linux/fs/autofs4/inode.c
Ian Kent ba8df43c0e [PATCH] autofs4: panic after mount fail
Resolve the panic on failed mount of an autofs filesystem originally
reported by Mao Bibo.

It addresses two issues that happen after the mount fail.  The first a NULL
pointer reference to a field (pipe) in the autofs superblock info structure
and second the lack of super block cleanup by the autofs and autofs4
modules.

Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-11-14 09:09:27 -08:00

465 lines
10 KiB
C

/* -*- c -*- --------------------------------------------------------------- *
*
* linux/fs/autofs/inode.c
*
* Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
* Copyright 2005-2006 Ian Kent <raven@themaw.net>
*
* This file is part of the Linux kernel and is made available under
* the terms of the GNU General Public License, version 2, or at your
* option, any later version, incorporated herein by reference.
*
* ------------------------------------------------------------------------- */
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/file.h>
#include <linux/seq_file.h>
#include <linux/pagemap.h>
#include <linux/parser.h>
#include <linux/bitops.h>
#include <linux/smp_lock.h>
#include <linux/magic.h>
#include "autofs_i.h"
#include <linux/module.h>
static void ino_lnkfree(struct autofs_info *ino)
{
kfree(ino->u.symlink);
ino->u.symlink = NULL;
}
struct autofs_info *autofs4_init_ino(struct autofs_info *ino,
struct autofs_sb_info *sbi, mode_t mode)
{
int reinit = 1;
if (ino == NULL) {
reinit = 0;
ino = kmalloc(sizeof(*ino), GFP_KERNEL);
}
if (ino == NULL)
return NULL;
ino->flags = 0;
ino->mode = mode;
ino->inode = NULL;
ino->dentry = NULL;
ino->size = 0;
ino->last_used = jiffies;
atomic_set(&ino->count, 0);
ino->sbi = sbi;
if (reinit && ino->free)
(ino->free)(ino);
memset(&ino->u, 0, sizeof(ino->u));
ino->free = NULL;
if (S_ISLNK(mode))
ino->free = ino_lnkfree;
return ino;
}
void autofs4_free_ino(struct autofs_info *ino)
{
struct autofs_info *p_ino;
if (ino->dentry) {
ino->dentry->d_fsdata = NULL;
if (ino->dentry->d_inode) {
struct dentry *parent = ino->dentry->d_parent;
if (atomic_dec_and_test(&ino->count)) {
p_ino = autofs4_dentry_ino(parent);
if (p_ino && parent != ino->dentry)
atomic_dec(&p_ino->count);
}
dput(ino->dentry);
}
ino->dentry = NULL;
}
if (ino->free)
(ino->free)(ino);
kfree(ino);
}
/*
* Deal with the infamous "Busy inodes after umount ..." message.
*
* Clean up the dentry tree. This happens with autofs if the user
* space program goes away due to a SIGKILL, SIGSEGV etc.
*/
static void autofs4_force_release(struct autofs_sb_info *sbi)
{
struct dentry *this_parent = sbi->sb->s_root;
struct list_head *next;
if (!sbi->sb->s_root)
return;
spin_lock(&dcache_lock);
repeat:
next = this_parent->d_subdirs.next;
resume:
while (next != &this_parent->d_subdirs) {
struct dentry *dentry = list_entry(next, struct dentry, d_u.d_child);
/* Negative dentry - don`t care */
if (!simple_positive(dentry)) {
next = next->next;
continue;
}
if (!list_empty(&dentry->d_subdirs)) {
this_parent = dentry;
goto repeat;
}
next = next->next;
spin_unlock(&dcache_lock);
DPRINTK("dentry %p %.*s",
dentry, (int)dentry->d_name.len, dentry->d_name.name);
dput(dentry);
spin_lock(&dcache_lock);
}
if (this_parent != sbi->sb->s_root) {
struct dentry *dentry = this_parent;
next = this_parent->d_u.d_child.next;
this_parent = this_parent->d_parent;
spin_unlock(&dcache_lock);
DPRINTK("parent dentry %p %.*s",
dentry, (int)dentry->d_name.len, dentry->d_name.name);
dput(dentry);
spin_lock(&dcache_lock);
goto resume;
}
spin_unlock(&dcache_lock);
}
void autofs4_kill_sb(struct super_block *sb)
{
struct autofs_sb_info *sbi = autofs4_sbi(sb);
/*
* In the event of a failure in get_sb_nodev the superblock
* info is not present so nothing else has been setup, so
* just exit when we are called from deactivate_super.
*/
if (!sbi)
return;
sb->s_fs_info = NULL;
if ( !sbi->catatonic )
autofs4_catatonic_mode(sbi); /* Free wait queues, close pipe */
/* Clean up and release dangling references */
autofs4_force_release(sbi);
kfree(sbi);
DPRINTK("shutting down");
kill_anon_super(sb);
}
static int autofs4_show_options(struct seq_file *m, struct vfsmount *mnt)
{
struct autofs_sb_info *sbi = autofs4_sbi(mnt->mnt_sb);
if (!sbi)
return 0;
seq_printf(m, ",fd=%d", sbi->pipefd);
seq_printf(m, ",pgrp=%d", sbi->oz_pgrp);
seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
seq_printf(m, ",minproto=%d", sbi->min_proto);
seq_printf(m, ",maxproto=%d", sbi->max_proto);
if (sbi->type & AUTOFS_TYPE_OFFSET)
seq_printf(m, ",offset");
else if (sbi->type & AUTOFS_TYPE_DIRECT)
seq_printf(m, ",direct");
else
seq_printf(m, ",indirect");
return 0;
}
static struct super_operations autofs4_sops = {
.statfs = simple_statfs,
.show_options = autofs4_show_options,
};
enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
Opt_indirect, Opt_direct, Opt_offset};
static match_table_t tokens = {
{Opt_fd, "fd=%u"},
{Opt_uid, "uid=%u"},
{Opt_gid, "gid=%u"},
{Opt_pgrp, "pgrp=%u"},
{Opt_minproto, "minproto=%u"},
{Opt_maxproto, "maxproto=%u"},
{Opt_indirect, "indirect"},
{Opt_direct, "direct"},
{Opt_offset, "offset"},
{Opt_err, NULL}
};
static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
pid_t *pgrp, unsigned int *type,
int *minproto, int *maxproto)
{
char *p;
substring_t args[MAX_OPT_ARGS];
int option;
*uid = current->uid;
*gid = current->gid;
*pgrp = process_group(current);
*minproto = AUTOFS_MIN_PROTO_VERSION;
*maxproto = AUTOFS_MAX_PROTO_VERSION;
*pipefd = -1;
if (!options)
return 1;
while ((p = strsep(&options, ",")) != NULL) {
int token;
if (!*p)
continue;
token = match_token(p, tokens, args);
switch (token) {
case Opt_fd:
if (match_int(args, pipefd))
return 1;
break;
case Opt_uid:
if (match_int(args, &option))
return 1;
*uid = option;
break;
case Opt_gid:
if (match_int(args, &option))
return 1;
*gid = option;
break;
case Opt_pgrp:
if (match_int(args, &option))
return 1;
*pgrp = option;
break;
case Opt_minproto:
if (match_int(args, &option))
return 1;
*minproto = option;
break;
case Opt_maxproto:
if (match_int(args, &option))
return 1;
*maxproto = option;
break;
case Opt_indirect:
*type = AUTOFS_TYPE_INDIRECT;
break;
case Opt_direct:
*type = AUTOFS_TYPE_DIRECT;
break;
case Opt_offset:
*type = AUTOFS_TYPE_DIRECT | AUTOFS_TYPE_OFFSET;
break;
default:
return 1;
}
}
return (*pipefd < 0);
}
static struct autofs_info *autofs4_mkroot(struct autofs_sb_info *sbi)
{
struct autofs_info *ino;
ino = autofs4_init_ino(NULL, sbi, S_IFDIR | 0755);
if (!ino)
return NULL;
return ino;
}
static struct dentry_operations autofs4_sb_dentry_operations = {
.d_release = autofs4_dentry_release,
};
int autofs4_fill_super(struct super_block *s, void *data, int silent)
{
struct inode * root_inode;
struct dentry * root;
struct file * pipe;
int pipefd;
struct autofs_sb_info *sbi;
struct autofs_info *ino;
sbi = (struct autofs_sb_info *) kmalloc(sizeof(*sbi), GFP_KERNEL);
if ( !sbi )
goto fail_unlock;
DPRINTK("starting up, sbi = %p",sbi);
memset(sbi, 0, sizeof(*sbi));
s->s_fs_info = sbi;
sbi->magic = AUTOFS_SBI_MAGIC;
sbi->pipefd = -1;
sbi->pipe = NULL;
sbi->catatonic = 1;
sbi->exp_timeout = 0;
sbi->oz_pgrp = process_group(current);
sbi->sb = s;
sbi->version = 0;
sbi->sub_version = 0;
sbi->type = 0;
sbi->min_proto = 0;
sbi->max_proto = 0;
mutex_init(&sbi->wq_mutex);
spin_lock_init(&sbi->fs_lock);
sbi->queues = NULL;
s->s_blocksize = 1024;
s->s_blocksize_bits = 10;
s->s_magic = AUTOFS_SUPER_MAGIC;
s->s_op = &autofs4_sops;
s->s_time_gran = 1;
/*
* Get the root inode and dentry, but defer checking for errors.
*/
ino = autofs4_mkroot(sbi);
if (!ino)
goto fail_free;
root_inode = autofs4_get_inode(s, ino);
if (!root_inode)
goto fail_ino;
root = d_alloc_root(root_inode);
if (!root)
goto fail_iput;
pipe = NULL;
root->d_op = &autofs4_sb_dentry_operations;
root->d_fsdata = ino;
/* Can this call block? */
if (parse_options(data, &pipefd,
&root_inode->i_uid, &root_inode->i_gid,
&sbi->oz_pgrp, &sbi->type,
&sbi->min_proto, &sbi->max_proto)) {
printk("autofs: called with bogus options\n");
goto fail_dput;
}
root_inode->i_fop = &autofs4_root_operations;
root_inode->i_op = sbi->type & AUTOFS_TYPE_DIRECT ?
&autofs4_direct_root_inode_operations :
&autofs4_indirect_root_inode_operations;
/* Couldn't this be tested earlier? */
if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
printk("autofs: kernel does not match daemon version "
"daemon (%d, %d) kernel (%d, %d)\n",
sbi->min_proto, sbi->max_proto,
AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
goto fail_dput;
}
/* Establish highest kernel protocol version */
if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
sbi->version = AUTOFS_MAX_PROTO_VERSION;
else
sbi->version = sbi->max_proto;
sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
DPRINTK("pipe fd = %d, pgrp = %u", pipefd, sbi->oz_pgrp);
pipe = fget(pipefd);
if ( !pipe ) {
printk("autofs: could not open pipe file descriptor\n");
goto fail_dput;
}
if ( !pipe->f_op || !pipe->f_op->write )
goto fail_fput;
sbi->pipe = pipe;
sbi->pipefd = pipefd;
sbi->catatonic = 0;
/*
* Success! Install the root dentry now to indicate completion.
*/
s->s_root = root;
return 0;
/*
* Failure ... clean up.
*/
fail_fput:
printk("autofs: pipe file descriptor does not contain proper ops\n");
fput(pipe);
/* fall through */
fail_dput:
dput(root);
goto fail_free;
fail_iput:
printk("autofs: get root dentry failed\n");
iput(root_inode);
fail_ino:
kfree(ino);
fail_free:
kfree(sbi);
s->s_fs_info = NULL;
kill_anon_super(s);
fail_unlock:
return -EINVAL;
}
struct inode *autofs4_get_inode(struct super_block *sb,
struct autofs_info *inf)
{
struct inode *inode = new_inode(sb);
if (inode == NULL)
return NULL;
inf->inode = inode;
inode->i_mode = inf->mode;
if (sb->s_root) {
inode->i_uid = sb->s_root->d_inode->i_uid;
inode->i_gid = sb->s_root->d_inode->i_gid;
} else {
inode->i_uid = 0;
inode->i_gid = 0;
}
inode->i_blocks = 0;
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
if (S_ISDIR(inf->mode)) {
inode->i_nlink = 2;
inode->i_op = &autofs4_dir_inode_operations;
inode->i_fop = &autofs4_dir_operations;
} else if (S_ISLNK(inf->mode)) {
inode->i_size = inf->size;
inode->i_op = &autofs4_symlink_inode_operations;
}
return inode;
}