![Ian Kent](/assets/img/avatar_default.png)
We need to be able to cope with the directory mutex being held during ->d_revalidate() in some cases, but not all cases, and not necessarily by us. Because we need to release the mutex when we call back to the daemon to do perform a mount we must be sure that it is us who holds the mutex so we must redirect mount requests to ->lookup() if the mutex is held. Signed-off-by: Ian Kent <raven@themaw.net> Cc: Sage Weil <sage@newdream.net> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Andreas Dilger <adilger@sun.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Yehuda Saheh <yehuda@newdream.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
474 lines
10 KiB
C
474 lines
10 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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* Copyright 2005-2006 Ian Kent <raven@themaw.net>
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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/seq_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 <linux/magic.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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if (!reinit) {
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ino->flags = 0;
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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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INIT_LIST_HEAD(&ino->active);
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INIT_LIST_HEAD(&ino->rehash_list);
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ino->active_count = 0;
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INIT_LIST_HEAD(&ino->expiring);
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atomic_set(&ino->count, 0);
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}
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ino->uid = 0;
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ino->gid = 0;
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ino->mode = mode;
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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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struct autofs_info *p_ino;
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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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struct dentry *parent = ino->dentry->d_parent;
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if (atomic_dec_and_test(&ino->count)) {
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p_ino = autofs4_dentry_ino(parent);
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if (p_ino && parent != ino->dentry)
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atomic_dec(&p_ino->count);
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}
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dput(ino->dentry);
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}
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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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/*
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* Deal with the infamous "Busy inodes after umount ..." message.
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*
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* Clean up the dentry tree. This happens with autofs if the user
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* space program goes away due to a SIGKILL, SIGSEGV etc.
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*/
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static void autofs4_force_release(struct autofs_sb_info *sbi)
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{
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struct dentry *this_parent = sbi->sb->s_root;
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struct list_head *next;
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if (!sbi->sb->s_root)
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return;
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spin_lock(&dcache_lock);
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repeat:
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next = this_parent->d_subdirs.next;
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resume:
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while (next != &this_parent->d_subdirs) {
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struct dentry *dentry = list_entry(next, struct dentry, d_u.d_child);
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/* Negative dentry - don`t care */
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if (!simple_positive(dentry)) {
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next = next->next;
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continue;
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}
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if (!list_empty(&dentry->d_subdirs)) {
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this_parent = dentry;
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goto repeat;
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}
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next = next->next;
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spin_unlock(&dcache_lock);
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DPRINTK("dentry %p %.*s",
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dentry, (int)dentry->d_name.len, dentry->d_name.name);
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dput(dentry);
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spin_lock(&dcache_lock);
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}
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if (this_parent != sbi->sb->s_root) {
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struct dentry *dentry = this_parent;
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next = this_parent->d_u.d_child.next;
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this_parent = this_parent->d_parent;
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spin_unlock(&dcache_lock);
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DPRINTK("parent dentry %p %.*s",
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dentry, (int)dentry->d_name.len, dentry->d_name.name);
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dput(dentry);
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spin_lock(&dcache_lock);
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goto resume;
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}
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spin_unlock(&dcache_lock);
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}
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void autofs4_kill_sb(struct super_block *sb)
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{
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struct autofs_sb_info *sbi = autofs4_sbi(sb);
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/*
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* In the event of a failure in get_sb_nodev the superblock
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* info is not present so nothing else has been setup, so
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* just call kill_anon_super when we are called from
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* deactivate_super.
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*/
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if (!sbi)
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goto out_kill_sb;
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/* Free wait queues, close pipe */
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autofs4_catatonic_mode(sbi);
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/* Clean up and release dangling references */
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autofs4_force_release(sbi);
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sb->s_fs_info = NULL;
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kfree(sbi);
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out_kill_sb:
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DPRINTK("shutting down");
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kill_anon_super(sb);
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}
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static int autofs4_show_options(struct seq_file *m, struct vfsmount *mnt)
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{
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struct autofs_sb_info *sbi = autofs4_sbi(mnt->mnt_sb);
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struct inode *root_inode = mnt->mnt_sb->s_root->d_inode;
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if (!sbi)
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return 0;
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seq_printf(m, ",fd=%d", sbi->pipefd);
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if (root_inode->i_uid != 0)
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seq_printf(m, ",uid=%u", root_inode->i_uid);
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if (root_inode->i_gid != 0)
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seq_printf(m, ",gid=%u", root_inode->i_gid);
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seq_printf(m, ",pgrp=%d", sbi->oz_pgrp);
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seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
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seq_printf(m, ",minproto=%d", sbi->min_proto);
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seq_printf(m, ",maxproto=%d", sbi->max_proto);
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if (autofs_type_offset(sbi->type))
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seq_printf(m, ",offset");
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else if (autofs_type_direct(sbi->type))
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seq_printf(m, ",direct");
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else
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seq_printf(m, ",indirect");
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return 0;
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}
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static const struct super_operations autofs4_sops = {
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.statfs = simple_statfs,
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.show_options = autofs4_show_options,
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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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Opt_indirect, Opt_direct, Opt_offset};
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static const 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_indirect, "indirect"},
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{Opt_direct, "direct"},
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{Opt_offset, "offset"},
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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, unsigned int *type, 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 = task_pgrp_nr(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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case Opt_indirect:
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set_autofs_type_indirect(type);
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break;
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case Opt_direct:
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set_autofs_type_direct(type);
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break;
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case Opt_offset:
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set_autofs_type_offset(type);
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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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static const struct dentry_operations autofs4_sb_dentry_operations = {
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.d_release = autofs4_dentry_release,
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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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sbi = kzalloc(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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s->s_fs_info = sbi;
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sbi->magic = AUTOFS_SBI_MAGIC;
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sbi->pipefd = -1;
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sbi->pipe = NULL;
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sbi->catatonic = 1;
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sbi->exp_timeout = 0;
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sbi->oz_pgrp = task_pgrp_nr(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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set_autofs_type_indirect(&sbi->type);
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sbi->min_proto = 0;
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sbi->max_proto = 0;
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mutex_init(&sbi->wq_mutex);
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spin_lock_init(&sbi->fs_lock);
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sbi->queues = NULL;
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spin_lock_init(&sbi->lookup_lock);
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INIT_LIST_HEAD(&sbi->active_list);
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INIT_LIST_HEAD(&sbi->expiring_list);
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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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if (!root_inode)
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goto fail_ino;
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root = d_alloc_root(root_inode);
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if (!root)
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goto fail_iput;
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pipe = NULL;
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root->d_op = &autofs4_sb_dentry_operations;
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root->d_fsdata = ino;
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/* Can this call block? */
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if (parse_options(data, &pipefd, &root_inode->i_uid, &root_inode->i_gid,
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&sbi->oz_pgrp, &sbi->type, &sbi->min_proto,
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&sbi->max_proto)) {
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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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root_inode->i_fop = &autofs4_root_operations;
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root_inode->i_op = autofs_type_trigger(sbi->type) ?
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&autofs4_direct_root_inode_operations :
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&autofs4_indirect_root_inode_operations;
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/* Couldn't this be tested earlier? */
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if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
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sbi->min_proto > 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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sbi->min_proto, sbi->max_proto,
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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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/* Establish highest kernel protocol version */
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if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
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sbi->version = AUTOFS_MAX_PROTO_VERSION;
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else
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sbi->version = sbi->max_proto;
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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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sbi->pipefd = pipefd;
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sbi->catatonic = 0;
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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_ino:
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kfree(ino);
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fail_free:
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kfree(sbi);
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s->s_fs_info = NULL;
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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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}
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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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