[mirror_ubuntu-artful-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);

		/*
		 * remove the attribute
		 */
		if (!value)
			goto out;
	} else {
		di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(inode),
					name, name_len, 0);
		if (IS_ERR(di)) {
			ret = PTR_ERR(di);
			goto out;
		}
		if (!di && !value)
			goto out;
		btrfs_release_path(path);
	}

again:
	ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(inode),
				      name, name_len, value, size);
	/*
	 * If we're setting an xattr to a new value but the new value is say
	 * exactly BTRFS_MAX_XATTR_SIZE, we could end up with EOVERFLOW getting
	 * back from split_leaf.  This is because it thinks we'll be extending
	 * the existing item size, but we're asking for enough space to add the
	 * item itself.  So if we get EOVERFLOW just set ret to EEXIST and let
	 * the rest of the function figure it out.
	 */
	if (ret == -EOVERFLOW)
		ret = -EEXIST;

	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;
}

/*
 * @value: "" makes the attribute to empty, NULL removes it
 */
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_inc_iversion(inode);
	inode->i_ctime = CURRENT_TIME;
	set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags);
	ret = btrfs_update_inode(trans, root, inode);
	BUG_ON(ret);
out:
	btrfs_end_transaction(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))
			goto next;

		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_initxattrs(struct inode *inode, const struct xattr *xattr_array,
		     void *fs_info)
{
	const struct xattr *xattr;
	struct btrfs_trans_handle *trans = fs_info;
	char *name;
	int err = 0;

	for (xattr = xattr_array; xattr->name != NULL; xattr++) {
		name = kmalloc(XATTR_SECURITY_PREFIX_LEN +
			       strlen(xattr->name) + 1, GFP_NOFS);
		if (!name) {
			err = -ENOMEM;
			break;
		}
		strcpy(name, XATTR_SECURITY_PREFIX);
		strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name);
		err = __btrfs_setxattr(trans, inode, name,
				       xattr->value, xattr->value_len, 0);
		kfree(name);
		if (err < 0)
			break;
	}
	return err;
}

int btrfs_xattr_security_init(struct btrfs_trans_handle *trans,
			      struct inode *inode, struct inode *dir,
			      const struct qstr *qstr)
{
	return security_inode_init_security(inode, dir, qstr,
					    &btrfs_initxattrs, trans);
}
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);
4815053a DS	119
	120	/*
	121	* remove the attribute
	122	*/
	123	if (!value)
	124	goto out;
01e6deb2 LB	125	} else {
	126	di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(inode),
	127	name, name_len, 0);
	128	if (IS_ERR(di)) {
	129	ret = PTR_ERR(di);
	130	goto out;
	131	}
	132	if (!di && !value)
	133	goto out;
	134	btrfs_release_path(path);
fa09200b	135	}
5103e947	136
fa09200b JB	137	again:
	138	ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(inode),
	139	name, name_len, value, size);
ed3ee9f4 JB	140	/*
	141	* If we're setting an xattr to a new value but the new value is say
	142	* exactly BTRFS_MAX_XATTR_SIZE, we could end up with EOVERFLOW getting
	143	* back from split_leaf. This is because it thinks we'll be extending
	144	* the existing item size, but we're asking for enough space to add the
	145	* item itself. So if we get EOVERFLOW just set ret to EEXIST and let
	146	* the rest of the function figure it out.
	147	*/
	148	if (ret == -EOVERFLOW)
	149	ret = -EEXIST;
	150
fa09200b JB	151	if (ret == -EEXIST) {
fa09200b JB	152	if (flags & XATTR_CREATE)
5103e947	153	goto out;
fa09200b JB	154	/*
	155	* We can't use the path we already have since we won't have the
	156	* proper locking for a delete, so release the path and
	157	* re-lookup to delete the thing.
	158	*/
b3b4aa74	159	btrfs_release_path(path);
fa09200b JB	160	di = btrfs_lookup_xattr(trans, root, path, btrfs_ino(inode),
	161	name, name_len, -1);
	162	if (IS_ERR(di)) {
	163	ret = PTR_ERR(di);
	164	goto out;
	165	} else if (!di) {
	166	/* Shouldn't happen but just in case... */
	167	btrfs_release_path(path);
	168	goto again;
	169	}
33268eaf	170
fa09200b JB	171	ret = btrfs_delete_one_dir_name(trans, root, path, di);
fa09200b JB	172	if (ret)
33268eaf	173	goto out;
fa09200b JB	174
	175	/*
	176	* We have a value to set, so go back and try to insert it now.
	177	*/
	178	if (value) {
	179	btrfs_release_path(path);
	180	goto again;
33268eaf	181	}
5103e947	182	}
f34f57a3 YZ	183	out:
	184	btrfs_free_path(path);
	185	return ret;
	186	}
	187
4815053a DS	188	/*
	189	* @value: "" makes the attribute to empty, NULL removes it
	190	*/
f34f57a3 YZ	191	int __btrfs_setxattr(struct btrfs_trans_handle *trans,
	192	struct inode inode, const char name,
	193	const void *value, size_t size, int flags)
	194	{
	195	struct btrfs_root *root = BTRFS_I(inode)->root;
	196	int ret;
	197
	198	if (trans)
	199	return do_setxattr(trans, inode, name, value, size, flags);
	200
a22285a6 YZ	201	trans = btrfs_start_transaction(root, 2);
	202	if (IS_ERR(trans))
	203	return PTR_ERR(trans);
5103e947	204
f34f57a3 YZ	205	ret = do_setxattr(trans, inode, name, value, size, flags);
	206	if (ret)
	207	goto out;
	208
0c4d2d95	209	inode_inc_iversion(inode);
f34f57a3	210	inode->i_ctime = CURRENT_TIME;
e9976151	211	set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags);
f34f57a3 YZ	212	ret = btrfs_update_inode(trans, root, inode);
	213	BUG_ON(ret);
	214	out:
7ad85bb7	215	btrfs_end_transaction(trans, root);
5103e947 JB	216	return ret;
	217	}
	218
	219	ssize_t btrfs_listxattr(struct dentry dentry, char buffer, size_t size)
	220	{
	221	struct btrfs_key key, found_key;
	222	struct inode *inode = dentry->d_inode;
	223	struct btrfs_root *root = BTRFS_I(inode)->root;
	224	struct btrfs_path *path;
5103e947 JB	225	struct extent_buffer *leaf;
5103e947 JB	226	struct btrfs_dir_item *di;
2e6a0035	227	int ret = 0, slot;
eaa47d86	228	size_t total_size = 0, size_left = size;
5103e947	229	unsigned long name_ptr;
eaa47d86	230	size_t name_len;
5103e947 JB	231
	232	/*
	233	* ok we want all objects associated with this id.
	234	* NOTE: we set key.offset = 0; because we want to start with the
	235	* first xattr that we find and walk forward
	236	*/
33345d01	237	key.objectid = btrfs_ino(inode);
5103e947 JB	238	btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
	239	key.offset = 0;
	240
	241	path = btrfs_alloc_path();
5103e947 JB	242	if (!path)
5103e947 JB	243	return -ENOMEM;
1caf9342	244	path->reada = 2;
5103e947	245
5103e947 JB	246	/* search for our xattrs */
	247	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
	248	if (ret < 0)
	249	goto err;
2e6a0035	250
5103e947 JB	251	while (1) {
5103e947 JB	252	leaf = path->nodes[0];
5103e947 JB	253	slot = path->slots[0];
	254
	255	/* this is where we start walking through the path */
2e6a0035	256	if (slot >= btrfs_header_nritems(leaf)) {
5103e947 JB	257	/*
	258	* if we've reached the last slot in this leaf we need
	259	* to go to the next leaf and reset everything
	260	*/
2e6a0035 LZ	261	ret = btrfs_next_leaf(root, path);
	262	if (ret < 0)
	263	goto err;
	264	else if (ret > 0)
	265	break;
	266	continue;
5103e947	267	}
5103e947	268
5103e947 JB	269	btrfs_item_key_to_cpu(leaf, &found_key, slot);
	270
	271	/* check to make sure this item is what we want */
	272	if (found_key.objectid != key.objectid)
	273	break;
	274	if (btrfs_key_type(&found_key) != BTRFS_XATTR_ITEM_KEY)
	275	break;
	276
	277	di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
22a94d44	278	if (verify_dir_item(root, leaf, di))
db2254bc	279	goto next;
5103e947	280
eaa47d86 CH	281	name_len = btrfs_dir_name_len(leaf, di);
eaa47d86 CH	282	total_size += name_len + 1;
5103e947 JB	283
	284	/* we are just looking for how big our buffer needs to be */
	285	if (!size)
2e6a0035	286	goto next;
5103e947	287
eaa47d86	288	if (!buffer \|\| (name_len + 1) > size_left) {
5103e947	289	ret = -ERANGE;
b16281c3	290	goto err;
5103e947 JB	291	}
5103e947 JB	292
eaa47d86 CH	293	name_ptr = (unsigned long)(di + 1);
	294	read_extent_buffer(leaf, buffer, name_ptr, name_len);
	295	buffer[name_len] = '\0';
	296
	297	size_left -= name_len + 1;
	298	buffer += name_len + 1;
2e6a0035 LZ	299	next:
2e6a0035 LZ	300	path->slots[0]++;
5103e947 JB	301	}
	302	ret = total_size;
	303
	304	err:
5103e947 JB	305	btrfs_free_path(path);
	306
	307	return ret;
	308	}
	309
5103e947	310	/*
95819c05 CH	311	* List of handlers for synthetic system.* attributes. All real ondisk
	312	* attributes are handled directly.
	313	*/
f01cbd3f	314	const struct xattr_handler *btrfs_xattr_handlers[] = {
0eda294d	315	#ifdef CONFIG_BTRFS_FS_POSIX_ACL
95819c05 CH	316	&btrfs_xattr_acl_access_handler,
	317	&btrfs_xattr_acl_default_handler,
	318	#endif
	319	NULL,
	320	};
	321
	322	/*
	323	* Check if the attribute is in a supported namespace.
	324	*
	325	* This applied after the check for the synthetic attributes in the system
	326	* namespace.
5103e947	327	*/
95819c05 CH	328	static bool btrfs_is_valid_xattr(const char *name)
95819c05 CH	329	{
d397712b CM	330	return !strncmp(name, XATTR_SECURITY_PREFIX,
d397712b CM	331	XATTR_SECURITY_PREFIX_LEN) \|\|
95819c05 CH	332	!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) \|\|
	333	!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) \|\|
	334	!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN);
69a32ac5 CM	335	}
69a32ac5 CM	336
95819c05 CH	337	ssize_t btrfs_getxattr(struct dentry dentry, const char name,
	338	void *buffer, size_t size)
	339	{
	340	/*
	341	* If this is a request for a synthetic attribute in the system.*
	342	* namespace use the generic infrastructure to resolve a handler
	343	* for it via sb->s_xattr.
	344	*/
	345	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
	346	return generic_getxattr(dentry, name, buffer, size);
5103e947	347
95819c05 CH	348	if (!btrfs_is_valid_xattr(name))
	349	return -EOPNOTSUPP;
	350	return __btrfs_getxattr(dentry->d_inode, name, buffer, size);
	351	}
5103e947	352
95819c05 CH	353	int btrfs_setxattr(struct dentry dentry, const char name, const void *value,
	354	size_t size, int flags)
	355	{
b83cc969 LZ	356	struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root;
	357
	358	/*
	359	* The permission on security.* and system.* is not checked
	360	* in permission().
	361	*/
	362	if (btrfs_root_readonly(root))
	363	return -EROFS;
	364
95819c05 CH	365	/*
	366	* If this is a request for a synthetic attribute in the system.*
	367	* namespace use the generic infrastructure to resolve a handler
	368	* for it via sb->s_xattr.
	369	*/
	370	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
	371	return generic_setxattr(dentry, name, value, size, flags);
5103e947	372
95819c05 CH	373	if (!btrfs_is_valid_xattr(name))
95819c05 CH	374	return -EOPNOTSUPP;
5103e947	375
95819c05 CH	376	if (size == 0)
95819c05 CH	377	value = ""; /* empty EA, do not remove */
f34f57a3 YZ	378
	379	return __btrfs_setxattr(NULL, dentry->d_inode, name, value, size,
	380	flags);
95819c05 CH	381	}
	382
	383	int btrfs_removexattr(struct dentry dentry, const char name)
	384	{
b83cc969 LZ	385	struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root;
	386
	387	/*
	388	* The permission on security.* and system.* is not checked
	389	* in permission().
	390	*/
	391	if (btrfs_root_readonly(root))
	392	return -EROFS;
	393
95819c05 CH	394	/*
	395	* If this is a request for a synthetic attribute in the system.*
	396	* namespace use the generic infrastructure to resolve a handler
	397	* for it via sb->s_xattr.
	398	*/
	399	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
	400	return generic_removexattr(dentry, name);
	401
	402	if (!btrfs_is_valid_xattr(name))
	403	return -EOPNOTSUPP;
f34f57a3 YZ	404
	405	return __btrfs_setxattr(NULL, dentry->d_inode, name, NULL, 0,
	406	XATTR_REPLACE);
95819c05	407	}
0279b4cd	408
9d8f13ba MZ	409	int btrfs_initxattrs(struct inode inode, const struct xattr xattr_array,
9d8f13ba MZ	410	void *fs_info)
0279b4cd	411	{
9d8f13ba MZ	412	const struct xattr *xattr;
9d8f13ba MZ	413	struct btrfs_trans_handle *trans = fs_info;
0279b4cd	414	char *name;
9d8f13ba	415	int err = 0;
0279b4cd	416
9d8f13ba MZ	417	for (xattr = xattr_array; xattr->name != NULL; xattr++) {
	418	name = kmalloc(XATTR_SECURITY_PREFIX_LEN +
	419	strlen(xattr->name) + 1, GFP_NOFS);
	420	if (!name) {
	421	err = -ENOMEM;
	422	break;
	423	}
0279b4cd	424	strcpy(name, XATTR_SECURITY_PREFIX);
9d8f13ba MZ	425	strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name);
	426	err = __btrfs_setxattr(trans, inode, name,
	427	xattr->value, xattr->value_len, 0);
0279b4cd	428	kfree(name);
9d8f13ba MZ	429	if (err < 0)
9d8f13ba MZ	430	break;
0279b4cd	431	}
0279b4cd JO	432	return err;
0279b4cd JO	433	}
9d8f13ba MZ	434
	435	int btrfs_xattr_security_init(struct btrfs_trans_handle *trans,
	436	struct inode inode, struct inode dir,
	437	const struct qstr *qstr)
	438	{
	439	return security_inode_init_security(inode, dir, qstr,
	440	&btrfs_initxattrs, trans);
	441	}