512 lines
11 KiB
C
512 lines
11 KiB
C
|
// SPDX-License-Identifier: GPL-2.0-only
|
||
|
/*
|
||
|
* Persistent Storage - ramfs parts.
|
||
|
*
|
||
|
* Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
|
||
|
*/
|
||
|
|
||
|
#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/uaccess.h>
|
||
|
|
||
|
#include "internal.h"
|
||
|
|
||
|
#define PSTORE_NAMELEN 64
|
||
|
|
||
|
static DEFINE_MUTEX(records_list_lock);
|
||
|
static LIST_HEAD(records_list);
|
||
|
|
||
|
static DEFINE_MUTEX(pstore_sb_lock);
|
||
|
static struct super_block *pstore_sb;
|
||
|
|
||
|
struct pstore_private {
|
||
|
struct list_head list;
|
||
|
struct dentry *dentry;
|
||
|
struct pstore_record *record;
|
||
|
size_t total_size;
|
||
|
};
|
||
|
|
||
|
struct pstore_ftrace_seq_data {
|
||
|
const void *ptr;
|
||
|
size_t off;
|
||
|
size_t size;
|
||
|
};
|
||
|
|
||
|
#define REC_SIZE sizeof(struct pstore_ftrace_record)
|
||
|
|
||
|
static void free_pstore_private(struct pstore_private *private)
|
||
|
{
|
||
|
if (!private)
|
||
|
return;
|
||
|
if (private->record) {
|
||
|
kfree(private->record->buf);
|
||
|
kfree(private->record->priv);
|
||
|
kfree(private->record);
|
||
|
}
|
||
|
kfree(private);
|
||
|
}
|
||
|
|
||
|
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->total_size % REC_SIZE;
|
||
|
data->off += *pos * REC_SIZE;
|
||
|
if (data->off + REC_SIZE > ps->total_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;
|
||
|
|
||
|
(*pos)++;
|
||
|
data->off += REC_SIZE;
|
||
|
if (data->off + REC_SIZE > ps->total_size)
|
||
|
return NULL;
|
||
|
|
||
|
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;
|
||
|
|
||
|
if (!data)
|
||
|
return 0;
|
||
|
|
||
|
rec = (struct pstore_ftrace_record *)(ps->record->buf + data->off);
|
||
|
|
||
|
seq_printf(s, "CPU:%d ts:%llu %08lx %08lx %ps <- %pS\n",
|
||
|
pstore_ftrace_decode_cpu(rec),
|
||
|
pstore_ftrace_read_timestamp(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->record->type == PSTORE_TYPE_FTRACE)
|
||
|
return seq_read(file, userbuf, count, ppos);
|
||
|
return simple_read_from_buffer(userbuf, count, ppos,
|
||
|
ps->record->buf, ps->total_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->record->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 = d_inode(dentry)->i_private;
|
||
|
struct pstore_record *record = p->record;
|
||
|
int rc = 0;
|
||
|
|
||
|
if (!record->psi->erase)
|
||
|
return -EPERM;
|
||
|
|
||
|
/* Make sure we can't race while removing this file. */
|
||
|
mutex_lock(&records_list_lock);
|
||
|
if (!list_empty(&p->list))
|
||
|
list_del_init(&p->list);
|
||
|
else
|
||
|
rc = -ENOENT;
|
||
|
p->dentry = NULL;
|
||
|
mutex_unlock(&records_list_lock);
|
||
|
if (rc)
|
||
|
return rc;
|
||
|
|
||
|
mutex_lock(&record->psi->read_mutex);
|
||
|
record->psi->erase(record);
|
||
|
mutex_unlock(&record->psi->read_mutex);
|
||
|
|
||
|
return simple_unlink(dir, dentry);
|
||
|
}
|
||
|
|
||
|
static void pstore_evict_inode(struct inode *inode)
|
||
|
{
|
||
|
struct pstore_private *p = inode->i_private;
|
||
|
|
||
|
clear_inode(inode);
|
||
|
free_pstore_private(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(inode);
|
||
|
}
|
||
|
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;
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* Display the mount options in /proc/mounts.
|
||
|
*/
|
||
|
static int pstore_show_options(struct seq_file *m, struct dentry *root)
|
||
|
{
|
||
|
if (kmsg_bytes != CONFIG_PSTORE_DEFAULT_KMSG_BYTES)
|
||
|
seq_printf(m, ",kmsg_bytes=%lu", kmsg_bytes);
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
static int pstore_remount(struct super_block *sb, int *flags, char *data)
|
||
|
{
|
||
|
sync_filesystem(sb);
|
||
|
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 = pstore_show_options,
|
||
|
};
|
||
|
|
||
|
static struct dentry *psinfo_lock_root(void)
|
||
|
{
|
||
|
struct dentry *root;
|
||
|
|
||
|
mutex_lock(&pstore_sb_lock);
|
||
|
/*
|
||
|
* Having no backend is fine -- no records appear.
|
||
|
* Not being mounted is fine -- nothing to do.
|
||
|
*/
|
||
|
if (!psinfo || !pstore_sb) {
|
||
|
mutex_unlock(&pstore_sb_lock);
|
||
|
return NULL;
|
||
|
}
|
||
|
|
||
|
root = pstore_sb->s_root;
|
||
|
inode_lock(d_inode(root));
|
||
|
mutex_unlock(&pstore_sb_lock);
|
||
|
|
||
|
return root;
|
||
|
}
|
||
|
|
||
|
int pstore_put_backend_records(struct pstore_info *psi)
|
||
|
{
|
||
|
struct pstore_private *pos, *tmp;
|
||
|
struct dentry *root;
|
||
|
int rc = 0;
|
||
|
|
||
|
root = psinfo_lock_root();
|
||
|
if (!root)
|
||
|
return 0;
|
||
|
|
||
|
mutex_lock(&records_list_lock);
|
||
|
list_for_each_entry_safe(pos, tmp, &records_list, list) {
|
||
|
if (pos->record->psi == psi) {
|
||
|
list_del_init(&pos->list);
|
||
|
rc = simple_unlink(d_inode(root), pos->dentry);
|
||
|
if (WARN_ON(rc))
|
||
|
break;
|
||
|
d_drop(pos->dentry);
|
||
|
dput(pos->dentry);
|
||
|
pos->dentry = NULL;
|
||
|
}
|
||
|
}
|
||
|
mutex_unlock(&records_list_lock);
|
||
|
|
||
|
inode_unlock(d_inode(root));
|
||
|
|
||
|
return rc;
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* 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(struct dentry *root, struct pstore_record *record)
|
||
|
{
|
||
|
struct dentry *dentry;
|
||
|
struct inode *inode;
|
||
|
int rc = 0;
|
||
|
char name[PSTORE_NAMELEN];
|
||
|
struct pstore_private *private, *pos;
|
||
|
size_t size = record->size + record->ecc_notice_size;
|
||
|
|
||
|
if (WARN_ON(!inode_is_locked(d_inode(root))))
|
||
|
return -EINVAL;
|
||
|
|
||
|
rc = -EEXIST;
|
||
|
/* Skip records that are already present in the filesystem. */
|
||
|
mutex_lock(&records_list_lock);
|
||
|
list_for_each_entry(pos, &records_list, list) {
|
||
|
if (pos->record->type == record->type &&
|
||
|
pos->record->id == record->id &&
|
||
|
pos->record->psi == record->psi)
|
||
|
goto fail;
|
||
|
}
|
||
|
|
||
|
rc = -ENOMEM;
|
||
|
inode = pstore_get_inode(root->d_sb);
|
||
|
if (!inode)
|
||
|
goto fail;
|
||
|
inode->i_mode = S_IFREG | 0444;
|
||
|
inode->i_fop = &pstore_file_operations;
|
||
|
scnprintf(name, sizeof(name), "%s-%s-%llu%s",
|
||
|
pstore_type_to_name(record->type),
|
||
|
record->psi->name, record->id,
|
||
|
record->compressed ? ".enc.z" : "");
|
||
|
|
||
|
private = kzalloc(sizeof(*private), GFP_KERNEL);
|
||
|
if (!private)
|
||
|
goto fail_inode;
|
||
|
|
||
|
dentry = d_alloc_name(root, name);
|
||
|
if (!dentry)
|
||
|
goto fail_private;
|
||
|
|
||
|
private->dentry = dentry;
|
||
|
private->record = record;
|
||
|
inode->i_size = private->total_size = size;
|
||
|
inode->i_private = private;
|
||
|
|
||
|
if (record->time.tv_sec)
|
||
|
inode->i_mtime = inode->i_ctime = record->time;
|
||
|
|
||
|
d_add(dentry, inode);
|
||
|
|
||
|
list_add(&private->list, &records_list);
|
||
|
mutex_unlock(&records_list_lock);
|
||
|
|
||
|
return 0;
|
||
|
|
||
|
fail_private:
|
||
|
free_pstore_private(private);
|
||
|
fail_inode:
|
||
|
iput(inode);
|
||
|
fail:
|
||
|
mutex_unlock(&records_list_lock);
|
||
|
return rc;
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* Read all the records from the persistent store. Create
|
||
|
* files in our filesystem. Don't warn about -EEXIST errors
|
||
|
* when we are re-scanning the backing store looking to add new
|
||
|
* error records.
|
||
|
*/
|
||
|
void pstore_get_records(int quiet)
|
||
|
{
|
||
|
struct dentry *root;
|
||
|
|
||
|
root = psinfo_lock_root();
|
||
|
if (!root)
|
||
|
return;
|
||
|
|
||
|
pstore_get_backend_records(psinfo, root, quiet);
|
||
|
inode_unlock(d_inode(root));
|
||
|
}
|
||
|
|
||
|
static int pstore_fill_super(struct super_block *sb, void *data, int silent)
|
||
|
{
|
||
|
struct inode *inode;
|
||
|
|
||
|
sb->s_maxbytes = MAX_LFS_FILESIZE;
|
||
|
sb->s_blocksize = PAGE_SIZE;
|
||
|
sb->s_blocksize_bits = PAGE_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 | 0750;
|
||
|
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;
|
||
|
|
||
|
mutex_lock(&pstore_sb_lock);
|
||
|
pstore_sb = sb;
|
||
|
mutex_unlock(&pstore_sb_lock);
|
||
|
|
||
|
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)
|
||
|
{
|
||
|
mutex_lock(&pstore_sb_lock);
|
||
|
WARN_ON(pstore_sb && pstore_sb != sb);
|
||
|
|
||
|
kill_litter_super(sb);
|
||
|
pstore_sb = NULL;
|
||
|
|
||
|
mutex_lock(&records_list_lock);
|
||
|
INIT_LIST_HEAD(&records_list);
|
||
|
mutex_unlock(&records_list_lock);
|
||
|
|
||
|
mutex_unlock(&pstore_sb_lock);
|
||
|
}
|
||
|
|
||
|
static struct file_system_type pstore_fs_type = {
|
||
|
.owner = THIS_MODULE,
|
||
|
.name = "pstore",
|
||
|
.mount = pstore_mount,
|
||
|
.kill_sb = pstore_kill_sb,
|
||
|
};
|
||
|
|
||
|
int __init pstore_init_fs(void)
|
||
|
{
|
||
|
int err;
|
||
|
|
||
|
/* Create a convenient mount point for people to access pstore */
|
||
|
err = sysfs_create_mount_point(fs_kobj, "pstore");
|
||
|
if (err)
|
||
|
goto out;
|
||
|
|
||
|
err = register_filesystem(&pstore_fs_type);
|
||
|
if (err < 0)
|
||
|
sysfs_remove_mount_point(fs_kobj, "pstore");
|
||
|
|
||
|
out:
|
||
|
return err;
|
||
|
}
|
||
|
|
||
|
void __exit pstore_exit_fs(void)
|
||
|
{
|
||
|
unregister_filesystem(&pstore_fs_type);
|
||
|
sysfs_remove_mount_point(fs_kobj, "pstore");
|
||
|
}
|