[net-next-2.6.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.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/configfs.h>
#include "configfs_internal.h"

extern struct super_block * configfs_sb;

static struct address_space_operations configfs_aops = {
	.readpage	= simple_readpage,
	.prepare_write	= simple_prepare_write,
	.commit_write	= simple_commit_write
};

static struct backing_dev_info configfs_backing_dev_info = {
	.ra_pages	= 0,	/* No readahead */
	.capabilities	= BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
};

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

int configfs_setattr(struct dentry * dentry, struct iattr * iattr)
{
	struct inode * inode = dentry->d_inode;
	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;

	error = inode_change_ok(inode, iattr);
	if (error)
		return error;

	error = inode_setattr(inode, iattr);
	if (error)
		return error;

	if (!sd_iattr) {
		/* setting attributes for the first time, allocate now */
		sd_iattr = kmalloc(sizeof(struct iattr), GFP_KERNEL);
		if (!sd_iattr)
			return -ENOMEM;
		/* assign default attributes */
		memset(sd_iattr, 0, sizeof(struct iattr));
		sd_iattr->ia_mode = sd->s_mode;
		sd_iattr->ia_uid = 0;
		sd_iattr->ia_gid = 0;
		sd_iattr->ia_atime = sd_iattr->ia_mtime = sd_iattr->ia_ctime = CURRENT_TIME;
		sd->s_iattr = sd_iattr;
	}

	/* attributes were changed atleast once in past */

	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, mode_t mode)
{
	inode->i_mode = mode;
	inode->i_uid = 0;
	inode->i_gid = 0;
	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
}

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(mode_t mode, struct configfs_dirent * sd)
{
	struct inode * inode = new_inode(configfs_sb);
	if (inode) {
		inode->i_blksize = PAGE_CACHE_SIZE;
		inode->i_blocks = 0;
		inode->i_mapping->a_ops = &configfs_aops;
		inode->i_mapping->backing_dev_info = &configfs_backing_dev_info;
		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;
}

int configfs_create(struct dentry * dentry, int mode, int (*init)(struct inode *))
{
	int error = 0;
	struct inode * inode = NULL;
	if (dentry) {
		if (!dentry->d_inode) {
			struct configfs_dirent *sd = dentry->d_fsdata;
			if ((inode = configfs_new_inode(mode, sd))) {
				if (dentry->d_parent && dentry->d_parent->d_inode) {
					struct inode *p_inode = dentry->d_parent->d_inode;
					p_inode->i_mtime = p_inode->i_ctime = CURRENT_TIME;
				}
				goto Proceed;
			}
			else
				error = -ENOMEM;
		} else
			error = -EEXIST;
	} else
		error = -ENOENT;
	goto Done;

 Proceed:
	if (init)
		error = init(inode);
	if (!error) {
		d_instantiate(dentry, inode);
		if (S_ISDIR(mode) || S_ISLNK(mode))
			dget(dentry);  /* pin link and directory dentries in core */
	} else
		iput(inode);
 Done:
	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) {
		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(&dcache_lock);
		spin_lock(&dentry->d_lock);
		if (!(d_unhashed(dentry) && dentry->d_inode)) {
			dget_locked(dentry);
			__d_drop(dentry);
			spin_unlock(&dentry->d_lock);
			spin_unlock(&dcache_lock);
			simple_unlink(parent->d_inode, dentry);
		} else {
			spin_unlock(&dentry->d_lock);
			spin_unlock(&dcache_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 (dir->d_inode == NULL)
		/* no inode means this hasn't been made visible yet */
		return;

	mutex_lock(&dir->d_inode->i_mutex);
	list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
		if (!sd->s_element)
			continue;
		if (!strcmp(configfs_get_name(sd), name)) {
			list_del_init(&sd->s_sibling);
			configfs_drop_dentry(sd, dir);
			configfs_put(sd);
			break;
		}
	}
	mutex_unlock(&dir->d_inode->i_mutex);
}
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	*
	26	* Please see Documentation/filesystems/configfs.txt for more information.
	27	*/
	28
	29	#undef DEBUG
	30
	31	#include <linux/pagemap.h>
	32	#include <linux/namei.h>
	33	#include <linux/backing-dev.h>
3d0f89bb	34	#include <linux/capability.h>
7063fbf2 JB	35
	36	#include <linux/configfs.h>
	37	#include "configfs_internal.h"
	38
	39	extern struct super_block * configfs_sb;
	40
	41	static struct address_space_operations configfs_aops = {
	42	.readpage = simple_readpage,
	43	.prepare_write = simple_prepare_write,
	44	.commit_write = simple_commit_write
	45	};
	46
	47	static struct backing_dev_info configfs_backing_dev_info = {
	48	.ra_pages = 0, /* No readahead */
	49	.capabilities = BDI_CAP_NO_ACCT_DIRTY \| BDI_CAP_NO_WRITEBACK,
	50	};
	51
3d0f89bb JB	52	static struct inode_operations configfs_inode_operations ={
	53	.setattr = configfs_setattr,
	54	};
	55
	56	int configfs_setattr(struct dentry * dentry, struct iattr * iattr)
	57	{
	58	struct inode * inode = dentry->d_inode;
	59	struct configfs_dirent * sd = dentry->d_fsdata;
	60	struct iattr * sd_iattr;
	61	unsigned int ia_valid = iattr->ia_valid;
	62	int error;
	63
	64	if (!sd)
	65	return -EINVAL;
	66
	67	sd_iattr = sd->s_iattr;
	68
	69	error = inode_change_ok(inode, iattr);
	70	if (error)
	71	return error;
	72
	73	error = inode_setattr(inode, iattr);
	74	if (error)
	75	return error;
	76
	77	if (!sd_iattr) {
	78	/* setting attributes for the first time, allocate now */
	79	sd_iattr = kmalloc(sizeof(struct iattr), GFP_KERNEL);
	80	if (!sd_iattr)
	81	return -ENOMEM;
	82	/* assign default attributes */
	83	memset(sd_iattr, 0, sizeof(struct iattr));
	84	sd_iattr->ia_mode = sd->s_mode;
	85	sd_iattr->ia_uid = 0;
	86	sd_iattr->ia_gid = 0;
	87	sd_iattr->ia_atime = sd_iattr->ia_mtime = sd_iattr->ia_ctime = CURRENT_TIME;
	88	sd->s_iattr = sd_iattr;
	89	}
	90
	91	/* attributes were changed atleast once in past */
	92
	93	if (ia_valid & ATTR_UID)
	94	sd_iattr->ia_uid = iattr->ia_uid;
	95	if (ia_valid & ATTR_GID)
	96	sd_iattr->ia_gid = iattr->ia_gid;
	97	if (ia_valid & ATTR_ATIME)
	98	sd_iattr->ia_atime = timespec_trunc(iattr->ia_atime,
	99	inode->i_sb->s_time_gran);
	100	if (ia_valid & ATTR_MTIME)
	101	sd_iattr->ia_mtime = timespec_trunc(iattr->ia_mtime,
	102	inode->i_sb->s_time_gran);
	103	if (ia_valid & ATTR_CTIME)
	104	sd_iattr->ia_ctime = timespec_trunc(iattr->ia_ctime,
	105	inode->i_sb->s_time_gran);
	106	if (ia_valid & ATTR_MODE) {
	107	umode_t mode = iattr->ia_mode;
	108
	109	if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
	110	mode &= ~S_ISGID;
	111	sd_iattr->ia_mode = sd->s_mode = mode;
	112	}
	113
	114	return error;
	115	}
116
117	static inline void set_default_inode_attr(struct inode * inode, mode_t mode)
118	{
119	inode->i_mode = mode;
120	inode->i_uid = 0;
121	inode->i_gid = 0;
122	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
123	}
124
125	static inline void set_inode_attr(struct inode * inode, struct iattr * iattr)
126	{
127	inode->i_mode = iattr->ia_mode;
128	inode->i_uid = iattr->ia_uid;
129	inode->i_gid = iattr->ia_gid;
130	inode->i_atime = iattr->ia_atime;
131	inode->i_mtime = iattr->ia_mtime;
132	inode->i_ctime = iattr->ia_ctime;
133	}
134
135	struct inode * configfs_new_inode(mode_t mode, struct configfs_dirent * sd)
7063fbf2 JB	136	{
	137	struct inode * inode = new_inode(configfs_sb);
	138	if (inode) {
7063fbf2 JB	139	inode->i_blksize = PAGE_CACHE_SIZE;
7063fbf2 JB	140	inode->i_blocks = 0;
7063fbf2 JB	141	inode->i_mapping->a_ops = &configfs_aops;
7063fbf2 JB	142	inode->i_mapping->backing_dev_info = &configfs_backing_dev_info;
3d0f89bb JB	143	inode->i_op = &configfs_inode_operations;
	144
	145	if (sd->s_iattr) {
	146	/* sysfs_dirent has non-default attributes
	147	* get them for the new inode from persistent copy
	148	* in sysfs_dirent
	149	*/
	150	set_inode_attr(inode, sd->s_iattr);
	151	} else
	152	set_default_inode_attr(inode, mode);
7063fbf2 JB	153	}
	154	return inode;
	155	}
	156
	157	int configfs_create(struct dentry * dentry, int mode, int (init)(struct inode ))
	158	{
	159	int error = 0;
	160	struct inode * inode = NULL;
	161	if (dentry) {
	162	if (!dentry->d_inode) {
3d0f89bb JB	163	struct configfs_dirent *sd = dentry->d_fsdata;
3d0f89bb JB	164	if ((inode = configfs_new_inode(mode, sd))) {
7063fbf2 JB	165	if (dentry->d_parent && dentry->d_parent->d_inode) {
	166	struct inode *p_inode = dentry->d_parent->d_inode;
	167	p_inode->i_mtime = p_inode->i_ctime = CURRENT_TIME;
	168	}
	169	goto Proceed;
	170	}
	171	else
	172	error = -ENOMEM;
	173	} else
	174	error = -EEXIST;
	175	} else
	176	error = -ENOENT;
	177	goto Done;
	178
	179	Proceed:
	180	if (init)
	181	error = init(inode);
	182	if (!error) {
	183	d_instantiate(dentry, inode);
	184	if (S_ISDIR(mode) \|\| S_ISLNK(mode))
	185	dget(dentry); /* pin link and directory dentries in core */
	186	} else
	187	iput(inode);
	188	Done:
	189	return error;
	190	}
	191
	192	/*
	193	* Get the name for corresponding element represented by the given configfs_dirent
	194	*/
	195	const unsigned char * configfs_get_name(struct configfs_dirent *sd)
	196	{
3d0f89bb	197	struct configfs_attribute *attr;
7063fbf2	198
1a1974fd	199	BUG_ON(!sd \|\| !sd->s_element);
7063fbf2 JB	200
	201	/* These always have a dentry, so use that */
	202	if (sd->s_type & (CONFIGFS_DIR \| CONFIGFS_ITEM_LINK))
	203	return sd->s_dentry->d_name.name;
	204
	205	if (sd->s_type & CONFIGFS_ITEM_ATTR) {
	206	attr = sd->s_element;
3d0f89bb	207	return attr->ca_name;
7063fbf2 JB	208	}
	209	return NULL;
	210	}
	211
	212
	213	/*
	214	* Unhashes the dentry corresponding to given configfs_dirent
1b1dcc1b	215	* Called with parent inode's i_mutex held.
7063fbf2 JB	216	*/
	217	void configfs_drop_dentry(struct configfs_dirent * sd, struct dentry * parent)
	218	{
	219	struct dentry * dentry = sd->s_dentry;
	220
	221	if (dentry) {
	222	spin_lock(&dcache_lock);
3d0f89bb	223	spin_lock(&dentry->d_lock);
7063fbf2 JB	224	if (!(d_unhashed(dentry) && dentry->d_inode)) {
	225	dget_locked(dentry);
	226	__d_drop(dentry);
3d0f89bb	227	spin_unlock(&dentry->d_lock);
7063fbf2 JB	228	spin_unlock(&dcache_lock);
7063fbf2 JB	229	simple_unlink(parent->d_inode, dentry);
3d0f89bb JB	230	} else {
3d0f89bb JB	231	spin_unlock(&dentry->d_lock);
7063fbf2	232	spin_unlock(&dcache_lock);
3d0f89bb	233	}
7063fbf2 JB	234	}
	235	}
	236
	237	void configfs_hash_and_remove(struct dentry * dir, const char * name)
	238	{
	239	struct configfs_dirent * sd;
	240	struct configfs_dirent * parent_sd = dir->d_fsdata;
	241
3d0f89bb JB	242	if (dir->d_inode == NULL)
	243	/* no inode means this hasn't been made visible yet */
	244	return;
	245
1b1dcc1b	246	mutex_lock(&dir->d_inode->i_mutex);
7063fbf2 JB	247	list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
	248	if (!sd->s_element)
	249	continue;
	250	if (!strcmp(configfs_get_name(sd), name)) {
	251	list_del_init(&sd->s_sibling);
	252	configfs_drop_dentry(sd, dir);
	253	configfs_put(sd);
	254	break;
	255	}
	256	}
1b1dcc1b	257	mutex_unlock(&dir->d_inode->i_mutex);
7063fbf2 JB	258	}
	259
	260