[mirror_ubuntu-artful-kernel.git] / fs / configfs / inode.c

/* -*- mode: c; c-basic-offset: 8; -*-
 * vim: noexpandtab sw=8 ts=8 sts=0:
 *
 * inode.c - basic inode and dentry operations.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * 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 021110-1307, USA.
 *
 * Based on sysfs:
 * 	sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
 *
 * configfs Copyright (C) 2005 Oracle.  All rights reserved.
 *
 * Please see Documentation/filesystems/configfs/configfs.txt for more
 * information.
 */

#undef DEBUG

#include <linux/pagemap.h>
#include <linux/namei.h>
#include <linux/backing-dev.h>
#include <linux/capability.h>
#include <linux/sched.h>
#include <linux/lockdep.h>
#include <linux/slab.h>

#include <linux/configfs.h>
#include "configfs_internal.h"

#ifdef CONFIG_LOCKDEP
static struct lock_class_key default_group_class[MAX_LOCK_DEPTH];
#endif

static const struct address_space_operations configfs_aops = {
	.readpage	= simple_readpage,
	.write_begin	= simple_write_begin,
	.write_end	= simple_write_end,
};

static const struct inode_operations configfs_inode_operations ={
	.setattr	= configfs_setattr,
};

int configfs_setattr(struct dentry * dentry, struct iattr * iattr)
{
	struct inode * inode = d_inode(dentry);
	struct configfs_dirent * sd = dentry->d_fsdata;
	struct iattr * sd_iattr;
	unsigned int ia_valid = iattr->ia_valid;
	int error;

	if (!sd)
		return -EINVAL;

	sd_iattr = sd->s_iattr;
	if (!sd_iattr) {
		/* setting attributes for the first time, allocate now */
		sd_iattr = kzalloc(sizeof(struct iattr), GFP_KERNEL);
		if (!sd_iattr)
			return -ENOMEM;
		/* assign default attributes */
		sd_iattr->ia_mode = sd->s_mode;
		sd_iattr->ia_uid = GLOBAL_ROOT_UID;
		sd_iattr->ia_gid = GLOBAL_ROOT_GID;
		sd_iattr->ia_atime = sd_iattr->ia_mtime =
			sd_iattr->ia_ctime = current_time(inode);
		sd->s_iattr = sd_iattr;
	}
	/* attributes were changed atleast once in past */

	error = simple_setattr(dentry, iattr);
	if (error)
		return error;

	if (ia_valid & ATTR_UID)
		sd_iattr->ia_uid = iattr->ia_uid;
	if (ia_valid & ATTR_GID)
		sd_iattr->ia_gid = iattr->ia_gid;
	if (ia_valid & ATTR_ATIME)
		sd_iattr->ia_atime = timespec_trunc(iattr->ia_atime,
						inode->i_sb->s_time_gran);
	if (ia_valid & ATTR_MTIME)
		sd_iattr->ia_mtime = timespec_trunc(iattr->ia_mtime,
						inode->i_sb->s_time_gran);
	if (ia_valid & ATTR_CTIME)
		sd_iattr->ia_ctime = timespec_trunc(iattr->ia_ctime,
						inode->i_sb->s_time_gran);
	if (ia_valid & ATTR_MODE) {
		umode_t mode = iattr->ia_mode;

		if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
			mode &= ~S_ISGID;
		sd_iattr->ia_mode = sd->s_mode = mode;
	}

	return error;
}

static inline void set_default_inode_attr(struct inode * inode, umode_t mode)
{
	inode->i_mode = mode;
	inode->i_atime = inode->i_mtime =
		inode->i_ctime = current_time(inode);
}

static inline void set_inode_attr(struct inode * inode, struct iattr * iattr)
{
	inode->i_mode = iattr->ia_mode;
	inode->i_uid = iattr->ia_uid;
	inode->i_gid = iattr->ia_gid;
	inode->i_atime = iattr->ia_atime;
	inode->i_mtime = iattr->ia_mtime;
	inode->i_ctime = iattr->ia_ctime;
}

struct inode *configfs_new_inode(umode_t mode, struct configfs_dirent *sd,
				 struct super_block *s)
{
	struct inode * inode = new_inode(s);
	if (inode) {
		inode->i_ino = get_next_ino();
		inode->i_mapping->a_ops = &configfs_aops;
		inode->i_op = &configfs_inode_operations;

		if (sd->s_iattr) {
			/* sysfs_dirent has non-default attributes
			 * get them for the new inode from persistent copy
			 * in sysfs_dirent
			 */
			set_inode_attr(inode, sd->s_iattr);
		} else
			set_default_inode_attr(inode, mode);
	}
	return inode;
}

#ifdef CONFIG_LOCKDEP

static void configfs_set_inode_lock_class(struct configfs_dirent *sd,
					  struct inode *inode)
{
	int depth = sd->s_depth;

	if (depth > 0) {
		if (depth <= ARRAY_SIZE(default_group_class)) {
			lockdep_set_class(&inode->i_rwsem,
					  &default_group_class[depth - 1]);
		} else {
			/*
			 * In practice the maximum level of locking depth is
			 * already reached. Just inform about possible reasons.
			 */
			pr_info("Too many levels of inodes for the locking correctness validator.\n");
			pr_info("Spurious warnings may appear.\n");
		}
	}
}

#else /* CONFIG_LOCKDEP */

static void configfs_set_inode_lock_class(struct configfs_dirent *sd,
					  struct inode *inode)
{
}

#endif /* CONFIG_LOCKDEP */

int configfs_create(struct dentry * dentry, umode_t mode, void (*init)(struct inode *))
{
	int error = 0;
	struct inode *inode = NULL;
	struct configfs_dirent *sd;
	struct inode *p_inode;

	if (!dentry)
		return -ENOENT;

	if (d_really_is_positive(dentry))
		return -EEXIST;

	sd = dentry->d_fsdata;
	inode = configfs_new_inode(mode, sd, dentry->d_sb);
	if (!inode)
		return -ENOMEM;

	p_inode = d_inode(dentry->d_parent);
	p_inode->i_mtime = p_inode->i_ctime = current_time(p_inode);
	configfs_set_inode_lock_class(sd, inode);

	init(inode);
	if (S_ISDIR(mode) || S_ISLNK(mode)) {
		/*
		 * ->symlink(), ->mkdir(), configfs_register_subsystem() or
		 * create_default_group() - already hashed.
		 */
		d_instantiate(dentry, inode);
		dget(dentry);  /* pin link and directory dentries in core */
	} else {
		/* ->lookup() */
		d_add(dentry, inode);
	}
	return error;
}

/*
 * Get the name for corresponding element represented by the given configfs_dirent
 */
const unsigned char * configfs_get_name(struct configfs_dirent *sd)
{
	struct configfs_attribute *attr;

	BUG_ON(!sd || !sd->s_element);

	/* These always have a dentry, so use that */
	if (sd->s_type & (CONFIGFS_DIR | CONFIGFS_ITEM_LINK))
		return sd->s_dentry->d_name.name;

	if (sd->s_type & (CONFIGFS_ITEM_ATTR | CONFIGFS_ITEM_BIN_ATTR)) {
		attr = sd->s_element;
		return attr->ca_name;
	}
	return NULL;
}


/*
 * Unhashes the dentry corresponding to given configfs_dirent
 * Called with parent inode's i_mutex held.
 */
void configfs_drop_dentry(struct configfs_dirent * sd, struct dentry * parent)
{
	struct dentry * dentry = sd->s_dentry;

	if (dentry) {
		spin_lock(&dentry->d_lock);
		if (simple_positive(dentry)) {
			dget_dlock(dentry);
			__d_drop(dentry);
			spin_unlock(&dentry->d_lock);
			simple_unlink(d_inode(parent), dentry);
		} else
			spin_unlock(&dentry->d_lock);
	}
}

void configfs_hash_and_remove(struct dentry * dir, const char * name)
{
	struct configfs_dirent * sd;
	struct configfs_dirent * parent_sd = dir->d_fsdata;

	if (d_really_is_negative(dir))
		/* no inode means this hasn't been made visible yet */
		return;

	inode_lock(d_inode(dir));
	list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
		if (!sd->s_element)
			continue;
		if (!strcmp(configfs_get_name(sd), name)) {
			spin_lock(&configfs_dirent_lock);
			list_del_init(&sd->s_sibling);
			spin_unlock(&configfs_dirent_lock);
			configfs_drop_dentry(sd, dir);
			configfs_put(sd);
			break;
		}
	}
	inode_unlock(d_inode(dir));
}
Commit	Line	Data
7063fbf2 JB	1	/* -- mode: c; c-basic-offset: 8; --
	2	* vim: noexpandtab sw=8 ts=8 sts=0:
	3	*
	4	* inode.c - basic inode and dentry operations.
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public
	8	* License as published by the Free Software Foundation; either
	9	* version 2 of the License, or (at your option) any later version.
	10	*
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	14	* General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU General Public
	17	* License along with this program; if not, write to the
	18	* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
	19	* Boston, MA 021110-1307, USA.
	20	*
	21	* Based on sysfs:
	22	* sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
	23	*
	24	* configfs Copyright (C) 2005 Oracle. All rights reserved.
	25	*
395cf969 PB	26	* Please see Documentation/filesystems/configfs/configfs.txt for more
395cf969 PB	27	* information.
7063fbf2 JB	28	*/
	29
	30	#undef DEBUG
	31
	32	#include <linux/pagemap.h>
	33	#include <linux/namei.h>
	34	#include <linux/backing-dev.h>
3d0f89bb	35	#include <linux/capability.h>
e8edc6e0	36	#include <linux/sched.h>
e74cc06d	37	#include <linux/lockdep.h>
5a0e3ad6	38	#include <linux/slab.h>
7063fbf2 JB	39
	40	#include <linux/configfs.h>
	41	#include "configfs_internal.h"
	42
e74cc06d LR	43	#ifdef CONFIG_LOCKDEP
	44	static struct lock_class_key default_group_class[MAX_LOCK_DEPTH];
	45	#endif
	46
f5e54d6e	47	static const struct address_space_operations configfs_aops = {
7063fbf2	48	.readpage = simple_readpage,
800d15a5 NP	49	.write_begin = simple_write_begin,
800d15a5 NP	50	.write_end = simple_write_end,
7063fbf2 JB	51	};
7063fbf2 JB	52
754661f1	53	static const struct inode_operations configfs_inode_operations ={
3d0f89bb JB	54	.setattr = configfs_setattr,
	55	};
	56
	57	int configfs_setattr(struct dentry * dentry, struct iattr * iattr)
	58	{
2b0143b5	59	struct inode * inode = d_inode(dentry);
3d0f89bb JB	60	struct configfs_dirent * sd = dentry->d_fsdata;
	61	struct iattr * sd_iattr;
	62	unsigned int ia_valid = iattr->ia_valid;
	63	int error;
	64
	65	if (!sd)
	66	return -EINVAL;
	67
3322e79a	68	sd_iattr = sd->s_iattr;
3d0f89bb JB	69	if (!sd_iattr) {
3d0f89bb JB	70	/* setting attributes for the first time, allocate now */
f8314dc6	71	sd_iattr = kzalloc(sizeof(struct iattr), GFP_KERNEL);
3d0f89bb JB	72	if (!sd_iattr)
	73	return -ENOMEM;
	74	/* assign default attributes */
3d0f89bb	75	sd_iattr->ia_mode = sd->s_mode;
69552c0c EB	76	sd_iattr->ia_uid = GLOBAL_ROOT_UID;
69552c0c EB	77	sd_iattr->ia_gid = GLOBAL_ROOT_GID;
b1f1a29d	78	sd_iattr->ia_atime = sd_iattr->ia_mtime =
c2050a45	79	sd_iattr->ia_ctime = current_time(inode);
3d0f89bb JB	80	sd->s_iattr = sd_iattr;
3d0f89bb JB	81	}
3d0f89bb JB	82	/* attributes were changed atleast once in past */
3d0f89bb JB	83
75de46b9 NP	84	error = simple_setattr(dentry, iattr);
	85	if (error)
	86	return error;
	87
3d0f89bb JB	88	if (ia_valid & ATTR_UID)
	89	sd_iattr->ia_uid = iattr->ia_uid;
	90	if (ia_valid & ATTR_GID)
	91	sd_iattr->ia_gid = iattr->ia_gid;
	92	if (ia_valid & ATTR_ATIME)
	93	sd_iattr->ia_atime = timespec_trunc(iattr->ia_atime,
	94	inode->i_sb->s_time_gran);
	95	if (ia_valid & ATTR_MTIME)
	96	sd_iattr->ia_mtime = timespec_trunc(iattr->ia_mtime,
	97	inode->i_sb->s_time_gran);
	98	if (ia_valid & ATTR_CTIME)
	99	sd_iattr->ia_ctime = timespec_trunc(iattr->ia_ctime,
	100	inode->i_sb->s_time_gran);
	101	if (ia_valid & ATTR_MODE) {
	102	umode_t mode = iattr->ia_mode;
	103
	104	if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
	105	mode &= ~S_ISGID;
	106	sd_iattr->ia_mode = sd->s_mode = mode;
	107	}
	108
	109	return error;
	110	}
	111
43947514	112	static inline void set_default_inode_attr(struct inode * inode, umode_t mode)
3d0f89bb JB	113	{
3d0f89bb JB	114	inode->i_mode = mode;
b1f1a29d	115	inode->i_atime = inode->i_mtime =
c2050a45	116	inode->i_ctime = current_time(inode);
3d0f89bb JB	117	}
	118
	119	static inline void set_inode_attr(struct inode * inode, struct iattr * iattr)
	120	{
	121	inode->i_mode = iattr->ia_mode;
	122	inode->i_uid = iattr->ia_uid;
	123	inode->i_gid = iattr->ia_gid;
	124	inode->i_atime = iattr->ia_atime;
	125	inode->i_mtime = iattr->ia_mtime;
	126	inode->i_ctime = iattr->ia_ctime;
	127	}
	128
b7c177fc AV	129	struct inode configfs_new_inode(umode_t mode, struct configfs_dirent sd,
b7c177fc AV	130	struct super_block *s)
7063fbf2	131	{
b7c177fc	132	struct inode * inode = new_inode(s);
7063fbf2	133	if (inode) {
85fe4025	134	inode->i_ino = get_next_ino();
7063fbf2	135	inode->i_mapping->a_ops = &configfs_aops;
3d0f89bb JB	136	inode->i_op = &configfs_inode_operations;
	137
	138	if (sd->s_iattr) {
	139	/* sysfs_dirent has non-default attributes
	140	* get them for the new inode from persistent copy
	141	* in sysfs_dirent
	142	*/
	143	set_inode_attr(inode, sd->s_iattr);
	144	} else
	145	set_default_inode_attr(inode, mode);
7063fbf2 JB	146	}
	147	return inode;
	148	}
	149
e74cc06d LR	150	#ifdef CONFIG_LOCKDEP
	151
	152	static void configfs_set_inode_lock_class(struct configfs_dirent *sd,
	153	struct inode *inode)
	154	{
	155	int depth = sd->s_depth;
	156
	157	if (depth > 0) {
	158	if (depth <= ARRAY_SIZE(default_group_class)) {
9902af79	159	lockdep_set_class(&inode->i_rwsem,
e74cc06d LR	160	&default_group_class[depth - 1]);
	161	} else {
	162	/*
	163	* In practice the maximum level of locking depth is
	164	* already reached. Just inform about possible reasons.
	165	*/
1d88aa44	166	pr_info("Too many levels of inodes for the locking correctness validator.\n");
c6686931	167	pr_info("Spurious warnings may appear.\n");
e74cc06d LR	168	}
	169	}
	170	}
	171
	172	#else /* CONFIG_LOCKDEP */
	173
	174	static void configfs_set_inode_lock_class(struct configfs_dirent *sd,
	175	struct inode *inode)
	176	{
	177	}
	178
	179	#endif /* CONFIG_LOCKDEP */
	180
c88b1e70	181	int configfs_create(struct dentry * dentry, umode_t mode, void (init)(struct inode ))
7063fbf2 JB	182	{
7063fbf2 JB	183	int error = 0;
16d13b59 AV	184	struct inode *inode = NULL;
	185	struct configfs_dirent *sd;
	186	struct inode *p_inode;
	187
	188	if (!dentry)
	189	return -ENOENT;
	190
2b0143b5	191	if (d_really_is_positive(dentry))
16d13b59	192	return -EEXIST;
7063fbf2	193
16d13b59 AV	194	sd = dentry->d_fsdata;
	195	inode = configfs_new_inode(mode, sd, dentry->d_sb);
	196	if (!inode)
	197	return -ENOMEM;
	198
2b0143b5	199	p_inode = d_inode(dentry->d_parent);
c2050a45	200	p_inode->i_mtime = p_inode->i_ctime = current_time(p_inode);
16d13b59 AV	201	configfs_set_inode_lock_class(sd, inode);
16d13b59 AV	202
c88b1e70	203	init(inode);
5cf3b560 AV	204	if (S_ISDIR(mode) \|\| S_ISLNK(mode)) {
	205	/*
	206	* ->symlink(), ->mkdir(), configfs_register_subsystem() or
	207	* create_default_group() - already hashed.
	208	*/
	209	d_instantiate(dentry, inode);
16d13b59	210	dget(dentry); /* pin link and directory dentries in core */
5cf3b560 AV	211	} else {
	212	/* ->lookup() */
	213	d_add(dentry, inode);
	214	}
7063fbf2 JB	215	return error;
	216	}
	217
	218	/*
	219	* Get the name for corresponding element represented by the given configfs_dirent
	220	*/
	221	const unsigned char * configfs_get_name(struct configfs_dirent *sd)
	222	{
3d0f89bb	223	struct configfs_attribute *attr;
7063fbf2	224
1a1974fd	225	BUG_ON(!sd \|\| !sd->s_element);
7063fbf2 JB	226
	227	/* These always have a dentry, so use that */
	228	if (sd->s_type & (CONFIGFS_DIR \| CONFIGFS_ITEM_LINK))
	229	return sd->s_dentry->d_name.name;
	230
03607ace	231	if (sd->s_type & (CONFIGFS_ITEM_ATTR \| CONFIGFS_ITEM_BIN_ATTR)) {
7063fbf2	232	attr = sd->s_element;
3d0f89bb	233	return attr->ca_name;
7063fbf2 JB	234	}
	235	return NULL;
	236	}
	237
	238
	239	/*
	240	* Unhashes the dentry corresponding to given configfs_dirent
1b1dcc1b	241	* Called with parent inode's i_mutex held.
7063fbf2 JB	242	*/
	243	void configfs_drop_dentry(struct configfs_dirent * sd, struct dentry * parent)
	244	{
	245	struct dentry * dentry = sd->s_dentry;
	246
	247	if (dentry) {
3d0f89bb	248	spin_lock(&dentry->d_lock);
dc3f4198	249	if (simple_positive(dentry)) {
dc0474be	250	dget_dlock(dentry);
7063fbf2	251	__d_drop(dentry);
3d0f89bb	252	spin_unlock(&dentry->d_lock);
2b0143b5	253	simple_unlink(d_inode(parent), dentry);
b5c84bf6	254	} else
3d0f89bb	255	spin_unlock(&dentry->d_lock);
7063fbf2 JB	256	}
	257	}
	258
	259	void configfs_hash_and_remove(struct dentry * dir, const char * name)
	260	{
	261	struct configfs_dirent * sd;
	262	struct configfs_dirent * parent_sd = dir->d_fsdata;
	263
2b0143b5	264	if (d_really_is_negative(dir))
3d0f89bb JB	265	/* no inode means this hasn't been made visible yet */
	266	return;
	267
5955102c	268	inode_lock(d_inode(dir));
7063fbf2 JB	269	list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
	270	if (!sd->s_element)
	271	continue;
	272	if (!strcmp(configfs_get_name(sd), name)) {
6f610764	273	spin_lock(&configfs_dirent_lock);
7063fbf2	274	list_del_init(&sd->s_sibling);
6f610764	275	spin_unlock(&configfs_dirent_lock);
7063fbf2 JB	276	configfs_drop_dentry(sd, dir);
	277	configfs_put(sd);
	278	break;
	279	}
	280	}
5955102c	281	inode_unlock(d_inode(dir));
7063fbf2	282	}