[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 "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, inode->i_ino, 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;
}

int __btrfs_setxattr(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_trans_handle *trans;
	struct btrfs_path *path;
	int ret = 0, mod = 0;

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

	trans = btrfs_start_transaction(root, 1);
	btrfs_set_trans_block_group(trans, inode);

	/* first lets see if we already have this xattr */
	di = btrfs_lookup_xattr(trans, root, path, inode->i_ino, name,
				strlen(name), -1);
	if (IS_ERR(di)) {
		ret = PTR_ERR(di);
		goto out;
	}

	/* ok we already have this xattr, lets remove it */
	if (di) {
		/* if we want create only exit */
		if (flags & XATTR_CREATE) {
			ret = -EEXIST;
			goto out;
		}

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

		/* if we don't have a value then we are removing the xattr */
		if (!value) {
			mod = 1;
			goto out;
		}
	} else {
		btrfs_release_path(root, path);

		if (flags & XATTR_REPLACE) {
			/* we couldn't find the attr to replace */
			ret = -ENODATA;
			goto out;
		}
	}

	/* ok we have to create a completely new xattr */
	ret = btrfs_insert_xattr_item(trans, root, name, strlen(name),
				      value, size, inode->i_ino);
	if (ret)
		goto out;
	mod = 1;

out:
	if (mod) {
		inode->i_ctime = CURRENT_TIME;
		ret = btrfs_update_inode(trans, root, inode);
	}

	btrfs_end_transaction(trans, root);
	btrfs_free_path(path);
	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 btrfs_item *item;
	struct extent_buffer *leaf;
	struct btrfs_dir_item *di;
	int ret = 0, slot, advance;
	size_t total_size = 0, size_left = size;
	unsigned long name_ptr;
	size_t name_len;
	u32 nritems;

	/*
	 * 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 = inode->i_ino;
	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;
	advance = 0;
	while (1) {
		leaf = path->nodes[0];
		nritems = btrfs_header_nritems(leaf);
		slot = path->slots[0];

		/* this is where we start walking through the path */
		if (advance || slot >= nritems) {
			/*
			 * if we've reached the last slot in this leaf we need
			 * to go to the next leaf and reset everything
			 */
			if (slot >= nritems-1) {
				ret = btrfs_next_leaf(root, path);
				if (ret)
					break;
				leaf = path->nodes[0];
				nritems = btrfs_header_nritems(leaf);
				slot = path->slots[0];
			} else {
				/*
				 * just walking through the slots on this leaf
				 */
				slot++;
				path->slots[0]++;
			}
		}
		advance = 1;

		item = btrfs_item_nr(leaf, slot);
		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);

		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)
			continue;

		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;
	}
	ret = total_size;

err:
	btrfs_free_path(path);

	return ret;
}

/*
 * List of handlers for synthetic system.* attributes.  All real ondisk
 * attributes are handled directly.
 */
struct xattr_handler *btrfs_xattr_handlers[] = {
#ifdef CONFIG_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)
{
	/*
	 * 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(dentry->d_inode, name, value, size, flags);
}

int btrfs_removexattr(struct dentry *dentry, const char *name)
{
	/*
	 * 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(dentry->d_inode, name, NULL, 0, XATTR_REPLACE);
}
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>
	24	#include "ctree.h"
	25	#include "btrfs_inode.h"
	26	#include "transaction.h"
	27	#include "xattr.h"
	28	#include "disk-io.h"
33268eaf	29
5103e947	30
95819c05 CH	31	ssize_t __btrfs_getxattr(struct inode inode, const char name,
95819c05 CH	32	void *buffer, size_t size)
5103e947 JB	33	{
	34	struct btrfs_dir_item *di;
	35	struct btrfs_root *root = BTRFS_I(inode)->root;
	36	struct btrfs_path *path;
	37	struct extent_buffer *leaf;
5103e947 JB	38	int ret = 0;
5103e947 JB	39	unsigned long data_ptr;
5103e947 JB	40
5103e947 JB	41	path = btrfs_alloc_path();
95819c05	42	if (!path)
5103e947	43	return -ENOMEM;
5103e947	44
5103e947 JB	45	/* lookup the xattr by name */
	46	di = btrfs_lookup_xattr(NULL, root, path, inode->i_ino, name,
	47	strlen(name), 0);
07060404	48	if (!di) {
5103e947 JB	49	ret = -ENODATA;
5103e947 JB	50	goto out;
07060404 JB	51	} else if (IS_ERR(di)) {
	52	ret = PTR_ERR(di);
	53	goto out;
5103e947 JB	54	}
	55
	56	leaf = path->nodes[0];
	57	/* if size is 0, that means we want the size of the attr */
	58	if (!size) {
	59	ret = btrfs_dir_data_len(leaf, di);
	60	goto out;
	61	}
	62
	63	/* now get the data out of our dir_item */
	64	if (btrfs_dir_data_len(leaf, di) > size) {
	65	ret = -ERANGE;
	66	goto out;
	67	}
07060404 JB	68
	69	/*
	70	* The way things are packed into the leaf is like this
	71	* \|struct btrfs_dir_item\|name\|data\|
	72	* where name is the xattr name, so security.foo, and data is the
	73	* content of the xattr. data_ptr points to the location in memory
	74	* where the data starts in the in memory leaf
	75	*/
5103e947 JB	76	data_ptr = (unsigned long)((char *)(di + 1) +
	77	btrfs_dir_name_len(leaf, di));
	78	read_extent_buffer(leaf, buffer, data_ptr,
3acd7ee8	79	btrfs_dir_data_len(leaf, di));
5103e947 JB	80	ret = btrfs_dir_data_len(leaf, di);
	81
	82	out:
5103e947 JB	83	btrfs_free_path(path);
	84	return ret;
	85	}
	86
95819c05 CH	87	int __btrfs_setxattr(struct inode inode, const char name,
95819c05 CH	88	const void *value, size_t size, int flags)
5103e947 JB	89	{
	90	struct btrfs_dir_item *di;
	91	struct btrfs_root *root = BTRFS_I(inode)->root;
	92	struct btrfs_trans_handle *trans;
	93	struct btrfs_path *path;
5103e947	94	int ret = 0, mod = 0;
5103e947 JB	95
5103e947 JB	96	path = btrfs_alloc_path();
95819c05	97	if (!path)
5103e947	98	return -ENOMEM;
5103e947	99
5103e947 JB	100	trans = btrfs_start_transaction(root, 1);
	101	btrfs_set_trans_block_group(trans, inode);
	102
	103	/* first lets see if we already have this xattr */
	104	di = btrfs_lookup_xattr(trans, root, path, inode->i_ino, name,
	105	strlen(name), -1);
	106	if (IS_ERR(di)) {
	107	ret = PTR_ERR(di);
	108	goto out;
	109	}
	110
	111	/* ok we already have this xattr, lets remove it */
	112	if (di) {
	113	/* if we want create only exit */
	114	if (flags & XATTR_CREATE) {
	115	ret = -EEXIST;
	116	goto out;
	117	}
	118
	119	ret = btrfs_delete_one_dir_name(trans, root, path, di);
	120	if (ret)
	121	goto out;
	122	btrfs_release_path(root, path);
	123
	124	/* if we don't have a value then we are removing the xattr */
	125	if (!value) {
	126	mod = 1;
	127	goto out;
	128	}
33268eaf JB	129	} else {
	130	btrfs_release_path(root, path);
	131
	132	if (flags & XATTR_REPLACE) {
	133	/* we couldn't find the attr to replace */
	134	ret = -ENODATA;
	135	goto out;
	136	}
5103e947 JB	137	}
	138
	139	/* ok we have to create a completely new xattr */
	140	ret = btrfs_insert_xattr_item(trans, root, name, strlen(name),
	141	value, size, inode->i_ino);
	142	if (ret)
	143	goto out;
	144	mod = 1;
	145
	146	out:
	147	if (mod) {
	148	inode->i_ctime = CURRENT_TIME;
	149	ret = btrfs_update_inode(trans, root, inode);
	150	}
	151
	152	btrfs_end_transaction(trans, root);
5103e947	153	btrfs_free_path(path);
5103e947 JB	154	return ret;
	155	}
	156
	157	ssize_t btrfs_listxattr(struct dentry dentry, char buffer, size_t size)
	158	{
	159	struct btrfs_key key, found_key;
	160	struct inode *inode = dentry->d_inode;
	161	struct btrfs_root *root = BTRFS_I(inode)->root;
	162	struct btrfs_path *path;
	163	struct btrfs_item *item;
	164	struct extent_buffer *leaf;
	165	struct btrfs_dir_item *di;
5103e947	166	int ret = 0, slot, advance;
eaa47d86	167	size_t total_size = 0, size_left = size;
5103e947	168	unsigned long name_ptr;
eaa47d86	169	size_t name_len;
5103e947 JB	170	u32 nritems;
	171
	172	/*
	173	* ok we want all objects associated with this id.
	174	* NOTE: we set key.offset = 0; because we want to start with the
	175	* first xattr that we find and walk forward
	176	*/
	177	key.objectid = inode->i_ino;
	178	btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
	179	key.offset = 0;
	180
	181	path = btrfs_alloc_path();
5103e947 JB	182	if (!path)
5103e947 JB	183	return -ENOMEM;
1caf9342	184	path->reada = 2;
5103e947	185
5103e947 JB	186	/* search for our xattrs */
	187	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
	188	if (ret < 0)
	189	goto err;
5103e947 JB	190	advance = 0;
	191	while (1) {
	192	leaf = path->nodes[0];
	193	nritems = btrfs_header_nritems(leaf);
	194	slot = path->slots[0];
	195
	196	/* this is where we start walking through the path */
	197	if (advance \|\| slot >= nritems) {
	198	/*
	199	* if we've reached the last slot in this leaf we need
	200	* to go to the next leaf and reset everything
	201	*/
	202	if (slot >= nritems-1) {
	203	ret = btrfs_next_leaf(root, path);
	204	if (ret)
	205	break;
	206	leaf = path->nodes[0];
	207	nritems = btrfs_header_nritems(leaf);
	208	slot = path->slots[0];
	209	} else {
	210	/*
	211	* just walking through the slots on this leaf
	212	*/
	213	slot++;
	214	path->slots[0]++;
	215	}
	216	}
	217	advance = 1;
	218
	219	item = btrfs_item_nr(leaf, slot);
	220	btrfs_item_key_to_cpu(leaf, &found_key, slot);
	221
	222	/* check to make sure this item is what we want */
	223	if (found_key.objectid != key.objectid)
	224	break;
	225	if (btrfs_key_type(&found_key) != BTRFS_XATTR_ITEM_KEY)
	226	break;
	227
	228	di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
	229
eaa47d86 CH	230	name_len = btrfs_dir_name_len(leaf, di);
eaa47d86 CH	231	total_size += name_len + 1;
5103e947 JB	232
	233	/* we are just looking for how big our buffer needs to be */
	234	if (!size)
	235	continue;
	236
eaa47d86	237	if (!buffer \|\| (name_len + 1) > size_left) {
5103e947	238	ret = -ERANGE;
b16281c3	239	goto err;
5103e947 JB	240	}
5103e947 JB	241
eaa47d86 CH	242	name_ptr = (unsigned long)(di + 1);
	243	read_extent_buffer(leaf, buffer, name_ptr, name_len);
	244	buffer[name_len] = '\0';
	245
	246	size_left -= name_len + 1;
	247	buffer += name_len + 1;
5103e947 JB	248	}
	249	ret = total_size;
	250
	251	err:
5103e947 JB	252	btrfs_free_path(path);
	253
	254	return ret;
	255	}
	256
5103e947	257	/*
95819c05 CH	258	* List of handlers for synthetic system.* attributes. All real ondisk
	259	* attributes are handled directly.
	260	*/
	261	struct xattr_handler *btrfs_xattr_handlers[] = {
	262	#ifdef CONFIG_FS_POSIX_ACL
	263	&btrfs_xattr_acl_access_handler,
	264	&btrfs_xattr_acl_default_handler,
	265	#endif
	266	NULL,
	267	};
	268
	269	/*
	270	* Check if the attribute is in a supported namespace.
	271	*
	272	* This applied after the check for the synthetic attributes in the system
	273	* namespace.
5103e947	274	*/
95819c05 CH	275	static bool btrfs_is_valid_xattr(const char *name)
95819c05 CH	276	{
d397712b CM	277	return !strncmp(name, XATTR_SECURITY_PREFIX,
d397712b CM	278	XATTR_SECURITY_PREFIX_LEN) \|\|
95819c05 CH	279	!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) \|\|
	280	!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) \|\|
	281	!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN);
69a32ac5 CM	282	}
69a32ac5 CM	283
95819c05 CH	284	ssize_t btrfs_getxattr(struct dentry dentry, const char name,
	285	void *buffer, size_t size)
	286	{
	287	/*
	288	* If this is a request for a synthetic attribute in the system.*
	289	* namespace use the generic infrastructure to resolve a handler
	290	* for it via sb->s_xattr.
	291	*/
	292	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
	293	return generic_getxattr(dentry, name, buffer, size);
5103e947	294
95819c05 CH	295	if (!btrfs_is_valid_xattr(name))
	296	return -EOPNOTSUPP;
	297	return __btrfs_getxattr(dentry->d_inode, name, buffer, size);
	298	}
5103e947	299
95819c05 CH	300	int btrfs_setxattr(struct dentry dentry, const char name, const void *value,
	301	size_t size, int flags)
	302	{
	303	/*
	304	* If this is a request for a synthetic attribute in the system.*
	305	* namespace use the generic infrastructure to resolve a handler
	306	* for it via sb->s_xattr.
	307	*/
	308	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
	309	return generic_setxattr(dentry, name, value, size, flags);
5103e947	310
95819c05 CH	311	if (!btrfs_is_valid_xattr(name))
95819c05 CH	312	return -EOPNOTSUPP;
5103e947	313
95819c05 CH	314	if (size == 0)
	315	value = ""; /* empty EA, do not remove */
	316	return __btrfs_setxattr(dentry->d_inode, name, value, size, flags);
	317	}
	318
	319	int btrfs_removexattr(struct dentry dentry, const char name)
	320	{
	321	/*
	322	* If this is a request for a synthetic attribute in the system.*
	323	* namespace use the generic infrastructure to resolve a handler
	324	* for it via sb->s_xattr.
	325	*/
	326	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
	327	return generic_removexattr(dentry, name);
	328
	329	if (!btrfs_is_valid_xattr(name))
	330	return -EOPNOTSUPP;
	331	return __btrfs_setxattr(dentry->d_inode, name, NULL, 0, XATTR_REPLACE);
	332	}