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![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>
325 lines
6.8 KiB
C
325 lines
6.8 KiB
C
/* -*- c -*- --------------------------------------------------------------- *
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*
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* linux/fs/autofs/inode.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/kernel.h>
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#include <linux/slab.h>
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#include <linux/file.h>
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#include <linux/pagemap.h>
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#include <linux/parser.h>
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#include <linux/bitops.h>
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#include "autofs_i.h"
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#include <linux/module.h>
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static void ino_lnkfree(struct autofs_info *ino)
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{
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if (ino->u.symlink) {
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kfree(ino->u.symlink);
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ino->u.symlink = NULL;
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}
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}
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struct autofs_info *autofs4_init_ino(struct autofs_info *ino,
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struct autofs_sb_info *sbi, mode_t mode)
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{
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int reinit = 1;
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if (ino == NULL) {
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reinit = 0;
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ino = kmalloc(sizeof(*ino), GFP_KERNEL);
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}
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if (ino == NULL)
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return NULL;
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ino->flags = 0;
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ino->mode = mode;
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ino->inode = NULL;
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ino->dentry = NULL;
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ino->size = 0;
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ino->last_used = jiffies;
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ino->sbi = sbi;
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if (reinit && ino->free)
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(ino->free)(ino);
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memset(&ino->u, 0, sizeof(ino->u));
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ino->free = NULL;
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if (S_ISLNK(mode))
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ino->free = ino_lnkfree;
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return ino;
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}
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void autofs4_free_ino(struct autofs_info *ino)
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{
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if (ino->dentry) {
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ino->dentry->d_fsdata = NULL;
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if (ino->dentry->d_inode)
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dput(ino->dentry);
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ino->dentry = NULL;
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}
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if (ino->free)
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(ino->free)(ino);
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kfree(ino);
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}
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static void autofs4_put_super(struct super_block *sb)
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{
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struct autofs_sb_info *sbi = autofs4_sbi(sb);
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sb->s_fs_info = NULL;
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if ( !sbi->catatonic )
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autofs4_catatonic_mode(sbi); /* Free wait queues, close pipe */
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kfree(sbi);
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DPRINTK("shutting down");
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}
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static struct super_operations autofs4_sops = {
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.put_super = autofs4_put_super,
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.statfs = simple_statfs,
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};
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enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto};
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static match_table_t tokens = {
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{Opt_fd, "fd=%u"},
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{Opt_uid, "uid=%u"},
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{Opt_gid, "gid=%u"},
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{Opt_pgrp, "pgrp=%u"},
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{Opt_minproto, "minproto=%u"},
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{Opt_maxproto, "maxproto=%u"},
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{Opt_err, NULL}
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};
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static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
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pid_t *pgrp, int *minproto, int *maxproto)
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{
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char *p;
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substring_t args[MAX_OPT_ARGS];
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int option;
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*uid = current->uid;
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*gid = current->gid;
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*pgrp = process_group(current);
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*minproto = AUTOFS_MIN_PROTO_VERSION;
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*maxproto = AUTOFS_MAX_PROTO_VERSION;
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*pipefd = -1;
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if (!options)
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return 1;
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while ((p = strsep(&options, ",")) != NULL) {
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int token;
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if (!*p)
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continue;
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token = match_token(p, tokens, args);
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switch (token) {
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case Opt_fd:
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if (match_int(args, pipefd))
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return 1;
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break;
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case Opt_uid:
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if (match_int(args, &option))
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return 1;
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*uid = option;
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break;
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case Opt_gid:
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if (match_int(args, &option))
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return 1;
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*gid = option;
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break;
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case Opt_pgrp:
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if (match_int(args, &option))
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return 1;
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*pgrp = option;
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break;
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case Opt_minproto:
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if (match_int(args, &option))
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return 1;
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*minproto = option;
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break;
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case Opt_maxproto:
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if (match_int(args, &option))
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return 1;
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*maxproto = option;
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break;
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default:
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return 1;
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}
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}
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return (*pipefd < 0);
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}
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static struct autofs_info *autofs4_mkroot(struct autofs_sb_info *sbi)
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{
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struct autofs_info *ino;
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ino = autofs4_init_ino(NULL, sbi, S_IFDIR | 0755);
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if (!ino)
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return NULL;
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return ino;
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}
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int autofs4_fill_super(struct super_block *s, void *data, int silent)
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{
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struct inode * root_inode;
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struct dentry * root;
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struct file * pipe;
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int pipefd;
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struct autofs_sb_info *sbi;
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struct autofs_info *ino;
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int minproto, maxproto;
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sbi = (struct autofs_sb_info *) kmalloc(sizeof(*sbi), GFP_KERNEL);
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if ( !sbi )
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goto fail_unlock;
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DPRINTK("starting up, sbi = %p",sbi);
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memset(sbi, 0, sizeof(*sbi));
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s->s_fs_info = sbi;
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sbi->magic = AUTOFS_SBI_MAGIC;
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sbi->catatonic = 0;
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sbi->exp_timeout = 0;
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sbi->oz_pgrp = process_group(current);
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sbi->sb = s;
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sbi->version = 0;
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sbi->sub_version = 0;
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init_MUTEX(&sbi->wq_sem);
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spin_lock_init(&sbi->fs_lock);
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sbi->queues = NULL;
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s->s_blocksize = 1024;
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s->s_blocksize_bits = 10;
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s->s_magic = AUTOFS_SUPER_MAGIC;
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s->s_op = &autofs4_sops;
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s->s_time_gran = 1;
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/*
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* Get the root inode and dentry, but defer checking for errors.
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*/
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ino = autofs4_mkroot(sbi);
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if (!ino)
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goto fail_free;
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root_inode = autofs4_get_inode(s, ino);
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kfree(ino);
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if (!root_inode)
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goto fail_free;
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root_inode->i_op = &autofs4_root_inode_operations;
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root_inode->i_fop = &autofs4_root_operations;
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root = d_alloc_root(root_inode);
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pipe = NULL;
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if (!root)
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goto fail_iput;
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/* Can this call block? */
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if (parse_options(data, &pipefd,
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&root_inode->i_uid, &root_inode->i_gid,
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&sbi->oz_pgrp,
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&minproto, &maxproto)) {
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printk("autofs: called with bogus options\n");
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goto fail_dput;
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}
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/* Couldn't this be tested earlier? */
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if (maxproto < AUTOFS_MIN_PROTO_VERSION ||
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minproto > AUTOFS_MAX_PROTO_VERSION) {
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printk("autofs: kernel does not match daemon version "
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"daemon (%d, %d) kernel (%d, %d)\n",
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minproto, maxproto,
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AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
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goto fail_dput;
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}
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sbi->version = maxproto > AUTOFS_MAX_PROTO_VERSION ? AUTOFS_MAX_PROTO_VERSION : maxproto;
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sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
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DPRINTK("pipe fd = %d, pgrp = %u", pipefd, sbi->oz_pgrp);
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pipe = fget(pipefd);
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if ( !pipe ) {
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printk("autofs: could not open pipe file descriptor\n");
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goto fail_dput;
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}
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if ( !pipe->f_op || !pipe->f_op->write )
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goto fail_fput;
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sbi->pipe = pipe;
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/*
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* Success! Install the root dentry now to indicate completion.
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*/
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s->s_root = root;
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return 0;
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/*
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* Failure ... clean up.
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*/
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fail_fput:
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printk("autofs: pipe file descriptor does not contain proper ops\n");
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fput(pipe);
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/* fall through */
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fail_dput:
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dput(root);
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goto fail_free;
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fail_iput:
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printk("autofs: get root dentry failed\n");
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iput(root_inode);
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fail_free:
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kfree(sbi);
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fail_unlock:
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return -EINVAL;
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}
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struct inode *autofs4_get_inode(struct super_block *sb,
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struct autofs_info *inf)
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{
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struct inode *inode = new_inode(sb);
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if (inode == NULL)
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return NULL;
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inf->inode = inode;
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inode->i_mode = inf->mode;
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if (sb->s_root) {
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inode->i_uid = sb->s_root->d_inode->i_uid;
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inode->i_gid = sb->s_root->d_inode->i_gid;
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} else {
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inode->i_uid = 0;
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inode->i_gid = 0;
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}
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inode->i_blksize = PAGE_CACHE_SIZE;
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inode->i_blocks = 0;
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inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
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if (S_ISDIR(inf->mode)) {
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inode->i_nlink = 2;
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inode->i_op = &autofs4_dir_inode_operations;
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inode->i_fop = &autofs4_dir_operations;
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} else if (S_ISLNK(inf->mode)) {
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inode->i_size = inf->size;
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inode->i_op = &autofs4_symlink_inode_operations;
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}
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return inode;
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}
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