[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/list.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/spinlock.h>
#include <linux/uaccess.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;
	ssize_t	size;
	char	data[];
};

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	= simple_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;

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

	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)
{
	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 = 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->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);

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

	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;

	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 = {
	.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>
6dda9266	27	#include <linux/list.h>
ca01d6dd TL	28	#include <linux/string.h>
	29	#include <linux/mount.h>
	30	#include <linux/ramfs.h>
366f7e7a	31	#include <linux/parser.h>
ca01d6dd TL	32	#include <linux/sched.h>
	33	#include <linux/magic.h>
	34	#include <linux/pstore.h>
	35	#include <linux/slab.h>
6dda9266	36	#include <linux/spinlock.h>
ca01d6dd TL	37	#include <linux/uaccess.h>
	38
	39	#include "internal.h"
	40
	41	#define PSTORE_NAMELEN 64
	42
6dda9266 TL	43	static DEFINE_SPINLOCK(allpstore_lock);
	44	static LIST_HEAD(allpstore);
	45
ca01d6dd	46	struct pstore_private {
6dda9266	47	struct list_head list;
638c1fd3	48	struct pstore_info *psi;
56280682 MG	49	enum pstore_type_id type;
56280682 MG	50	u64 id;
fbe0aa1f TL	51	ssize_t size;
fbe0aa1f TL	52	char data[];
ca01d6dd TL	53	};
ca01d6dd TL	54
fbe0aa1f TL	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 = {
234e3405	64	.open = simple_open,
fbe0aa1f TL	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
2174f6df KC	77	if (p->psi->erase)
2174f6df KC	78	p->psi->erase(p->type, p->id, p->psi);
ca01d6dd TL	79
	80	return simple_unlink(dir, dentry);
	81	}
	82
a872d510 TL	83	static void pstore_evict_inode(struct inode *inode)
a872d510 TL	84	{
6dda9266 TL	85	struct pstore_private *p = inode->i_private;
	86	unsigned long flags;
	87
dbd5768f	88	clear_inode(inode);
6dda9266 TL	89	if (p) {
	90	spin_lock_irqsave(&allpstore_lock, flags);
	91	list_del(&p->list);
	92	spin_unlock_irqrestore(&allpstore_lock, flags);
	93	kfree(p);
	94	}
a872d510 TL	95	}
a872d510 TL	96
ca01d6dd TL	97	static const struct inode_operations pstore_dir_inode_operations = {
	98	.lookup = simple_lookup,
	99	.unlink = pstore_unlink,
	100	};
	101
22a71c30	102	static struct inode pstore_get_inode(struct super_block sb)
fbe0aa1f TL	103	{
fbe0aa1f TL	104	struct inode *inode = new_inode(sb);
fbe0aa1f TL	105	if (inode) {
fbe0aa1f TL	106	inode->i_ino = get_next_ino();
fbe0aa1f	107	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
fbe0aa1f TL	108	}
	109	return inode;
	110	}
	111
366f7e7a TL	112	enum {
	113	Opt_kmsg_bytes, Opt_err
	114	};
	115
	116	static const match_table_t tokens = {
	117	{Opt_kmsg_bytes, "kmsg_bytes=%u"},
	118	{Opt_err, NULL}
	119	};
	120
	121	static void parse_options(char *options)
	122	{
	123	char *p;
	124	substring_t args[MAX_OPT_ARGS];
	125	int option;
	126
	127	if (!options)
	128	return;
	129
	130	while ((p = strsep(&options, ",")) != NULL) {
	131	int token;
	132
	133	if (!*p)
	134	continue;
	135
	136	token = match_token(p, tokens, args);
	137	switch (token) {
	138	case Opt_kmsg_bytes:
	139	if (!match_int(&args[0], &option))
	140	pstore_set_kmsg_bytes(option);
	141	break;
	142	}
	143	}
	144	}
	145
	146	static int pstore_remount(struct super_block sb, int flags, char *data)
	147	{
	148	parse_options(data);
	149
	150	return 0;
	151	}
	152
ca01d6dd TL	153	static const struct super_operations pstore_ops = {
	154	.statfs = simple_statfs,
	155	.drop_inode = generic_delete_inode,
a872d510	156	.evict_inode = pstore_evict_inode,
366f7e7a	157	.remount_fs = pstore_remount,
ca01d6dd TL	158	.show_options = generic_show_options,
	159	};
	160
	161	static struct super_block *pstore_sb;
ca01d6dd TL	162
	163	int pstore_is_mounted(void)
	164	{
fbe0aa1f	165	return pstore_sb != NULL;
ca01d6dd TL	166	}
	167
	168	/*
	169	* Make a regular file in the root directory of our file system.
	170	* Load it up with "size" bytes of data from "buf".
	171	* Set the mtime & ctime to the date that this record was originally stored.
	172	*/
	173	int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id,
638c1fd3 MG	174	char *data, size_t size, struct timespec time,
638c1fd3 MG	175	struct pstore_info *psi)
ca01d6dd TL	176	{
	177	struct dentry *root = pstore_sb->s_root;
	178	struct dentry *dentry;
	179	struct inode *inode;
6dda9266	180	int rc = 0;
ca01d6dd	181	char name[PSTORE_NAMELEN];
6dda9266 TL	182	struct pstore_private private, pos;
	183	unsigned long flags;
	184
	185	spin_lock_irqsave(&allpstore_lock, flags);
	186	list_for_each_entry(pos, &allpstore, list) {
	187	if (pos->type == type &&
	188	pos->id == id &&
	189	pos->psi == psi) {
	190	rc = -EEXIST;
	191	break;
	192	}
	193	}
	194	spin_unlock_irqrestore(&allpstore_lock, flags);
	195	if (rc)
	196	return rc;
ca01d6dd TL	197
ca01d6dd TL	198	rc = -ENOMEM;
22a71c30	199	inode = pstore_get_inode(pstore_sb);
ca01d6dd TL	200	if (!inode)
ca01d6dd TL	201	goto fail;
22a71c30 AV	202	inode->i_mode = S_IFREG \| 0444;
22a71c30 AV	203	inode->i_fop = &pstore_file_operations;
fbe0aa1f	204	private = kmalloc(sizeof *private + size, GFP_KERNEL);
ca01d6dd TL	205	if (!private)
ca01d6dd TL	206	goto fail_alloc;
56280682	207	private->type = type;
ca01d6dd	208	private->id = id;
638c1fd3	209	private->psi = psi;
ca01d6dd TL	210
	211	switch (type) {
	212	case PSTORE_TYPE_DMESG:
	213	sprintf(name, "dmesg-%s-%lld", psname, id);
	214	break;
	215	case PSTORE_TYPE_MCE:
	216	sprintf(name, "mce-%s-%lld", psname, id);
	217	break;
	218	case PSTORE_TYPE_UNKNOWN:
	219	sprintf(name, "unknown-%s-%lld", psname, id);
	220	break;
	221	default:
	222	sprintf(name, "type%d-%s-%lld", type, psname, id);
	223	break;
	224	}
	225
	226	mutex_lock(&root->d_inode->i_mutex);
	227
	228	rc = -ENOSPC;
	229	dentry = d_alloc_name(root, name);
	230	if (IS_ERR(dentry))
	231	goto fail_lockedalloc;
	232
fbe0aa1f TL	233	memcpy(private->data, data, size);
fbe0aa1f TL	234	inode->i_size = private->size = size;
ca01d6dd TL	235
	236	inode->i_private = private;
	237
	238	if (time.tv_sec)
	239	inode->i_mtime = inode->i_ctime = time;
	240
fbe0aa1f	241	d_add(dentry, inode);
ca01d6dd	242
6dda9266 TL	243	spin_lock_irqsave(&allpstore_lock, flags);
	244	list_add(&private->list, &allpstore);
	245	spin_unlock_irqrestore(&allpstore_lock, flags);
	246
ca01d6dd	247	mutex_unlock(&root->d_inode->i_mutex);
fbe0aa1f TL	248
fbe0aa1f TL	249	return 0;
ca01d6dd TL	250
	251	fail_lockedalloc:
	252	mutex_unlock(&root->d_inode->i_mutex);
	253	kfree(private);
	254	fail_alloc:
	255	iput(inode);
	256
	257	fail:
	258	return rc;
	259	}
	260
	261	int pstore_fill_super(struct super_block sb, void data, int silent)
	262	{
318ceed0	263	struct inode *inode;
ca01d6dd TL	264
	265	save_mount_options(sb, data);
	266
	267	pstore_sb = sb;
	268
	269	sb->s_maxbytes = MAX_LFS_FILESIZE;
	270	sb->s_blocksize = PAGE_CACHE_SIZE;
	271	sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
	272	sb->s_magic = PSTOREFS_MAGIC;
	273	sb->s_op = &pstore_ops;
	274	sb->s_time_gran = 1;
	275
366f7e7a TL	276	parse_options(data);
366f7e7a TL	277
22a71c30	278	inode = pstore_get_inode(sb);
318ceed0	279	if (inode) {
22a71c30	280	inode->i_mode = S_IFDIR \| 0755;
318ceed0	281	inode->i_op = &pstore_dir_inode_operations;
22a71c30 AV	282	inode->i_fop = &simple_dir_operations;
22a71c30 AV	283	inc_nlink(inode);
ca01d6dd	284	}
318ceed0 AV	285	sb->s_root = d_make_root(inode);
	286	if (!sb->s_root)
	287	return -ENOMEM;
ca01d6dd	288
6dda9266	289	pstore_get_records(0);
ca01d6dd TL	290
ca01d6dd TL	291	return 0;
ca01d6dd TL	292	}
ca01d6dd TL	293
fbe0aa1f TL	294	static struct dentry pstore_mount(struct file_system_type fs_type,
fbe0aa1f TL	295	int flags, const char dev_name, void data)
ca01d6dd	296	{
fbe0aa1f	297	return mount_single(fs_type, flags, data, pstore_fill_super);
ca01d6dd TL	298	}
	299
	300	static void pstore_kill_sb(struct super_block *sb)
	301	{
	302	kill_litter_super(sb);
	303	pstore_sb = NULL;
ca01d6dd TL	304	}
	305
	306	static struct file_system_type pstore_fs_type = {
	307	.name = "pstore",
fbe0aa1f	308	.mount = pstore_mount,
ca01d6dd TL	309	.kill_sb = pstore_kill_sb,
	310	};
	311
	312	static int __init init_pstore_fs(void)
	313	{
366f7e7a	314	return register_filesystem(&pstore_fs_type);
ca01d6dd TL	315	}
	316	module_init(init_pstore_fs)
	317
	318	MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
	319	MODULE_LICENSE("GPL");