[linux-block.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_info *psi;
	enum pstore_type_id type;
	u64	id;
	int	count;
	ssize_t	size;
	char    *buf;
};

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;
	kfree(private->buf);
	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->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->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->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->type == PSTORE_TYPE_FTRACE)
		return seq_read(file, userbuf, count, ppos);
	return simple_read_from_buffer(userbuf, count, ppos, ps->buf, 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;

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

	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 = d_inode(dentry)->i_private;
	int err;

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

	if (p->psi->erase) {
		mutex_lock(&p->psi->read_mutex);
		p->psi->erase(p->type, p->id, p->count,
			      d_inode(dentry)->i_ctime, p->psi);
		mutex_unlock(&p->psi->read_mutex);
	} 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);
		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 pstore_record *record)
{
	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;
	size_t			size = record->size + record->ecc_notice_size;

	spin_lock_irqsave(&allpstore_lock, flags);
	list_for_each_entry(pos, &allpstore, list) {
		if (pos->type == record->type &&
		    pos->id == record->id &&
		    pos->psi == record->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 = kzalloc(sizeof(*private), GFP_KERNEL);
	if (!private)
		goto fail_alloc;
	private->type = record->type;
	private->id = record->id;
	private->count = record->count;
	private->psi = record->psi;

	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;
	}

	inode_lock(d_inode(root));

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

	private->buf = record->buf;
	inode->i_size = private->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);

	inode_unlock(d_inode(root));

	return 0;

fail_lockedalloc:
	inode_unlock(d_inode(root));
	free_pstore_private(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_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 LT	45	static DEFINE_SPINLOCK(allpstore_lock);
	46	static LIST_HEAD(allpstore);
	47
ca01d6dd	48	struct pstore_private {
6dda9266	49	struct list_head list;
638c1fd3	50	struct pstore_info *psi;
56280682 MG	51	enum pstore_type_id type;
56280682 MG	52	u64 id;
755d4fe4	53	int count;
fbe0aa1f	54	ssize_t size;
1dfff7dd	55	char *buf;
ca01d6dd TL	56	};
ca01d6dd TL	57
060287b8 AV	58	struct pstore_ftrace_seq_data {
	59	const void *ptr;
	60	size_t off;
	61	size_t size;
	62	};
	63
	64	#define REC_SIZE sizeof(struct pstore_ftrace_record)
	65
1dfff7dd KC	66	static void free_pstore_private(struct pstore_private *private)
	67	{
	68	if (!private)
	69	return;
	70	kfree(private->buf);
	71	kfree(private);
	72	}
	73
060287b8 AV	74	static void pstore_ftrace_seq_start(struct seq_file s, loff_t *pos)
	75	{
	76	struct pstore_private *ps = s->private;
	77	struct pstore_ftrace_seq_data *data;
	78
	79	data = kzalloc(sizeof(*data), GFP_KERNEL);
	80	if (!data)
	81	return NULL;
	82
	83	data->off = ps->size % REC_SIZE;
	84	data->off += pos REC_SIZE;
	85	if (data->off + REC_SIZE > ps->size) {
	86	kfree(data);
	87	return NULL;
	88	}
	89
	90	return data;
	91
	92	}
	93
	94	static void pstore_ftrace_seq_stop(struct seq_file s, void v)
	95	{
	96	kfree(v);
	97	}
	98
	99	static void pstore_ftrace_seq_next(struct seq_file s, void v, loff_t pos)
	100	{
	101	struct pstore_private *ps = s->private;
	102	struct pstore_ftrace_seq_data *data = v;
	103
	104	data->off += REC_SIZE;
	105	if (data->off + REC_SIZE > ps->size)
	106	return NULL;
	107
	108	(*pos)++;
	109	return data;
	110	}
	111
	112	static int pstore_ftrace_seq_show(struct seq_file s, void v)
	113	{
	114	struct pstore_private *ps = s->private;
	115	struct pstore_ftrace_seq_data *data = v;
1dfff7dd	116	struct pstore_ftrace_record rec = (void )(ps->buf + data->off);
060287b8	117
fbccdeb8 JF	118	seq_printf(s, "CPU:%d ts:%llu %08lx %08lx %pf <- %pF\n",
	119	pstore_ftrace_decode_cpu(rec),
	120	pstore_ftrace_read_timestamp(rec),
	121	rec->ip, rec->parent_ip, (void *)rec->ip,
	122	(void *)rec->parent_ip);
060287b8 AV	123
	124	return 0;
	125	}
	126
	127	static const struct seq_operations pstore_ftrace_seq_ops = {
	128	.start = pstore_ftrace_seq_start,
	129	.next = pstore_ftrace_seq_next,
	130	.stop = pstore_ftrace_seq_stop,
	131	.show = pstore_ftrace_seq_show,
	132	};
	133
68c4a4f8 SS	134	static int pstore_check_syslog_permissions(struct pstore_private *ps)
	135	{
	136	switch (ps->type) {
	137	case PSTORE_TYPE_DMESG:
	138	case PSTORE_TYPE_CONSOLE:
	139	return check_syslog_permissions(SYSLOG_ACTION_READ_ALL,
	140	SYSLOG_FROM_READER);
	141	default:
	142	return 0;
	143	}
	144	}
	145
fbe0aa1f TL	146	static ssize_t pstore_file_read(struct file file, char __user userbuf,
	147	size_t count, loff_t *ppos)
	148	{
060287b8 AV	149	struct seq_file *sf = file->private_data;
060287b8 AV	150	struct pstore_private *ps = sf->private;
fbe0aa1f	151
060287b8 AV	152	if (ps->type == PSTORE_TYPE_FTRACE)
060287b8 AV	153	return seq_read(file, userbuf, count, ppos);
1dfff7dd	154	return simple_read_from_buffer(userbuf, count, ppos, ps->buf, ps->size);
fbe0aa1f TL	155	}
fbe0aa1f TL	156
060287b8 AV	157	static int pstore_file_open(struct inode inode, struct file file)
	158	{
	159	struct pstore_private *ps = inode->i_private;
	160	struct seq_file *sf;
	161	int err;
	162	const struct seq_operations *sops = NULL;
	163
68c4a4f8 SS	164	err = pstore_check_syslog_permissions(ps);
	165	if (err)
	166	return err;
	167
060287b8 AV	168	if (ps->type == PSTORE_TYPE_FTRACE)
	169	sops = &pstore_ftrace_seq_ops;
	170
	171	err = seq_open(file, sops);
	172	if (err < 0)
	173	return err;
	174
	175	sf = file->private_data;
	176	sf->private = ps;
	177
	178	return 0;
	179	}
	180
965c8e59	181	static loff_t pstore_file_llseek(struct file *file, loff_t off, int whence)
060287b8 AV	182	{
	183	struct seq_file *sf = file->private_data;
	184
	185	if (sf->op)
965c8e59 AM	186	return seq_lseek(file, off, whence);
965c8e59 AM	187	return default_llseek(file, off, whence);
060287b8 AV	188	}
060287b8 AV	189
fbe0aa1f	190	static const struct file_operations pstore_file_operations = {
060287b8 AV	191	.open = pstore_file_open,
	192	.read = pstore_file_read,
	193	.llseek = pstore_file_llseek,
	194	.release = seq_release,
fbe0aa1f	195	};
ca01d6dd TL	196
	197	/*
	198	* When a file is unlinked from our file system we call the
	199	* platform driver to erase the record from persistent store.
	200	*/
	201	static int pstore_unlink(struct inode dir, struct dentry dentry)
	202	{
2b0143b5	203	struct pstore_private *p = d_inode(dentry)->i_private;
68c4a4f8 SS	204	int err;
	205
	206	err = pstore_check_syslog_permissions(p);
	207	if (err)
	208	return err;
ca01d6dd	209
e9e360b0 NK	210	if (p->psi->erase) {
e9e360b0 NK	211	mutex_lock(&p->psi->read_mutex);
755d4fe4	212	p->psi->erase(p->type, p->id, p->count,
2b0143b5	213	d_inode(dentry)->i_ctime, p->psi);
e9e360b0 NK	214	mutex_unlock(&p->psi->read_mutex);
e9e360b0 NK	215	} else {
bf288333	216	return -EPERM;
e9e360b0	217	}
ca01d6dd TL	218
	219	return simple_unlink(dir, dentry);
	220	}
	221
a872d510 TL	222	static void pstore_evict_inode(struct inode *inode)
a872d510 TL	223	{
6dda9266 LT	224	struct pstore_private *p = inode->i_private;
	225	unsigned long flags;
	226
dbd5768f	227	clear_inode(inode);
6dda9266 LT	228	if (p) {
	229	spin_lock_irqsave(&allpstore_lock, flags);
	230	list_del(&p->list);
	231	spin_unlock_irqrestore(&allpstore_lock, flags);
1dfff7dd	232	free_pstore_private(p);
6dda9266	233	}
a872d510 TL	234	}
a872d510 TL	235
ca01d6dd TL	236	static const struct inode_operations pstore_dir_inode_operations = {
	237	.lookup = simple_lookup,
	238	.unlink = pstore_unlink,
	239	};
	240
22a71c30	241	static struct inode pstore_get_inode(struct super_block sb)
fbe0aa1f TL	242	{
fbe0aa1f TL	243	struct inode *inode = new_inode(sb);
fbe0aa1f TL	244	if (inode) {
fbe0aa1f TL	245	inode->i_ino = get_next_ino();
078cd827	246	inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
fbe0aa1f TL	247	}
	248	return inode;
	249	}
	250
366f7e7a LT	251	enum {
	252	Opt_kmsg_bytes, Opt_err
	253	};
	254
	255	static const match_table_t tokens = {
	256	{Opt_kmsg_bytes, "kmsg_bytes=%u"},
	257	{Opt_err, NULL}
	258	};
	259
	260	static void parse_options(char *options)
	261	{
	262	char *p;
	263	substring_t args[MAX_OPT_ARGS];
	264	int option;
	265
	266	if (!options)
	267	return;
	268
	269	while ((p = strsep(&options, ",")) != NULL) {
	270	int token;
	271
	272	if (!*p)
	273	continue;
	274
	275	token = match_token(p, tokens, args);
	276	switch (token) {
	277	case Opt_kmsg_bytes:
	278	if (!match_int(&args[0], &option))
	279	pstore_set_kmsg_bytes(option);
	280	break;
	281	}
	282	}
	283	}
	284
	285	static int pstore_remount(struct super_block sb, int flags, char *data)
	286	{
02b9984d	287	sync_filesystem(sb);
366f7e7a LT	288	parse_options(data);
	289
	290	return 0;
	291	}
	292
ca01d6dd TL	293	static const struct super_operations pstore_ops = {
	294	.statfs = simple_statfs,
	295	.drop_inode = generic_delete_inode,
a872d510	296	.evict_inode = pstore_evict_inode,
366f7e7a	297	.remount_fs = pstore_remount,
ca01d6dd TL	298	.show_options = generic_show_options,
	299	};
	300
	301	static struct super_block *pstore_sb;
ca01d6dd	302
7e26e9ff	303	bool pstore_is_mounted(void)
ca01d6dd	304	{
fbe0aa1f	305	return pstore_sb != NULL;
ca01d6dd TL	306	}
	307
	308	/*
	309	* Make a regular file in the root directory of our file system.
	310	* Load it up with "size" bytes of data from "buf".
	311	* Set the mtime & ctime to the date that this record was originally stored.
	312	*/
1edd1aa3	313	int pstore_mkfile(struct pstore_record *record)
ca01d6dd TL	314	{
	315	struct dentry *root = pstore_sb->s_root;
	316	struct dentry *dentry;
	317	struct inode *inode;
6dda9266	318	int rc = 0;
ca01d6dd	319	char name[PSTORE_NAMELEN];
6dda9266 LT	320	struct pstore_private private, pos;
6dda9266 LT	321	unsigned long flags;
1edd1aa3	322	size_t size = record->size + record->ecc_notice_size;
6dda9266 LT	323
	324	spin_lock_irqsave(&allpstore_lock, flags);
	325	list_for_each_entry(pos, &allpstore, list) {
1edd1aa3 KC	326	if (pos->type == record->type &&
	327	pos->id == record->id &&
	328	pos->psi == record->psi) {
6dda9266 LT	329	rc = -EEXIST;
	330	break;
	331	}
	332	}
	333	spin_unlock_irqrestore(&allpstore_lock, flags);
	334	if (rc)
	335	return rc;
ca01d6dd TL	336
ca01d6dd TL	337	rc = -ENOMEM;
22a71c30	338	inode = pstore_get_inode(pstore_sb);
ca01d6dd TL	339	if (!inode)
ca01d6dd TL	340	goto fail;
22a71c30 AV	341	inode->i_mode = S_IFREG \| 0444;
22a71c30 AV	342	inode->i_fop = &pstore_file_operations;
1dfff7dd	343	private = kzalloc(sizeof(*private), GFP_KERNEL);
ca01d6dd TL	344	if (!private)
ca01d6dd TL	345	goto fail_alloc;
1edd1aa3 KC	346	private->type = record->type;
	347	private->id = record->id;
	348	private->count = record->count;
	349	private->psi = record->psi;
ca01d6dd	350
1edd1aa3	351	switch (record->type) {
ca01d6dd	352	case PSTORE_TYPE_DMESG:
dbaffde7	353	scnprintf(name, sizeof(name), "dmesg-%s-%lld%s",
1edd1aa3 KC	354	record->psi->name, record->id,
1edd1aa3 KC	355	record->compressed ? ".enc.z" : "");
ca01d6dd	356	break;
f29e5956	357	case PSTORE_TYPE_CONSOLE:
1edd1aa3 KC	358	scnprintf(name, sizeof(name), "console-%s-%lld",
1edd1aa3 KC	359	record->psi->name, record->id);
f29e5956	360	break;
060287b8	361	case PSTORE_TYPE_FTRACE:
1edd1aa3 KC	362	scnprintf(name, sizeof(name), "ftrace-%s-%lld",
1edd1aa3 KC	363	record->psi->name, record->id);
060287b8	364	break;
ca01d6dd	365	case PSTORE_TYPE_MCE:
1edd1aa3 KC	366	scnprintf(name, sizeof(name), "mce-%s-%lld",
1edd1aa3 KC	367	record->psi->name, record->id);
ca01d6dd	368	break;
69020eea	369	case PSTORE_TYPE_PPC_RTAS:
1edd1aa3 KC	370	scnprintf(name, sizeof(name), "rtas-%s-%lld",
1edd1aa3 KC	371	record->psi->name, record->id);
69020eea	372	break;
f33f748c	373	case PSTORE_TYPE_PPC_OF:
dbaffde7	374	scnprintf(name, sizeof(name), "powerpc-ofw-%s-%lld",
1edd1aa3	375	record->psi->name, record->id);
f33f748c	376	break;
a5e4797b	377	case PSTORE_TYPE_PPC_COMMON:
dbaffde7	378	scnprintf(name, sizeof(name), "powerpc-common-%s-%lld",
1edd1aa3	379	record->psi->name, record->id);
a5e4797b	380	break;
9d5438f4	381	case PSTORE_TYPE_PMSG:
1edd1aa3 KC	382	scnprintf(name, sizeof(name), "pmsg-%s-%lld",
1edd1aa3 KC	383	record->psi->name, record->id);
9d5438f4	384	break;
ae011d2e	385	case PSTORE_TYPE_PPC_OPAL:
1edd1aa3 KC	386	scnprintf(name, sizeof(name), "powerpc-opal-%s-%lld",
1edd1aa3 KC	387	record->psi->name, record->id);
ae011d2e	388	break;
ca01d6dd	389	case PSTORE_TYPE_UNKNOWN:
1edd1aa3 KC	390	scnprintf(name, sizeof(name), "unknown-%s-%lld",
1edd1aa3 KC	391	record->psi->name, record->id);
ca01d6dd TL	392	break;
ca01d6dd TL	393	default:
dbaffde7	394	scnprintf(name, sizeof(name), "type%d-%s-%lld",
1edd1aa3	395	record->type, record->psi->name, record->id);
ca01d6dd TL	396	break;
	397	}
	398
5955102c	399	inode_lock(d_inode(root));
ca01d6dd	400
ca01d6dd	401	dentry = d_alloc_name(root, name);
c39524e6	402	if (!dentry)
ca01d6dd TL	403	goto fail_lockedalloc;
ca01d6dd TL	404
1dfff7dd	405	private->buf = record->buf;
fbe0aa1f	406	inode->i_size = private->size = size;
ca01d6dd TL	407
	408	inode->i_private = private;
	409
1edd1aa3 KC	410	if (record->time.tv_sec)
1edd1aa3 KC	411	inode->i_mtime = inode->i_ctime = record->time;
ca01d6dd	412
fbe0aa1f	413	d_add(dentry, inode);
ca01d6dd	414
6dda9266 LT	415	spin_lock_irqsave(&allpstore_lock, flags);
	416	list_add(&private->list, &allpstore);
	417	spin_unlock_irqrestore(&allpstore_lock, flags);
	418
5955102c	419	inode_unlock(d_inode(root));
fbe0aa1f TL	420
fbe0aa1f TL	421	return 0;
ca01d6dd TL	422
ca01d6dd TL	423	fail_lockedalloc:
5955102c	424	inode_unlock(d_inode(root));
1dfff7dd	425	free_pstore_private(private);
ca01d6dd TL	426	fail_alloc:
	427	iput(inode);
	428
	429	fail:
	430	return rc;
	431	}
	432
364ed2f4	433	static int pstore_fill_super(struct super_block sb, void data, int silent)
ca01d6dd	434	{
318ceed0	435	struct inode *inode;
ca01d6dd TL	436
	437	save_mount_options(sb, data);
	438
	439	pstore_sb = sb;
	440
	441	sb->s_maxbytes = MAX_LFS_FILESIZE;
09cbfeaf KS	442	sb->s_blocksize = PAGE_SIZE;
09cbfeaf KS	443	sb->s_blocksize_bits = PAGE_SHIFT;
ca01d6dd TL	444	sb->s_magic = PSTOREFS_MAGIC;
	445	sb->s_op = &pstore_ops;
	446	sb->s_time_gran = 1;
	447
366f7e7a LT	448	parse_options(data);
366f7e7a LT	449
22a71c30	450	inode = pstore_get_inode(sb);
318ceed0	451	if (inode) {
22a71c30	452	inode->i_mode = S_IFDIR \| 0755;
318ceed0	453	inode->i_op = &pstore_dir_inode_operations;
22a71c30 AV	454	inode->i_fop = &simple_dir_operations;
22a71c30 AV	455	inc_nlink(inode);
ca01d6dd	456	}
318ceed0 AV	457	sb->s_root = d_make_root(inode);
	458	if (!sb->s_root)
	459	return -ENOMEM;
ca01d6dd	460
6dda9266	461	pstore_get_records(0);
ca01d6dd TL	462
ca01d6dd TL	463	return 0;
ca01d6dd TL	464	}
ca01d6dd TL	465
fbe0aa1f TL	466	static struct dentry pstore_mount(struct file_system_type fs_type,
fbe0aa1f TL	467	int flags, const char dev_name, void data)
ca01d6dd	468	{
fbe0aa1f	469	return mount_single(fs_type, flags, data, pstore_fill_super);
ca01d6dd TL	470	}
	471
	472	static void pstore_kill_sb(struct super_block *sb)
	473	{
	474	kill_litter_super(sb);
	475	pstore_sb = NULL;
ca01d6dd TL	476	}
	477
	478	static struct file_system_type pstore_fs_type = {
ee1d2674	479	.owner = THIS_MODULE,
ca01d6dd	480	.name = "pstore",
fbe0aa1f	481	.mount = pstore_mount,
ca01d6dd TL	482	.kill_sb = pstore_kill_sb,
	483	};
	484
	485	static int __init init_pstore_fs(void)
	486	{
f9bb4882	487	int err;
fb0af3f2 JB	488
fb0af3f2 JB	489	/* Create a convenient mount point for people to access pstore */
f9bb4882 EB	490	err = sysfs_create_mount_point(fs_kobj, "pstore");
f9bb4882 EB	491	if (err)
fb0af3f2	492	goto out;
fb0af3f2 JB	493
	494	err = register_filesystem(&pstore_fs_type);
	495	if (err < 0)
f9bb4882	496	sysfs_remove_mount_point(fs_kobj, "pstore");
fb0af3f2 JB	497
	498	out:
	499	return err;
ca01d6dd TL	500	}
	501	module_init(init_pstore_fs)
	502
ee1d2674 GT	503	static void __exit exit_pstore_fs(void)
	504	{
	505	unregister_filesystem(&pstore_fs_type);
	506	sysfs_remove_mount_point(fs_kobj, "pstore");
	507	}
	508	module_exit(exit_pstore_fs)
	509
ca01d6dd TL	510	MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
ca01d6dd TL	511	MODULE_LICENSE("GPL");