nr, inode->i_ino, DT_DIR) < 0)
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goto out;
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filp->f_pos = ++nr;
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/* fall through */
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default:
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while (onr = nr, ent = autofs_hash_enum(dirhash,&nr,ent)) {
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if (!ent->dentry || d_mountpoint(ent->dentry)) {
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if (filldir(dirent,ent->name,ent->len,onr,ent->ino,DT_UNKNOWN) < 0)
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goto out;
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filp->f_pos = nr;
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}
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}
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break;
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}
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out:
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unlock_kernel();
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return 0;
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}
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static int try_to_fill_dentry(struct dentry *dentry, struct super_block *sb, struct autofs_sb_info *sbi)
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{
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struct inode * inode;
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struct autofs_dir_ent *ent;
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int status = 0;
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if (!(ent = autofs_hash_lookup(&sbi->dirhash, &dentry->d_name))) {
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do {
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if (status && dentry->d_inode) {
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if (status != -ENOENT)
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printk("autofs warning: lookup failure on positive dentry, status = %d, name = %s\n", status, dentry->d_name.name);
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return 0; /* Try to get the kernel to invalidate this dentry */
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}
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/* Turn this into a real negative dentry? */
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if (status == -ENOENT) {
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dentry->d_time = jiffies + AUTOFS_NEGATIVE_TIMEOUT;
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dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
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return 1;
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} else if (status) {
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/* Return a negative dentry, but leave it "pending" */
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return 1;
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}
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status = autofs_wait(sbi, &dentry->d_name);
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} while (!(ent = autofs_hash_lookup(&sbi->dirhash, &dentry->d_name)));
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}
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/* Abuse this field as a pointer to the directory entry, used to
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find the expire list pointers */
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dentry->d_time = (unsigned long) ent;
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if (!dentry->d_inode) {
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inode = autofs_iget(sb, ent->ino);
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if (IS_ERR(inode)) {
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/* Failed, but leave pending for next time */
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return 1;
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}
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dentry->d_inode = inode;
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}
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/* If this is a directory that isn't a mount point, bitch at the
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daemon and fix it in user space */
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if (S_ISDIR(dentry->d_inode->i_mode) && !d_mountpoint(dentry)) {
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return !autofs_wait(sbi, &dentry->d_name);
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}
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/* We don't update the usages for the autofs daemon itself, this
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is necessary for recursive autofs mounts */
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if (!autofs_oz_mode(sbi)) {
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autofs_update_usage(&sbi->dirhash,ent);
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}
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dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
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return 1;
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}
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/*
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* Revalidate is called on every cache lookup. Some of those
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* cache lookups may actually happen while the dentry is not
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* yet completely filled in, and revalidate has to delay such
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* lookups..
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*/
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static int autofs_revalidate(struct dentry * dentry, struct nameidata *nd)
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{
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struct inode * dir;
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struct autofs_sb_info *sbi;
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struct autofs_dir_ent *ent;
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int res;
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lock_kernel();
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dir = dentry->d_parent->d_inode;
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sbi = autofs_sbi(dir->i_sb);
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/* Pending dentry */
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if (dentry->d_flags & DCACHE_AUTOFS_PENDING) {
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if (autofs_oz_mode(sbi))
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res = 1;
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else
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res = try_to_fill_dentry(dentry, dir->i_sb, sbi);
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unlock_kernel();
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return res;
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}
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/* Negative dentry.. invalidate if "old" */
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if (!dentry->d_inode) {
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unlock_kernel();
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return (dentry->d_time - jiffies <= AUTOFS_NEGATIVE_TIMEOUT);
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}
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/* Check for a non-mountpoint directory */
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if (S_ISDIR(dentry->d_inode->i_mode) && !d_mountpoint(dentry)) {
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if (autofs_oz_mode(sbi))
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res = 1;
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else
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res = try_to_fill_dentry(dentry, dir->i_sb, sbi);
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unlock_kernel();
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return res;
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}
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/* Update the usage list */
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if (!autofs_oz_mode(sbi)) {
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ent = (struct autofs_dir_ent *) dentry->d_time;
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if (ent)
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autofs_update_usage(&sbi->dirhash,ent);
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}
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unlock_kernel();
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return 1;
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}
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static const struct dentry_operations autofs_dentry_operations = {
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.d_revalidate = autofs_revalidate,
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};
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static struct dentry *autofs_root_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
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{
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struct autofs_sb_info *sbi;
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int oz_mode;
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DPRINTK(("autofs_root_lookup: name = "));
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lock_kernel();
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autofs_say(dentry->d_name.name,dentry->d_name.len);
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if (dentry->d_name.len > NAME_MAX) {
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unlock_kernel();
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return ERR_PTR(-ENAMETOOLONG);/* File name too long to exist */
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}
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sbi = autofs_sbi(dir->i_sb);
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oz_mode = autofs_oz_mode(sbi);
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DPRINTK(("autofs_lookup: pid = %u, pgrp = %u, catatonic = %d, "
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"oz_mode = %d\n", task_pid_nr(current),
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task_pgrp_nr(current), sbi->catatonic,
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oz_mode));
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/*
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* Mark the dentry incomplete, but add it. This is needed so
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* that the VFS layer knows about the dentry, and we can count
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* on catching any lookups through the revalidate.
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*
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* Let all the hard work be done by the revalidate function that
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* needs to be able to do this anyway..
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*
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* We need to do this before we release the directory semaphore.
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*/
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dentry->d_op = &autofs_dentry_operations;
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dentry->d_flags |= DCACHE_AUTOFS_PENDING;
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d_add(dentry, NULL);
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mutex_unlock(&dir->i_mutex);
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autofs_revalidate(dentry, nd);
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mutex_lock(&dir->i_mutex);
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/*
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* If we are still pending, check if we had to handle
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* a signal. If so we can force a restart..
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*/
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if (dentry->d_flags & DCACHE_AUTOFS_PENDING) {
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/* See if we were interrupted */
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if (signal_pending(current)) {
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sigset_t *sigset = ¤t->pending.signal;
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if (sigismember (sigset, SIGKILL) ||
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sigismember (sigset, SIGQUIT) ||
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sigismember (sigset, SIGINT)) {
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unlock_kernel();
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return ERR_PTR(-ERESTARTNOINTR);
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}
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}
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}
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unlock_kernel();
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/*
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* If this dentry is unhashed, then we shouldn't honour this
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* lookup even if the dentry is positive. Returning ENOENT here
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* doesn't do the right thing for all system calls, but it should
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* be OK for the operations we permit from an autofs.
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*/
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if (dentry->d_inode && d_unhashed(dentry))
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return ERR_PTR(-ENOENT);
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return NULL;
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}
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static int autofs_root_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
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{
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struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb);
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struct autofs_dirhash *dh = &sbi->dirhash;
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struct autofs_dir_ent *ent;
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unsigned int n;
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int slsize;
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struct autofs_symlink *sl;
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struct inode *inode;
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DPRINTK(("autofs_root_symlink: %s <- ", symname));
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autofs_say(dentry->d_name.name,dentry->d_name.len);
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lock_kernel();
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if (!autofs_oz_mode(sbi)) {
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unlock_kernel();
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return -EACCES;
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}
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if (autofs_hash_lookup(dh, &dentry->d_name)) {
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unlock_kernel();
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return -EEXIST;
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}
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n = find_first_zero_bit(sbi->symlink_bitmap,AUTOFS_MAX_SYMLINKS);
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if (n >= AUTOFS_MAX_SYMLINKS) {
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unlock_kernel();
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return -ENOSPC;
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}
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set_bit(n,sbi->symlink_bitmap);
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sl = &sbi->symlink[n];
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sl->len = strlen(symname);
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sl->data = kmalloc(slsize = sl->len+1, GFP_KERNEL);
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if (!sl->data) {
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clear_bit(n,sbi->symlink_bitmap);
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unlock_kernel();
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return -ENOSPC;
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}
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ent = kmalloc(sizeof(struct autofs_dir_ent), GFP_KERNEL);
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if (!ent) {
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kfree(sl->data);
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clear_bit(n,sbi->symlink_bitmap);
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unlock_kernel();
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return -ENOSPC;
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}
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ent->name = kmalloc(dentry->d_name.len+1, GFP_KERNEL);
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if (!ent->name) {
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kfree(sl->data);
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kfree(ent);
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clear_bit(n,sbi->symlink_bitmap);
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unlock_kernel();
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return -ENOSPC;
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}
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memcpy(sl->data,symname,slsize);
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sl->mtime = get_seconds();
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ent->ino = AUTOFS_FIRST_SYMLINK + n;
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ent->hash = dentry->d_name.hash;
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memcpy(ent->name, dentry->d_name.name, 1+(ent->len = dentry->d_name.len));
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ent->dentry = NULL; /* We don't keep the dentry for symlinks */
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autofs_hash_insert(dh,ent);
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inode = autofs_iget(dir->i_sb, ent->ino);
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if (IS_ERR(inode))
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return PTR_ERR(inode);
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d_instantiate(dentry, inode);
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unlock_kernel();
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return 0;
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}
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/*
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* NOTE!
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*
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* Normal filesystems would do a "d_delete()" to tell the VFS dcache
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* that the file no longer exists. However, doing that means that the
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* VFS layer can turn the dentry into a negative dentry, which we
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* obviously do not want (we're dropping the entry not because it
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* doesn't exist, but because it has timed out).
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*
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* Also see autofs_root_rmdir()..
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*/
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static int autofs_root_unlink(struct inode *dir, struct dentry *dentry)
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{
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struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb);
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struct autofs_dirhash *dh = &sbi->dirhash;
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struct autofs_dir_ent *ent;
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unsigned int n;
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/* This allows root to remove symlinks */
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lock_kernel();
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if (!autofs_oz_mode(sbi) && !capable(CAP_SYS_ADMIN)) {
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unlock_kernel();
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return -EACCES;
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}
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ent = autofs_hash_lookup(dh, &dentry->d_name);
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if (!ent) {
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unlock_kernel();
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return -ENOENT;
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}
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n = ent->ino - AUTOFS_FIRST_SYMLINK;
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if (n >= AUTOFS_MAX_SYMLINKS) {
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unlock_kernel();
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return -EISDIR; /* It's a directory, dummy */
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}
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if (!test_bit(n,sbi->symlink_bitmap)) {
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unlock_kernel();
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return -EINVAL; /* Nonexistent symlink? Shouldn't happen */
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}
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dentry->d_time = (unsigned long)(struct autofs_dirhash *)NULL;
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autofs_hash_delete(ent);
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clear_bit(n,sbi->symlink_bitmap);
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kfree(sbi->symlink[n].data);
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d_drop(dentry);
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unlock_kernel();
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return 0;
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}
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static int autofs_root_rmdir(struct inode *dir, struct dentry *dentry)
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{
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struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb);
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struct autofs_dirhash *dh = &sbi->dirhash;
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struct autofs_dir_ent *ent;
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lock_kernel();
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if (!autofs_oz_mode(sbi)) {
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unlock_kernel();
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return -EACCES;
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}
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ent = autofs_hash_lookup(dh, &dentry->d_name);
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if (!ent) {
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unlock_kernel();
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return -ENOENT;
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}
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if ((unsigned int)ent->ino < AUTOFS_FIRST_DIR_INO) {
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unlock_kernel();
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return -ENOTDIR; /* Not a directory */
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}
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if (ent->dentry != dentry) {
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printk("autofs_rmdir: odentry != dentry for entry %s\n", dentry->d_name.name);
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}
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dentry->d_time = (unsigned long)(struct autofs_dir_ent *)NULL;
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autofs_hash_delete(ent);
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drop_nlink(dir);
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d_drop(dentry);
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unlock_kernel();
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return 0;
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}
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static int autofs_root_mkdir(struct inode *dir, struct dentry *dentry, int mode)
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{
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struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb);
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struct autofs_dirhash *dh = &sbi->dirhash;
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struct autofs_dir_ent *ent;
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struct inode *inode;
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ino_t ino;
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lock_kernel();
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if (!autofs_oz_mode(sbi)) {
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unlock_kernel();
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return -EACCES;
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}
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ent = autofs_hash_lookup(dh, &dentry->d_name);
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if (ent) {
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unlock_kernel();
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return -EEXIST;
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}
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if (sbi->next_dir_ino < AUTOFS_FIRST_DIR_INO) {
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printk("autofs: Out of inode numbers -- what the heck did you do??\n");
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unlock_kernel();
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return -ENOSPC;
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}
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ino = sbi->next_dir_ino++;
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ent = kmalloc(sizeof(struct autofs_dir_ent), GFP_KERNEL);
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if (!ent) {
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unlock_kernel();
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return -ENOSPC;
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}
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ent->name = kmalloc(dentry->d_name.len+1, GFP_KERNEL);
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if (!ent->name) {
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kfree(ent);
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unlock_kernel();
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return -ENOSPC;
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}
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ent->hash = dentry->d_name.hash;
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memcpy(ent->name, dentry->d_name.name, 1+(ent->len = dentry->d_name.len));
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ent->ino = ino;
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ent->dentry = dentry;
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autofs_hash_insert(dh,ent);
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inc_nlink(dir);
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inode = autofs_iget(dir->i_sb, ino);
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if (IS_ERR(inode)) {
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drop_nlink(dir);
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return PTR_ERR(inode);
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}
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|
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d_instantiate(dentry, inode);
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unlock_kernel();
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return 0;
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}
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|
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/* Get/set timeout ioctl() operation */
|
|
static inline int autofs_get_set_timeout(struct autofs_sb_info *sbi,
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unsigned long __user *p)
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{
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unsigned long ntimeout;
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|
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if (get_user(ntimeout, p) ||
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put_user(sbi->exp_timeout / HZ, p))
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return -EFAULT;
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|
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if (ntimeout > ULONG_MAX/HZ)
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sbi->exp_timeout = 0;
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else
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sbi->exp_timeout = ntimeout * HZ;
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|
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return 0;
|
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}
|
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|
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/* Return protocol version */
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static inline int autofs_get_protover(int __user *p)
|
|
{
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|
return put_user(AUTOFS_PROTO_VERSION, p);
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|
}
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|
|
|
/* Perform an expiry operation */
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|
static inline int autofs_expire_run(struct super_block *sb,
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struct autofs_sb_info *sbi,
|
|
struct vfsmount *mnt,
|
|
struct autofs_packet_expire __user *pkt_p)
|
|
{
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|
struct autofs_dir_ent *ent;
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|
struct autofs_packet_expire pkt;
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|
|
|
memset(&pkt,0,sizeof pkt);
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|
|
|
pkt.hdr.proto_version = AUTOFS_PROTO_VERSION;
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pkt.hdr.type = autofs_ptype_expire;
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|
|
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if (!sbi->exp_timeout || !(ent = autofs_expire(sb,sbi,mnt)))
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return -EAGAIN;
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|
|
|
pkt.len = ent->len;
|
|
memcpy(pkt.name, ent->name, pkt.len);
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|
pkt.name[pkt.len] = '\0';
|
|
|
|
if (copy_to_user(pkt_p, &pkt, sizeof(struct autofs_packet_expire)))
|
|
return -EFAULT;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* ioctl()'s on the root directory is the chief method for the daemon to
|
|
* generate kernel reactions
|
|
*/
|
|
static int autofs_root_ioctl(struct inode *inode, struct file *filp,
|
|
unsigned int cmd, unsigned long arg)
|
|
{
|
|
struct autofs_sb_info *sbi = autofs_sbi(inode->i_sb);
|
|
void __user *argp = (void __user *)arg;
|
|
|
|
DPRINTK(("autofs_ioctl: cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u\n",cmd,arg,sbi,task_pgrp_nr(current)));
|
|
|
|
if (_IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) ||
|
|
_IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT)
|
|
return -ENOTTY;
|
|
|
|
if (!autofs_oz_mode(sbi) && !capable(CAP_SYS_ADMIN))
|
|
return -EPERM;
|
|
|
|
switch(cmd) {
|
|
case AUTOFS_IOC_READY: /* Wait queue: go ahead and retry */
|
|
return autofs_wait_release(sbi,(autofs_wqt_t)arg,0);
|
|
case AUTOFS_IOC_FAIL: /* Wait queue: fail with ENOENT */
|
|
return autofs_wait_release(sbi,(autofs_wqt_t)arg,-ENOENT);
|
|
case AUTOFS_IOC_CATATONIC: /* Enter catatonic mode (daemon shutdown) */
|
|
autofs_catatonic_mode(sbi);
|
|
return 0;
|
|
case AUTOFS_IOC_PROTOVER: /* Get protocol version */
|
|
return autofs_get_protover(argp);
|
|
case AUTOFS_IOC_SETTIMEOUT:
|
|
return autofs_get_set_timeout(sbi, argp);
|
|
case AUTOFS_IOC_EXPIRE:
|
|
return autofs_expire_run(inode->i_sb, sbi, filp->f_path.mnt,
|
|
argp);
|
|
default:
|
|
return -ENOSYS;
|
|
}
|
|
}
|