[mirror_ubuntu-artful-kernel.git] / fs / pstore / inode.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 <linux/syslog.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_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);
	}
	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;

	data->off += REC_SIZE;
	if (data->off + REC_SIZE > ps->total_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;

	rec = (struct pstore_ftrace_record *)(ps->record->buf + data->off);

	seq_printf(s, "CPU:%d ts:%llu %08lx  %08lx  %pf <- %pF\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 int pstore_check_syslog_permissions(struct pstore_private *ps)
{
	switch (ps->record->type) {
	case PSTORE_TYPE_DMESG:
	case PSTORE_TYPE_CONSOLE:
		return check_syslog_permissions(SYSLOG_ACTION_READ_ALL,
			SYSLOG_FROM_READER);
	default:
		return 0;
	}
}

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;

	err = pstore_check_syslog_permissions(ps);
	if (err)
		return err;

	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 err;

	err = pstore_check_syslog_permissions(p);
	if (err)
		return err;

	if (!record->psi->erase)
		return -EPERM;

	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;
	unsigned long		flags;

	clear_inode(inode);
	if (p) {
		spin_lock_irqsave(&allpstore_lock, flags);
		list_del(&p->list);
		spin_unlock_irqrestore(&allpstore_lock, flags);
		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;
		}
	}
}

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	= generic_show_options,
};

static struct super_block *pstore_sb;

bool 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(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;
	unsigned long		flags;
	size_t			size = record->size + record->ecc_notice_size;

	WARN_ON(!inode_is_locked(d_inode(root)));

	spin_lock_irqsave(&allpstore_lock, flags);
	list_for_each_entry(pos, &allpstore, list) {
		if (pos->record->type == record->type &&
		    pos->record->id == record->id &&
		    pos->record->psi == record->psi) {
			rc = -EEXIST;
			break;
		}
	}
	spin_unlock_irqrestore(&allpstore_lock, flags);
	if (rc)
		return rc;

	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;
	private = kzalloc(sizeof(*private), GFP_KERNEL);
	if (!private)
		goto fail_alloc;
	private->record = record;

	switch (record->type) {
	case PSTORE_TYPE_DMESG:
		scnprintf(name, sizeof(name), "dmesg-%s-%lld%s",
			  record->psi->name, record->id,
			  record->compressed ? ".enc.z" : "");
		break;
	case PSTORE_TYPE_CONSOLE:
		scnprintf(name, sizeof(name), "console-%s-%lld",
			  record->psi->name, record->id);
		break;
	case PSTORE_TYPE_FTRACE:
		scnprintf(name, sizeof(name), "ftrace-%s-%lld",
			  record->psi->name, record->id);
		break;
	case PSTORE_TYPE_MCE:
		scnprintf(name, sizeof(name), "mce-%s-%lld",
			  record->psi->name, record->id);
		break;
	case PSTORE_TYPE_PPC_RTAS:
		scnprintf(name, sizeof(name), "rtas-%s-%lld",
			  record->psi->name, record->id);
		break;
	case PSTORE_TYPE_PPC_OF:
		scnprintf(name, sizeof(name), "powerpc-ofw-%s-%lld",
			  record->psi->name, record->id);
		break;
	case PSTORE_TYPE_PPC_COMMON:
		scnprintf(name, sizeof(name), "powerpc-common-%s-%lld",
			  record->psi->name, record->id);
		break;
	case PSTORE_TYPE_PMSG:
		scnprintf(name, sizeof(name), "pmsg-%s-%lld",
			  record->psi->name, record->id);
		break;
	case PSTORE_TYPE_PPC_OPAL:
		scnprintf(name, sizeof(name), "powerpc-opal-%s-%lld",
			  record->psi->name, record->id);
		break;
	case PSTORE_TYPE_UNKNOWN:
		scnprintf(name, sizeof(name), "unknown-%s-%lld",
			  record->psi->name, record->id);
		break;
	default:
		scnprintf(name, sizeof(name), "type%d-%s-%lld",
			  record->type, record->psi->name, record->id);
		break;
	}

	dentry = d_alloc_name(root, name);
	if (!dentry)
		goto fail_private;

	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);

	spin_lock_irqsave(&allpstore_lock, flags);
	list_add(&private->list, &allpstore);
	spin_unlock_irqrestore(&allpstore_lock, flags);

	return 0;

fail_private:
	free_pstore_private(private);
fail_alloc:
	iput(inode);

fail:
	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 pstore_info *psi = psinfo;
	struct dentry *root;

	if (!psi || !pstore_sb)
		return;

	root = pstore_sb->s_root;

	inode_lock(d_inode(root));
	pstore_get_backend_records(psi, root, quiet);
	inode_unlock(d_inode(root));
}

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_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 | 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 = {
	.owner          = THIS_MODULE,
	.name		= "pstore",
	.mount		= pstore_mount,
	.kill_sb	= pstore_kill_sb,
};

static int __init init_pstore_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;
}
module_init(init_pstore_fs)

static void __exit exit_pstore_fs(void)
{
	unregister_filesystem(&pstore_fs_type);
	sysfs_remove_mount_point(fs_kobj, "pstore");
}
module_exit(exit_pstore_fs)

MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
MODULE_LICENSE("GPL");
Commit	Line	Data
ca01d6dd TL	1	/*
	2	* Persistent Storage - ramfs parts.
	3	*
	4	* Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 as
	8	* published by the Free Software Foundation.
	9	*
	10	* This program is distributed in the hope that it will be useful,
	11	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	13	* GNU General Public License for more details.
	14	*
	15	* You should have received a copy of the GNU General Public License
	16	* along with this program; if not, write to the Free Software
	17	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	18	*/
	19
	20	#include <linux/module.h>
	21	#include <linux/fs.h>
	22	#include <linux/fsnotify.h>
	23	#include <linux/pagemap.h>
	24	#include <linux/highmem.h>
	25	#include <linux/time.h>
	26	#include <linux/init.h>
6dda9266	27	#include <linux/list.h>
ca01d6dd TL	28	#include <linux/string.h>
ca01d6dd TL	29	#include <linux/mount.h>
060287b8	30	#include <linux/seq_file.h>
ca01d6dd	31	#include <linux/ramfs.h>
366f7e7a	32	#include <linux/parser.h>
ca01d6dd TL	33	#include <linux/sched.h>
	34	#include <linux/magic.h>
	35	#include <linux/pstore.h>
	36	#include <linux/slab.h>
6dda9266	37	#include <linux/spinlock.h>
ca01d6dd	38	#include <linux/uaccess.h>
68c4a4f8	39	#include <linux/syslog.h>
ca01d6dd TL	40
	41	#include "internal.h"
	42
	43	#define PSTORE_NAMELEN 64
	44
6dda9266 TL	45	static DEFINE_SPINLOCK(allpstore_lock);
	46	static LIST_HEAD(allpstore);
	47
ca01d6dd	48	struct pstore_private {
6dda9266	49	struct list_head list;
83f70f07 KC	50	struct pstore_record *record;
83f70f07 KC	51	size_t total_size;
ca01d6dd TL	52	};
ca01d6dd TL	53
060287b8 AV	54	struct pstore_ftrace_seq_data {
	55	const void *ptr;
	56	size_t off;
	57	size_t size;
	58	};
	59
	60	#define REC_SIZE sizeof(struct pstore_ftrace_record)
	61
1dfff7dd KC	62	static void free_pstore_private(struct pstore_private *private)
	63	{
	64	if (!private)
	65	return;
83f70f07 KC	66	if (private->record) {
	67	kfree(private->record->buf);
	68	kfree(private->record);
	69	}
1dfff7dd KC	70	kfree(private);
	71	}
	72
060287b8 AV	73	static void pstore_ftrace_seq_start(struct seq_file s, loff_t *pos)
	74	{
	75	struct pstore_private *ps = s->private;
	76	struct pstore_ftrace_seq_data *data;
	77
	78	data = kzalloc(sizeof(*data), GFP_KERNEL);
	79	if (!data)
	80	return NULL;
	81
83f70f07	82	data->off = ps->total_size % REC_SIZE;
060287b8	83	data->off += pos REC_SIZE;
83f70f07	84	if (data->off + REC_SIZE > ps->total_size) {
060287b8 AV	85	kfree(data);
	86	return NULL;
	87	}
	88
	89	return data;
	90
	91	}
	92
	93	static void pstore_ftrace_seq_stop(struct seq_file s, void v)
	94	{
	95	kfree(v);
	96	}
	97
	98	static void pstore_ftrace_seq_next(struct seq_file s, void v, loff_t pos)
	99	{
	100	struct pstore_private *ps = s->private;
	101	struct pstore_ftrace_seq_data *data = v;
	102
	103	data->off += REC_SIZE;
83f70f07	104	if (data->off + REC_SIZE > ps->total_size)
060287b8 AV	105	return NULL;
	106
	107	(*pos)++;
	108	return data;
	109	}
	110
	111	static int pstore_ftrace_seq_show(struct seq_file s, void v)
	112	{
	113	struct pstore_private *ps = s->private;
	114	struct pstore_ftrace_seq_data *data = v;
83f70f07 KC	115	struct pstore_ftrace_record *rec;
	116
	117	rec = (struct pstore_ftrace_record *)(ps->record->buf + data->off);
060287b8	118
fbccdeb8 JF	119	seq_printf(s, "CPU:%d ts:%llu %08lx %08lx %pf <- %pF\n",
	120	pstore_ftrace_decode_cpu(rec),
	121	pstore_ftrace_read_timestamp(rec),
	122	rec->ip, rec->parent_ip, (void *)rec->ip,
	123	(void *)rec->parent_ip);
060287b8 AV	124
	125	return 0;
	126	}
	127
	128	static const struct seq_operations pstore_ftrace_seq_ops = {
	129	.start = pstore_ftrace_seq_start,
	130	.next = pstore_ftrace_seq_next,
	131	.stop = pstore_ftrace_seq_stop,
	132	.show = pstore_ftrace_seq_show,
	133	};
	134
68c4a4f8 SS	135	static int pstore_check_syslog_permissions(struct pstore_private *ps)
68c4a4f8 SS	136	{
83f70f07	137	switch (ps->record->type) {
68c4a4f8 SS	138	case PSTORE_TYPE_DMESG:
	139	case PSTORE_TYPE_CONSOLE:
	140	return check_syslog_permissions(SYSLOG_ACTION_READ_ALL,
	141	SYSLOG_FROM_READER);
	142	default:
	143	return 0;
	144	}
	145	}
	146
fbe0aa1f TL	147	static ssize_t pstore_file_read(struct file file, char __user userbuf,
	148	size_t count, loff_t *ppos)
	149	{
060287b8 AV	150	struct seq_file *sf = file->private_data;
060287b8 AV	151	struct pstore_private *ps = sf->private;
fbe0aa1f	152
83f70f07	153	if (ps->record->type == PSTORE_TYPE_FTRACE)
060287b8	154	return seq_read(file, userbuf, count, ppos);
83f70f07 KC	155	return simple_read_from_buffer(userbuf, count, ppos,
83f70f07 KC	156	ps->record->buf, ps->total_size);
fbe0aa1f TL	157	}
fbe0aa1f TL	158
060287b8 AV	159	static int pstore_file_open(struct inode inode, struct file file)
	160	{
	161	struct pstore_private *ps = inode->i_private;
	162	struct seq_file *sf;
	163	int err;
	164	const struct seq_operations *sops = NULL;
	165
68c4a4f8 SS	166	err = pstore_check_syslog_permissions(ps);
	167	if (err)
	168	return err;
	169
83f70f07	170	if (ps->record->type == PSTORE_TYPE_FTRACE)
060287b8 AV	171	sops = &pstore_ftrace_seq_ops;
	172
	173	err = seq_open(file, sops);
	174	if (err < 0)
	175	return err;
	176
	177	sf = file->private_data;
	178	sf->private = ps;
	179
	180	return 0;
	181	}
	182
965c8e59	183	static loff_t pstore_file_llseek(struct file *file, loff_t off, int whence)
060287b8 AV	184	{
	185	struct seq_file *sf = file->private_data;
	186
	187	if (sf->op)
965c8e59 AM	188	return seq_lseek(file, off, whence);
965c8e59 AM	189	return default_llseek(file, off, whence);
060287b8 AV	190	}
060287b8 AV	191
fbe0aa1f	192	static const struct file_operations pstore_file_operations = {
060287b8 AV	193	.open = pstore_file_open,
	194	.read = pstore_file_read,
	195	.llseek = pstore_file_llseek,
	196	.release = seq_release,
fbe0aa1f	197	};
ca01d6dd TL	198
	199	/*
	200	* When a file is unlinked from our file system we call the
	201	* platform driver to erase the record from persistent store.
	202	*/
	203	static int pstore_unlink(struct inode dir, struct dentry dentry)
	204	{
2b0143b5	205	struct pstore_private *p = d_inode(dentry)->i_private;
83f70f07	206	struct pstore_record *record = p->record;
68c4a4f8 SS	207	int err;
	208
	209	err = pstore_check_syslog_permissions(p);
	210	if (err)
	211	return err;
ca01d6dd	212
a61072aa	213	if (!record->psi->erase)
bf288333	214	return -EPERM;
a61072aa KC	215
	216	mutex_lock(&record->psi->read_mutex);
	217	record->psi->erase(record);
	218	mutex_unlock(&record->psi->read_mutex);
ca01d6dd TL	219
	220	return simple_unlink(dir, dentry);
	221	}
	222
a872d510 TL	223	static void pstore_evict_inode(struct inode *inode)
a872d510 TL	224	{
6dda9266 TL	225	struct pstore_private *p = inode->i_private;
	226	unsigned long flags;
	227
dbd5768f	228	clear_inode(inode);
6dda9266 TL	229	if (p) {
	230	spin_lock_irqsave(&allpstore_lock, flags);
	231	list_del(&p->list);
	232	spin_unlock_irqrestore(&allpstore_lock, flags);
1dfff7dd	233	free_pstore_private(p);
6dda9266	234	}
a872d510 TL	235	}
a872d510 TL	236
ca01d6dd TL	237	static const struct inode_operations pstore_dir_inode_operations = {
	238	.lookup = simple_lookup,
	239	.unlink = pstore_unlink,
	240	};
	241
22a71c30	242	static struct inode pstore_get_inode(struct super_block sb)
fbe0aa1f TL	243	{
fbe0aa1f TL	244	struct inode *inode = new_inode(sb);
fbe0aa1f TL	245	if (inode) {
fbe0aa1f TL	246	inode->i_ino = get_next_ino();
078cd827	247	inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
fbe0aa1f TL	248	}
	249	return inode;
	250	}
	251
366f7e7a TL	252	enum {
	253	Opt_kmsg_bytes, Opt_err
	254	};
	255
	256	static const match_table_t tokens = {
	257	{Opt_kmsg_bytes, "kmsg_bytes=%u"},
	258	{Opt_err, NULL}
	259	};
	260
	261	static void parse_options(char *options)
	262	{
	263	char *p;
	264	substring_t args[MAX_OPT_ARGS];
	265	int option;
	266
	267	if (!options)
	268	return;
	269
	270	while ((p = strsep(&options, ",")) != NULL) {
	271	int token;
	272
	273	if (!*p)
	274	continue;
	275
	276	token = match_token(p, tokens, args);
	277	switch (token) {
	278	case Opt_kmsg_bytes:
	279	if (!match_int(&args[0], &option))
	280	pstore_set_kmsg_bytes(option);
	281	break;
	282	}
	283	}
	284	}
	285
	286	static int pstore_remount(struct super_block sb, int flags, char *data)
	287	{
02b9984d	288	sync_filesystem(sb);
366f7e7a TL	289	parse_options(data);
	290
	291	return 0;
	292	}
	293
ca01d6dd TL	294	static const struct super_operations pstore_ops = {
	295	.statfs = simple_statfs,
	296	.drop_inode = generic_delete_inode,
a872d510	297	.evict_inode = pstore_evict_inode,
366f7e7a	298	.remount_fs = pstore_remount,
ca01d6dd TL	299	.show_options = generic_show_options,
	300	};
	301
	302	static struct super_block *pstore_sb;
ca01d6dd	303
7e26e9ff	304	bool pstore_is_mounted(void)
ca01d6dd	305	{
fbe0aa1f	306	return pstore_sb != NULL;
ca01d6dd TL	307	}
	308
	309	/*
	310	* Make a regular file in the root directory of our file system.
	311	* Load it up with "size" bytes of data from "buf".
	312	* Set the mtime & ctime to the date that this record was originally stored.
	313	*/
3a7d2fd1	314	int pstore_mkfile(struct dentry root, struct pstore_record record)
ca01d6dd	315	{
ca01d6dd TL	316	struct dentry *dentry;
ca01d6dd TL	317	struct inode *inode;
6dda9266	318	int rc = 0;
ca01d6dd	319	char name[PSTORE_NAMELEN];
6dda9266 TL	320	struct pstore_private private, pos;
6dda9266 TL	321	unsigned long flags;
1edd1aa3	322	size_t size = record->size + record->ecc_notice_size;
6dda9266	323
3a7d2fd1 KC	324	WARN_ON(!inode_is_locked(d_inode(root)));
3a7d2fd1 KC	325
6dda9266 TL	326	spin_lock_irqsave(&allpstore_lock, flags);
6dda9266 TL	327	list_for_each_entry(pos, &allpstore, list) {
83f70f07 KC	328	if (pos->record->type == record->type &&
	329	pos->record->id == record->id &&
	330	pos->record->psi == record->psi) {
6dda9266 TL	331	rc = -EEXIST;
	332	break;
	333	}
	334	}
	335	spin_unlock_irqrestore(&allpstore_lock, flags);
	336	if (rc)
	337	return rc;
ca01d6dd TL	338
ca01d6dd TL	339	rc = -ENOMEM;
3a7d2fd1	340	inode = pstore_get_inode(root->d_sb);
ca01d6dd TL	341	if (!inode)
ca01d6dd TL	342	goto fail;
22a71c30 AV	343	inode->i_mode = S_IFREG \| 0444;
22a71c30 AV	344	inode->i_fop = &pstore_file_operations;
1dfff7dd	345	private = kzalloc(sizeof(*private), GFP_KERNEL);
ca01d6dd TL	346	if (!private)
ca01d6dd TL	347	goto fail_alloc;
83f70f07	348	private->record = record;
ca01d6dd	349
1edd1aa3	350	switch (record->type) {
ca01d6dd	351	case PSTORE_TYPE_DMESG:
dbaffde7	352	scnprintf(name, sizeof(name), "dmesg-%s-%lld%s",
1edd1aa3 KC	353	record->psi->name, record->id,
1edd1aa3 KC	354	record->compressed ? ".enc.z" : "");
ca01d6dd	355	break;
f29e5956	356	case PSTORE_TYPE_CONSOLE:
1edd1aa3 KC	357	scnprintf(name, sizeof(name), "console-%s-%lld",
1edd1aa3 KC	358	record->psi->name, record->id);
f29e5956	359	break;
060287b8	360	case PSTORE_TYPE_FTRACE:
1edd1aa3 KC	361	scnprintf(name, sizeof(name), "ftrace-%s-%lld",
1edd1aa3 KC	362	record->psi->name, record->id);
060287b8	363	break;
ca01d6dd	364	case PSTORE_TYPE_MCE:
1edd1aa3 KC	365	scnprintf(name, sizeof(name), "mce-%s-%lld",
1edd1aa3 KC	366	record->psi->name, record->id);
ca01d6dd	367	break;
69020eea	368	case PSTORE_TYPE_PPC_RTAS:
1edd1aa3 KC	369	scnprintf(name, sizeof(name), "rtas-%s-%lld",
1edd1aa3 KC	370	record->psi->name, record->id);
69020eea	371	break;
f33f748c	372	case PSTORE_TYPE_PPC_OF:
dbaffde7	373	scnprintf(name, sizeof(name), "powerpc-ofw-%s-%lld",
1edd1aa3	374	record->psi->name, record->id);
f33f748c	375	break;
a5e4797b	376	case PSTORE_TYPE_PPC_COMMON:
dbaffde7	377	scnprintf(name, sizeof(name), "powerpc-common-%s-%lld",
1edd1aa3	378	record->psi->name, record->id);
a5e4797b	379	break;
9d5438f4	380	case PSTORE_TYPE_PMSG:
1edd1aa3 KC	381	scnprintf(name, sizeof(name), "pmsg-%s-%lld",
1edd1aa3 KC	382	record->psi->name, record->id);
9d5438f4	383	break;
ae011d2e	384	case PSTORE_TYPE_PPC_OPAL:
1edd1aa3 KC	385	scnprintf(name, sizeof(name), "powerpc-opal-%s-%lld",
1edd1aa3 KC	386	record->psi->name, record->id);
ae011d2e	387	break;
ca01d6dd	388	case PSTORE_TYPE_UNKNOWN:
1edd1aa3 KC	389	scnprintf(name, sizeof(name), "unknown-%s-%lld",
1edd1aa3 KC	390	record->psi->name, record->id);
ca01d6dd TL	391	break;
ca01d6dd TL	392	default:
dbaffde7	393	scnprintf(name, sizeof(name), "type%d-%s-%lld",
1edd1aa3	394	record->type, record->psi->name, record->id);
ca01d6dd TL	395	break;
	396	}
	397
ca01d6dd	398	dentry = d_alloc_name(root, name);
c39524e6	399	if (!dentry)
3a7d2fd1	400	goto fail_private;
ca01d6dd	401
83f70f07	402	inode->i_size = private->total_size = size;
ca01d6dd TL	403
	404	inode->i_private = private;
	405
1edd1aa3 KC	406	if (record->time.tv_sec)
1edd1aa3 KC	407	inode->i_mtime = inode->i_ctime = record->time;
ca01d6dd	408
fbe0aa1f	409	d_add(dentry, inode);
ca01d6dd	410
6dda9266 TL	411	spin_lock_irqsave(&allpstore_lock, flags);
	412	list_add(&private->list, &allpstore);
	413	spin_unlock_irqrestore(&allpstore_lock, flags);
	414
fbe0aa1f	415	return 0;
ca01d6dd	416
3a7d2fd1	417	fail_private:
1dfff7dd	418	free_pstore_private(private);
ca01d6dd TL	419	fail_alloc:
	420	iput(inode);
	421
	422	fail:
	423	return rc;
	424	}
	425
3a7d2fd1 KC	426	/*
	427	* Read all the records from the persistent store. Create
	428	* files in our filesystem. Don't warn about -EEXIST errors
	429	* when we are re-scanning the backing store looking to add new
	430	* error records.
	431	*/
	432	void pstore_get_records(int quiet)
	433	{
	434	struct pstore_info *psi = psinfo;
	435	struct dentry *root;
	436
	437	if (!psi \|\| !pstore_sb)
	438	return;
	439
	440	root = pstore_sb->s_root;
	441
	442	inode_lock(d_inode(root));
	443	pstore_get_backend_records(psi, root, quiet);
	444	inode_unlock(d_inode(root));
	445	}
	446
364ed2f4	447	static int pstore_fill_super(struct super_block sb, void data, int silent)
ca01d6dd	448	{
318ceed0	449	struct inode *inode;
ca01d6dd TL	450
	451	save_mount_options(sb, data);
	452
	453	pstore_sb = sb;
	454
	455	sb->s_maxbytes = MAX_LFS_FILESIZE;
09cbfeaf KS	456	sb->s_blocksize = PAGE_SIZE;
09cbfeaf KS	457	sb->s_blocksize_bits = PAGE_SHIFT;
ca01d6dd TL	458	sb->s_magic = PSTOREFS_MAGIC;
	459	sb->s_op = &pstore_ops;
	460	sb->s_time_gran = 1;
	461
366f7e7a TL	462	parse_options(data);
366f7e7a TL	463
22a71c30	464	inode = pstore_get_inode(sb);
318ceed0	465	if (inode) {
22a71c30	466	inode->i_mode = S_IFDIR \| 0755;
318ceed0	467	inode->i_op = &pstore_dir_inode_operations;
22a71c30 AV	468	inode->i_fop = &simple_dir_operations;
22a71c30 AV	469	inc_nlink(inode);
ca01d6dd	470	}
318ceed0 AV	471	sb->s_root = d_make_root(inode);
	472	if (!sb->s_root)
	473	return -ENOMEM;
ca01d6dd	474
6dda9266	475	pstore_get_records(0);
ca01d6dd TL	476
ca01d6dd TL	477	return 0;
ca01d6dd TL	478	}
ca01d6dd TL	479
fbe0aa1f TL	480	static struct dentry pstore_mount(struct file_system_type fs_type,
fbe0aa1f TL	481	int flags, const char dev_name, void data)
ca01d6dd	482	{
fbe0aa1f	483	return mount_single(fs_type, flags, data, pstore_fill_super);
ca01d6dd TL	484	}
	485
	486	static void pstore_kill_sb(struct super_block *sb)
	487	{
	488	kill_litter_super(sb);
	489	pstore_sb = NULL;
ca01d6dd TL	490	}
	491
	492	static struct file_system_type pstore_fs_type = {
ee1d2674	493	.owner = THIS_MODULE,
ca01d6dd	494	.name = "pstore",
fbe0aa1f	495	.mount = pstore_mount,
ca01d6dd TL	496	.kill_sb = pstore_kill_sb,
	497	};
	498
	499	static int __init init_pstore_fs(void)
	500	{
f9bb4882	501	int err;
fb0af3f2 JB	502
fb0af3f2 JB	503	/* Create a convenient mount point for people to access pstore */
f9bb4882 EB	504	err = sysfs_create_mount_point(fs_kobj, "pstore");
f9bb4882 EB	505	if (err)
fb0af3f2	506	goto out;
fb0af3f2 JB	507
	508	err = register_filesystem(&pstore_fs_type);
	509	if (err < 0)
f9bb4882	510	sysfs_remove_mount_point(fs_kobj, "pstore");
fb0af3f2 JB	511
	512	out:
	513	return err;
ca01d6dd TL	514	}
	515	module_init(init_pstore_fs)
	516
ee1d2674 GT	517	static void __exit exit_pstore_fs(void)
	518	{
	519	unregister_filesystem(&pstore_fs_type);
	520	sysfs_remove_mount_point(fs_kobj, "pstore");
	521	}
	522	module_exit(exit_pstore_fs)
	523
ca01d6dd TL	524	MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
ca01d6dd TL	525	MODULE_LICENSE("GPL");