[GitHub/mt8127/android_kernel_alcatel_ttab.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/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 {
	struct pstore_info *psi;
	enum pstore_type_id type;
	u64	id;
	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->type, 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->type = type;
	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 <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>
	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 {
638c1fd3	42	struct pstore_info *psi;
56280682 MG	43	enum pstore_type_id type;
56280682 MG	44	u64 id;
fbe0aa1f TL	45	ssize_t size;
fbe0aa1f TL	46	char data[];
ca01d6dd TL	47	};
ca01d6dd TL	48
fbe0aa1f TL	49	static int pstore_file_open(struct inode inode, struct file file)
	50	{
	51	file->private_data = inode->i_private;
	52	return 0;
	53	}
	54
	55	static ssize_t pstore_file_read(struct file file, char __user userbuf,
	56	size_t count, loff_t *ppos)
	57	{
	58	struct pstore_private *ps = file->private_data;
	59
	60	return simple_read_from_buffer(userbuf, count, ppos, ps->data, ps->size);
	61	}
	62
	63	static const struct file_operations pstore_file_operations = {
	64	.open = pstore_file_open,
	65	.read = pstore_file_read,
	66	.llseek = default_llseek,
	67	};
ca01d6dd TL	68
	69	/*
	70	* When a file is unlinked from our file system we call the
	71	* platform driver to erase the record from persistent store.
	72	*/
	73	static int pstore_unlink(struct inode dir, struct dentry dentry)
	74	{
	75	struct pstore_private *p = dentry->d_inode->i_private;
	76
56280682	77	p->psi->erase(p->type, p->id, p->psi);
ca01d6dd TL	78
	79	return simple_unlink(dir, dentry);
	80	}
	81
a872d510 TL	82	static void pstore_evict_inode(struct inode *inode)
	83	{
	84	end_writeback(inode);
	85	kfree(inode->i_private);
	86	}
	87
ca01d6dd TL	88	static const struct inode_operations pstore_dir_inode_operations = {
	89	.lookup = simple_lookup,
	90	.unlink = pstore_unlink,
	91	};
	92
fbe0aa1f TL	93	static struct inode pstore_get_inode(struct super_block sb,
	94	const struct inode *dir, int mode, dev_t dev)
	95	{
	96	struct inode *inode = new_inode(sb);
	97
	98	if (inode) {
	99	inode->i_ino = get_next_ino();
	100	inode->i_uid = inode->i_gid = 0;
	101	inode->i_mode = mode;
	102	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
	103	switch (mode & S_IFMT) {
	104	case S_IFREG:
	105	inode->i_fop = &pstore_file_operations;
	106	break;
	107	case S_IFDIR:
	108	inode->i_op = &pstore_dir_inode_operations;
	109	inode->i_fop = &simple_dir_operations;
	110	inc_nlink(inode);
	111	break;
	112	}
	113	}
	114	return inode;
	115	}
	116
366f7e7a TL	117	enum {
	118	Opt_kmsg_bytes, Opt_err
	119	};
	120
	121	static const match_table_t tokens = {
	122	{Opt_kmsg_bytes, "kmsg_bytes=%u"},
	123	{Opt_err, NULL}
	124	};
	125
	126	static void parse_options(char *options)
	127	{
	128	char *p;
	129	substring_t args[MAX_OPT_ARGS];
	130	int option;
	131
	132	if (!options)
	133	return;
	134
	135	while ((p = strsep(&options, ",")) != NULL) {
	136	int token;
	137
	138	if (!*p)
	139	continue;
	140
	141	token = match_token(p, tokens, args);
	142	switch (token) {
	143	case Opt_kmsg_bytes:
	144	if (!match_int(&args[0], &option))
	145	pstore_set_kmsg_bytes(option);
	146	break;
	147	}
	148	}
	149	}
	150
	151	static int pstore_remount(struct super_block sb, int flags, char *data)
	152	{
	153	parse_options(data);
	154
	155	return 0;
	156	}
	157
ca01d6dd TL	158	static const struct super_operations pstore_ops = {
	159	.statfs = simple_statfs,
	160	.drop_inode = generic_delete_inode,
a872d510	161	.evict_inode = pstore_evict_inode,
366f7e7a	162	.remount_fs = pstore_remount,
ca01d6dd TL	163	.show_options = generic_show_options,
	164	};
	165
	166	static struct super_block *pstore_sb;
ca01d6dd TL	167
	168	int pstore_is_mounted(void)
	169	{
fbe0aa1f	170	return pstore_sb != NULL;
ca01d6dd TL	171	}
	172
	173	/*
	174	* Make a regular file in the root directory of our file system.
	175	* Load it up with "size" bytes of data from "buf".
	176	* Set the mtime & ctime to the date that this record was originally stored.
	177	*/
	178	int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id,
638c1fd3 MG	179	char *data, size_t size, struct timespec time,
638c1fd3 MG	180	struct pstore_info *psi)
ca01d6dd TL	181	{
	182	struct dentry *root = pstore_sb->s_root;
	183	struct dentry *dentry;
	184	struct inode *inode;
	185	int rc;
	186	char name[PSTORE_NAMELEN];
	187	struct pstore_private *private;
	188
	189	rc = -ENOMEM;
	190	inode = pstore_get_inode(pstore_sb, root->d_inode, S_IFREG \| 0444, 0);
	191	if (!inode)
	192	goto fail;
fbe0aa1f	193	private = kmalloc(sizeof *private + size, GFP_KERNEL);
ca01d6dd TL	194	if (!private)
ca01d6dd TL	195	goto fail_alloc;
56280682	196	private->type = type;
ca01d6dd	197	private->id = id;
638c1fd3	198	private->psi = psi;
ca01d6dd TL	199
	200	switch (type) {
	201	case PSTORE_TYPE_DMESG:
	202	sprintf(name, "dmesg-%s-%lld", psname, id);
	203	break;
	204	case PSTORE_TYPE_MCE:
	205	sprintf(name, "mce-%s-%lld", psname, id);
	206	break;
	207	case PSTORE_TYPE_UNKNOWN:
	208	sprintf(name, "unknown-%s-%lld", psname, id);
	209	break;
	210	default:
	211	sprintf(name, "type%d-%s-%lld", type, psname, id);
	212	break;
	213	}
	214
	215	mutex_lock(&root->d_inode->i_mutex);
	216
	217	rc = -ENOSPC;
	218	dentry = d_alloc_name(root, name);
	219	if (IS_ERR(dentry))
	220	goto fail_lockedalloc;
	221
fbe0aa1f TL	222	memcpy(private->data, data, size);
fbe0aa1f TL	223	inode->i_size = private->size = size;
ca01d6dd TL	224
	225	inode->i_private = private;
	226
	227	if (time.tv_sec)
	228	inode->i_mtime = inode->i_ctime = time;
	229
fbe0aa1f	230	d_add(dentry, inode);
ca01d6dd	231
ca01d6dd	232	mutex_unlock(&root->d_inode->i_mutex);
fbe0aa1f TL	233
fbe0aa1f TL	234	return 0;
ca01d6dd TL	235
	236	fail_lockedalloc:
	237	mutex_unlock(&root->d_inode->i_mutex);
	238	kfree(private);
	239	fail_alloc:
	240	iput(inode);
	241
	242	fail:
	243	return rc;
	244	}
	245
	246	int pstore_fill_super(struct super_block sb, void data, int silent)
	247	{
	248	struct inode *inode = NULL;
	249	struct dentry *root;
	250	int err;
	251
	252	save_mount_options(sb, data);
	253
	254	pstore_sb = sb;
	255
	256	sb->s_maxbytes = MAX_LFS_FILESIZE;
	257	sb->s_blocksize = PAGE_CACHE_SIZE;
	258	sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
	259	sb->s_magic = PSTOREFS_MAGIC;
	260	sb->s_op = &pstore_ops;
	261	sb->s_time_gran = 1;
	262
366f7e7a TL	263	parse_options(data);
366f7e7a TL	264
ca01d6dd TL	265	inode = pstore_get_inode(sb, NULL, S_IFDIR \| 0755, 0);
	266	if (!inode) {
	267	err = -ENOMEM;
	268	goto fail;
	269	}
	270	/* override ramfs "dir" options so we catch unlink(2) */
	271	inode->i_op = &pstore_dir_inode_operations;
	272
	273	root = d_alloc_root(inode);
	274	sb->s_root = root;
	275	if (!root) {
	276	err = -ENOMEM;
	277	goto fail;
	278	}
	279
	280	pstore_get_records();
	281
	282	return 0;
	283	fail:
	284	iput(inode);
	285	return err;
	286	}
	287
fbe0aa1f TL	288	static struct dentry pstore_mount(struct file_system_type fs_type,
fbe0aa1f TL	289	int flags, const char dev_name, void data)
ca01d6dd	290	{
fbe0aa1f	291	return mount_single(fs_type, flags, data, pstore_fill_super);
ca01d6dd TL	292	}
	293
	294	static void pstore_kill_sb(struct super_block *sb)
	295	{
	296	kill_litter_super(sb);
	297	pstore_sb = NULL;
ca01d6dd TL	298	}
	299
	300	static struct file_system_type pstore_fs_type = {
	301	.name = "pstore",
fbe0aa1f	302	.mount = pstore_mount,
ca01d6dd TL	303	.kill_sb = pstore_kill_sb,
	304	};
	305
	306	static int __init init_pstore_fs(void)
	307	{
366f7e7a	308	return register_filesystem(&pstore_fs_type);
ca01d6dd TL	309	}
	310	module_init(init_pstore_fs)
	311
	312	MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
	313	MODULE_LICENSE("GPL");