[deliverable/linux.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 <linux/posix_acl_xattr.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
	&posix_acl_access_xattr_handler,
	&posix_acl_default_xattr_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);
}

static 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>
996a710d	25	#include <linux/posix_acl_xattr.h>
5103e947 JB	26	#include "ctree.h"
	27	#include "btrfs_inode.h"
	28	#include "transaction.h"
	29	#include "xattr.h"
	30	#include "disk-io.h"
33268eaf	31
5103e947	32
95819c05 CH	33	ssize_t __btrfs_getxattr(struct inode inode, const char name,
95819c05 CH	34	void *buffer, size_t size)
5103e947 JB	35	{
	36	struct btrfs_dir_item *di;
	37	struct btrfs_root *root = BTRFS_I(inode)->root;
	38	struct btrfs_path *path;
	39	struct extent_buffer *leaf;
5103e947 JB	40	int ret = 0;
5103e947 JB	41	unsigned long data_ptr;
5103e947 JB	42
5103e947 JB	43	path = btrfs_alloc_path();
95819c05	44	if (!path)
5103e947	45	return -ENOMEM;
5103e947	46
5103e947	47	/* lookup the xattr by name */
33345d01	48	di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(inode), name,
5103e947	49	strlen(name), 0);
07060404	50	if (!di) {
5103e947 JB	51	ret = -ENODATA;
5103e947 JB	52	goto out;
07060404 JB	53	} else if (IS_ERR(di)) {
	54	ret = PTR_ERR(di);
	55	goto out;
5103e947 JB	56	}
	57
	58	leaf = path->nodes[0];
	59	/* if size is 0, that means we want the size of the attr */
	60	if (!size) {
	61	ret = btrfs_dir_data_len(leaf, di);
	62	goto out;
	63	}
	64
	65	/* now get the data out of our dir_item */
	66	if (btrfs_dir_data_len(leaf, di) > size) {
	67	ret = -ERANGE;
	68	goto out;
	69	}
07060404 JB	70
	71	/*
	72	* The way things are packed into the leaf is like this
	73	* \|struct btrfs_dir_item\|name\|data\|
	74	* where name is the xattr name, so security.foo, and data is the
	75	* content of the xattr. data_ptr points to the location in memory
	76	* where the data starts in the in memory leaf
	77	*/
5103e947 JB	78	data_ptr = (unsigned long)((char *)(di + 1) +
	79	btrfs_dir_name_len(leaf, di));
	80	read_extent_buffer(leaf, buffer, data_ptr,
3acd7ee8	81	btrfs_dir_data_len(leaf, di));
5103e947 JB	82	ret = btrfs_dir_data_len(leaf, di);
	83
	84	out:
5103e947 JB	85	btrfs_free_path(path);
	86	return ret;
	87	}
	88
f34f57a3 YZ	89	static int do_setxattr(struct btrfs_trans_handle *trans,
	90	struct inode inode, const char name,
	91	const void *value, size_t size, int flags)
5103e947 JB	92	{
	93	struct btrfs_dir_item *di;
	94	struct btrfs_root *root = BTRFS_I(inode)->root;
5103e947	95	struct btrfs_path *path;
f34f57a3 YZ	96	size_t name_len = strlen(name);
	97	int ret = 0;
	98
	99	if (name_len + size > BTRFS_MAX_XATTR_SIZE(root))
	100	return -ENOSPC;
5103e947 JB	101
5103e947 JB	102	path = btrfs_alloc_path();
95819c05	103	if (!path)
5103e947	104	return -ENOMEM;
5103e947	105
fa09200b JB	106	if (flags & XATTR_REPLACE) {
	107	di = btrfs_lookup_xattr(trans, root, path, btrfs_ino(inode), name,
	108	name_len, -1);
	109	if (IS_ERR(di)) {
	110	ret = PTR_ERR(di);
	111	goto out;
	112	} else if (!di) {
	113	ret = -ENODATA;
5103e947 JB	114	goto out;
5103e947 JB	115	}
5103e947	116	ret = btrfs_delete_one_dir_name(trans, root, path, di);
fa09200b JB	117	if (ret)
fa09200b JB	118	goto out;
b3b4aa74	119	btrfs_release_path(path);
4815053a DS	120
	121	/*
	122	* remove the attribute
	123	*/
	124	if (!value)
	125	goto out;
01e6deb2 LB	126	} else {
	127	di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(inode),
	128	name, name_len, 0);
	129	if (IS_ERR(di)) {
	130	ret = PTR_ERR(di);
	131	goto out;
	132	}
	133	if (!di && !value)
	134	goto out;
	135	btrfs_release_path(path);
fa09200b	136	}
5103e947	137
fa09200b JB	138	again:
	139	ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(inode),
	140	name, name_len, value, size);
ed3ee9f4 JB	141	/*
	142	* If we're setting an xattr to a new value but the new value is say
	143	* exactly BTRFS_MAX_XATTR_SIZE, we could end up with EOVERFLOW getting
	144	* back from split_leaf. This is because it thinks we'll be extending
	145	* the existing item size, but we're asking for enough space to add the
	146	* item itself. So if we get EOVERFLOW just set ret to EEXIST and let
	147	* the rest of the function figure it out.
	148	*/
	149	if (ret == -EOVERFLOW)
	150	ret = -EEXIST;
	151
fa09200b JB	152	if (ret == -EEXIST) {
fa09200b JB	153	if (flags & XATTR_CREATE)
5103e947	154	goto out;
fa09200b JB	155	/*
	156	* We can't use the path we already have since we won't have the
	157	* proper locking for a delete, so release the path and
	158	* re-lookup to delete the thing.
	159	*/
b3b4aa74	160	btrfs_release_path(path);
fa09200b JB	161	di = btrfs_lookup_xattr(trans, root, path, btrfs_ino(inode),
	162	name, name_len, -1);
	163	if (IS_ERR(di)) {
	164	ret = PTR_ERR(di);
	165	goto out;
	166	} else if (!di) {
	167	/* Shouldn't happen but just in case... */
	168	btrfs_release_path(path);
	169	goto again;
	170	}
33268eaf	171
fa09200b JB	172	ret = btrfs_delete_one_dir_name(trans, root, path, di);
fa09200b JB	173	if (ret)
33268eaf	174	goto out;
fa09200b JB	175
	176	/*
	177	* We have a value to set, so go back and try to insert it now.
	178	*/
	179	if (value) {
	180	btrfs_release_path(path);
	181	goto again;
33268eaf	182	}
5103e947	183	}
f34f57a3 YZ	184	out:
	185	btrfs_free_path(path);
	186	return ret;
	187	}
	188
4815053a DS	189	/*
	190	* @value: "" makes the attribute to empty, NULL removes it
	191	*/
f34f57a3 YZ	192	int __btrfs_setxattr(struct btrfs_trans_handle *trans,
	193	struct inode inode, const char name,
	194	const void *value, size_t size, int flags)
	195	{
	196	struct btrfs_root *root = BTRFS_I(inode)->root;
	197	int ret;
	198
	199	if (trans)
	200	return do_setxattr(trans, inode, name, value, size, flags);
	201
a22285a6 YZ	202	trans = btrfs_start_transaction(root, 2);
	203	if (IS_ERR(trans))
	204	return PTR_ERR(trans);
5103e947	205
f34f57a3 YZ	206	ret = do_setxattr(trans, inode, name, value, size, flags);
	207	if (ret)
	208	goto out;
	209
0c4d2d95	210	inode_inc_iversion(inode);
f34f57a3	211	inode->i_ctime = CURRENT_TIME;
e9976151	212	set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags);
f34f57a3 YZ	213	ret = btrfs_update_inode(trans, root, inode);
	214	BUG_ON(ret);
	215	out:
7ad85bb7	216	btrfs_end_transaction(trans, root);
5103e947 JB	217	return ret;
	218	}
	219
	220	ssize_t btrfs_listxattr(struct dentry dentry, char buffer, size_t size)
	221	{
	222	struct btrfs_key key, found_key;
	223	struct inode *inode = dentry->d_inode;
	224	struct btrfs_root *root = BTRFS_I(inode)->root;
	225	struct btrfs_path *path;
5103e947 JB	226	struct extent_buffer *leaf;
5103e947 JB	227	struct btrfs_dir_item *di;
2e6a0035	228	int ret = 0, slot;
eaa47d86	229	size_t total_size = 0, size_left = size;
5103e947	230	unsigned long name_ptr;
eaa47d86	231	size_t name_len;
5103e947 JB	232
	233	/*
	234	* ok we want all objects associated with this id.
	235	* NOTE: we set key.offset = 0; because we want to start with the
	236	* first xattr that we find and walk forward
	237	*/
33345d01	238	key.objectid = btrfs_ino(inode);
5103e947 JB	239	btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
	240	key.offset = 0;
	241
	242	path = btrfs_alloc_path();
5103e947 JB	243	if (!path)
5103e947 JB	244	return -ENOMEM;
1caf9342	245	path->reada = 2;
5103e947	246
5103e947 JB	247	/* search for our xattrs */
	248	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
	249	if (ret < 0)
	250	goto err;
2e6a0035	251
5103e947 JB	252	while (1) {
5103e947 JB	253	leaf = path->nodes[0];
5103e947 JB	254	slot = path->slots[0];
	255
	256	/* this is where we start walking through the path */
2e6a0035	257	if (slot >= btrfs_header_nritems(leaf)) {
5103e947 JB	258	/*
	259	* if we've reached the last slot in this leaf we need
	260	* to go to the next leaf and reset everything
	261	*/
2e6a0035 LZ	262	ret = btrfs_next_leaf(root, path);
	263	if (ret < 0)
	264	goto err;
	265	else if (ret > 0)
	266	break;
	267	continue;
5103e947	268	}
5103e947	269
5103e947 JB	270	btrfs_item_key_to_cpu(leaf, &found_key, slot);
	271
	272	/* check to make sure this item is what we want */
	273	if (found_key.objectid != key.objectid)
	274	break;
	275	if (btrfs_key_type(&found_key) != BTRFS_XATTR_ITEM_KEY)
	276	break;
	277
	278	di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
22a94d44	279	if (verify_dir_item(root, leaf, di))
db2254bc	280	goto next;
5103e947	281
eaa47d86 CH	282	name_len = btrfs_dir_name_len(leaf, di);
eaa47d86 CH	283	total_size += name_len + 1;
5103e947 JB	284
	285	/* we are just looking for how big our buffer needs to be */
	286	if (!size)
2e6a0035	287	goto next;
5103e947	288
eaa47d86	289	if (!buffer \|\| (name_len + 1) > size_left) {
5103e947	290	ret = -ERANGE;
b16281c3	291	goto err;
5103e947 JB	292	}
5103e947 JB	293
eaa47d86 CH	294	name_ptr = (unsigned long)(di + 1);
	295	read_extent_buffer(leaf, buffer, name_ptr, name_len);
	296	buffer[name_len] = '\0';
	297
	298	size_left -= name_len + 1;
	299	buffer += name_len + 1;
2e6a0035 LZ	300	next:
2e6a0035 LZ	301	path->slots[0]++;
5103e947 JB	302	}
	303	ret = total_size;
	304
	305	err:
5103e947 JB	306	btrfs_free_path(path);
	307
	308	return ret;
	309	}
	310
5103e947	311	/*
95819c05 CH	312	* List of handlers for synthetic system.* attributes. All real ondisk
	313	* attributes are handled directly.
	314	*/
f01cbd3f	315	const struct xattr_handler *btrfs_xattr_handlers[] = {
0eda294d	316	#ifdef CONFIG_BTRFS_FS_POSIX_ACL
996a710d CH	317	&posix_acl_access_xattr_handler,
996a710d CH	318	&posix_acl_default_xattr_handler,
95819c05 CH	319	#endif
	320	NULL,
	321	};
	322
	323	/*
	324	* Check if the attribute is in a supported namespace.
	325	*
	326	* This applied after the check for the synthetic attributes in the system
	327	* namespace.
5103e947	328	*/
95819c05 CH	329	static bool btrfs_is_valid_xattr(const char *name)
95819c05 CH	330	{
d397712b CM	331	return !strncmp(name, XATTR_SECURITY_PREFIX,
d397712b CM	332	XATTR_SECURITY_PREFIX_LEN) \|\|
95819c05 CH	333	!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) \|\|
	334	!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) \|\|
	335	!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN);
69a32ac5 CM	336	}
69a32ac5 CM	337
95819c05 CH	338	ssize_t btrfs_getxattr(struct dentry dentry, const char name,
	339	void *buffer, size_t size)
	340	{
	341	/*
	342	* If this is a request for a synthetic attribute in the system.*
	343	* namespace use the generic infrastructure to resolve a handler
	344	* for it via sb->s_xattr.
	345	*/
	346	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
	347	return generic_getxattr(dentry, name, buffer, size);
5103e947	348
95819c05 CH	349	if (!btrfs_is_valid_xattr(name))
	350	return -EOPNOTSUPP;
	351	return __btrfs_getxattr(dentry->d_inode, name, buffer, size);
	352	}
5103e947	353
95819c05 CH	354	int btrfs_setxattr(struct dentry dentry, const char name, const void *value,
	355	size_t size, int flags)
	356	{
b83cc969 LZ	357	struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root;
	358
	359	/*
	360	* The permission on security.* and system.* is not checked
	361	* in permission().
	362	*/
	363	if (btrfs_root_readonly(root))
	364	return -EROFS;
	365
95819c05 CH	366	/*
	367	* If this is a request for a synthetic attribute in the system.*
	368	* namespace use the generic infrastructure to resolve a handler
	369	* for it via sb->s_xattr.
	370	*/
	371	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
	372	return generic_setxattr(dentry, name, value, size, flags);
5103e947	373
95819c05 CH	374	if (!btrfs_is_valid_xattr(name))
95819c05 CH	375	return -EOPNOTSUPP;
5103e947	376
95819c05 CH	377	if (size == 0)
95819c05 CH	378	value = ""; /* empty EA, do not remove */
f34f57a3 YZ	379
	380	return __btrfs_setxattr(NULL, dentry->d_inode, name, value, size,
	381	flags);
95819c05 CH	382	}
	383
	384	int btrfs_removexattr(struct dentry dentry, const char name)
	385	{
b83cc969 LZ	386	struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root;
	387
	388	/*
	389	* The permission on security.* and system.* is not checked
	390	* in permission().
	391	*/
	392	if (btrfs_root_readonly(root))
	393	return -EROFS;
	394
95819c05 CH	395	/*
	396	* If this is a request for a synthetic attribute in the system.*
	397	* namespace use the generic infrastructure to resolve a handler
	398	* for it via sb->s_xattr.
	399	*/
	400	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
	401	return generic_removexattr(dentry, name);
	402
	403	if (!btrfs_is_valid_xattr(name))
	404	return -EOPNOTSUPP;
f34f57a3 YZ	405
	406	return __btrfs_setxattr(NULL, dentry->d_inode, name, NULL, 0,
	407	XATTR_REPLACE);
95819c05	408	}
0279b4cd	409
48a3b636 ES	410	static int btrfs_initxattrs(struct inode *inode,
48a3b636 ES	411	const struct xattr xattr_array, void fs_info)
0279b4cd	412	{
9d8f13ba MZ	413	const struct xattr *xattr;
9d8f13ba MZ	414	struct btrfs_trans_handle *trans = fs_info;
0279b4cd	415	char *name;
9d8f13ba	416	int err = 0;
0279b4cd	417
9d8f13ba MZ	418	for (xattr = xattr_array; xattr->name != NULL; xattr++) {
	419	name = kmalloc(XATTR_SECURITY_PREFIX_LEN +
	420	strlen(xattr->name) + 1, GFP_NOFS);
	421	if (!name) {
	422	err = -ENOMEM;
	423	break;
	424	}
0279b4cd	425	strcpy(name, XATTR_SECURITY_PREFIX);
9d8f13ba MZ	426	strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name);
	427	err = __btrfs_setxattr(trans, inode, name,
	428	xattr->value, xattr->value_len, 0);
0279b4cd	429	kfree(name);
9d8f13ba MZ	430	if (err < 0)
9d8f13ba MZ	431	break;
0279b4cd	432	}
0279b4cd JO	433	return err;
0279b4cd JO	434	}
9d8f13ba MZ	435
	436	int btrfs_xattr_security_init(struct btrfs_trans_handle *trans,
	437	struct inode inode, struct inode dir,
	438	const struct qstr *qstr)
	439	{
	440	return security_inode_init_security(inode, dir, qstr,
	441	&btrfs_initxattrs, trans);
	442	}