[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"
#include "props.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) ||
		!strncmp(name, XATTR_BTRFS_PREFIX, XATTR_BTRFS_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 (!strncmp(name, XATTR_BTRFS_PREFIX, XATTR_BTRFS_PREFIX_LEN))
		return btrfs_set_prop(dentry->d_inode, name,
				      value, size, flags);

	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;

	if (!strncmp(name, XATTR_BTRFS_PREFIX, XATTR_BTRFS_PREFIX_LEN))
		return btrfs_set_prop(dentry->d_inode, name,
				      NULL, 0, XATTR_REPLACE);

	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"
63541927	31	#include "props.h"
33268eaf	32
5103e947	33
95819c05 CH	34	ssize_t __btrfs_getxattr(struct inode inode, const char name,
95819c05 CH	35	void *buffer, size_t size)
5103e947 JB	36	{
	37	struct btrfs_dir_item *di;
	38	struct btrfs_root *root = BTRFS_I(inode)->root;
	39	struct btrfs_path *path;
	40	struct extent_buffer *leaf;
5103e947 JB	41	int ret = 0;
5103e947 JB	42	unsigned long data_ptr;
5103e947 JB	43
5103e947 JB	44	path = btrfs_alloc_path();
95819c05	45	if (!path)
5103e947	46	return -ENOMEM;
5103e947	47
5103e947	48	/* lookup the xattr by name */
33345d01	49	di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(inode), name,
5103e947	50	strlen(name), 0);
07060404	51	if (!di) {
5103e947 JB	52	ret = -ENODATA;
5103e947 JB	53	goto out;
07060404 JB	54	} else if (IS_ERR(di)) {
	55	ret = PTR_ERR(di);
	56	goto out;
5103e947 JB	57	}
	58
	59	leaf = path->nodes[0];
	60	/* if size is 0, that means we want the size of the attr */
	61	if (!size) {
	62	ret = btrfs_dir_data_len(leaf, di);
	63	goto out;
	64	}
	65
	66	/* now get the data out of our dir_item */
	67	if (btrfs_dir_data_len(leaf, di) > size) {
	68	ret = -ERANGE;
	69	goto out;
	70	}
07060404 JB	71
	72	/*
	73	* The way things are packed into the leaf is like this
	74	* \|struct btrfs_dir_item\|name\|data\|
	75	* where name is the xattr name, so security.foo, and data is the
	76	* content of the xattr. data_ptr points to the location in memory
	77	* where the data starts in the in memory leaf
	78	*/
5103e947 JB	79	data_ptr = (unsigned long)((char *)(di + 1) +
	80	btrfs_dir_name_len(leaf, di));
	81	read_extent_buffer(leaf, buffer, data_ptr,
3acd7ee8	82	btrfs_dir_data_len(leaf, di));
5103e947 JB	83	ret = btrfs_dir_data_len(leaf, di);
	84
	85	out:
5103e947 JB	86	btrfs_free_path(path);
	87	return ret;
	88	}
	89
f34f57a3 YZ	90	static int do_setxattr(struct btrfs_trans_handle *trans,
	91	struct inode inode, const char name,
	92	const void *value, size_t size, int flags)
5103e947 JB	93	{
	94	struct btrfs_dir_item *di;
	95	struct btrfs_root *root = BTRFS_I(inode)->root;
5103e947	96	struct btrfs_path *path;
f34f57a3 YZ	97	size_t name_len = strlen(name);
	98	int ret = 0;
	99
	100	if (name_len + size > BTRFS_MAX_XATTR_SIZE(root))
	101	return -ENOSPC;
5103e947 JB	102
5103e947 JB	103	path = btrfs_alloc_path();
95819c05	104	if (!path)
5103e947	105	return -ENOMEM;
5103e947	106
fa09200b JB	107	if (flags & XATTR_REPLACE) {
	108	di = btrfs_lookup_xattr(trans, root, path, btrfs_ino(inode), name,
	109	name_len, -1);
	110	if (IS_ERR(di)) {
	111	ret = PTR_ERR(di);
	112	goto out;
	113	} else if (!di) {
	114	ret = -ENODATA;
5103e947 JB	115	goto out;
5103e947 JB	116	}
5103e947	117	ret = btrfs_delete_one_dir_name(trans, root, path, di);
fa09200b JB	118	if (ret)
fa09200b JB	119	goto out;
b3b4aa74	120	btrfs_release_path(path);
4815053a DS	121
	122	/*
	123	* remove the attribute
	124	*/
	125	if (!value)
	126	goto out;
01e6deb2 LB	127	} else {
	128	di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(inode),
	129	name, name_len, 0);
	130	if (IS_ERR(di)) {
	131	ret = PTR_ERR(di);
	132	goto out;
	133	}
	134	if (!di && !value)
	135	goto out;
	136	btrfs_release_path(path);
fa09200b	137	}
5103e947	138
fa09200b JB	139	again:
	140	ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(inode),
	141	name, name_len, value, size);
ed3ee9f4 JB	142	/*
	143	* If we're setting an xattr to a new value but the new value is say
	144	* exactly BTRFS_MAX_XATTR_SIZE, we could end up with EOVERFLOW getting
	145	* back from split_leaf. This is because it thinks we'll be extending
	146	* the existing item size, but we're asking for enough space to add the
	147	* item itself. So if we get EOVERFLOW just set ret to EEXIST and let
	148	* the rest of the function figure it out.
	149	*/
	150	if (ret == -EOVERFLOW)
	151	ret = -EEXIST;
	152
fa09200b JB	153	if (ret == -EEXIST) {
fa09200b JB	154	if (flags & XATTR_CREATE)
5103e947	155	goto out;
fa09200b JB	156	/*
	157	* We can't use the path we already have since we won't have the
	158	* proper locking for a delete, so release the path and
	159	* re-lookup to delete the thing.
	160	*/
b3b4aa74	161	btrfs_release_path(path);
fa09200b JB	162	di = btrfs_lookup_xattr(trans, root, path, btrfs_ino(inode),
	163	name, name_len, -1);
	164	if (IS_ERR(di)) {
	165	ret = PTR_ERR(di);
	166	goto out;
	167	} else if (!di) {
	168	/* Shouldn't happen but just in case... */
	169	btrfs_release_path(path);
	170	goto again;
	171	}
33268eaf	172
fa09200b JB	173	ret = btrfs_delete_one_dir_name(trans, root, path, di);
fa09200b JB	174	if (ret)
33268eaf	175	goto out;
fa09200b JB	176
	177	/*
	178	* We have a value to set, so go back and try to insert it now.
	179	*/
	180	if (value) {
	181	btrfs_release_path(path);
	182	goto again;
33268eaf	183	}
5103e947	184	}
f34f57a3 YZ	185	out:
	186	btrfs_free_path(path);
	187	return ret;
	188	}
	189
4815053a DS	190	/*
	191	* @value: "" makes the attribute to empty, NULL removes it
	192	*/
f34f57a3 YZ	193	int __btrfs_setxattr(struct btrfs_trans_handle *trans,
	194	struct inode inode, const char name,
	195	const void *value, size_t size, int flags)
	196	{
	197	struct btrfs_root *root = BTRFS_I(inode)->root;
	198	int ret;
	199
	200	if (trans)
	201	return do_setxattr(trans, inode, name, value, size, flags);
	202
a22285a6 YZ	203	trans = btrfs_start_transaction(root, 2);
	204	if (IS_ERR(trans))
	205	return PTR_ERR(trans);
5103e947	206
f34f57a3 YZ	207	ret = do_setxattr(trans, inode, name, value, size, flags);
	208	if (ret)
	209	goto out;
	210
0c4d2d95	211	inode_inc_iversion(inode);
f34f57a3	212	inode->i_ctime = CURRENT_TIME;
e9976151	213	set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags);
f34f57a3 YZ	214	ret = btrfs_update_inode(trans, root, inode);
	215	BUG_ON(ret);
	216	out:
7ad85bb7	217	btrfs_end_transaction(trans, root);
5103e947 JB	218	return ret;
	219	}
	220
	221	ssize_t btrfs_listxattr(struct dentry dentry, char buffer, size_t size)
	222	{
	223	struct btrfs_key key, found_key;
	224	struct inode *inode = dentry->d_inode;
	225	struct btrfs_root *root = BTRFS_I(inode)->root;
	226	struct btrfs_path *path;
5103e947 JB	227	struct extent_buffer *leaf;
5103e947 JB	228	struct btrfs_dir_item *di;
2e6a0035	229	int ret = 0, slot;
eaa47d86	230	size_t total_size = 0, size_left = size;
5103e947	231	unsigned long name_ptr;
eaa47d86	232	size_t name_len;
5103e947 JB	233
	234	/*
	235	* ok we want all objects associated with this id.
	236	* NOTE: we set key.offset = 0; because we want to start with the
	237	* first xattr that we find and walk forward
	238	*/
33345d01	239	key.objectid = btrfs_ino(inode);
5103e947 JB	240	btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
	241	key.offset = 0;
	242
	243	path = btrfs_alloc_path();
5103e947 JB	244	if (!path)
5103e947 JB	245	return -ENOMEM;
1caf9342	246	path->reada = 2;
5103e947	247
5103e947 JB	248	/* search for our xattrs */
	249	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
	250	if (ret < 0)
	251	goto err;
2e6a0035	252
5103e947 JB	253	while (1) {
5103e947 JB	254	leaf = path->nodes[0];
5103e947 JB	255	slot = path->slots[0];
	256
	257	/* this is where we start walking through the path */
2e6a0035	258	if (slot >= btrfs_header_nritems(leaf)) {
5103e947 JB	259	/*
	260	* if we've reached the last slot in this leaf we need
	261	* to go to the next leaf and reset everything
	262	*/
2e6a0035 LZ	263	ret = btrfs_next_leaf(root, path);
	264	if (ret < 0)
	265	goto err;
	266	else if (ret > 0)
	267	break;
	268	continue;
5103e947	269	}
5103e947	270
5103e947 JB	271	btrfs_item_key_to_cpu(leaf, &found_key, slot);
	272
	273	/* check to make sure this item is what we want */
	274	if (found_key.objectid != key.objectid)
	275	break;
	276	if (btrfs_key_type(&found_key) != BTRFS_XATTR_ITEM_KEY)
	277	break;
	278
	279	di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
22a94d44	280	if (verify_dir_item(root, leaf, di))
db2254bc	281	goto next;
5103e947	282
eaa47d86 CH	283	name_len = btrfs_dir_name_len(leaf, di);
eaa47d86 CH	284	total_size += name_len + 1;
5103e947 JB	285
	286	/* we are just looking for how big our buffer needs to be */
	287	if (!size)
2e6a0035	288	goto next;
5103e947	289
eaa47d86	290	if (!buffer \|\| (name_len + 1) > size_left) {
5103e947	291	ret = -ERANGE;
b16281c3	292	goto err;
5103e947 JB	293	}
5103e947 JB	294
eaa47d86 CH	295	name_ptr = (unsigned long)(di + 1);
	296	read_extent_buffer(leaf, buffer, name_ptr, name_len);
	297	buffer[name_len] = '\0';
	298
	299	size_left -= name_len + 1;
	300	buffer += name_len + 1;
2e6a0035 LZ	301	next:
2e6a0035 LZ	302	path->slots[0]++;
5103e947 JB	303	}
	304	ret = total_size;
	305
	306	err:
5103e947 JB	307	btrfs_free_path(path);
	308
	309	return ret;
	310	}
	311
5103e947	312	/*
95819c05 CH	313	* List of handlers for synthetic system.* attributes. All real ondisk
	314	* attributes are handled directly.
	315	*/
f01cbd3f	316	const struct xattr_handler *btrfs_xattr_handlers[] = {
0eda294d	317	#ifdef CONFIG_BTRFS_FS_POSIX_ACL
996a710d CH	318	&posix_acl_access_xattr_handler,
996a710d CH	319	&posix_acl_default_xattr_handler,
95819c05 CH	320	#endif
	321	NULL,
	322	};
	323
	324	/*
	325	* Check if the attribute is in a supported namespace.
	326	*
	327	* This applied after the check for the synthetic attributes in the system
	328	* namespace.
5103e947	329	*/
95819c05 CH	330	static bool btrfs_is_valid_xattr(const char *name)
95819c05 CH	331	{
d397712b CM	332	return !strncmp(name, XATTR_SECURITY_PREFIX,
d397712b CM	333	XATTR_SECURITY_PREFIX_LEN) \|\|
95819c05 CH	334	!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) \|\|
95819c05 CH	335	!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) \|\|
63541927 FDBM	336	!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN) \|\|
63541927 FDBM	337	!strncmp(name, XATTR_BTRFS_PREFIX, XATTR_BTRFS_PREFIX_LEN);
69a32ac5 CM	338	}
69a32ac5 CM	339
95819c05 CH	340	ssize_t btrfs_getxattr(struct dentry dentry, const char name,
	341	void *buffer, size_t size)
	342	{
	343	/*
	344	* If this is a request for a synthetic attribute in the system.*
	345	* namespace use the generic infrastructure to resolve a handler
	346	* for it via sb->s_xattr.
	347	*/
	348	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
	349	return generic_getxattr(dentry, name, buffer, size);
5103e947	350
95819c05 CH	351	if (!btrfs_is_valid_xattr(name))
	352	return -EOPNOTSUPP;
	353	return __btrfs_getxattr(dentry->d_inode, name, buffer, size);
	354	}
5103e947	355
95819c05 CH	356	int btrfs_setxattr(struct dentry dentry, const char name, const void *value,
	357	size_t size, int flags)
	358	{
b83cc969 LZ	359	struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root;
	360
	361	/*
	362	* The permission on security.* and system.* is not checked
	363	* in permission().
	364	*/
	365	if (btrfs_root_readonly(root))
	366	return -EROFS;
	367
95819c05 CH	368	/*
	369	* If this is a request for a synthetic attribute in the system.*
	370	* namespace use the generic infrastructure to resolve a handler
	371	* for it via sb->s_xattr.
	372	*/
	373	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
	374	return generic_setxattr(dentry, name, value, size, flags);
5103e947	375
95819c05 CH	376	if (!btrfs_is_valid_xattr(name))
95819c05 CH	377	return -EOPNOTSUPP;
5103e947	378
63541927 FDBM	379	if (!strncmp(name, XATTR_BTRFS_PREFIX, XATTR_BTRFS_PREFIX_LEN))
	380	return btrfs_set_prop(dentry->d_inode, name,
	381	value, size, flags);
	382
95819c05 CH	383	if (size == 0)
95819c05 CH	384	value = ""; /* empty EA, do not remove */
f34f57a3 YZ	385
	386	return __btrfs_setxattr(NULL, dentry->d_inode, name, value, size,
	387	flags);
95819c05 CH	388	}
	389
	390	int btrfs_removexattr(struct dentry dentry, const char name)
	391	{
b83cc969 LZ	392	struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root;
	393
	394	/*
	395	* The permission on security.* and system.* is not checked
	396	* in permission().
	397	*/
	398	if (btrfs_root_readonly(root))
	399	return -EROFS;
	400
95819c05 CH	401	/*
	402	* If this is a request for a synthetic attribute in the system.*
	403	* namespace use the generic infrastructure to resolve a handler
	404	* for it via sb->s_xattr.
	405	*/
	406	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
	407	return generic_removexattr(dentry, name);
	408
	409	if (!btrfs_is_valid_xattr(name))
	410	return -EOPNOTSUPP;
f34f57a3	411
63541927 FDBM	412	if (!strncmp(name, XATTR_BTRFS_PREFIX, XATTR_BTRFS_PREFIX_LEN))
	413	return btrfs_set_prop(dentry->d_inode, name,
	414	NULL, 0, XATTR_REPLACE);
	415
f34f57a3 YZ	416	return __btrfs_setxattr(NULL, dentry->d_inode, name, NULL, 0,
f34f57a3 YZ	417	XATTR_REPLACE);
95819c05	418	}
0279b4cd	419
48a3b636 ES	420	static int btrfs_initxattrs(struct inode *inode,
48a3b636 ES	421	const struct xattr xattr_array, void fs_info)
0279b4cd	422	{
9d8f13ba MZ	423	const struct xattr *xattr;
9d8f13ba MZ	424	struct btrfs_trans_handle *trans = fs_info;
0279b4cd	425	char *name;
9d8f13ba	426	int err = 0;
0279b4cd	427
9d8f13ba MZ	428	for (xattr = xattr_array; xattr->name != NULL; xattr++) {
	429	name = kmalloc(XATTR_SECURITY_PREFIX_LEN +
	430	strlen(xattr->name) + 1, GFP_NOFS);
	431	if (!name) {
	432	err = -ENOMEM;
	433	break;
	434	}
0279b4cd	435	strcpy(name, XATTR_SECURITY_PREFIX);
9d8f13ba MZ	436	strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name);
	437	err = __btrfs_setxattr(trans, inode, name,
	438	xattr->value, xattr->value_len, 0);
0279b4cd	439	kfree(name);
9d8f13ba MZ	440	if (err < 0)
9d8f13ba MZ	441	break;
0279b4cd	442	}
0279b4cd JO	443	return err;
0279b4cd JO	444	}
9d8f13ba MZ	445
	446	int btrfs_xattr_security_init(struct btrfs_trans_handle *trans,
	447	struct inode inode, struct inode dir,
	448	const struct qstr *qstr)
	449	{
	450	return security_inode_init_security(inode, dir, qstr,
	451	&btrfs_initxattrs, trans);
	452	}