mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 19:00:25 +00:00
![Josh Boyer](/assets/img/avatar_default.png)
Using /dev/pstore as a mount point for the pstore filesystem is slightly awkward. We don't normally mount filesystems in /dev/ and the /dev/pstore file isn't created automatically by anything. While this method will still work, we can create a persistent mount point in sysfs. This will put pstore on par with things like cgroups and efivarfs. Signed-off-by: Josh Boyer <jwboyer@redhat.com> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Tony Luck <tony.luck@intel.com>
444 lines
9.7 KiB
C
444 lines
9.7 KiB
C
/*
|
|
* Persistent Storage - ramfs parts.
|
|
*
|
|
* Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
|
*/
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/fsnotify.h>
|
|
#include <linux/pagemap.h>
|
|
#include <linux/highmem.h>
|
|
#include <linux/time.h>
|
|
#include <linux/init.h>
|
|
#include <linux/list.h>
|
|
#include <linux/string.h>
|
|
#include <linux/mount.h>
|
|
#include <linux/seq_file.h>
|
|
#include <linux/ramfs.h>
|
|
#include <linux/parser.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/magic.h>
|
|
#include <linux/pstore.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/spinlock.h>
|
|
#include <linux/uaccess.h>
|
|
|
|
#include "internal.h"
|
|
|
|
#define PSTORE_NAMELEN 64
|
|
|
|
static DEFINE_SPINLOCK(allpstore_lock);
|
|
static LIST_HEAD(allpstore);
|
|
|
|
struct pstore_private {
|
|
struct list_head list;
|
|
struct pstore_info *psi;
|
|
enum pstore_type_id type;
|
|
u64 id;
|
|
int count;
|
|
ssize_t size;
|
|
char data[];
|
|
};
|
|
|
|
struct pstore_ftrace_seq_data {
|
|
const void *ptr;
|
|
size_t off;
|
|
size_t size;
|
|
};
|
|
|
|
#define REC_SIZE sizeof(struct pstore_ftrace_record)
|
|
|
|
static void *pstore_ftrace_seq_start(struct seq_file *s, loff_t *pos)
|
|
{
|
|
struct pstore_private *ps = s->private;
|
|
struct pstore_ftrace_seq_data *data;
|
|
|
|
data = kzalloc(sizeof(*data), GFP_KERNEL);
|
|
if (!data)
|
|
return NULL;
|
|
|
|
data->off = ps->size % REC_SIZE;
|
|
data->off += *pos * REC_SIZE;
|
|
if (data->off + REC_SIZE > ps->size) {
|
|
kfree(data);
|
|
return NULL;
|
|
}
|
|
|
|
return data;
|
|
|
|
}
|
|
|
|
static void pstore_ftrace_seq_stop(struct seq_file *s, void *v)
|
|
{
|
|
kfree(v);
|
|
}
|
|
|
|
static void *pstore_ftrace_seq_next(struct seq_file *s, void *v, loff_t *pos)
|
|
{
|
|
struct pstore_private *ps = s->private;
|
|
struct pstore_ftrace_seq_data *data = v;
|
|
|
|
data->off += REC_SIZE;
|
|
if (data->off + REC_SIZE > ps->size)
|
|
return NULL;
|
|
|
|
(*pos)++;
|
|
return data;
|
|
}
|
|
|
|
static int pstore_ftrace_seq_show(struct seq_file *s, void *v)
|
|
{
|
|
struct pstore_private *ps = s->private;
|
|
struct pstore_ftrace_seq_data *data = v;
|
|
struct pstore_ftrace_record *rec = (void *)(ps->data + data->off);
|
|
|
|
seq_printf(s, "%d %08lx %08lx %pf <- %pF\n",
|
|
pstore_ftrace_decode_cpu(rec), rec->ip, rec->parent_ip,
|
|
(void *)rec->ip, (void *)rec->parent_ip);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct seq_operations pstore_ftrace_seq_ops = {
|
|
.start = pstore_ftrace_seq_start,
|
|
.next = pstore_ftrace_seq_next,
|
|
.stop = pstore_ftrace_seq_stop,
|
|
.show = pstore_ftrace_seq_show,
|
|
};
|
|
|
|
static ssize_t pstore_file_read(struct file *file, char __user *userbuf,
|
|
size_t count, loff_t *ppos)
|
|
{
|
|
struct seq_file *sf = file->private_data;
|
|
struct pstore_private *ps = sf->private;
|
|
|
|
if (ps->type == PSTORE_TYPE_FTRACE)
|
|
return seq_read(file, userbuf, count, ppos);
|
|
return simple_read_from_buffer(userbuf, count, ppos, ps->data, ps->size);
|
|
}
|
|
|
|
static int pstore_file_open(struct inode *inode, struct file *file)
|
|
{
|
|
struct pstore_private *ps = inode->i_private;
|
|
struct seq_file *sf;
|
|
int err;
|
|
const struct seq_operations *sops = NULL;
|
|
|
|
if (ps->type == PSTORE_TYPE_FTRACE)
|
|
sops = &pstore_ftrace_seq_ops;
|
|
|
|
err = seq_open(file, sops);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
sf = file->private_data;
|
|
sf->private = ps;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static loff_t pstore_file_llseek(struct file *file, loff_t off, int whence)
|
|
{
|
|
struct seq_file *sf = file->private_data;
|
|
|
|
if (sf->op)
|
|
return seq_lseek(file, off, whence);
|
|
return default_llseek(file, off, whence);
|
|
}
|
|
|
|
static const struct file_operations pstore_file_operations = {
|
|
.open = pstore_file_open,
|
|
.read = pstore_file_read,
|
|
.llseek = pstore_file_llseek,
|
|
.release = seq_release,
|
|
};
|
|
|
|
/*
|
|
* When a file is unlinked from our file system we call the
|
|
* platform driver to erase the record from persistent store.
|
|
*/
|
|
static int pstore_unlink(struct inode *dir, struct dentry *dentry)
|
|
{
|
|
struct pstore_private *p = dentry->d_inode->i_private;
|
|
|
|
if (p->psi->erase)
|
|
p->psi->erase(p->type, p->id, p->count,
|
|
dentry->d_inode->i_ctime, p->psi);
|
|
|
|
return simple_unlink(dir, dentry);
|
|
}
|
|
|
|
static void pstore_evict_inode(struct inode *inode)
|
|
{
|
|
struct pstore_private *p = inode->i_private;
|
|
unsigned long flags;
|
|
|
|
clear_inode(inode);
|
|
if (p) {
|
|
spin_lock_irqsave(&allpstore_lock, flags);
|
|
list_del(&p->list);
|
|
spin_unlock_irqrestore(&allpstore_lock, flags);
|
|
kfree(p);
|
|
}
|
|
}
|
|
|
|
static const struct inode_operations pstore_dir_inode_operations = {
|
|
.lookup = simple_lookup,
|
|
.unlink = pstore_unlink,
|
|
};
|
|
|
|
static struct inode *pstore_get_inode(struct super_block *sb)
|
|
{
|
|
struct inode *inode = new_inode(sb);
|
|
if (inode) {
|
|
inode->i_ino = get_next_ino();
|
|
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
|
|
}
|
|
return inode;
|
|
}
|
|
|
|
enum {
|
|
Opt_kmsg_bytes, Opt_err
|
|
};
|
|
|
|
static const match_table_t tokens = {
|
|
{Opt_kmsg_bytes, "kmsg_bytes=%u"},
|
|
{Opt_err, NULL}
|
|
};
|
|
|
|
static void parse_options(char *options)
|
|
{
|
|
char *p;
|
|
substring_t args[MAX_OPT_ARGS];
|
|
int option;
|
|
|
|
if (!options)
|
|
return;
|
|
|
|
while ((p = strsep(&options, ",")) != NULL) {
|
|
int token;
|
|
|
|
if (!*p)
|
|
continue;
|
|
|
|
token = match_token(p, tokens, args);
|
|
switch (token) {
|
|
case Opt_kmsg_bytes:
|
|
if (!match_int(&args[0], &option))
|
|
pstore_set_kmsg_bytes(option);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
static int pstore_remount(struct super_block *sb, int *flags, char *data)
|
|
{
|
|
parse_options(data);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct super_operations pstore_ops = {
|
|
.statfs = simple_statfs,
|
|
.drop_inode = generic_delete_inode,
|
|
.evict_inode = pstore_evict_inode,
|
|
.remount_fs = pstore_remount,
|
|
.show_options = generic_show_options,
|
|
};
|
|
|
|
static struct super_block *pstore_sb;
|
|
|
|
int pstore_is_mounted(void)
|
|
{
|
|
return pstore_sb != NULL;
|
|
}
|
|
|
|
/*
|
|
* Make a regular file in the root directory of our file system.
|
|
* Load it up with "size" bytes of data from "buf".
|
|
* Set the mtime & ctime to the date that this record was originally stored.
|
|
*/
|
|
int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id, int count,
|
|
char *data, size_t size, struct timespec time,
|
|
struct pstore_info *psi)
|
|
{
|
|
struct dentry *root = pstore_sb->s_root;
|
|
struct dentry *dentry;
|
|
struct inode *inode;
|
|
int rc = 0;
|
|
char name[PSTORE_NAMELEN];
|
|
struct pstore_private *private, *pos;
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&allpstore_lock, flags);
|
|
list_for_each_entry(pos, &allpstore, list) {
|
|
if (pos->type == type &&
|
|
pos->id == id &&
|
|
pos->psi == psi) {
|
|
rc = -EEXIST;
|
|
break;
|
|
}
|
|
}
|
|
spin_unlock_irqrestore(&allpstore_lock, flags);
|
|
if (rc)
|
|
return rc;
|
|
|
|
rc = -ENOMEM;
|
|
inode = pstore_get_inode(pstore_sb);
|
|
if (!inode)
|
|
goto fail;
|
|
inode->i_mode = S_IFREG | 0444;
|
|
inode->i_fop = &pstore_file_operations;
|
|
private = kmalloc(sizeof *private + size, GFP_KERNEL);
|
|
if (!private)
|
|
goto fail_alloc;
|
|
private->type = type;
|
|
private->id = id;
|
|
private->count = count;
|
|
private->psi = psi;
|
|
|
|
switch (type) {
|
|
case PSTORE_TYPE_DMESG:
|
|
sprintf(name, "dmesg-%s-%lld", psname, id);
|
|
break;
|
|
case PSTORE_TYPE_CONSOLE:
|
|
sprintf(name, "console-%s", psname);
|
|
break;
|
|
case PSTORE_TYPE_FTRACE:
|
|
sprintf(name, "ftrace-%s", psname);
|
|
break;
|
|
case PSTORE_TYPE_MCE:
|
|
sprintf(name, "mce-%s-%lld", psname, id);
|
|
break;
|
|
case PSTORE_TYPE_UNKNOWN:
|
|
sprintf(name, "unknown-%s-%lld", psname, id);
|
|
break;
|
|
default:
|
|
sprintf(name, "type%d-%s-%lld", type, psname, id);
|
|
break;
|
|
}
|
|
|
|
mutex_lock(&root->d_inode->i_mutex);
|
|
|
|
rc = -ENOSPC;
|
|
dentry = d_alloc_name(root, name);
|
|
if (IS_ERR(dentry))
|
|
goto fail_lockedalloc;
|
|
|
|
memcpy(private->data, data, size);
|
|
inode->i_size = private->size = size;
|
|
|
|
inode->i_private = private;
|
|
|
|
if (time.tv_sec)
|
|
inode->i_mtime = inode->i_ctime = time;
|
|
|
|
d_add(dentry, inode);
|
|
|
|
spin_lock_irqsave(&allpstore_lock, flags);
|
|
list_add(&private->list, &allpstore);
|
|
spin_unlock_irqrestore(&allpstore_lock, flags);
|
|
|
|
mutex_unlock(&root->d_inode->i_mutex);
|
|
|
|
return 0;
|
|
|
|
fail_lockedalloc:
|
|
mutex_unlock(&root->d_inode->i_mutex);
|
|
kfree(private);
|
|
fail_alloc:
|
|
iput(inode);
|
|
|
|
fail:
|
|
return rc;
|
|
}
|
|
|
|
static int pstore_fill_super(struct super_block *sb, void *data, int silent)
|
|
{
|
|
struct inode *inode;
|
|
|
|
save_mount_options(sb, data);
|
|
|
|
pstore_sb = sb;
|
|
|
|
sb->s_maxbytes = MAX_LFS_FILESIZE;
|
|
sb->s_blocksize = PAGE_CACHE_SIZE;
|
|
sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
|
|
sb->s_magic = PSTOREFS_MAGIC;
|
|
sb->s_op = &pstore_ops;
|
|
sb->s_time_gran = 1;
|
|
|
|
parse_options(data);
|
|
|
|
inode = pstore_get_inode(sb);
|
|
if (inode) {
|
|
inode->i_mode = S_IFDIR | 0755;
|
|
inode->i_op = &pstore_dir_inode_operations;
|
|
inode->i_fop = &simple_dir_operations;
|
|
inc_nlink(inode);
|
|
}
|
|
sb->s_root = d_make_root(inode);
|
|
if (!sb->s_root)
|
|
return -ENOMEM;
|
|
|
|
pstore_get_records(0);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct dentry *pstore_mount(struct file_system_type *fs_type,
|
|
int flags, const char *dev_name, void *data)
|
|
{
|
|
return mount_single(fs_type, flags, data, pstore_fill_super);
|
|
}
|
|
|
|
static void pstore_kill_sb(struct super_block *sb)
|
|
{
|
|
kill_litter_super(sb);
|
|
pstore_sb = NULL;
|
|
}
|
|
|
|
static struct file_system_type pstore_fs_type = {
|
|
.name = "pstore",
|
|
.mount = pstore_mount,
|
|
.kill_sb = pstore_kill_sb,
|
|
};
|
|
|
|
static struct kobject *pstore_kobj;
|
|
|
|
static int __init init_pstore_fs(void)
|
|
{
|
|
int err = 0;
|
|
|
|
/* Create a convenient mount point for people to access pstore */
|
|
pstore_kobj = kobject_create_and_add("pstore", fs_kobj);
|
|
if (!pstore_kobj) {
|
|
err = -ENOMEM;
|
|
goto out;
|
|
}
|
|
|
|
err = register_filesystem(&pstore_fs_type);
|
|
if (err < 0)
|
|
kobject_put(pstore_kobj);
|
|
|
|
out:
|
|
return err;
|
|
}
|
|
module_init(init_pstore_fs)
|
|
|
|
MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
|
|
MODULE_LICENSE("GPL");
|