[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/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 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;

	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;

	end_writeback(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,
					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 = 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, 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);

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

	pstore_get_records(0);

	return 0;
fail:
	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>
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 int pstore_file_open(struct inode inode, struct file file)
	56	{
	57	file->private_data = inode->i_private;
	58	return 0;
	59	}
	60
	61	static ssize_t pstore_file_read(struct file file, char __user userbuf,
	62	size_t count, loff_t *ppos)
	63	{
	64	struct pstore_private *ps = file->private_data;
	65
	66	return simple_read_from_buffer(userbuf, count, ppos, ps->data, ps->size);
	67	}
	68
	69	static const struct file_operations pstore_file_operations = {
	70	.open = pstore_file_open,
	71	.read = pstore_file_read,
	72	.llseek = default_llseek,
	73	};
ca01d6dd TL	74
	75	/*
	76	* When a file is unlinked from our file system we call the
	77	* platform driver to erase the record from persistent store.
	78	*/
	79	static int pstore_unlink(struct inode dir, struct dentry dentry)
	80	{
	81	struct pstore_private *p = dentry->d_inode->i_private;
	82
2174f6df KC	83	if (p->psi->erase)
2174f6df KC	84	p->psi->erase(p->type, p->id, p->psi);
ca01d6dd TL	85
	86	return simple_unlink(dir, dentry);
	87	}
	88
a872d510 TL	89	static void pstore_evict_inode(struct inode *inode)
a872d510 TL	90	{
6dda9266 TL	91	struct pstore_private *p = inode->i_private;
	92	unsigned long flags;
	93
a872d510	94	end_writeback(inode);
6dda9266 TL	95	if (p) {
	96	spin_lock_irqsave(&allpstore_lock, flags);
	97	list_del(&p->list);
	98	spin_unlock_irqrestore(&allpstore_lock, flags);
	99	kfree(p);
	100	}
a872d510 TL	101	}
a872d510 TL	102
ca01d6dd TL	103	static const struct inode_operations pstore_dir_inode_operations = {
	104	.lookup = simple_lookup,
	105	.unlink = pstore_unlink,
	106	};
	107
fbe0aa1f TL	108	static struct inode pstore_get_inode(struct super_block sb,
	109	const struct inode *dir, int mode, dev_t dev)
	110	{
	111	struct inode *inode = new_inode(sb);
	112
	113	if (inode) {
	114	inode->i_ino = get_next_ino();
	115	inode->i_uid = inode->i_gid = 0;
	116	inode->i_mode = mode;
	117	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
	118	switch (mode & S_IFMT) {
	119	case S_IFREG:
	120	inode->i_fop = &pstore_file_operations;
	121	break;
	122	case S_IFDIR:
	123	inode->i_op = &pstore_dir_inode_operations;
	124	inode->i_fop = &simple_dir_operations;
	125	inc_nlink(inode);
	126	break;
	127	}
	128	}
	129	return inode;
	130	}
	131
366f7e7a TL	132	enum {
	133	Opt_kmsg_bytes, Opt_err
	134	};
	135
	136	static const match_table_t tokens = {
	137	{Opt_kmsg_bytes, "kmsg_bytes=%u"},
	138	{Opt_err, NULL}
	139	};
	140
	141	static void parse_options(char *options)
	142	{
	143	char *p;
	144	substring_t args[MAX_OPT_ARGS];
	145	int option;
	146
	147	if (!options)
	148	return;
	149
	150	while ((p = strsep(&options, ",")) != NULL) {
	151	int token;
	152
	153	if (!*p)
	154	continue;
	155
	156	token = match_token(p, tokens, args);
	157	switch (token) {
	158	case Opt_kmsg_bytes:
	159	if (!match_int(&args[0], &option))
	160	pstore_set_kmsg_bytes(option);
	161	break;
	162	}
	163	}
	164	}
	165
	166	static int pstore_remount(struct super_block sb, int flags, char *data)
	167	{
	168	parse_options(data);
	169
	170	return 0;
	171	}
	172
ca01d6dd TL	173	static const struct super_operations pstore_ops = {
	174	.statfs = simple_statfs,
	175	.drop_inode = generic_delete_inode,
a872d510	176	.evict_inode = pstore_evict_inode,
366f7e7a	177	.remount_fs = pstore_remount,
ca01d6dd TL	178	.show_options = generic_show_options,
	179	};
	180
	181	static struct super_block *pstore_sb;
ca01d6dd TL	182
	183	int pstore_is_mounted(void)
	184	{
fbe0aa1f	185	return pstore_sb != NULL;
ca01d6dd TL	186	}
	187
	188	/*
	189	* Make a regular file in the root directory of our file system.
	190	* Load it up with "size" bytes of data from "buf".
	191	* Set the mtime & ctime to the date that this record was originally stored.
	192	*/
	193	int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id,
638c1fd3 MG	194	char *data, size_t size, struct timespec time,
638c1fd3 MG	195	struct pstore_info *psi)
ca01d6dd TL	196	{
	197	struct dentry *root = pstore_sb->s_root;
	198	struct dentry *dentry;
	199	struct inode *inode;
6dda9266	200	int rc = 0;
ca01d6dd	201	char name[PSTORE_NAMELEN];
6dda9266 TL	202	struct pstore_private private, pos;
	203	unsigned long flags;
	204
	205	spin_lock_irqsave(&allpstore_lock, flags);
	206	list_for_each_entry(pos, &allpstore, list) {
	207	if (pos->type == type &&
	208	pos->id == id &&
	209	pos->psi == psi) {
	210	rc = -EEXIST;
	211	break;
	212	}
	213	}
	214	spin_unlock_irqrestore(&allpstore_lock, flags);
	215	if (rc)
	216	return rc;
ca01d6dd TL	217
	218	rc = -ENOMEM;
	219	inode = pstore_get_inode(pstore_sb, root->d_inode, S_IFREG \| 0444, 0);
	220	if (!inode)
	221	goto fail;
fbe0aa1f	222	private = kmalloc(sizeof *private + size, GFP_KERNEL);
ca01d6dd TL	223	if (!private)
ca01d6dd TL	224	goto fail_alloc;
56280682	225	private->type = type;
ca01d6dd	226	private->id = id;
638c1fd3	227	private->psi = psi;
ca01d6dd TL	228
	229	switch (type) {
	230	case PSTORE_TYPE_DMESG:
	231	sprintf(name, "dmesg-%s-%lld", psname, id);
	232	break;
	233	case PSTORE_TYPE_MCE:
	234	sprintf(name, "mce-%s-%lld", psname, id);
	235	break;
	236	case PSTORE_TYPE_UNKNOWN:
	237	sprintf(name, "unknown-%s-%lld", psname, id);
	238	break;
	239	default:
	240	sprintf(name, "type%d-%s-%lld", type, psname, id);
	241	break;
	242	}
	243
	244	mutex_lock(&root->d_inode->i_mutex);
	245
	246	rc = -ENOSPC;
	247	dentry = d_alloc_name(root, name);
	248	if (IS_ERR(dentry))
	249	goto fail_lockedalloc;
	250
fbe0aa1f TL	251	memcpy(private->data, data, size);
fbe0aa1f TL	252	inode->i_size = private->size = size;
ca01d6dd TL	253
	254	inode->i_private = private;
	255
	256	if (time.tv_sec)
	257	inode->i_mtime = inode->i_ctime = time;
	258
fbe0aa1f	259	d_add(dentry, inode);
ca01d6dd	260
6dda9266 TL	261	spin_lock_irqsave(&allpstore_lock, flags);
	262	list_add(&private->list, &allpstore);
	263	spin_unlock_irqrestore(&allpstore_lock, flags);
	264
ca01d6dd	265	mutex_unlock(&root->d_inode->i_mutex);
fbe0aa1f TL	266
fbe0aa1f TL	267	return 0;
ca01d6dd TL	268
	269	fail_lockedalloc:
	270	mutex_unlock(&root->d_inode->i_mutex);
	271	kfree(private);
	272	fail_alloc:
	273	iput(inode);
	274
	275	fail:
	276	return rc;
	277	}
	278
	279	int pstore_fill_super(struct super_block sb, void data, int silent)
	280	{
	281	struct inode *inode = NULL;
	282	struct dentry *root;
	283	int err;
	284
	285	save_mount_options(sb, data);
	286
	287	pstore_sb = sb;
	288
	289	sb->s_maxbytes = MAX_LFS_FILESIZE;
	290	sb->s_blocksize = PAGE_CACHE_SIZE;
	291	sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
	292	sb->s_magic = PSTOREFS_MAGIC;
	293	sb->s_op = &pstore_ops;
	294	sb->s_time_gran = 1;
	295
366f7e7a TL	296	parse_options(data);
366f7e7a TL	297
ca01d6dd TL	298	inode = pstore_get_inode(sb, NULL, S_IFDIR \| 0755, 0);
	299	if (!inode) {
	300	err = -ENOMEM;
	301	goto fail;
	302	}
	303	/* override ramfs "dir" options so we catch unlink(2) */
	304	inode->i_op = &pstore_dir_inode_operations;
	305
48fde701	306	root = d_make_root(inode);
ca01d6dd TL	307	sb->s_root = root;
	308	if (!root) {
	309	err = -ENOMEM;
	310	goto fail;
	311	}
	312
6dda9266	313	pstore_get_records(0);
ca01d6dd TL	314
	315	return 0;
	316	fail:
ca01d6dd TL	317	return err;
	318	}
	319
fbe0aa1f TL	320	static struct dentry pstore_mount(struct file_system_type fs_type,
fbe0aa1f TL	321	int flags, const char dev_name, void data)
ca01d6dd	322	{
fbe0aa1f	323	return mount_single(fs_type, flags, data, pstore_fill_super);
ca01d6dd TL	324	}
	325
	326	static void pstore_kill_sb(struct super_block *sb)
	327	{
	328	kill_litter_super(sb);
	329	pstore_sb = NULL;
ca01d6dd TL	330	}
	331
	332	static struct file_system_type pstore_fs_type = {
	333	.name = "pstore",
fbe0aa1f	334	.mount = pstore_mount,
ca01d6dd TL	335	.kill_sb = pstore_kill_sb,
	336	};
	337
	338	static int __init init_pstore_fs(void)
	339	{
366f7e7a	340	return register_filesystem(&pstore_fs_type);
ca01d6dd TL	341	}
	342	module_init(init_pstore_fs)
	343
	344	MODULE_AUTHOR("Tony Luck <[email protected]>");
	345	MODULE_LICENSE("GPL");