[mirror_ubuntu-zesty-kernel.git] / fs / btrfs / xattr.c

/*
 * Copyright (C) 2007 Red Hat.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License v2 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 021110-1307, USA.
 */

#include <linux/init.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/rwsem.h>
#include <linux/xattr.h>
#include <linux/security.h>
#include "ctree.h"
#include "btrfs_inode.h"
#include "transaction.h"
#include "xattr.h"
#include "disk-io.h"


ssize_t __btrfs_getxattr(struct inode *inode, const char *name,
				void *buffer, size_t size)
{
	struct btrfs_dir_item *di;
	struct btrfs_root *root = BTRFS_I(inode)->root;
	struct btrfs_path *path;
	struct extent_buffer *leaf;
	int ret = 0;
	unsigned long data_ptr;

	path = btrfs_alloc_path();
	if (!path)
		return -ENOMEM;

	/* lookup the xattr by name */
	di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(inode), name,
				strlen(name), 0);
	if (!di) {
		ret = -ENODATA;
		goto out;
	} else if (IS_ERR(di)) {
		ret = PTR_ERR(di);
		goto out;
	}

	leaf = path->nodes[0];
	/* if size is 0, that means we want the size of the attr */
	if (!size) {
		ret = btrfs_dir_data_len(leaf, di);
		goto out;
	}

	/* now get the data out of our dir_item */
	if (btrfs_dir_data_len(leaf, di) > size) {
		ret = -ERANGE;
		goto out;
	}

	/*
	 * The way things are packed into the leaf is like this
	 * |struct btrfs_dir_item|name|data|
	 * where name is the xattr name, so security.foo, and data is the
	 * content of the xattr.  data_ptr points to the location in memory
	 * where the data starts in the in memory leaf
	 */
	data_ptr = (unsigned long)((char *)(di + 1) +
				   btrfs_dir_name_len(leaf, di));
	read_extent_buffer(leaf, buffer, data_ptr,
			   btrfs_dir_data_len(leaf, di));
	ret = btrfs_dir_data_len(leaf, di);

out:
	btrfs_free_path(path);
	return ret;
}

static int do_setxattr(struct btrfs_trans_handle *trans,
		       struct inode *inode, const char *name,
		       const void *value, size_t size, int flags)
{
	struct btrfs_dir_item *di;
	struct btrfs_root *root = BTRFS_I(inode)->root;
	struct btrfs_path *path;
	size_t name_len = strlen(name);
	int ret = 0;

	if (name_len + size > BTRFS_MAX_XATTR_SIZE(root))
		return -ENOSPC;

	path = btrfs_alloc_path();
	if (!path)
		return -ENOMEM;

	if (flags & XATTR_REPLACE) {
		di = btrfs_lookup_xattr(trans, root, path, btrfs_ino(inode), name,
					name_len, -1);
		if (IS_ERR(di)) {
			ret = PTR_ERR(di);
			goto out;
		} else if (!di) {
			ret = -ENODATA;
			goto out;
		}
		ret = btrfs_delete_one_dir_name(trans, root, path, di);
		if (ret)
			goto out;
		btrfs_release_path(path);
	}

again:
	ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(inode),
				      name, name_len, value, size);
	if (ret == -EEXIST) {
		if (flags & XATTR_CREATE)
			goto out;
		/*
		 * We can't use the path we already have since we won't have the
		 * proper locking for a delete, so release the path and
		 * re-lookup to delete the thing.
		 */
		btrfs_release_path(path);
		di = btrfs_lookup_xattr(trans, root, path, btrfs_ino(inode),
					name, name_len, -1);
		if (IS_ERR(di)) {
			ret = PTR_ERR(di);
			goto out;
		} else if (!di) {
			/* Shouldn't happen but just in case... */
			btrfs_release_path(path);
			goto again;
		}

		ret = btrfs_delete_one_dir_name(trans, root, path, di);
		if (ret)
			goto out;

		/*
		 * We have a value to set, so go back and try to insert it now.
		 */
		if (value) {
			btrfs_release_path(path);
			goto again;
		}
	}
out:
	btrfs_free_path(path);
	return ret;
}

int __btrfs_setxattr(struct btrfs_trans_handle *trans,
		     struct inode *inode, const char *name,
		     const void *value, size_t size, int flags)
{
	struct btrfs_root *root = BTRFS_I(inode)->root;
	int ret;

	if (trans)
		return do_setxattr(trans, inode, name, value, size, flags);

	trans = btrfs_start_transaction(root, 2);
	if (IS_ERR(trans))
		return PTR_ERR(trans);

	ret = do_setxattr(trans, inode, name, value, size, flags);
	if (ret)
		goto out;

	inode->i_ctime = CURRENT_TIME;
	ret = btrfs_update_inode(trans, root, inode);
	BUG_ON(ret);
out:
	btrfs_end_transaction_throttle(trans, root);
	return ret;
}

ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
{
	struct btrfs_key key, found_key;
	struct inode *inode = dentry->d_inode;
	struct btrfs_root *root = BTRFS_I(inode)->root;
	struct btrfs_path *path;
	struct extent_buffer *leaf;
	struct btrfs_dir_item *di;
	int ret = 0, slot;
	size_t total_size = 0, size_left = size;
	unsigned long name_ptr;
	size_t name_len;

	/*
	 * ok we want all objects associated with this id.
	 * NOTE: we set key.offset = 0; because we want to start with the
	 * first xattr that we find and walk forward
	 */
	key.objectid = btrfs_ino(inode);
	btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
	key.offset = 0;

	path = btrfs_alloc_path();
	if (!path)
		return -ENOMEM;
	path->reada = 2;

	/* search for our xattrs */
	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
	if (ret < 0)
		goto err;

	while (1) {
		leaf = path->nodes[0];
		slot = path->slots[0];

		/* this is where we start walking through the path */
		if (slot >= btrfs_header_nritems(leaf)) {
			/*
			 * if we've reached the last slot in this leaf we need
			 * to go to the next leaf and reset everything
			 */
			ret = btrfs_next_leaf(root, path);
			if (ret < 0)
				goto err;
			else if (ret > 0)
				break;
			continue;
		}

		btrfs_item_key_to_cpu(leaf, &found_key, slot);

		/* check to make sure this item is what we want */
		if (found_key.objectid != key.objectid)
			break;
		if (btrfs_key_type(&found_key) != BTRFS_XATTR_ITEM_KEY)
			break;

		di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
		if (verify_dir_item(root, leaf, di))
			continue;

		name_len = btrfs_dir_name_len(leaf, di);
		total_size += name_len + 1;

		/* we are just looking for how big our buffer needs to be */
		if (!size)
			goto next;

		if (!buffer || (name_len + 1) > size_left) {
			ret = -ERANGE;
			goto err;
		}

		name_ptr = (unsigned long)(di + 1);
		read_extent_buffer(leaf, buffer, name_ptr, name_len);
		buffer[name_len] = '\0';

		size_left -= name_len + 1;
		buffer += name_len + 1;
next:
		path->slots[0]++;
	}
	ret = total_size;

err:
	btrfs_free_path(path);

	return ret;
}

/*
 * List of handlers for synthetic system.* attributes.  All real ondisk
 * attributes are handled directly.
 */
const struct xattr_handler *btrfs_xattr_handlers[] = {
#ifdef CONFIG_BTRFS_FS_POSIX_ACL
	&btrfs_xattr_acl_access_handler,
	&btrfs_xattr_acl_default_handler,
#endif
	NULL,
};

/*
 * Check if the attribute is in a supported namespace.
 *
 * This applied after the check for the synthetic attributes in the system
 * namespace.
 */
static bool btrfs_is_valid_xattr(const char *name)
{
	return !strncmp(name, XATTR_SECURITY_PREFIX,
			XATTR_SECURITY_PREFIX_LEN) ||
	       !strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) ||
	       !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) ||
	       !strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN);
}

ssize_t btrfs_getxattr(struct dentry *dentry, const char *name,
		       void *buffer, size_t size)
{
	/*
	 * If this is a request for a synthetic attribute in the system.*
	 * namespace use the generic infrastructure to resolve a handler
	 * for it via sb->s_xattr.
	 */
	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
		return generic_getxattr(dentry, name, buffer, size);

	if (!btrfs_is_valid_xattr(name))
		return -EOPNOTSUPP;
	return __btrfs_getxattr(dentry->d_inode, name, buffer, size);
}

int btrfs_setxattr(struct dentry *dentry, const char *name, const void *value,
		   size_t size, int flags)
{
	struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root;

	/*
	 * The permission on security.* and system.* is not checked
	 * in permission().
	 */
	if (btrfs_root_readonly(root))
		return -EROFS;

	/*
	 * If this is a request for a synthetic attribute in the system.*
	 * namespace use the generic infrastructure to resolve a handler
	 * for it via sb->s_xattr.
	 */
	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
		return generic_setxattr(dentry, name, value, size, flags);

	if (!btrfs_is_valid_xattr(name))
		return -EOPNOTSUPP;

	if (size == 0)
		value = "";  /* empty EA, do not remove */

	return __btrfs_setxattr(NULL, dentry->d_inode, name, value, size,
				flags);
}

int btrfs_removexattr(struct dentry *dentry, const char *name)
{
	struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root;

	/*
	 * The permission on security.* and system.* is not checked
	 * in permission().
	 */
	if (btrfs_root_readonly(root))
		return -EROFS;

	/*
	 * If this is a request for a synthetic attribute in the system.*
	 * namespace use the generic infrastructure to resolve a handler
	 * for it via sb->s_xattr.
	 */
	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
		return generic_removexattr(dentry, name);

	if (!btrfs_is_valid_xattr(name))
		return -EOPNOTSUPP;

	return __btrfs_setxattr(NULL, dentry->d_inode, name, NULL, 0,
				XATTR_REPLACE);
}

int btrfs_xattr_security_init(struct btrfs_trans_handle *trans,
			      struct inode *inode, struct inode *dir,
			      const struct qstr *qstr)
{
	int err;
	size_t len;
	void *value;
	char *suffix;
	char *name;

	err = security_inode_init_security(inode, dir, qstr, &suffix, &value,
					   &len);
	if (err) {
		if (err == -EOPNOTSUPP)
			return 0;
		return err;
	}

	name = kmalloc(XATTR_SECURITY_PREFIX_LEN + strlen(suffix) + 1,
		       GFP_NOFS);
	if (!name) {
		err = -ENOMEM;
	} else {
		strcpy(name, XATTR_SECURITY_PREFIX);
		strcpy(name + XATTR_SECURITY_PREFIX_LEN, suffix);
		err = __btrfs_setxattr(trans, inode, name, value, len, 0);
		kfree(name);
	}

	kfree(suffix);
	kfree(value);
	return err;
}
Commit	Line	Data
5103e947 JB	1	/*
	2	* Copyright (C) 2007 Red Hat. All rights reserved.
	3	*
	4	* This program is free software; you can redistribute it and/or
	5	* modify it under the terms of the GNU General Public
	6	* License v2 as published by the Free Software Foundation.
	7	*
	8	* This program is distributed in the hope that it will be useful,
	9	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	10	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	11	* General Public License for more details.
	12	*
	13	* You should have received a copy of the GNU General Public
	14	* License along with this program; if not, write to the
	15	* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
	16	* Boston, MA 021110-1307, USA.
	17	*/
	18
	19	#include <linux/init.h>
	20	#include <linux/fs.h>
	21	#include <linux/slab.h>
	22	#include <linux/rwsem.h>
	23	#include <linux/xattr.h>
0279b4cd	24	#include <linux/security.h>
5103e947 JB	25	#include "ctree.h"
	26	#include "btrfs_inode.h"
	27	#include "transaction.h"
	28	#include "xattr.h"
	29	#include "disk-io.h"
33268eaf	30
5103e947	31
95819c05 CH	32	ssize_t __btrfs_getxattr(struct inode inode, const char name,
95819c05 CH	33	void *buffer, size_t size)
5103e947 JB	34	{
	35	struct btrfs_dir_item *di;
	36	struct btrfs_root *root = BTRFS_I(inode)->root;
	37	struct btrfs_path *path;
	38	struct extent_buffer *leaf;
5103e947 JB	39	int ret = 0;
5103e947 JB	40	unsigned long data_ptr;
5103e947 JB	41
5103e947 JB	42	path = btrfs_alloc_path();
95819c05	43	if (!path)
5103e947	44	return -ENOMEM;
5103e947	45
5103e947	46	/* lookup the xattr by name */
33345d01	47	di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(inode), name,
5103e947	48	strlen(name), 0);
07060404	49	if (!di) {
5103e947 JB	50	ret = -ENODATA;
5103e947 JB	51	goto out;
07060404 JB	52	} else if (IS_ERR(di)) {
	53	ret = PTR_ERR(di);
	54	goto out;
5103e947 JB	55	}
	56
	57	leaf = path->nodes[0];
	58	/* if size is 0, that means we want the size of the attr */
	59	if (!size) {
	60	ret = btrfs_dir_data_len(leaf, di);
	61	goto out;
	62	}
	63
	64	/* now get the data out of our dir_item */
	65	if (btrfs_dir_data_len(leaf, di) > size) {
	66	ret = -ERANGE;
	67	goto out;
	68	}
07060404 JB	69
	70	/*
	71	* The way things are packed into the leaf is like this
	72	* \|struct btrfs_dir_item\|name\|data\|
	73	* where name is the xattr name, so security.foo, and data is the
	74	* content of the xattr. data_ptr points to the location in memory
	75	* where the data starts in the in memory leaf
	76	*/
5103e947 JB	77	data_ptr = (unsigned long)((char *)(di + 1) +
	78	btrfs_dir_name_len(leaf, di));
	79	read_extent_buffer(leaf, buffer, data_ptr,
3acd7ee8	80	btrfs_dir_data_len(leaf, di));
5103e947 JB	81	ret = btrfs_dir_data_len(leaf, di);
	82
	83	out:
5103e947 JB	84	btrfs_free_path(path);
	85	return ret;
	86	}
	87
f34f57a3 YZ	88	static int do_setxattr(struct btrfs_trans_handle *trans,
	89	struct inode inode, const char name,
	90	const void *value, size_t size, int flags)
5103e947 JB	91	{
	92	struct btrfs_dir_item *di;
	93	struct btrfs_root *root = BTRFS_I(inode)->root;
5103e947	94	struct btrfs_path *path;
f34f57a3 YZ	95	size_t name_len = strlen(name);
	96	int ret = 0;
	97
	98	if (name_len + size > BTRFS_MAX_XATTR_SIZE(root))
	99	return -ENOSPC;
5103e947 JB	100
5103e947 JB	101	path = btrfs_alloc_path();
95819c05	102	if (!path)
5103e947	103	return -ENOMEM;
5103e947	104
fa09200b JB	105	if (flags & XATTR_REPLACE) {
	106	di = btrfs_lookup_xattr(trans, root, path, btrfs_ino(inode), name,
	107	name_len, -1);
	108	if (IS_ERR(di)) {
	109	ret = PTR_ERR(di);
	110	goto out;
	111	} else if (!di) {
	112	ret = -ENODATA;
5103e947 JB	113	goto out;
5103e947 JB	114	}
5103e947	115	ret = btrfs_delete_one_dir_name(trans, root, path, di);
fa09200b JB	116	if (ret)
fa09200b JB	117	goto out;
b3b4aa74	118	btrfs_release_path(path);
fa09200b	119	}
5103e947	120
fa09200b JB	121	again:
	122	ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(inode),
	123	name, name_len, value, size);
	124	if (ret == -EEXIST) {
	125	if (flags & XATTR_CREATE)
5103e947	126	goto out;
fa09200b JB	127	/*
	128	* We can't use the path we already have since we won't have the
	129	* proper locking for a delete, so release the path and
	130	* re-lookup to delete the thing.
	131	*/
b3b4aa74	132	btrfs_release_path(path);
fa09200b JB	133	di = btrfs_lookup_xattr(trans, root, path, btrfs_ino(inode),
	134	name, name_len, -1);
	135	if (IS_ERR(di)) {
	136	ret = PTR_ERR(di);
	137	goto out;
	138	} else if (!di) {
	139	/* Shouldn't happen but just in case... */
	140	btrfs_release_path(path);
	141	goto again;
	142	}
33268eaf	143
fa09200b JB	144	ret = btrfs_delete_one_dir_name(trans, root, path, di);
fa09200b JB	145	if (ret)
33268eaf	146	goto out;
fa09200b JB	147
	148	/*
	149	* We have a value to set, so go back and try to insert it now.
	150	*/
	151	if (value) {
	152	btrfs_release_path(path);
	153	goto again;
33268eaf	154	}
5103e947	155	}
f34f57a3 YZ	156	out:
	157	btrfs_free_path(path);
	158	return ret;
	159	}
	160
	161	int __btrfs_setxattr(struct btrfs_trans_handle *trans,
	162	struct inode inode, const char name,
	163	const void *value, size_t size, int flags)
	164	{
	165	struct btrfs_root *root = BTRFS_I(inode)->root;
	166	int ret;
	167
	168	if (trans)
	169	return do_setxattr(trans, inode, name, value, size, flags);
	170
a22285a6 YZ	171	trans = btrfs_start_transaction(root, 2);
	172	if (IS_ERR(trans))
	173	return PTR_ERR(trans);
5103e947	174
f34f57a3 YZ	175	ret = do_setxattr(trans, inode, name, value, size, flags);
	176	if (ret)
	177	goto out;
	178
	179	inode->i_ctime = CURRENT_TIME;
	180	ret = btrfs_update_inode(trans, root, inode);
	181	BUG_ON(ret);
	182	out:
	183	btrfs_end_transaction_throttle(trans, root);
5103e947 JB	184	return ret;
	185	}
	186
	187	ssize_t btrfs_listxattr(struct dentry dentry, char buffer, size_t size)
	188	{
	189	struct btrfs_key key, found_key;
	190	struct inode *inode = dentry->d_inode;
	191	struct btrfs_root *root = BTRFS_I(inode)->root;
	192	struct btrfs_path *path;
5103e947 JB	193	struct extent_buffer *leaf;
5103e947 JB	194	struct btrfs_dir_item *di;
2e6a0035	195	int ret = 0, slot;
eaa47d86	196	size_t total_size = 0, size_left = size;
5103e947	197	unsigned long name_ptr;
eaa47d86	198	size_t name_len;
5103e947 JB	199
	200	/*
	201	* ok we want all objects associated with this id.
	202	* NOTE: we set key.offset = 0; because we want to start with the
	203	* first xattr that we find and walk forward
	204	*/
33345d01	205	key.objectid = btrfs_ino(inode);
5103e947 JB	206	btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
	207	key.offset = 0;
	208
	209	path = btrfs_alloc_path();
5103e947 JB	210	if (!path)
5103e947 JB	211	return -ENOMEM;
1caf9342	212	path->reada = 2;
5103e947	213
5103e947 JB	214	/* search for our xattrs */
	215	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
	216	if (ret < 0)
	217	goto err;
2e6a0035	218
5103e947 JB	219	while (1) {
5103e947 JB	220	leaf = path->nodes[0];
5103e947 JB	221	slot = path->slots[0];
	222
	223	/* this is where we start walking through the path */
2e6a0035	224	if (slot >= btrfs_header_nritems(leaf)) {
5103e947 JB	225	/*
	226	* if we've reached the last slot in this leaf we need
	227	* to go to the next leaf and reset everything
	228	*/
2e6a0035 LZ	229	ret = btrfs_next_leaf(root, path);
	230	if (ret < 0)
	231	goto err;
	232	else if (ret > 0)
	233	break;
	234	continue;
5103e947	235	}
5103e947	236
5103e947 JB	237	btrfs_item_key_to_cpu(leaf, &found_key, slot);
	238
	239	/* check to make sure this item is what we want */
	240	if (found_key.objectid != key.objectid)
	241	break;
	242	if (btrfs_key_type(&found_key) != BTRFS_XATTR_ITEM_KEY)
	243	break;
	244
	245	di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
22a94d44 JB	246	if (verify_dir_item(root, leaf, di))
22a94d44 JB	247	continue;
5103e947	248
eaa47d86 CH	249	name_len = btrfs_dir_name_len(leaf, di);
eaa47d86 CH	250	total_size += name_len + 1;
5103e947 JB	251
	252	/* we are just looking for how big our buffer needs to be */
	253	if (!size)
2e6a0035	254	goto next;
5103e947	255
eaa47d86	256	if (!buffer \|\| (name_len + 1) > size_left) {
5103e947	257	ret = -ERANGE;
b16281c3	258	goto err;
5103e947 JB	259	}
5103e947 JB	260
eaa47d86 CH	261	name_ptr = (unsigned long)(di + 1);
	262	read_extent_buffer(leaf, buffer, name_ptr, name_len);
	263	buffer[name_len] = '\0';
	264
	265	size_left -= name_len + 1;
	266	buffer += name_len + 1;
2e6a0035 LZ	267	next:
2e6a0035 LZ	268	path->slots[0]++;
5103e947 JB	269	}
	270	ret = total_size;
	271
	272	err:
5103e947 JB	273	btrfs_free_path(path);
	274
	275	return ret;
	276	}
	277
5103e947	278	/*
95819c05 CH	279	* List of handlers for synthetic system.* attributes. All real ondisk
	280	* attributes are handled directly.
	281	*/
f01cbd3f	282	const struct xattr_handler *btrfs_xattr_handlers[] = {
0eda294d	283	#ifdef CONFIG_BTRFS_FS_POSIX_ACL
95819c05 CH	284	&btrfs_xattr_acl_access_handler,
	285	&btrfs_xattr_acl_default_handler,
	286	#endif
	287	NULL,
	288	};
	289
	290	/*
	291	* Check if the attribute is in a supported namespace.
	292	*
	293	* This applied after the check for the synthetic attributes in the system
	294	* namespace.
5103e947	295	*/
95819c05 CH	296	static bool btrfs_is_valid_xattr(const char *name)
95819c05 CH	297	{
d397712b CM	298	return !strncmp(name, XATTR_SECURITY_PREFIX,
d397712b CM	299	XATTR_SECURITY_PREFIX_LEN) \|\|
95819c05 CH	300	!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) \|\|
	301	!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) \|\|
	302	!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN);
69a32ac5 CM	303	}
69a32ac5 CM	304
95819c05 CH	305	ssize_t btrfs_getxattr(struct dentry dentry, const char name,
	306	void *buffer, size_t size)
	307	{
	308	/*
	309	* If this is a request for a synthetic attribute in the system.*
	310	* namespace use the generic infrastructure to resolve a handler
	311	* for it via sb->s_xattr.
	312	*/
	313	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
	314	return generic_getxattr(dentry, name, buffer, size);
5103e947	315
95819c05 CH	316	if (!btrfs_is_valid_xattr(name))
	317	return -EOPNOTSUPP;
	318	return __btrfs_getxattr(dentry->d_inode, name, buffer, size);
	319	}
5103e947	320
95819c05 CH	321	int btrfs_setxattr(struct dentry dentry, const char name, const void *value,
	322	size_t size, int flags)
	323	{
b83cc969 LZ	324	struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root;
	325
	326	/*
	327	* The permission on security.* and system.* is not checked
	328	* in permission().
	329	*/
	330	if (btrfs_root_readonly(root))
	331	return -EROFS;
	332
95819c05 CH	333	/*
	334	* If this is a request for a synthetic attribute in the system.*
	335	* namespace use the generic infrastructure to resolve a handler
	336	* for it via sb->s_xattr.
	337	*/
	338	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
	339	return generic_setxattr(dentry, name, value, size, flags);
5103e947	340
95819c05 CH	341	if (!btrfs_is_valid_xattr(name))
95819c05 CH	342	return -EOPNOTSUPP;
5103e947	343
95819c05 CH	344	if (size == 0)
95819c05 CH	345	value = ""; /* empty EA, do not remove */
f34f57a3 YZ	346
	347	return __btrfs_setxattr(NULL, dentry->d_inode, name, value, size,
	348	flags);
95819c05 CH	349	}
	350
	351	int btrfs_removexattr(struct dentry dentry, const char name)
	352	{
b83cc969 LZ	353	struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root;
	354
	355	/*
	356	* The permission on security.* and system.* is not checked
	357	* in permission().
	358	*/
	359	if (btrfs_root_readonly(root))
	360	return -EROFS;
	361
95819c05 CH	362	/*
	363	* If this is a request for a synthetic attribute in the system.*
	364	* namespace use the generic infrastructure to resolve a handler
	365	* for it via sb->s_xattr.
	366	*/
	367	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
	368	return generic_removexattr(dentry, name);
	369
	370	if (!btrfs_is_valid_xattr(name))
	371	return -EOPNOTSUPP;
f34f57a3 YZ	372
	373	return __btrfs_setxattr(NULL, dentry->d_inode, name, NULL, 0,
	374	XATTR_REPLACE);
95819c05	375	}
0279b4cd	376
f34f57a3	377	int btrfs_xattr_security_init(struct btrfs_trans_handle *trans,
2a7dba39 EP	378	struct inode inode, struct inode dir,
2a7dba39 EP	379	const struct qstr *qstr)
0279b4cd JO	380	{
	381	int err;
	382	size_t len;
	383	void *value;
	384	char *suffix;
	385	char *name;
	386
2a7dba39 EP	387	err = security_inode_init_security(inode, dir, qstr, &suffix, &value,
2a7dba39 EP	388	&len);
0279b4cd JO	389	if (err) {
	390	if (err == -EOPNOTSUPP)
	391	return 0;
	392	return err;
	393	}
	394
	395	name = kmalloc(XATTR_SECURITY_PREFIX_LEN + strlen(suffix) + 1,
	396	GFP_NOFS);
	397	if (!name) {
	398	err = -ENOMEM;
	399	} else {
	400	strcpy(name, XATTR_SECURITY_PREFIX);
	401	strcpy(name + XATTR_SECURITY_PREFIX_LEN, suffix);
f34f57a3	402	err = __btrfs_setxattr(trans, inode, name, value, len, 0);
0279b4cd JO	403	kfree(name);
	404	}
	405
	406	kfree(suffix);
	407	kfree(value);
	408	return err;
	409	}