[linux.git] / fs / ubifs / xattr.c

/*
 * This file is part of UBIFS.
 *
 * Copyright (C) 2006-2008 Nokia Corporation.
 *
 * 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., 51
 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 *
 * Authors: Artem Bityutskiy (Битюцкий Артём)
 *          Adrian Hunter
 */

/*
 * This file implements UBIFS extended attributes support.
 *
 * Extended attributes are implemented as regular inodes with attached data,
 * which limits extended attribute size to UBIFS block size (4KiB). Names of
 * extended attributes are described by extended attribute entries (xentries),
 * which are almost identical to directory entries, but have different key type.
 *
 * In other words, the situation with extended attributes is very similar to
 * directories. Indeed, any inode (but of course not xattr inodes) may have a
 * number of associated xentries, just like directory inodes have associated
 * directory entries. Extended attribute entries store the name of the extended
 * attribute, the host inode number, and the extended attribute inode number.
 * Similarly, direntries store the name, the parent and the target inode
 * numbers. Thus, most of the common UBIFS mechanisms may be re-used for
 * extended attributes.
 *
 * The number of extended attributes is not limited, but there is Linux
 * limitation on the maximum possible size of the list of all extended
 * attributes associated with an inode (%XATTR_LIST_MAX), so UBIFS makes sure
 * the sum of all extended attribute names of the inode does not exceed that
 * limit.
 *
 * Extended attributes are synchronous, which means they are written to the
 * flash media synchronously and there is no write-back for extended attribute
 * inodes. The extended attribute values are not stored in compressed form on
 * the media.
 *
 * Since extended attributes are represented by regular inodes, they are cached
 * in the VFS inode cache. The xentries are cached in the LNC cache (see
 * tnc.c).
 *
 * ACL support is not implemented.
 */

#include "ubifs.h"
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/xattr.h>
#include <linux/posix_acl_xattr.h>

/*
 * Limit the number of extended attributes per inode so that the total size
 * (@xattr_size) is guaranteeded to fit in an 'unsigned int'.
 */
#define MAX_XATTRS_PER_INODE 65535

/*
 * Extended attribute type constants.
 *
 * USER_XATTR: user extended attribute ("user.*")
 * TRUSTED_XATTR: trusted extended attribute ("trusted.*)
 * SECURITY_XATTR: security extended attribute ("security.*")
 */
enum {
	USER_XATTR,
	TRUSTED_XATTR,
	SECURITY_XATTR,
};

static const struct inode_operations empty_iops;
static const struct file_operations empty_fops;

/**
 * create_xattr - create an extended attribute.
 * @c: UBIFS file-system description object
 * @host: host inode
 * @nm: extended attribute name
 * @value: extended attribute value
 * @size: size of extended attribute value
 *
 * This is a helper function which creates an extended attribute of name @nm
 * and value @value for inode @host. The host inode is also updated on flash
 * because the ctime and extended attribute accounting data changes. This
 * function returns zero in case of success and a negative error code in case
 * of failure.
 */
static int create_xattr(struct ubifs_info *c, struct inode *host,
			const struct qstr *nm, const void *value, int size)
{
	int err;
	struct inode *inode;
	struct ubifs_inode *ui, *host_ui = ubifs_inode(host);
	struct ubifs_budget_req req = { .new_ino = 1, .new_dent = 1,
				.new_ino_d = ALIGN(size, 8), .dirtied_ino = 1,
				.dirtied_ino_d = ALIGN(host_ui->data_len, 8) };

	if (host_ui->xattr_cnt >= MAX_XATTRS_PER_INODE)
		return -ENOSPC;
	/*
	 * Linux limits the maximum size of the extended attribute names list
	 * to %XATTR_LIST_MAX. This means we should not allow creating more
	 * extended attributes if the name list becomes larger. This limitation
	 * is artificial for UBIFS, though.
	 */
	if (host_ui->xattr_names + host_ui->xattr_cnt +
					nm->len + 1 > XATTR_LIST_MAX)
		return -ENOSPC;

	err = ubifs_budget_space(c, &req);
	if (err)
		return err;

	inode = ubifs_new_inode(c, host, S_IFREG | S_IRWXUGO);
	if (IS_ERR(inode)) {
		err = PTR_ERR(inode);
		goto out_budg;
	}

	/* Re-define all operations to be "nothing" */
	inode->i_mapping->a_ops = &empty_aops;
	inode->i_op = &empty_iops;
	inode->i_fop = &empty_fops;

	inode->i_flags |= S_SYNC | S_NOATIME | S_NOCMTIME | S_NOQUOTA;
	ui = ubifs_inode(inode);
	ui->xattr = 1;
	ui->flags |= UBIFS_XATTR_FL;
	ui->data = kmemdup(value, size, GFP_NOFS);
	if (!ui->data) {
		err = -ENOMEM;
		goto out_free;
	}
	inode->i_size = ui->ui_size = size;
	ui->data_len = size;

	mutex_lock(&host_ui->ui_mutex);
	host->i_ctime = ubifs_current_time(host);
	host_ui->xattr_cnt += 1;
	host_ui->xattr_size += CALC_DENT_SIZE(nm->len);
	host_ui->xattr_size += CALC_XATTR_BYTES(size);
	host_ui->xattr_names += nm->len;

	err = ubifs_jnl_update(c, host, nm, inode, 0, 1);
	if (err)
		goto out_cancel;
	mutex_unlock(&host_ui->ui_mutex);

	ubifs_release_budget(c, &req);
	insert_inode_hash(inode);
	iput(inode);
	return 0;

out_cancel:
	host_ui->xattr_cnt -= 1;
	host_ui->xattr_size -= CALC_DENT_SIZE(nm->len);
	host_ui->xattr_size -= CALC_XATTR_BYTES(size);
	mutex_unlock(&host_ui->ui_mutex);
out_free:
	make_bad_inode(inode);
	iput(inode);
out_budg:
	ubifs_release_budget(c, &req);
	return err;
}

/**
 * change_xattr - change an extended attribute.
 * @c: UBIFS file-system description object
 * @host: host inode
 * @inode: extended attribute inode
 * @value: extended attribute value
 * @size: size of extended attribute value
 *
 * This helper function changes the value of extended attribute @inode with new
 * data from @value. Returns zero in case of success and a negative error code
 * in case of failure.
 */
static int change_xattr(struct ubifs_info *c, struct inode *host,
			struct inode *inode, const void *value, int size)
{
	int err;
	struct ubifs_inode *host_ui = ubifs_inode(host);
	struct ubifs_inode *ui = ubifs_inode(inode);
	struct ubifs_budget_req req = { .dirtied_ino = 2,
		.dirtied_ino_d = ALIGN(size, 8) + ALIGN(host_ui->data_len, 8) };

	ubifs_assert(ui->data_len == inode->i_size);
	err = ubifs_budget_space(c, &req);
	if (err)
		return err;

	kfree(ui->data);
	ui->data = kmemdup(value, size, GFP_NOFS);
	if (!ui->data) {
		err = -ENOMEM;
		goto out_free;
	}
	inode->i_size = ui->ui_size = size;
	ui->data_len = size;

	mutex_lock(&host_ui->ui_mutex);
	host->i_ctime = ubifs_current_time(host);
	host_ui->xattr_size -= CALC_XATTR_BYTES(ui->data_len);
	host_ui->xattr_size += CALC_XATTR_BYTES(size);

	/*
	 * It is important to write the host inode after the xattr inode
	 * because if the host inode gets synchronized (via 'fsync()'), then
	 * the extended attribute inode gets synchronized, because it goes
	 * before the host inode in the write-buffer.
	 */
	err = ubifs_jnl_change_xattr(c, inode, host);
	if (err)
		goto out_cancel;
	mutex_unlock(&host_ui->ui_mutex);

	ubifs_release_budget(c, &req);
	return 0;

out_cancel:
	host_ui->xattr_size -= CALC_XATTR_BYTES(size);
	host_ui->xattr_size += CALC_XATTR_BYTES(ui->data_len);
	mutex_unlock(&host_ui->ui_mutex);
	make_bad_inode(inode);
out_free:
	ubifs_release_budget(c, &req);
	return err;
}

/**
 * check_namespace - check extended attribute name-space.
 * @nm: extended attribute name
 *
 * This function makes sure the extended attribute name belongs to one of the
 * supported extended attribute name-spaces. Returns name-space index in case
 * of success and a negative error code in case of failure.
 */
static int check_namespace(const struct qstr *nm)
{
	int type;

	if (nm->len > UBIFS_MAX_NLEN)
		return -ENAMETOOLONG;

	if (!strncmp(nm->name, XATTR_TRUSTED_PREFIX,
		     XATTR_TRUSTED_PREFIX_LEN)) {
		if (nm->name[sizeof(XATTR_TRUSTED_PREFIX) - 1] == '\0')
			return -EINVAL;
		type = TRUSTED_XATTR;
	} else if (!strncmp(nm->name, XATTR_USER_PREFIX,
				      XATTR_USER_PREFIX_LEN)) {
		if (nm->name[XATTR_USER_PREFIX_LEN] == '\0')
			return -EINVAL;
		type = USER_XATTR;
	} else if (!strncmp(nm->name, XATTR_SECURITY_PREFIX,
				     XATTR_SECURITY_PREFIX_LEN)) {
		if (nm->name[sizeof(XATTR_SECURITY_PREFIX) - 1] == '\0')
			return -EINVAL;
		type = SECURITY_XATTR;
	} else
		return -EOPNOTSUPP;

	return type;
}

static struct inode *iget_xattr(struct ubifs_info *c, ino_t inum)
{
	struct inode *inode;

	inode = ubifs_iget(c->vfs_sb, inum);
	if (IS_ERR(inode)) {
		ubifs_err("dead extended attribute entry, error %d",
			  (int)PTR_ERR(inode));
		return inode;
	}
	if (ubifs_inode(inode)->xattr)
		return inode;
	ubifs_err("corrupt extended attribute entry");
	iput(inode);
	return ERR_PTR(-EINVAL);
}

int ubifs_setxattr(struct dentry *dentry, const char *name,
		   const void *value, size_t size, int flags)
{
	struct inode *inode, *host = dentry->d_inode;
	struct ubifs_info *c = host->i_sb->s_fs_info;
	struct qstr nm = QSTR_INIT(name, strlen(name));
	struct ubifs_dent_node *xent;
	union ubifs_key key;
	int err, type;

	dbg_gen("xattr '%s', host ino %lu ('%.*s'), size %zd", name,
		host->i_ino, dentry->d_name.len, dentry->d_name.name, size);
	ubifs_assert(mutex_is_locked(&host->i_mutex));

	if (size > UBIFS_MAX_INO_DATA)
		return -ERANGE;

	type = check_namespace(&nm);
	if (type < 0)
		return type;

	xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
	if (!xent)
		return -ENOMEM;

	/*
	 * The extended attribute entries are stored in LNC, so multiple
	 * look-ups do not involve reading the flash.
	 */
	xent_key_init(c, &key, host->i_ino, &nm);
	err = ubifs_tnc_lookup_nm(c, &key, xent, &nm);
	if (err) {
		if (err != -ENOENT)
			goto out_free;

		if (flags & XATTR_REPLACE)
			/* We are asked not to create the xattr */
			err = -ENODATA;
		else
			err = create_xattr(c, host, &nm, value, size);
		goto out_free;
	}

	if (flags & XATTR_CREATE) {
		/* We are asked not to replace the xattr */
		err = -EEXIST;
		goto out_free;
	}

	inode = iget_xattr(c, le64_to_cpu(xent->inum));
	if (IS_ERR(inode)) {
		err = PTR_ERR(inode);
		goto out_free;
	}

	err = change_xattr(c, host, inode, value, size);
	iput(inode);

out_free:
	kfree(xent);
	return err;
}

ssize_t ubifs_getxattr(struct dentry *dentry, const char *name, void *buf,
		       size_t size)
{
	struct inode *inode, *host = dentry->d_inode;
	struct ubifs_info *c = host->i_sb->s_fs_info;
	struct qstr nm = QSTR_INIT(name, strlen(name));
	struct ubifs_inode *ui;
	struct ubifs_dent_node *xent;
	union ubifs_key key;
	int err;

	dbg_gen("xattr '%s', ino %lu ('%.*s'), buf size %zd", name,
		host->i_ino, dentry->d_name.len, dentry->d_name.name, size);

	err = check_namespace(&nm);
	if (err < 0)
		return err;

	xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
	if (!xent)
		return -ENOMEM;

	xent_key_init(c, &key, host->i_ino, &nm);
	err = ubifs_tnc_lookup_nm(c, &key, xent, &nm);
	if (err) {
		if (err == -ENOENT)
			err = -ENODATA;
		goto out_unlock;
	}

	inode = iget_xattr(c, le64_to_cpu(xent->inum));
	if (IS_ERR(inode)) {
		err = PTR_ERR(inode);
		goto out_unlock;
	}

	ui = ubifs_inode(inode);
	ubifs_assert(inode->i_size == ui->data_len);
	ubifs_assert(ubifs_inode(host)->xattr_size > ui->data_len);

	if (buf) {
		/* If @buf is %NULL we are supposed to return the length */
		if (ui->data_len > size) {
			ubifs_err("buffer size %zd, xattr len %d",
				  size, ui->data_len);
			err = -ERANGE;
			goto out_iput;
		}

		memcpy(buf, ui->data, ui->data_len);
	}
	err = ui->data_len;

out_iput:
	iput(inode);
out_unlock:
	kfree(xent);
	return err;
}

ssize_t ubifs_listxattr(struct dentry *dentry, char *buffer, size_t size)
{
	union ubifs_key key;
	struct inode *host = dentry->d_inode;
	struct ubifs_info *c = host->i_sb->s_fs_info;
	struct ubifs_inode *host_ui = ubifs_inode(host);
	struct ubifs_dent_node *xent, *pxent = NULL;
	int err, len, written = 0;
	struct qstr nm = { .name = NULL };

	dbg_gen("ino %lu ('%.*s'), buffer size %zd", host->i_ino,
		dentry->d_name.len, dentry->d_name.name, size);

	len = host_ui->xattr_names + host_ui->xattr_cnt;
	if (!buffer)
		/*
		 * We should return the minimum buffer size which will fit a
		 * null-terminated list of all the extended attribute names.
		 */
		return len;

	if (len > size)
		return -ERANGE;

	lowest_xent_key(c, &key, host->i_ino);
	while (1) {
		int type;

		xent = ubifs_tnc_next_ent(c, &key, &nm);
		if (IS_ERR(xent)) {
			err = PTR_ERR(xent);
			break;
		}

		nm.name = xent->name;
		nm.len = le16_to_cpu(xent->nlen);

		type = check_namespace(&nm);
		if (unlikely(type < 0)) {
			err = type;
			break;
		}

		/* Show trusted namespace only for "power" users */
		if (type != TRUSTED_XATTR || capable(CAP_SYS_ADMIN)) {
			memcpy(buffer + written, nm.name, nm.len + 1);
			written += nm.len + 1;
		}

		kfree(pxent);
		pxent = xent;
		key_read(c, &xent->key, &key);
	}

	kfree(pxent);
	if (err != -ENOENT) {
		ubifs_err("cannot find next direntry, error %d", err);
		return err;
	}

	ubifs_assert(written <= size);
	return written;
}

static int remove_xattr(struct ubifs_info *c, struct inode *host,
			struct inode *inode, const struct qstr *nm)
{
	int err;
	struct ubifs_inode *host_ui = ubifs_inode(host);
	struct ubifs_inode *ui = ubifs_inode(inode);
	struct ubifs_budget_req req = { .dirtied_ino = 2, .mod_dent = 1,
				.dirtied_ino_d = ALIGN(host_ui->data_len, 8) };

	ubifs_assert(ui->data_len == inode->i_size);

	err = ubifs_budget_space(c, &req);
	if (err)
		return err;

	mutex_lock(&host_ui->ui_mutex);
	host->i_ctime = ubifs_current_time(host);
	host_ui->xattr_cnt -= 1;
	host_ui->xattr_size -= CALC_DENT_SIZE(nm->len);
	host_ui->xattr_size -= CALC_XATTR_BYTES(ui->data_len);
	host_ui->xattr_names -= nm->len;

	err = ubifs_jnl_delete_xattr(c, host, inode, nm);
	if (err)
		goto out_cancel;
	mutex_unlock(&host_ui->ui_mutex);

	ubifs_release_budget(c, &req);
	return 0;

out_cancel:
	host_ui->xattr_cnt += 1;
	host_ui->xattr_size += CALC_DENT_SIZE(nm->len);
	host_ui->xattr_size += CALC_XATTR_BYTES(ui->data_len);
	mutex_unlock(&host_ui->ui_mutex);
	ubifs_release_budget(c, &req);
	make_bad_inode(inode);
	return err;
}

int ubifs_removexattr(struct dentry *dentry, const char *name)
{
	struct inode *inode, *host = dentry->d_inode;
	struct ubifs_info *c = host->i_sb->s_fs_info;
	struct qstr nm = QSTR_INIT(name, strlen(name));
	struct ubifs_dent_node *xent;
	union ubifs_key key;
	int err;

	dbg_gen("xattr '%s', ino %lu ('%.*s')", name,
		host->i_ino, dentry->d_name.len, dentry->d_name.name);
	ubifs_assert(mutex_is_locked(&host->i_mutex));

	err = check_namespace(&nm);
	if (err < 0)
		return err;

	xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
	if (!xent)
		return -ENOMEM;

	xent_key_init(c, &key, host->i_ino, &nm);
	err = ubifs_tnc_lookup_nm(c, &key, xent, &nm);
	if (err) {
		if (err == -ENOENT)
			err = -ENODATA;
		goto out_free;
	}

	inode = iget_xattr(c, le64_to_cpu(xent->inum));
	if (IS_ERR(inode)) {
		err = PTR_ERR(inode);
		goto out_free;
	}

	ubifs_assert(inode->i_nlink == 1);
	clear_nlink(inode);
	err = remove_xattr(c, host, inode, &nm);
	if (err)
		set_nlink(inode, 1);

	/* If @i_nlink is 0, 'iput()' will delete the inode */
	iput(inode);

out_free:
	kfree(xent);
	return err;
}
Commit	Line	Data
1e51764a AB	1	/*
	2	* This file is part of UBIFS.
	3	*
	4	* Copyright (C) 2006-2008 Nokia Corporation.
	5	*
	6	* This program is free software; you can redistribute it and/or modify it
	7	* under the terms of the GNU General Public License version 2 as published by
	8	* the Free Software Foundation.
	9	*
	10	* This program is distributed in the hope that it will be useful, but WITHOUT
	11	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	12	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	13	* more details.
	14	*
	15	* You should have received a copy of the GNU General Public License along with
	16	* this program; if not, write to the Free Software Foundation, Inc., 51
	17	* Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
	18	*
	19	* Authors: Artem Bityutskiy (Битюцкий Артём)
	20	* Adrian Hunter
	21	*/
	22
	23	/*
	24	* This file implements UBIFS extended attributes support.
	25	*
	26	* Extended attributes are implemented as regular inodes with attached data,
	27	* which limits extended attribute size to UBIFS block size (4KiB). Names of
	28	* extended attributes are described by extended attribute entries (xentries),
	29	* which are almost identical to directory entries, but have different key type.
	30	*
	31	* In other words, the situation with extended attributes is very similar to
	32	* directories. Indeed, any inode (but of course not xattr inodes) may have a
	33	* number of associated xentries, just like directory inodes have associated
	34	* directory entries. Extended attribute entries store the name of the extended
	35	* attribute, the host inode number, and the extended attribute inode number.
	36	* Similarly, direntries store the name, the parent and the target inode
	37	* numbers. Thus, most of the common UBIFS mechanisms may be re-used for
	38	* extended attributes.
	39	*
	40	* The number of extended attributes is not limited, but there is Linux
	41	* limitation on the maximum possible size of the list of all extended
	42	* attributes associated with an inode (%XATTR_LIST_MAX), so UBIFS makes sure
	43	* the sum of all extended attribute names of the inode does not exceed that
	44	* limit.
	45	*
	46	* Extended attributes are synchronous, which means they are written to the
	47	* flash media synchronously and there is no write-back for extended attribute
	48	* inodes. The extended attribute values are not stored in compressed form on
	49	* the media.
	50	*
	51	* Since extended attributes are represented by regular inodes, they are cached
	52	* in the VFS inode cache. The xentries are cached in the LNC cache (see
	53	* tnc.c).
	54	*
	55	* ACL support is not implemented.
	56	*/
	57
073aaa1b	58	#include "ubifs.h"
7dcda1c9	59	#include <linux/fs.h>
5a0e3ad6	60	#include <linux/slab.h>
1e51764a AB	61	#include <linux/xattr.h>
1e51764a AB	62	#include <linux/posix_acl_xattr.h>
1e51764a AB	63
	64	/*
	65	* Limit the number of extended attributes per inode so that the total size
c78c7e35	66	* (@xattr_size) is guaranteeded to fit in an 'unsigned int'.
1e51764a AB	67	*/
	68	#define MAX_XATTRS_PER_INODE 65535
	69
	70	/*
	71	* Extended attribute type constants.
	72	*
	73	* USER_XATTR: user extended attribute ("user.*")
	74	* TRUSTED_XATTR: trusted extended attribute ("trusted.*)
	75	* SECURITY_XATTR: security extended attribute ("security.*")
	76	*/
	77	enum {
	78	USER_XATTR,
	79	TRUSTED_XATTR,
	80	SECURITY_XATTR,
	81	};
	82
14ffd5d0 SD	83	static const struct inode_operations empty_iops;
14ffd5d0 SD	84	static const struct file_operations empty_fops;
1e51764a AB	85
	86	/**
	87	* create_xattr - create an extended attribute.
	88	* @c: UBIFS file-system description object
	89	* @host: host inode
	90	* @nm: extended attribute name
	91	* @value: extended attribute value
	92	* @size: size of extended attribute value
	93	*
	94	* This is a helper function which creates an extended attribute of name @nm
	95	* and value @value for inode @host. The host inode is also updated on flash
	96	* because the ctime and extended attribute accounting data changes. This
	97	* function returns zero in case of success and a negative error code in case
	98	* of failure.
	99	*/
	100	static int create_xattr(struct ubifs_info c, struct inode host,
	101	const struct qstr nm, const void value, int size)
	102	{
	103	int err;
	104	struct inode *inode;
	105	struct ubifs_inode ui, host_ui = ubifs_inode(host);
	106	struct ubifs_budget_req req = { .new_ino = 1, .new_dent = 1,
5acd6ff8 ZS	107	.new_ino_d = ALIGN(size, 8), .dirtied_ino = 1,
5acd6ff8 ZS	108	.dirtied_ino_d = ALIGN(host_ui->data_len, 8) };
1e51764a AB	109
	110	if (host_ui->xattr_cnt >= MAX_XATTRS_PER_INODE)
	111	return -ENOSPC;
	112	/*
	113	* Linux limits the maximum size of the extended attribute names list
c78c7e35	114	* to %XATTR_LIST_MAX. This means we should not allow creating more
1e51764a AB	115	* extended attributes if the name list becomes larger. This limitation
	116	* is artificial for UBIFS, though.
	117	*/
	118	if (host_ui->xattr_names + host_ui->xattr_cnt +
	119	nm->len + 1 > XATTR_LIST_MAX)
	120	return -ENOSPC;
	121
	122	err = ubifs_budget_space(c, &req);
	123	if (err)
	124	return err;
	125
	126	inode = ubifs_new_inode(c, host, S_IFREG \| S_IRWXUGO);
	127	if (IS_ERR(inode)) {
	128	err = PTR_ERR(inode);
	129	goto out_budg;
	130	}
	131
1e51764a	132	/* Re-define all operations to be "nothing" */
7dcda1c9	133	inode->i_mapping->a_ops = &empty_aops;
14ffd5d0 SD	134	inode->i_op = &empty_iops;
14ffd5d0 SD	135	inode->i_fop = &empty_fops;
1e51764a AB	136
	137	inode->i_flags \|= S_SYNC \| S_NOATIME \| S_NOCMTIME \| S_NOQUOTA;
	138	ui = ubifs_inode(inode);
	139	ui->xattr = 1;
	140	ui->flags \|= UBIFS_XATTR_FL;
eaecf43a	141	ui->data = kmemdup(value, size, GFP_NOFS);
1e51764a AB	142	if (!ui->data) {
1e51764a AB	143	err = -ENOMEM;
c78c7e35	144	goto out_free;
1e51764a	145	}
c78c7e35 AB	146	inode->i_size = ui->ui_size = size;
	147	ui->data_len = size;
	148
	149	mutex_lock(&host_ui->ui_mutex);
1e51764a AB	150	host->i_ctime = ubifs_current_time(host);
	151	host_ui->xattr_cnt += 1;
	152	host_ui->xattr_size += CALC_DENT_SIZE(nm->len);
	153	host_ui->xattr_size += CALC_XATTR_BYTES(size);
	154	host_ui->xattr_names += nm->len;
	155
1e51764a AB	156	err = ubifs_jnl_update(c, host, nm, inode, 0, 1);
	157	if (err)
	158	goto out_cancel;
	159	mutex_unlock(&host_ui->ui_mutex);
	160
	161	ubifs_release_budget(c, &req);
	162	insert_inode_hash(inode);
	163	iput(inode);
	164	return 0;
	165
	166	out_cancel:
	167	host_ui->xattr_cnt -= 1;
	168	host_ui->xattr_size -= CALC_DENT_SIZE(nm->len);
	169	host_ui->xattr_size -= CALC_XATTR_BYTES(size);
1e51764a	170	mutex_unlock(&host_ui->ui_mutex);
c78c7e35	171	out_free:
1e51764a AB	172	make_bad_inode(inode);
	173	iput(inode);
	174	out_budg:
	175	ubifs_release_budget(c, &req);
	176	return err;
	177	}
	178
	179	/**
	180	* change_xattr - change an extended attribute.
	181	* @c: UBIFS file-system description object
	182	* @host: host inode
	183	* @inode: extended attribute inode
	184	* @value: extended attribute value
	185	* @size: size of extended attribute value
	186	*
	187	* This helper function changes the value of extended attribute @inode with new
	188	* data from @value. Returns zero in case of success and a negative error code
	189	* in case of failure.
	190	*/
	191	static int change_xattr(struct ubifs_info c, struct inode host,
	192	struct inode inode, const void value, int size)
	193	{
	194	int err;
	195	struct ubifs_inode *host_ui = ubifs_inode(host);
	196	struct ubifs_inode *ui = ubifs_inode(inode);
	197	struct ubifs_budget_req req = { .dirtied_ino = 2,
5acd6ff8	198	.dirtied_ino_d = ALIGN(size, 8) + ALIGN(host_ui->data_len, 8) };
1e51764a AB	199
	200	ubifs_assert(ui->data_len == inode->i_size);
	201	err = ubifs_budget_space(c, &req);
	202	if (err)
	203	return err;
	204
1e51764a	205	kfree(ui->data);
eaecf43a	206	ui->data = kmemdup(value, size, GFP_NOFS);
1e51764a AB	207	if (!ui->data) {
1e51764a AB	208	err = -ENOMEM;
c78c7e35	209	goto out_free;
1e51764a	210	}
1e51764a AB	211	inode->i_size = ui->ui_size = size;
	212	ui->data_len = size;
	213
c78c7e35 AB	214	mutex_lock(&host_ui->ui_mutex);
	215	host->i_ctime = ubifs_current_time(host);
	216	host_ui->xattr_size -= CALC_XATTR_BYTES(ui->data_len);
	217	host_ui->xattr_size += CALC_XATTR_BYTES(size);
	218
1e51764a AB	219	/*
	220	* It is important to write the host inode after the xattr inode
	221	* because if the host inode gets synchronized (via 'fsync()'), then
	222	* the extended attribute inode gets synchronized, because it goes
	223	* before the host inode in the write-buffer.
	224	*/
	225	err = ubifs_jnl_change_xattr(c, inode, host);
	226	if (err)
	227	goto out_cancel;
	228	mutex_unlock(&host_ui->ui_mutex);
	229
	230	ubifs_release_budget(c, &req);
	231	return 0;
	232
	233	out_cancel:
	234	host_ui->xattr_size -= CALC_XATTR_BYTES(size);
	235	host_ui->xattr_size += CALC_XATTR_BYTES(ui->data_len);
1e51764a	236	mutex_unlock(&host_ui->ui_mutex);
c78c7e35 AB	237	make_bad_inode(inode);
c78c7e35 AB	238	out_free:
1e51764a AB	239	ubifs_release_budget(c, &req);
	240	return err;
	241	}
	242
	243	/**
	244	* check_namespace - check extended attribute name-space.
	245	* @nm: extended attribute name
	246	*
	247	* This function makes sure the extended attribute name belongs to one of the
	248	* supported extended attribute name-spaces. Returns name-space index in case
	249	* of success and a negative error code in case of failure.
	250	*/
	251	static int check_namespace(const struct qstr *nm)
	252	{
	253	int type;
	254
	255	if (nm->len > UBIFS_MAX_NLEN)
	256	return -ENAMETOOLONG;
	257
	258	if (!strncmp(nm->name, XATTR_TRUSTED_PREFIX,
	259	XATTR_TRUSTED_PREFIX_LEN)) {
	260	if (nm->name[sizeof(XATTR_TRUSTED_PREFIX) - 1] == '\0')
	261	return -EINVAL;
	262	type = TRUSTED_XATTR;
	263	} else if (!strncmp(nm->name, XATTR_USER_PREFIX,
	264	XATTR_USER_PREFIX_LEN)) {
	265	if (nm->name[XATTR_USER_PREFIX_LEN] == '\0')
	266	return -EINVAL;
	267	type = USER_XATTR;
	268	} else if (!strncmp(nm->name, XATTR_SECURITY_PREFIX,
	269	XATTR_SECURITY_PREFIX_LEN)) {
	270	if (nm->name[sizeof(XATTR_SECURITY_PREFIX) - 1] == '\0')
	271	return -EINVAL;
	272	type = SECURITY_XATTR;
	273	} else
	274	return -EOPNOTSUPP;
	275
	276	return type;
	277	}
	278
	279	static struct inode iget_xattr(struct ubifs_info c, ino_t inum)
	280	{
	281	struct inode *inode;
	282
	283	inode = ubifs_iget(c->vfs_sb, inum);
	284	if (IS_ERR(inode)) {
	285	ubifs_err("dead extended attribute entry, error %d",
	286	(int)PTR_ERR(inode));
	287	return inode;
	288	}
	289	if (ubifs_inode(inode)->xattr)
	290	return inode;
	291	ubifs_err("corrupt extended attribute entry");
	292	iput(inode);
	293	return ERR_PTR(-EINVAL);
	294	}
	295
	296	int ubifs_setxattr(struct dentry dentry, const char name,
	297	const void *value, size_t size, int flags)
	298	{
	299	struct inode inode, host = dentry->d_inode;
	300	struct ubifs_info *c = host->i_sb->s_fs_info;
26fe5750	301	struct qstr nm = QSTR_INIT(name, strlen(name));
1e51764a AB	302	struct ubifs_dent_node *xent;
	303	union ubifs_key key;
	304	int err, type;
	305
	306	dbg_gen("xattr '%s', host ino %lu ('%.*s'), size %zd", name,
	307	host->i_ino, dentry->d_name.len, dentry->d_name.name, size);
c78c7e35	308	ubifs_assert(mutex_is_locked(&host->i_mutex));
1e51764a AB	309
	310	if (size > UBIFS_MAX_INO_DATA)
	311	return -ERANGE;
	312
	313	type = check_namespace(&nm);
	314	if (type < 0)
	315	return type;
	316
	317	xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
	318	if (!xent)
	319	return -ENOMEM;
	320
	321	/*
	322	* The extended attribute entries are stored in LNC, so multiple
	323	* look-ups do not involve reading the flash.
	324	*/
	325	xent_key_init(c, &key, host->i_ino, &nm);
	326	err = ubifs_tnc_lookup_nm(c, &key, xent, &nm);
	327	if (err) {
	328	if (err != -ENOENT)
	329	goto out_free;
	330
	331	if (flags & XATTR_REPLACE)
	332	/* We are asked not to create the xattr */
	333	err = -ENODATA;
	334	else
	335	err = create_xattr(c, host, &nm, value, size);
	336	goto out_free;
	337	}
	338
	339	if (flags & XATTR_CREATE) {
	340	/* We are asked not to replace the xattr */
	341	err = -EEXIST;
	342	goto out_free;
	343	}
	344
	345	inode = iget_xattr(c, le64_to_cpu(xent->inum));
	346	if (IS_ERR(inode)) {
	347	err = PTR_ERR(inode);
	348	goto out_free;
	349	}
	350
	351	err = change_xattr(c, host, inode, value, size);
	352	iput(inode);
	353
	354	out_free:
	355	kfree(xent);
	356	return err;
	357	}
	358
	359	ssize_t ubifs_getxattr(struct dentry dentry, const char name, void *buf,
	360	size_t size)
	361	{
	362	struct inode inode, host = dentry->d_inode;
	363	struct ubifs_info *c = host->i_sb->s_fs_info;
26fe5750	364	struct qstr nm = QSTR_INIT(name, strlen(name));
1e51764a AB	365	struct ubifs_inode *ui;
	366	struct ubifs_dent_node *xent;
	367	union ubifs_key key;
	368	int err;
	369
	370	dbg_gen("xattr '%s', ino %lu ('%.*s'), buf size %zd", name,
	371	host->i_ino, dentry->d_name.len, dentry->d_name.name, size);
	372
	373	err = check_namespace(&nm);
	374	if (err < 0)
	375	return err;
	376
	377	xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
	378	if (!xent)
	379	return -ENOMEM;
	380
1e51764a AB	381	xent_key_init(c, &key, host->i_ino, &nm);
	382	err = ubifs_tnc_lookup_nm(c, &key, xent, &nm);
	383	if (err) {
	384	if (err == -ENOENT)
	385	err = -ENODATA;
	386	goto out_unlock;
	387	}
	388
	389	inode = iget_xattr(c, le64_to_cpu(xent->inum));
	390	if (IS_ERR(inode)) {
	391	err = PTR_ERR(inode);
	392	goto out_unlock;
	393	}
	394
	395	ui = ubifs_inode(inode);
	396	ubifs_assert(inode->i_size == ui->data_len);
	397	ubifs_assert(ubifs_inode(host)->xattr_size > ui->data_len);
	398
	399	if (buf) {
	400	/* If @buf is %NULL we are supposed to return the length */
	401	if (ui->data_len > size) {
a6aae4dd AB	402	ubifs_err("buffer size %zd, xattr len %d",
a6aae4dd AB	403	size, ui->data_len);
1e51764a AB	404	err = -ERANGE;
	405	goto out_iput;
	406	}
	407
	408	memcpy(buf, ui->data, ui->data_len);
	409	}
	410	err = ui->data_len;
	411
	412	out_iput:
	413	iput(inode);
	414	out_unlock:
1e51764a AB	415	kfree(xent);
	416	return err;
	417	}
	418
	419	ssize_t ubifs_listxattr(struct dentry dentry, char buffer, size_t size)
	420	{
	421	union ubifs_key key;
	422	struct inode *host = dentry->d_inode;
	423	struct ubifs_info *c = host->i_sb->s_fs_info;
	424	struct ubifs_inode *host_ui = ubifs_inode(host);
	425	struct ubifs_dent_node xent, pxent = NULL;
	426	int err, len, written = 0;
	427	struct qstr nm = { .name = NULL };
	428
	429	dbg_gen("ino %lu ('%.*s'), buffer size %zd", host->i_ino,
	430	dentry->d_name.len, dentry->d_name.name, size);
	431
	432	len = host_ui->xattr_names + host_ui->xattr_cnt;
	433	if (!buffer)
	434	/*
	435	* We should return the minimum buffer size which will fit a
	436	* null-terminated list of all the extended attribute names.
	437	*/
	438	return len;
	439
	440	if (len > size)
	441	return -ERANGE;
	442
	443	lowest_xent_key(c, &key, host->i_ino);
1e51764a AB	444	while (1) {
	445	int type;
	446
	447	xent = ubifs_tnc_next_ent(c, &key, &nm);
8d47aef4	448	if (IS_ERR(xent)) {
1e51764a AB	449	err = PTR_ERR(xent);
	450	break;
	451	}
	452
	453	nm.name = xent->name;
	454	nm.len = le16_to_cpu(xent->nlen);
	455
	456	type = check_namespace(&nm);
	457	if (unlikely(type < 0)) {
	458	err = type;
	459	break;
	460	}
	461
	462	/* Show trusted namespace only for "power" users */
	463	if (type != TRUSTED_XATTR \|\| capable(CAP_SYS_ADMIN)) {
	464	memcpy(buffer + written, nm.name, nm.len + 1);
	465	written += nm.len + 1;
	466	}
	467
	468	kfree(pxent);
	469	pxent = xent;
	470	key_read(c, &xent->key, &key);
	471	}
1e51764a AB	472
	473	kfree(pxent);
	474	if (err != -ENOENT) {
	475	ubifs_err("cannot find next direntry, error %d", err);
	476	return err;
	477	}
	478
	479	ubifs_assert(written <= size);
	480	return written;
	481	}
	482
	483	static int remove_xattr(struct ubifs_info c, struct inode host,
	484	struct inode inode, const struct qstr nm)
	485	{
	486	int err;
	487	struct ubifs_inode *host_ui = ubifs_inode(host);
	488	struct ubifs_inode *ui = ubifs_inode(inode);
5acd6ff8 ZS	489	struct ubifs_budget_req req = { .dirtied_ino = 2, .mod_dent = 1,
5acd6ff8 ZS	490	.dirtied_ino_d = ALIGN(host_ui->data_len, 8) };
1e51764a AB	491
	492	ubifs_assert(ui->data_len == inode->i_size);
	493
	494	err = ubifs_budget_space(c, &req);
	495	if (err)
	496	return err;
	497
	498	mutex_lock(&host_ui->ui_mutex);
	499	host->i_ctime = ubifs_current_time(host);
	500	host_ui->xattr_cnt -= 1;
	501	host_ui->xattr_size -= CALC_DENT_SIZE(nm->len);
	502	host_ui->xattr_size -= CALC_XATTR_BYTES(ui->data_len);
	503	host_ui->xattr_names -= nm->len;
	504
	505	err = ubifs_jnl_delete_xattr(c, host, inode, nm);
	506	if (err)
	507	goto out_cancel;
	508	mutex_unlock(&host_ui->ui_mutex);
	509
	510	ubifs_release_budget(c, &req);
	511	return 0;
	512
	513	out_cancel:
	514	host_ui->xattr_cnt += 1;
	515	host_ui->xattr_size += CALC_DENT_SIZE(nm->len);
	516	host_ui->xattr_size += CALC_XATTR_BYTES(ui->data_len);
	517	mutex_unlock(&host_ui->ui_mutex);
	518	ubifs_release_budget(c, &req);
	519	make_bad_inode(inode);
	520	return err;
	521	}
	522
	523	int ubifs_removexattr(struct dentry dentry, const char name)
	524	{
	525	struct inode inode, host = dentry->d_inode;
	526	struct ubifs_info *c = host->i_sb->s_fs_info;
26fe5750	527	struct qstr nm = QSTR_INIT(name, strlen(name));
1e51764a AB	528	struct ubifs_dent_node *xent;
	529	union ubifs_key key;
	530	int err;
	531
	532	dbg_gen("xattr '%s', ino %lu ('%.*s')", name,
	533	host->i_ino, dentry->d_name.len, dentry->d_name.name);
	534	ubifs_assert(mutex_is_locked(&host->i_mutex));
	535
	536	err = check_namespace(&nm);
	537	if (err < 0)
	538	return err;
	539
	540	xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
	541	if (!xent)
	542	return -ENOMEM;
	543
	544	xent_key_init(c, &key, host->i_ino, &nm);
	545	err = ubifs_tnc_lookup_nm(c, &key, xent, &nm);
	546	if (err) {
	547	if (err == -ENOENT)
	548	err = -ENODATA;
	549	goto out_free;
	550	}
	551
	552	inode = iget_xattr(c, le64_to_cpu(xent->inum));
	553	if (IS_ERR(inode)) {
	554	err = PTR_ERR(inode);
	555	goto out_free;
	556	}
	557
	558	ubifs_assert(inode->i_nlink == 1);
6d6b77f1	559	clear_nlink(inode);
1e51764a AB	560	err = remove_xattr(c, host, inode, &nm);
1e51764a AB	561	if (err)
bfe86848	562	set_nlink(inode, 1);
1e51764a AB	563
	564	/* If @i_nlink is 0, 'iput()' will delete the inode */
	565	iput(inode);
	566
	567	out_free:
	568	kfree(xent);
	569	return err;
	570	}