linux/fs/pstore/inode.c at master · fabgithub/linux · GitHub

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* Persistent Storage - ramfs parts.

* 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);

else

return -EPERM;

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_PPC_RTAS:

sprintf(name, "rtas-%s-%lld", psname, id);

break;

case PSTORE_TYPE_PPC_OF:

sprintf(name, "powerpc-ofw-%s-%lld", psname, id);

break;

case PSTORE_TYPE_PPC_COMMON:

sprintf(name, "powerpc-common-%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");

linux/fs/pstore/inode.c at master · fabgithub/linux · GitHub

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