[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/string.h>
#include <linux/mount.h>
#include <linux/ramfs.h>
#include <linux/parser.h>
#include <linux/sched.h>
#include <linux/magic.h>
#include <linux/pstore.h>
#include <linux/slab.h>
#include <linux/uaccess.h>

#include "internal.h"

#define	PSTORE_NAMELEN	64

struct pstore_private {
	u64	id;
	struct pstore_info *psi;
	ssize_t	size;
	char	data[];
};

static int pstore_file_open(struct inode *inode, struct file *file)
{
	file->private_data = inode->i_private;
	return 0;
}

static ssize_t pstore_file_read(struct file *file, char __user *userbuf,
						size_t count, loff_t *ppos)
{
	struct pstore_private *ps = file->private_data;

	return simple_read_from_buffer(userbuf, count, ppos, ps->data, ps->size);
}

static const struct file_operations pstore_file_operations = {
	.open	= pstore_file_open,
	.read	= pstore_file_read,
	.llseek	= default_llseek,
};

/*
 * 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;

	p->psi->erase(p->id, p->psi);

	return simple_unlink(dir, dentry);
}

static void pstore_evict_inode(struct inode *inode)
{
	end_writeback(inode);
	kfree(inode->i_private);
}

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,
					const struct inode *dir, int mode, dev_t dev)
{
	struct inode *inode = new_inode(sb);

	if (inode) {
		inode->i_ino = get_next_ino();
		inode->i_uid = inode->i_gid = 0;
		inode->i_mode = mode;
		inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
		switch (mode & S_IFMT) {
		case S_IFREG:
			inode->i_fop = &pstore_file_operations;
			break;
		case S_IFDIR:
			inode->i_op = &pstore_dir_inode_operations;
			inode->i_fop = &simple_dir_operations;
			inc_nlink(inode);
			break;
		}
	}
	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,
		  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;
	char			name[PSTORE_NAMELEN];
	struct pstore_private	*private;

	rc = -ENOMEM;
	inode = pstore_get_inode(pstore_sb, root->d_inode, S_IFREG | 0444, 0);
	if (!inode)
		goto fail;
	private = kmalloc(sizeof *private + size, GFP_KERNEL);
	if (!private)
		goto fail_alloc;
	private->id = id;
	private->psi = psi;

	switch (type) {
	case PSTORE_TYPE_DMESG:
		sprintf(name, "dmesg-%s-%lld", psname, id);
		break;
	case PSTORE_TYPE_MCE:
		sprintf(name, "mce-%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);

	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;
}

int pstore_fill_super(struct super_block *sb, void *data, int silent)
{
	struct inode *inode = NULL;
	struct dentry *root;
	int err;

	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, NULL, S_IFDIR | 0755, 0);
	if (!inode) {
		err = -ENOMEM;
		goto fail;
	}
	/* override ramfs "dir" options so we catch unlink(2) */
	inode->i_op = &pstore_dir_inode_operations;

	root = d_alloc_root(inode);
	sb->s_root = root;
	if (!root) {
		err = -ENOMEM;
		goto fail;
	}

	pstore_get_records();

	return 0;
fail:
	iput(inode);
	return err;
}

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 int __init init_pstore_fs(void)
{
	return register_filesystem(&pstore_fs_type);
}
module_init(init_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>
	27	#include <linux/string.h>
	28	#include <linux/mount.h>
	29	#include <linux/ramfs.h>
366f7e7a	30	#include <linux/parser.h>
ca01d6dd TL	31	#include <linux/sched.h>
	32	#include <linux/magic.h>
	33	#include <linux/pstore.h>
	34	#include <linux/slab.h>
	35	#include <linux/uaccess.h>
	36
	37	#include "internal.h"
	38
	39	#define PSTORE_NAMELEN 64
	40
	41	struct pstore_private {
	42	u64 id;
638c1fd3	43	struct pstore_info *psi;
fbe0aa1f TL	44	ssize_t size;
fbe0aa1f TL	45	char data[];
ca01d6dd TL	46	};
ca01d6dd TL	47
fbe0aa1f TL	48	static int pstore_file_open(struct inode inode, struct file file)
	49	{
	50	file->private_data = inode->i_private;
	51	return 0;
	52	}
	53
	54	static ssize_t pstore_file_read(struct file file, char __user userbuf,
	55	size_t count, loff_t *ppos)
	56	{
	57	struct pstore_private *ps = file->private_data;
	58
	59	return simple_read_from_buffer(userbuf, count, ppos, ps->data, ps->size);
	60	}
	61
	62	static const struct file_operations pstore_file_operations = {
	63	.open = pstore_file_open,
	64	.read = pstore_file_read,
	65	.llseek = default_llseek,
	66	};
ca01d6dd TL	67
	68	/*
	69	* When a file is unlinked from our file system we call the
	70	* platform driver to erase the record from persistent store.
	71	*/
	72	static int pstore_unlink(struct inode dir, struct dentry dentry)
	73	{
	74	struct pstore_private *p = dentry->d_inode->i_private;
	75
638c1fd3	76	p->psi->erase(p->id, p->psi);
ca01d6dd TL	77
	78	return simple_unlink(dir, dentry);
	79	}
	80
a872d510 TL	81	static void pstore_evict_inode(struct inode *inode)
	82	{
	83	end_writeback(inode);
	84	kfree(inode->i_private);
	85	}
	86
ca01d6dd TL	87	static const struct inode_operations pstore_dir_inode_operations = {
	88	.lookup = simple_lookup,
	89	.unlink = pstore_unlink,
	90	};
	91
fbe0aa1f TL	92	static struct inode pstore_get_inode(struct super_block sb,
	93	const struct inode *dir, int mode, dev_t dev)
	94	{
	95	struct inode *inode = new_inode(sb);
	96
	97	if (inode) {
	98	inode->i_ino = get_next_ino();
	99	inode->i_uid = inode->i_gid = 0;
	100	inode->i_mode = mode;
	101	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
	102	switch (mode & S_IFMT) {
	103	case S_IFREG:
	104	inode->i_fop = &pstore_file_operations;
	105	break;
	106	case S_IFDIR:
	107	inode->i_op = &pstore_dir_inode_operations;
	108	inode->i_fop = &simple_dir_operations;
	109	inc_nlink(inode);
	110	break;
	111	}
	112	}
	113	return inode;
	114	}
	115
366f7e7a TL	116	enum {
	117	Opt_kmsg_bytes, Opt_err
	118	};
	119
	120	static const match_table_t tokens = {
	121	{Opt_kmsg_bytes, "kmsg_bytes=%u"},
	122	{Opt_err, NULL}
	123	};
	124
	125	static void parse_options(char *options)
	126	{
	127	char *p;
	128	substring_t args[MAX_OPT_ARGS];
	129	int option;
	130
	131	if (!options)
	132	return;
	133
	134	while ((p = strsep(&options, ",")) != NULL) {
	135	int token;
	136
	137	if (!*p)
	138	continue;
	139
	140	token = match_token(p, tokens, args);
	141	switch (token) {
	142	case Opt_kmsg_bytes:
	143	if (!match_int(&args[0], &option))
	144	pstore_set_kmsg_bytes(option);
	145	break;
	146	}
	147	}
	148	}
	149
	150	static int pstore_remount(struct super_block sb, int flags, char *data)
	151	{
	152	parse_options(data);
	153
	154	return 0;
	155	}
	156
ca01d6dd TL	157	static const struct super_operations pstore_ops = {
	158	.statfs = simple_statfs,
	159	.drop_inode = generic_delete_inode,
a872d510	160	.evict_inode = pstore_evict_inode,
366f7e7a	161	.remount_fs = pstore_remount,
ca01d6dd TL	162	.show_options = generic_show_options,
	163	};
	164
	165	static struct super_block *pstore_sb;
ca01d6dd TL	166
	167	int pstore_is_mounted(void)
	168	{
fbe0aa1f	169	return pstore_sb != NULL;
ca01d6dd TL	170	}
	171
	172	/*
	173	* Make a regular file in the root directory of our file system.
	174	* Load it up with "size" bytes of data from "buf".
	175	* Set the mtime & ctime to the date that this record was originally stored.
	176	*/
	177	int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id,
638c1fd3 MG	178	char *data, size_t size, struct timespec time,
638c1fd3 MG	179	struct pstore_info *psi)
ca01d6dd TL	180	{
	181	struct dentry *root = pstore_sb->s_root;
	182	struct dentry *dentry;
	183	struct inode *inode;
	184	int rc;
	185	char name[PSTORE_NAMELEN];
	186	struct pstore_private *private;
	187
	188	rc = -ENOMEM;
	189	inode = pstore_get_inode(pstore_sb, root->d_inode, S_IFREG \| 0444, 0);
	190	if (!inode)
	191	goto fail;
fbe0aa1f	192	private = kmalloc(sizeof *private + size, GFP_KERNEL);
ca01d6dd TL	193	if (!private)
	194	goto fail_alloc;
	195	private->id = id;
638c1fd3	196	private->psi = psi;
ca01d6dd TL	197
	198	switch (type) {
	199	case PSTORE_TYPE_DMESG:
	200	sprintf(name, "dmesg-%s-%lld", psname, id);
	201	break;
	202	case PSTORE_TYPE_MCE:
	203	sprintf(name, "mce-%s-%lld", psname, id);
	204	break;
	205	case PSTORE_TYPE_UNKNOWN:
	206	sprintf(name, "unknown-%s-%lld", psname, id);
	207	break;
	208	default:
	209	sprintf(name, "type%d-%s-%lld", type, psname, id);
	210	break;
	211	}
	212
	213	mutex_lock(&root->d_inode->i_mutex);
	214
	215	rc = -ENOSPC;
	216	dentry = d_alloc_name(root, name);
	217	if (IS_ERR(dentry))
	218	goto fail_lockedalloc;
	219
fbe0aa1f TL	220	memcpy(private->data, data, size);
fbe0aa1f TL	221	inode->i_size = private->size = size;
ca01d6dd TL	222
	223	inode->i_private = private;
	224
	225	if (time.tv_sec)
	226	inode->i_mtime = inode->i_ctime = time;
	227
fbe0aa1f	228	d_add(dentry, inode);
ca01d6dd	229
ca01d6dd	230	mutex_unlock(&root->d_inode->i_mutex);
fbe0aa1f TL	231
fbe0aa1f TL	232	return 0;
ca01d6dd TL	233
	234	fail_lockedalloc:
	235	mutex_unlock(&root->d_inode->i_mutex);
	236	kfree(private);
	237	fail_alloc:
	238	iput(inode);
	239
	240	fail:
	241	return rc;
	242	}
	243
	244	int pstore_fill_super(struct super_block sb, void data, int silent)
	245	{
	246	struct inode *inode = NULL;
	247	struct dentry *root;
	248	int err;
	249
	250	save_mount_options(sb, data);
	251
	252	pstore_sb = sb;
	253
	254	sb->s_maxbytes = MAX_LFS_FILESIZE;
	255	sb->s_blocksize = PAGE_CACHE_SIZE;
	256	sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
	257	sb->s_magic = PSTOREFS_MAGIC;
	258	sb->s_op = &pstore_ops;
	259	sb->s_time_gran = 1;
	260
366f7e7a TL	261	parse_options(data);
366f7e7a TL	262
ca01d6dd TL	263	inode = pstore_get_inode(sb, NULL, S_IFDIR \| 0755, 0);
	264	if (!inode) {
	265	err = -ENOMEM;
	266	goto fail;
	267	}
	268	/* override ramfs "dir" options so we catch unlink(2) */
	269	inode->i_op = &pstore_dir_inode_operations;
	270
	271	root = d_alloc_root(inode);
	272	sb->s_root = root;
	273	if (!root) {
	274	err = -ENOMEM;
	275	goto fail;
	276	}
	277
	278	pstore_get_records();
	279
	280	return 0;
	281	fail:
	282	iput(inode);
	283	return err;
	284	}
	285
fbe0aa1f TL	286	static struct dentry pstore_mount(struct file_system_type fs_type,
fbe0aa1f TL	287	int flags, const char dev_name, void data)
ca01d6dd	288	{
fbe0aa1f	289	return mount_single(fs_type, flags, data, pstore_fill_super);
ca01d6dd TL	290	}
	291
	292	static void pstore_kill_sb(struct super_block *sb)
	293	{
	294	kill_litter_super(sb);
	295	pstore_sb = NULL;
ca01d6dd TL	296	}
	297
	298	static struct file_system_type pstore_fs_type = {
	299	.name = "pstore",
fbe0aa1f	300	.mount = pstore_mount,
ca01d6dd TL	301	.kill_sb = pstore_kill_sb,
	302	};
	303
	304	static int __init init_pstore_fs(void)
	305	{
366f7e7a	306	return register_filesystem(&pstore_fs_type);
ca01d6dd TL	307	}
	308	module_init(init_pstore_fs)
	309
	310	MODULE_AUTHOR("Tony Luck <[email protected]>");
	311	MODULE_LICENSE("GPL");