[linux.git] / fs / pstore / inode.c

/*
 * Persistent Storage - ramfs parts.
 *
 * Copyright (C) 2010 Intel Corporation <[email protected]>
 *
 *  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	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 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->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;

	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 = {
	.owner		= THIS_MODULE,
	.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)
		p->psi->erase(p->type, p->id, p->count,
			      d_inode(dentry)->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)
{
	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(enum pstore_type_id type, char *psname, u64 id, int count,
		  char *data, bool compressed, 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:
		scnprintf(name, sizeof(name), "dmesg-%s-%lld%s",
			  psname, id, compressed ? ".enc.z" : "");
		break;
	case PSTORE_TYPE_CONSOLE:
		scnprintf(name, sizeof(name), "console-%s-%lld", psname, id);
		break;
	case PSTORE_TYPE_FTRACE:
		scnprintf(name, sizeof(name), "ftrace-%s-%lld", psname, id);
		break;
	case PSTORE_TYPE_MCE:
		scnprintf(name, sizeof(name), "mce-%s-%lld", psname, id);
		break;
	case PSTORE_TYPE_PPC_RTAS:
		scnprintf(name, sizeof(name), "rtas-%s-%lld", psname, id);
		break;
	case PSTORE_TYPE_PPC_OF:
		scnprintf(name, sizeof(name), "powerpc-ofw-%s-%lld",
			  psname, id);
		break;
	case PSTORE_TYPE_PPC_COMMON:
		scnprintf(name, sizeof(name), "powerpc-common-%s-%lld",
			  psname, id);
		break;
	case PSTORE_TYPE_PMSG:
		scnprintf(name, sizeof(name), "pmsg-%s-%lld", psname, id);
		break;
	case PSTORE_TYPE_PPC_OPAL:
		sprintf(name, "powerpc-opal-%s-%lld", psname, id);
		break;
	case PSTORE_TYPE_UNKNOWN:
		scnprintf(name, sizeof(name), "unknown-%s-%lld", psname, id);
		break;
	default:
		scnprintf(name, sizeof(name), "type%d-%s-%lld",
			  type, psname, id);
		break;
	}

	inode_lock(d_inode(root));

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

	inode_unlock(d_inode(root));

	return 0;

fail_lockedalloc:
	inode_unlock(d_inode(root));
	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 = {
	.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 <[email protected]>");
MODULE_LICENSE("GPL");
Commit	Line	Data
ca01d6dd TL	1	/*
	2	* Persistent Storage - ramfs parts.
	3	*
	4	* Copyright (C) 2010 Intel Corporation <[email protected]>
	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;
638c1fd3	50	struct pstore_info *psi;
56280682 MG	51	enum pstore_type_id type;
56280682 MG	52	u64 id;
755d4fe4	53	int count;
fbe0aa1f TL	54	ssize_t size;
fbe0aa1f TL	55	char data[];
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
	66	static void pstore_ftrace_seq_start(struct seq_file s, loff_t *pos)
	67	{
	68	struct pstore_private *ps = s->private;
	69	struct pstore_ftrace_seq_data *data;
	70
	71	data = kzalloc(sizeof(*data), GFP_KERNEL);
	72	if (!data)
	73	return NULL;
	74
	75	data->off = ps->size % REC_SIZE;
	76	data->off += pos REC_SIZE;
	77	if (data->off + REC_SIZE > ps->size) {
	78	kfree(data);
	79	return NULL;
	80	}
	81
	82	return data;
	83
	84	}
	85
	86	static void pstore_ftrace_seq_stop(struct seq_file s, void v)
	87	{
	88	kfree(v);
	89	}
	90
	91	static void pstore_ftrace_seq_next(struct seq_file s, void v, loff_t pos)
	92	{
	93	struct pstore_private *ps = s->private;
	94	struct pstore_ftrace_seq_data *data = v;
	95
	96	data->off += REC_SIZE;
	97	if (data->off + REC_SIZE > ps->size)
	98	return NULL;
	99
	100	(*pos)++;
	101	return data;
	102	}
	103
	104	static int pstore_ftrace_seq_show(struct seq_file s, void v)
	105	{
	106	struct pstore_private *ps = s->private;
	107	struct pstore_ftrace_seq_data *data = v;
	108	struct pstore_ftrace_record rec = (void )(ps->data + data->off);
	109
	110	seq_printf(s, "%d %08lx %08lx %pf <- %pF\n",
	111	pstore_ftrace_decode_cpu(rec), rec->ip, rec->parent_ip,
	112	(void )rec->ip, (void )rec->parent_ip);
	113
	114	return 0;
	115	}
	116
	117	static const struct seq_operations pstore_ftrace_seq_ops = {
	118	.start = pstore_ftrace_seq_start,
	119	.next = pstore_ftrace_seq_next,
	120	.stop = pstore_ftrace_seq_stop,
	121	.show = pstore_ftrace_seq_show,
122	};
123
68c4a4f8 SS	124	static int pstore_check_syslog_permissions(struct pstore_private *ps)
	125	{
	126	switch (ps->type) {
	127	case PSTORE_TYPE_DMESG:
	128	case PSTORE_TYPE_CONSOLE:
	129	return check_syslog_permissions(SYSLOG_ACTION_READ_ALL,
	130	SYSLOG_FROM_READER);
	131	default:
	132	return 0;
	133	}
	134	}
	135
fbe0aa1f TL	136	static ssize_t pstore_file_read(struct file file, char __user userbuf,
	137	size_t count, loff_t *ppos)
	138	{
060287b8 AV	139	struct seq_file *sf = file->private_data;
060287b8 AV	140	struct pstore_private *ps = sf->private;
fbe0aa1f	141
060287b8 AV	142	if (ps->type == PSTORE_TYPE_FTRACE)
060287b8 AV	143	return seq_read(file, userbuf, count, ppos);
fbe0aa1f TL	144	return simple_read_from_buffer(userbuf, count, ppos, ps->data, ps->size);
	145	}
	146
060287b8 AV	147	static int pstore_file_open(struct inode inode, struct file file)
	148	{
	149	struct pstore_private *ps = inode->i_private;
	150	struct seq_file *sf;
	151	int err;
	152	const struct seq_operations *sops = NULL;
	153
68c4a4f8 SS	154	err = pstore_check_syslog_permissions(ps);
	155	if (err)
	156	return err;
	157
060287b8 AV	158	if (ps->type == PSTORE_TYPE_FTRACE)
	159	sops = &pstore_ftrace_seq_ops;
	160
	161	err = seq_open(file, sops);
	162	if (err < 0)
	163	return err;
	164
	165	sf = file->private_data;
	166	sf->private = ps;
	167
	168	return 0;
	169	}
	170
965c8e59	171	static loff_t pstore_file_llseek(struct file *file, loff_t off, int whence)
060287b8 AV	172	{
	173	struct seq_file *sf = file->private_data;
	174
	175	if (sf->op)
965c8e59 AM	176	return seq_lseek(file, off, whence);
965c8e59 AM	177	return default_llseek(file, off, whence);
060287b8 AV	178	}
060287b8 AV	179
fbe0aa1f	180	static const struct file_operations pstore_file_operations = {
ee1d2674	181	.owner = THIS_MODULE,
060287b8 AV	182	.open = pstore_file_open,
	183	.read = pstore_file_read,
	184	.llseek = pstore_file_llseek,
	185	.release = seq_release,
fbe0aa1f	186	};
ca01d6dd TL	187
	188	/*
	189	* When a file is unlinked from our file system we call the
	190	* platform driver to erase the record from persistent store.
	191	*/
	192	static int pstore_unlink(struct inode dir, struct dentry dentry)
	193	{
2b0143b5	194	struct pstore_private *p = d_inode(dentry)->i_private;
68c4a4f8 SS	195	int err;
	196
	197	err = pstore_check_syslog_permissions(p);
	198	if (err)
	199	return err;
ca01d6dd	200
2174f6df	201	if (p->psi->erase)
755d4fe4	202	p->psi->erase(p->type, p->id, p->count,
2b0143b5	203	d_inode(dentry)->i_ctime, p->psi);
bf288333 AB	204	else
bf288333 AB	205	return -EPERM;
ca01d6dd TL	206
	207	return simple_unlink(dir, dentry);
	208	}
	209
a872d510 TL	210	static void pstore_evict_inode(struct inode *inode)
a872d510 TL	211	{
6dda9266 TL	212	struct pstore_private *p = inode->i_private;
	213	unsigned long flags;
	214
dbd5768f	215	clear_inode(inode);
6dda9266 TL	216	if (p) {
	217	spin_lock_irqsave(&allpstore_lock, flags);
	218	list_del(&p->list);
	219	spin_unlock_irqrestore(&allpstore_lock, flags);
	220	kfree(p);
	221	}
a872d510 TL	222	}
a872d510 TL	223
ca01d6dd TL	224	static const struct inode_operations pstore_dir_inode_operations = {
	225	.lookup = simple_lookup,
	226	.unlink = pstore_unlink,
	227	};
	228
22a71c30	229	static struct inode pstore_get_inode(struct super_block sb)
fbe0aa1f TL	230	{
fbe0aa1f TL	231	struct inode *inode = new_inode(sb);
fbe0aa1f TL	232	if (inode) {
fbe0aa1f TL	233	inode->i_ino = get_next_ino();
fbe0aa1f	234	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
fbe0aa1f TL	235	}
	236	return inode;
	237	}
	238
366f7e7a TL	239	enum {
	240	Opt_kmsg_bytes, Opt_err
	241	};
	242
	243	static const match_table_t tokens = {
	244	{Opt_kmsg_bytes, "kmsg_bytes=%u"},
	245	{Opt_err, NULL}
	246	};
	247
	248	static void parse_options(char *options)
	249	{
	250	char *p;
	251	substring_t args[MAX_OPT_ARGS];
	252	int option;
	253
	254	if (!options)
	255	return;
	256
	257	while ((p = strsep(&options, ",")) != NULL) {
	258	int token;
	259
	260	if (!*p)
	261	continue;
	262
	263	token = match_token(p, tokens, args);
	264	switch (token) {
	265	case Opt_kmsg_bytes:
	266	if (!match_int(&args[0], &option))
	267	pstore_set_kmsg_bytes(option);
	268	break;
	269	}
	270	}
	271	}
	272
	273	static int pstore_remount(struct super_block sb, int flags, char *data)
	274	{
02b9984d	275	sync_filesystem(sb);
366f7e7a TL	276	parse_options(data);
	277
	278	return 0;
	279	}
	280
ca01d6dd TL	281	static const struct super_operations pstore_ops = {
	282	.statfs = simple_statfs,
	283	.drop_inode = generic_delete_inode,
a872d510	284	.evict_inode = pstore_evict_inode,
366f7e7a	285	.remount_fs = pstore_remount,
ca01d6dd TL	286	.show_options = generic_show_options,
	287	};
	288
	289	static struct super_block *pstore_sb;
ca01d6dd	290
7e26e9ff	291	bool pstore_is_mounted(void)
ca01d6dd	292	{
fbe0aa1f	293	return pstore_sb != NULL;
ca01d6dd TL	294	}
	295
	296	/*
	297	* Make a regular file in the root directory of our file system.
	298	* Load it up with "size" bytes of data from "buf".
	299	* Set the mtime & ctime to the date that this record was originally stored.
	300	*/
755d4fe4	301	int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id, int count,
9ad2cbe0 AB	302	char *data, bool compressed, size_t size,
9ad2cbe0 AB	303	struct timespec time, struct pstore_info *psi)
ca01d6dd TL	304	{
	305	struct dentry *root = pstore_sb->s_root;
	306	struct dentry *dentry;
	307	struct inode *inode;
6dda9266	308	int rc = 0;
ca01d6dd	309	char name[PSTORE_NAMELEN];
6dda9266 TL	310	struct pstore_private private, pos;
	311	unsigned long flags;
	312
	313	spin_lock_irqsave(&allpstore_lock, flags);
	314	list_for_each_entry(pos, &allpstore, list) {
	315	if (pos->type == type &&
	316	pos->id == id &&
	317	pos->psi == psi) {
	318	rc = -EEXIST;
	319	break;
	320	}
	321	}
	322	spin_unlock_irqrestore(&allpstore_lock, flags);
	323	if (rc)
	324	return rc;
ca01d6dd TL	325
ca01d6dd TL	326	rc = -ENOMEM;
22a71c30	327	inode = pstore_get_inode(pstore_sb);
ca01d6dd TL	328	if (!inode)
ca01d6dd TL	329	goto fail;
22a71c30 AV	330	inode->i_mode = S_IFREG \| 0444;
22a71c30 AV	331	inode->i_fop = &pstore_file_operations;
fbe0aa1f	332	private = kmalloc(sizeof *private + size, GFP_KERNEL);
ca01d6dd TL	333	if (!private)
ca01d6dd TL	334	goto fail_alloc;
56280682	335	private->type = type;
ca01d6dd	336	private->id = id;
755d4fe4	337	private->count = count;
638c1fd3	338	private->psi = psi;
ca01d6dd TL	339
	340	switch (type) {
	341	case PSTORE_TYPE_DMESG:
dbaffde7 MS	342	scnprintf(name, sizeof(name), "dmesg-%s-%lld%s",
dbaffde7 MS	343	psname, id, compressed ? ".enc.z" : "");
ca01d6dd	344	break;
f29e5956	345	case PSTORE_TYPE_CONSOLE:
dbaffde7	346	scnprintf(name, sizeof(name), "console-%s-%lld", psname, id);
f29e5956	347	break;
060287b8	348	case PSTORE_TYPE_FTRACE:
dbaffde7	349	scnprintf(name, sizeof(name), "ftrace-%s-%lld", psname, id);
060287b8	350	break;
ca01d6dd	351	case PSTORE_TYPE_MCE:
dbaffde7	352	scnprintf(name, sizeof(name), "mce-%s-%lld", psname, id);
ca01d6dd	353	break;
69020eea	354	case PSTORE_TYPE_PPC_RTAS:
dbaffde7	355	scnprintf(name, sizeof(name), "rtas-%s-%lld", psname, id);
69020eea	356	break;
f33f748c	357	case PSTORE_TYPE_PPC_OF:
dbaffde7 MS	358	scnprintf(name, sizeof(name), "powerpc-ofw-%s-%lld",
dbaffde7 MS	359	psname, id);
f33f748c	360	break;
a5e4797b	361	case PSTORE_TYPE_PPC_COMMON:
dbaffde7 MS	362	scnprintf(name, sizeof(name), "powerpc-common-%s-%lld",
dbaffde7 MS	363	psname, id);
a5e4797b	364	break;
9d5438f4 MS	365	case PSTORE_TYPE_PMSG:
	366	scnprintf(name, sizeof(name), "pmsg-%s-%lld", psname, id);
	367	break;
ae011d2e HB	368	case PSTORE_TYPE_PPC_OPAL:
	369	sprintf(name, "powerpc-opal-%s-%lld", psname, id);
	370	break;
ca01d6dd	371	case PSTORE_TYPE_UNKNOWN:
dbaffde7	372	scnprintf(name, sizeof(name), "unknown-%s-%lld", psname, id);
ca01d6dd TL	373	break;
ca01d6dd TL	374	default:
dbaffde7 MS	375	scnprintf(name, sizeof(name), "type%d-%s-%lld",
dbaffde7 MS	376	type, psname, id);
ca01d6dd TL	377	break;
	378	}
	379
5955102c	380	inode_lock(d_inode(root));
ca01d6dd	381
ca01d6dd	382	dentry = d_alloc_name(root, name);
c39524e6	383	if (!dentry)
ca01d6dd TL	384	goto fail_lockedalloc;
ca01d6dd TL	385
fbe0aa1f TL	386	memcpy(private->data, data, size);
fbe0aa1f TL	387	inode->i_size = private->size = size;
ca01d6dd TL	388
	389	inode->i_private = private;
	390
	391	if (time.tv_sec)
	392	inode->i_mtime = inode->i_ctime = time;
	393
fbe0aa1f	394	d_add(dentry, inode);
ca01d6dd	395
6dda9266 TL	396	spin_lock_irqsave(&allpstore_lock, flags);
	397	list_add(&private->list, &allpstore);
	398	spin_unlock_irqrestore(&allpstore_lock, flags);
	399
5955102c	400	inode_unlock(d_inode(root));
fbe0aa1f TL	401
fbe0aa1f TL	402	return 0;
ca01d6dd TL	403
ca01d6dd TL	404	fail_lockedalloc:
5955102c	405	inode_unlock(d_inode(root));
ca01d6dd TL	406	kfree(private);
	407	fail_alloc:
	408	iput(inode);
	409
	410	fail:
	411	return rc;
	412	}
	413
364ed2f4	414	static int pstore_fill_super(struct super_block sb, void data, int silent)
ca01d6dd	415	{
318ceed0	416	struct inode *inode;
ca01d6dd TL	417
	418	save_mount_options(sb, data);
	419
	420	pstore_sb = sb;
	421
	422	sb->s_maxbytes = MAX_LFS_FILESIZE;
	423	sb->s_blocksize = PAGE_CACHE_SIZE;
	424	sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
	425	sb->s_magic = PSTOREFS_MAGIC;
	426	sb->s_op = &pstore_ops;
	427	sb->s_time_gran = 1;
	428
366f7e7a TL	429	parse_options(data);
366f7e7a TL	430
22a71c30	431	inode = pstore_get_inode(sb);
318ceed0	432	if (inode) {
22a71c30	433	inode->i_mode = S_IFDIR \| 0755;
318ceed0	434	inode->i_op = &pstore_dir_inode_operations;
22a71c30 AV	435	inode->i_fop = &simple_dir_operations;
22a71c30 AV	436	inc_nlink(inode);
ca01d6dd	437	}
318ceed0 AV	438	sb->s_root = d_make_root(inode);
	439	if (!sb->s_root)
	440	return -ENOMEM;
ca01d6dd	441
6dda9266	442	pstore_get_records(0);
ca01d6dd TL	443
ca01d6dd TL	444	return 0;
ca01d6dd TL	445	}
ca01d6dd TL	446
fbe0aa1f TL	447	static struct dentry pstore_mount(struct file_system_type fs_type,
fbe0aa1f TL	448	int flags, const char dev_name, void data)
ca01d6dd	449	{
fbe0aa1f	450	return mount_single(fs_type, flags, data, pstore_fill_super);
ca01d6dd TL	451	}
	452
	453	static void pstore_kill_sb(struct super_block *sb)
	454	{
	455	kill_litter_super(sb);
	456	pstore_sb = NULL;
ca01d6dd TL	457	}
	458
	459	static struct file_system_type pstore_fs_type = {
ee1d2674	460	.owner = THIS_MODULE,
ca01d6dd	461	.name = "pstore",
fbe0aa1f	462	.mount = pstore_mount,
ca01d6dd TL	463	.kill_sb = pstore_kill_sb,
	464	};
	465
	466	static int __init init_pstore_fs(void)
	467	{
f9bb4882	468	int err;
fb0af3f2 JB	469
fb0af3f2 JB	470	/* Create a convenient mount point for people to access pstore */
f9bb4882 EB	471	err = sysfs_create_mount_point(fs_kobj, "pstore");
f9bb4882 EB	472	if (err)
fb0af3f2	473	goto out;
fb0af3f2 JB	474
	475	err = register_filesystem(&pstore_fs_type);
	476	if (err < 0)
f9bb4882	477	sysfs_remove_mount_point(fs_kobj, "pstore");
fb0af3f2 JB	478
	479	out:
	480	return err;
ca01d6dd TL	481	}
	482	module_init(init_pstore_fs)
	483
ee1d2674 GT	484	static void __exit exit_pstore_fs(void)
	485	{
	486	unregister_filesystem(&pstore_fs_type);
	487	sysfs_remove_mount_point(fs_kobj, "pstore");
	488	}
	489	module_exit(exit_pstore_fs)
	490
ca01d6dd TL	491	MODULE_AUTHOR("Tony Luck <[email protected]>");
ca01d6dd TL	492	MODULE_LICENSE("GPL");