linux/fs/autofs/inode.c

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/* -*- linux-c -*- --------------------------------------------------------- *
*
* linux/fs/autofs/inode.c
*
* Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
*
* 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/mm.h>
#include <linux/slab.h>
#include <linux/file.h>
#include <linux/parser.h>
#include <linux/bitops.h>
#include <linux/magic.h>
#include "autofs_i.h"
#include <linux/module.h>
void autofs_kill_sb(struct super_block *sb)
{
struct autofs_sb_info *sbi = autofs_sbi(sb);
unsigned int n;
/*
* In the event of a failure in get_sb_nodev the superblock
* info is not present so nothing else has been setup, so
[PATCH] autofs: fix error code path in autofs_fill_sb() When kernel is compiled with old version of autofs (CONFIG_AUTOFS_FS), and new (observed at least with 5.x.x) automount deamon is started, kernel correctly reports incompatible version of kernel and userland daemon, but then screws things up instead of correct handling of the error: autofs: kernel does not match daemon version ===================================== [ BUG: bad unlock balance detected! ] ------------------------------------- automount/4199 is trying to release lock (&type->s_umount_key) at: [<c0163b9e>] get_sb_nodev+0x76/0xa4 but there are no more locks to release! other info that might help us debug this: no locks held by automount/4199. stack backtrace: [<c0103b15>] dump_trace+0x68/0x1b2 [<c0103c77>] show_trace_log_lvl+0x18/0x2c [<c01041db>] show_trace+0xf/0x11 [<c010424d>] dump_stack+0x12/0x14 [<c012e02c>] print_unlock_inbalance_bug+0xe7/0xf3 [<c012fd4f>] lock_release+0x8d/0x164 [<c012b452>] up_write+0x14/0x27 [<c0163b9e>] get_sb_nodev+0x76/0xa4 [<c0163689>] vfs_kern_mount+0x83/0xf6 [<c016373e>] do_kern_mount+0x2d/0x3e [<c017513f>] do_mount+0x607/0x67a [<c0175224>] sys_mount+0x72/0xa4 [<c0102b96>] sysenter_past_esp+0x5f/0x99 DWARF2 unwinder stuck at sysenter_past_esp+0x5f/0x99 Leftover inexact backtrace: ======================= and then deadlock comes. The problem: autofs_fill_super() returns EINVAL to get_sb_nodev(), but before that, it calls kill_anon_super() to destroy the superblock which won't be needed. This is however way too soon to call kill_anon_super(), because get_sb_nodev() has to perform its own cleanup of the superblock first (deactivate_super(), etc.). The correct time to call kill_anon_super() is in the autofs_kill_sb() callback, which is called by deactivate_super() at proper time, when the superblock is ready to be killed. I can see the same faulty codepath also in autofs4. This patch solves issues in both filesystems in a same way - it postpones the kill_anon_super() until the proper time is signalized by deactivate_super() calling the kill_sb() callback. [raven@themaw.net: update comment] Signed-off-by: Jiri Kosina <jkosina@suse.cz> Acked-by: Ian Kent <raven@themaw.net> Cc: <stable@kernel.org> Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07 04:39:38 +00:00
* just call kill_anon_super when we are called from
* deactivate_super.
*/
if (!sbi)
[PATCH] autofs: fix error code path in autofs_fill_sb() When kernel is compiled with old version of autofs (CONFIG_AUTOFS_FS), and new (observed at least with 5.x.x) automount deamon is started, kernel correctly reports incompatible version of kernel and userland daemon, but then screws things up instead of correct handling of the error: autofs: kernel does not match daemon version ===================================== [ BUG: bad unlock balance detected! ] ------------------------------------- automount/4199 is trying to release lock (&type->s_umount_key) at: [<c0163b9e>] get_sb_nodev+0x76/0xa4 but there are no more locks to release! other info that might help us debug this: no locks held by automount/4199. stack backtrace: [<c0103b15>] dump_trace+0x68/0x1b2 [<c0103c77>] show_trace_log_lvl+0x18/0x2c [<c01041db>] show_trace+0xf/0x11 [<c010424d>] dump_stack+0x12/0x14 [<c012e02c>] print_unlock_inbalance_bug+0xe7/0xf3 [<c012fd4f>] lock_release+0x8d/0x164 [<c012b452>] up_write+0x14/0x27 [<c0163b9e>] get_sb_nodev+0x76/0xa4 [<c0163689>] vfs_kern_mount+0x83/0xf6 [<c016373e>] do_kern_mount+0x2d/0x3e [<c017513f>] do_mount+0x607/0x67a [<c0175224>] sys_mount+0x72/0xa4 [<c0102b96>] sysenter_past_esp+0x5f/0x99 DWARF2 unwinder stuck at sysenter_past_esp+0x5f/0x99 Leftover inexact backtrace: ======================= and then deadlock comes. The problem: autofs_fill_super() returns EINVAL to get_sb_nodev(), but before that, it calls kill_anon_super() to destroy the superblock which won't be needed. This is however way too soon to call kill_anon_super(), because get_sb_nodev() has to perform its own cleanup of the superblock first (deactivate_super(), etc.). The correct time to call kill_anon_super() is in the autofs_kill_sb() callback, which is called by deactivate_super() at proper time, when the superblock is ready to be killed. I can see the same faulty codepath also in autofs4. This patch solves issues in both filesystems in a same way - it postpones the kill_anon_super() until the proper time is signalized by deactivate_super() calling the kill_sb() callback. [raven@themaw.net: update comment] Signed-off-by: Jiri Kosina <jkosina@suse.cz> Acked-by: Ian Kent <raven@themaw.net> Cc: <stable@kernel.org> Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07 04:39:38 +00:00
goto out_kill_sb;
if (!sbi->catatonic)
autofs_catatonic_mode(sbi); /* Free wait queues, close pipe */
put_pid(sbi->oz_pgrp);
autofs_hash_nuke(sbi);
for (n = 0; n < AUTOFS_MAX_SYMLINKS; n++) {
if (test_bit(n, sbi->symlink_bitmap))
kfree(sbi->symlink[n].data);
}
kfree(sb->s_fs_info);
[PATCH] autofs: fix error code path in autofs_fill_sb() When kernel is compiled with old version of autofs (CONFIG_AUTOFS_FS), and new (observed at least with 5.x.x) automount deamon is started, kernel correctly reports incompatible version of kernel and userland daemon, but then screws things up instead of correct handling of the error: autofs: kernel does not match daemon version ===================================== [ BUG: bad unlock balance detected! ] ------------------------------------- automount/4199 is trying to release lock (&type->s_umount_key) at: [<c0163b9e>] get_sb_nodev+0x76/0xa4 but there are no more locks to release! other info that might help us debug this: no locks held by automount/4199. stack backtrace: [<c0103b15>] dump_trace+0x68/0x1b2 [<c0103c77>] show_trace_log_lvl+0x18/0x2c [<c01041db>] show_trace+0xf/0x11 [<c010424d>] dump_stack+0x12/0x14 [<c012e02c>] print_unlock_inbalance_bug+0xe7/0xf3 [<c012fd4f>] lock_release+0x8d/0x164 [<c012b452>] up_write+0x14/0x27 [<c0163b9e>] get_sb_nodev+0x76/0xa4 [<c0163689>] vfs_kern_mount+0x83/0xf6 [<c016373e>] do_kern_mount+0x2d/0x3e [<c017513f>] do_mount+0x607/0x67a [<c0175224>] sys_mount+0x72/0xa4 [<c0102b96>] sysenter_past_esp+0x5f/0x99 DWARF2 unwinder stuck at sysenter_past_esp+0x5f/0x99 Leftover inexact backtrace: ======================= and then deadlock comes. The problem: autofs_fill_super() returns EINVAL to get_sb_nodev(), but before that, it calls kill_anon_super() to destroy the superblock which won't be needed. This is however way too soon to call kill_anon_super(), because get_sb_nodev() has to perform its own cleanup of the superblock first (deactivate_super(), etc.). The correct time to call kill_anon_super() is in the autofs_kill_sb() callback, which is called by deactivate_super() at proper time, when the superblock is ready to be killed. I can see the same faulty codepath also in autofs4. This patch solves issues in both filesystems in a same way - it postpones the kill_anon_super() until the proper time is signalized by deactivate_super() calling the kill_sb() callback. [raven@themaw.net: update comment] Signed-off-by: Jiri Kosina <jkosina@suse.cz> Acked-by: Ian Kent <raven@themaw.net> Cc: <stable@kernel.org> Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07 04:39:38 +00:00
out_kill_sb:
DPRINTK(("autofs: shutting down\n"));
kill_anon_super(sb);
}
static void autofs_read_inode(struct inode *inode);
static const struct super_operations autofs_sops = {
.read_inode = autofs_read_inode,
.statfs = simple_statfs,
};
enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto};
static match_table_t autofs_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_err, NULL}
};
static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
pid_t *pgrp, int *minproto, int *maxproto)
{
char *p;
substring_t args[MAX_OPT_ARGS];
int option;
*uid = current->uid;
*gid = current->gid;
*pgrp = task_pgrp_nr(current);
*minproto = *maxproto = AUTOFS_PROTO_VERSION;
*pipefd = -1;
if (!options)
return 1;
while ((p = strsep(&options, ",")) != NULL) {
int token;
if (!*p)
continue;
token = match_token(p, autofs_tokens, args);
switch (token) {
case Opt_fd:
if (match_int(&args[0], &option))
return 1;
*pipefd = option;
break;
case Opt_uid:
if (match_int(&args[0], &option))
return 1;
*uid = option;
break;
case Opt_gid:
if (match_int(&args[0], &option))
return 1;
*gid = option;
break;
case Opt_pgrp:
if (match_int(&args[0], &option))
return 1;
*pgrp = option;
break;
case Opt_minproto:
if (match_int(&args[0], &option))
return 1;
*minproto = option;
break;
case Opt_maxproto:
if (match_int(&args[0], &option))
return 1;
*maxproto = option;
break;
default:
return 1;
}
}
return (*pipefd < 0);
}
int autofs_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;
int minproto, maxproto;
pid_t pgid;
sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
if (!sbi)
goto fail_unlock;
DPRINTK(("autofs: starting up, sbi = %p\n",sbi));
s->s_fs_info = sbi;
sbi->magic = AUTOFS_SBI_MAGIC;
sbi->pipe = NULL;
sbi->catatonic = 1;
sbi->exp_timeout = 0;
autofs_initialize_hash(&sbi->dirhash);
sbi->queues = NULL;
memset(sbi->symlink_bitmap, 0, sizeof(long)*AUTOFS_SYMLINK_BITMAP_LEN);
sbi->next_dir_ino = AUTOFS_FIRST_DIR_INO;
s->s_blocksize = 1024;
s->s_blocksize_bits = 10;
s->s_magic = AUTOFS_SUPER_MAGIC;
s->s_op = &autofs_sops;
s->s_time_gran = 1;
sbi->sb = s;
root_inode = iget(s, AUTOFS_ROOT_INO);
root = d_alloc_root(root_inode);
pipe = NULL;
if (!root)
goto fail_iput;
/* Can this call block? - WTF cares? s is locked. */
if (parse_options(data, &pipefd, &root_inode->i_uid,
&root_inode->i_gid, &pgid, &minproto,
&maxproto)) {
printk("autofs: called with bogus options\n");
goto fail_dput;
}
/* Couldn't this be tested earlier? */
if (minproto > AUTOFS_PROTO_VERSION ||
maxproto < AUTOFS_PROTO_VERSION) {
printk("autofs: kernel does not match daemon version\n");
goto fail_dput;
}
DPRINTK(("autofs: pipe fd = %d, pgrp = %u\n", pipefd, pgid));
sbi->oz_pgrp = find_get_pid(pgid);
if (!sbi->oz_pgrp) {
printk("autofs: could not find process group %d\n", pgid);
goto fail_dput;
}
pipe = fget(pipefd);
if (!pipe) {
printk("autofs: could not open pipe file descriptor\n");
goto fail_put_pid;
}
if (!pipe->f_op || !pipe->f_op->write)
goto fail_fput;
sbi->pipe = pipe;
sbi->catatonic = 0;
/*
* Success! Install the root dentry now to indicate completion.
*/
s->s_root = root;
return 0;
fail_fput:
printk("autofs: pipe file descriptor does not contain proper ops\n");
fput(pipe);
fail_put_pid:
put_pid(sbi->oz_pgrp);
fail_dput:
dput(root);
goto fail_free;
fail_iput:
printk("autofs: get root dentry failed\n");
iput(root_inode);
fail_free:
kfree(sbi);
s->s_fs_info = NULL;
fail_unlock:
return -EINVAL;
}
static void autofs_read_inode(struct inode *inode)
{
ino_t ino = inode->i_ino;
unsigned int n;
struct autofs_sb_info *sbi = autofs_sbi(inode->i_sb);
/* Initialize to the default case (stub directory) */
inode->i_op = &simple_dir_inode_operations;
inode->i_fop = &simple_dir_operations;
inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
inode->i_nlink = 2;
inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
inode->i_blocks = 0;
if (ino == AUTOFS_ROOT_INO) {
inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR;
inode->i_op = &autofs_root_inode_operations;
inode->i_fop = &autofs_root_operations;
inode->i_uid = inode->i_gid = 0; /* Changed in read_super */
return;
}
inode->i_uid = inode->i_sb->s_root->d_inode->i_uid;
inode->i_gid = inode->i_sb->s_root->d_inode->i_gid;
if (ino >= AUTOFS_FIRST_SYMLINK && ino < AUTOFS_FIRST_DIR_INO) {
/* Symlink inode - should be in symlink list */
struct autofs_symlink *sl;
n = ino - AUTOFS_FIRST_SYMLINK;
if (n >= AUTOFS_MAX_SYMLINKS || !test_bit(n,sbi->symlink_bitmap)) {
printk("autofs: Looking for bad symlink inode %u\n", (unsigned int) ino);
return;
}
inode->i_op = &autofs_symlink_inode_operations;
sl = &sbi->symlink[n];
inode->i_private = sl;
inode->i_mode = S_IFLNK | S_IRWXUGO;
inode->i_mtime.tv_sec = inode->i_ctime.tv_sec = sl->mtime;
inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = 0;
inode->i_size = sl->len;
inode->i_nlink = 1;
}
}