[net-next-2.6.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 || IS_ERR(di)) {
		ret = -ENODATA;
		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;
	}
	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;
	ret = 0;
	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);
	48	if (!di \|\| IS_ERR(di)) {
	49	ret = -ENODATA;
	50	goto out;
	51	}
	52
	53	leaf = path->nodes[0];
	54	/* if size is 0, that means we want the size of the attr */
	55	if (!size) {
	56	ret = btrfs_dir_data_len(leaf, di);
	57	goto out;
	58	}
	59
	60	/* now get the data out of our dir_item */
	61	if (btrfs_dir_data_len(leaf, di) > size) {
	62	ret = -ERANGE;
	63	goto out;
	64	}
	65	data_ptr = (unsigned long)((char *)(di + 1) +
	66	btrfs_dir_name_len(leaf, di));
	67	read_extent_buffer(leaf, buffer, data_ptr,
3acd7ee8	68	btrfs_dir_data_len(leaf, di));
5103e947 JB	69	ret = btrfs_dir_data_len(leaf, di);
	70
	71	out:
5103e947 JB	72	btrfs_free_path(path);
	73	return ret;
	74	}
	75
95819c05 CH	76	int __btrfs_setxattr(struct inode inode, const char name,
95819c05 CH	77	const void *value, size_t size, int flags)
5103e947 JB	78	{
	79	struct btrfs_dir_item *di;
	80	struct btrfs_root *root = BTRFS_I(inode)->root;
	81	struct btrfs_trans_handle *trans;
	82	struct btrfs_path *path;
5103e947	83	int ret = 0, mod = 0;
5103e947 JB	84
5103e947 JB	85	path = btrfs_alloc_path();
95819c05	86	if (!path)
5103e947	87	return -ENOMEM;
5103e947	88
5103e947 JB	89	trans = btrfs_start_transaction(root, 1);
	90	btrfs_set_trans_block_group(trans, inode);
	91
	92	/* first lets see if we already have this xattr */
	93	di = btrfs_lookup_xattr(trans, root, path, inode->i_ino, name,
	94	strlen(name), -1);
	95	if (IS_ERR(di)) {
	96	ret = PTR_ERR(di);
	97	goto out;
	98	}
	99
	100	/* ok we already have this xattr, lets remove it */
	101	if (di) {
	102	/* if we want create only exit */
	103	if (flags & XATTR_CREATE) {
	104	ret = -EEXIST;
	105	goto out;
	106	}
	107
	108	ret = btrfs_delete_one_dir_name(trans, root, path, di);
	109	if (ret)
	110	goto out;
	111	btrfs_release_path(root, path);
	112
	113	/* if we don't have a value then we are removing the xattr */
	114	if (!value) {
	115	mod = 1;
	116	goto out;
	117	}
33268eaf JB	118	} else {
	119	btrfs_release_path(root, path);
	120
	121	if (flags & XATTR_REPLACE) {
	122	/* we couldn't find the attr to replace */
	123	ret = -ENODATA;
	124	goto out;
	125	}
5103e947 JB	126	}
	127
	128	/* ok we have to create a completely new xattr */
	129	ret = btrfs_insert_xattr_item(trans, root, name, strlen(name),
	130	value, size, inode->i_ino);
	131	if (ret)
	132	goto out;
	133	mod = 1;
	134
	135	out:
	136	if (mod) {
	137	inode->i_ctime = CURRENT_TIME;
	138	ret = btrfs_update_inode(trans, root, inode);
	139	}
	140
	141	btrfs_end_transaction(trans, root);
5103e947	142	btrfs_free_path(path);
5103e947 JB	143	return ret;
	144	}
	145
	146	ssize_t btrfs_listxattr(struct dentry dentry, char buffer, size_t size)
	147	{
	148	struct btrfs_key key, found_key;
	149	struct inode *inode = dentry->d_inode;
	150	struct btrfs_root *root = BTRFS_I(inode)->root;
	151	struct btrfs_path *path;
	152	struct btrfs_item *item;
	153	struct extent_buffer *leaf;
	154	struct btrfs_dir_item *di;
5103e947	155	int ret = 0, slot, advance;
eaa47d86	156	size_t total_size = 0, size_left = size;
5103e947	157	unsigned long name_ptr;
eaa47d86	158	size_t name_len;
5103e947 JB	159	u32 nritems;
	160
	161	/*
	162	* ok we want all objects associated with this id.
	163	* NOTE: we set key.offset = 0; because we want to start with the
	164	* first xattr that we find and walk forward
	165	*/
	166	key.objectid = inode->i_ino;
	167	btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
	168	key.offset = 0;
	169
	170	path = btrfs_alloc_path();
5103e947 JB	171	if (!path)
5103e947 JB	172	return -ENOMEM;
1caf9342	173	path->reada = 2;
5103e947	174
5103e947 JB	175	/* search for our xattrs */
	176	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
	177	if (ret < 0)
	178	goto err;
	179	ret = 0;
	180	advance = 0;
	181	while (1) {
	182	leaf = path->nodes[0];
	183	nritems = btrfs_header_nritems(leaf);
	184	slot = path->slots[0];
	185
	186	/* this is where we start walking through the path */
	187	if (advance \|\| slot >= nritems) {
	188	/*
	189	* if we've reached the last slot in this leaf we need
	190	* to go to the next leaf and reset everything
	191	*/
	192	if (slot >= nritems-1) {
	193	ret = btrfs_next_leaf(root, path);
	194	if (ret)
	195	break;
	196	leaf = path->nodes[0];
	197	nritems = btrfs_header_nritems(leaf);
	198	slot = path->slots[0];
	199	} else {
	200	/*
	201	* just walking through the slots on this leaf
	202	*/
	203	slot++;
	204	path->slots[0]++;
	205	}
	206	}
	207	advance = 1;
	208
	209	item = btrfs_item_nr(leaf, slot);
	210	btrfs_item_key_to_cpu(leaf, &found_key, slot);
	211
	212	/* check to make sure this item is what we want */
	213	if (found_key.objectid != key.objectid)
	214	break;
	215	if (btrfs_key_type(&found_key) != BTRFS_XATTR_ITEM_KEY)
	216	break;
	217
	218	di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
	219
eaa47d86 CH	220	name_len = btrfs_dir_name_len(leaf, di);
eaa47d86 CH	221	total_size += name_len + 1;
5103e947 JB	222
	223	/* we are just looking for how big our buffer needs to be */
	224	if (!size)
	225	continue;
	226
eaa47d86	227	if (!buffer \|\| (name_len + 1) > size_left) {
5103e947	228	ret = -ERANGE;
b16281c3	229	goto err;
5103e947 JB	230	}
5103e947 JB	231
eaa47d86 CH	232	name_ptr = (unsigned long)(di + 1);
	233	read_extent_buffer(leaf, buffer, name_ptr, name_len);
	234	buffer[name_len] = '\0';
	235
	236	size_left -= name_len + 1;
	237	buffer += name_len + 1;
5103e947 JB	238	}
	239	ret = total_size;
	240
	241	err:
5103e947 JB	242	btrfs_free_path(path);
	243
	244	return ret;
	245	}
	246
5103e947	247	/*
95819c05 CH	248	* List of handlers for synthetic system.* attributes. All real ondisk
	249	* attributes are handled directly.
	250	*/
	251	struct xattr_handler *btrfs_xattr_handlers[] = {
	252	#ifdef CONFIG_FS_POSIX_ACL
	253	&btrfs_xattr_acl_access_handler,
	254	&btrfs_xattr_acl_default_handler,
	255	#endif
	256	NULL,
	257	};
	258
	259	/*
	260	* Check if the attribute is in a supported namespace.
	261	*
	262	* This applied after the check for the synthetic attributes in the system
	263	* namespace.
5103e947	264	*/
95819c05 CH	265	static bool btrfs_is_valid_xattr(const char *name)
	266	{
	267	return !strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) \|\|
	268	!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) \|\|
	269	!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) \|\|
	270	!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN);
69a32ac5 CM	271	}
69a32ac5 CM	272
95819c05 CH	273	ssize_t btrfs_getxattr(struct dentry dentry, const char name,
	274	void *buffer, size_t size)
	275	{
	276	/*
	277	* If this is a request for a synthetic attribute in the system.*
	278	* namespace use the generic infrastructure to resolve a handler
	279	* for it via sb->s_xattr.
	280	*/
	281	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
	282	return generic_getxattr(dentry, name, buffer, size);
5103e947	283
95819c05 CH	284	if (!btrfs_is_valid_xattr(name))
	285	return -EOPNOTSUPP;
	286	return __btrfs_getxattr(dentry->d_inode, name, buffer, size);
	287	}
5103e947	288
95819c05 CH	289	int btrfs_setxattr(struct dentry dentry, const char name, const void *value,
	290	size_t size, int flags)
	291	{
	292	/*
	293	* If this is a request for a synthetic attribute in the system.*
	294	* namespace use the generic infrastructure to resolve a handler
	295	* for it via sb->s_xattr.
	296	*/
	297	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
	298	return generic_setxattr(dentry, name, value, size, flags);
5103e947	299
95819c05 CH	300	if (!btrfs_is_valid_xattr(name))
95819c05 CH	301	return -EOPNOTSUPP;
5103e947	302
95819c05 CH	303	if (size == 0)
	304	value = ""; /* empty EA, do not remove */
	305	return __btrfs_setxattr(dentry->d_inode, name, value, size, flags);
	306	}
	307
	308	int btrfs_removexattr(struct dentry dentry, const char name)
	309	{
	310	/*
	311	* If this is a request for a synthetic attribute in the system.*
	312	* namespace use the generic infrastructure to resolve a handler
	313	* for it via sb->s_xattr.
	314	*/
	315	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
	316	return generic_removexattr(dentry, name);
	317
	318	if (!btrfs_is_valid_xattr(name))
	319	return -EOPNOTSUPP;
	320	return __btrfs_setxattr(dentry->d_inode, name, NULL, 0, XATTR_REPLACE);
	321	}