[linux-2.6-block.git] / fs / btrfs / props.c

/*
 * Copyright (C) 2014 Filipe David Borba Manana <fdmanana@gmail.com>
 *
 * 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/hashtable.h>
#include "props.h"
#include "btrfs_inode.h"
#include "hash.h"
#include "transaction.h"
#include "xattr.h"

#define BTRFS_PROP_HANDLERS_HT_BITS 8
static DEFINE_HASHTABLE(prop_handlers_ht, BTRFS_PROP_HANDLERS_HT_BITS);

struct prop_handler {
	struct hlist_node node;
	const char *xattr_name;
	int (*validate)(const char *value, size_t len);
	int (*apply)(struct inode *inode, const char *value, size_t len);
	const char *(*extract)(struct inode *inode);
	int inheritable;
};

static int prop_compression_validate(const char *value, size_t len);
static int prop_compression_apply(struct inode *inode,
				  const char *value,
				  size_t len);
static const char *prop_compression_extract(struct inode *inode);

static struct prop_handler prop_handlers[] = {
	{
		.xattr_name = XATTR_BTRFS_PREFIX "compression",
		.validate = prop_compression_validate,
		.apply = prop_compression_apply,
		.extract = prop_compression_extract,
		.inheritable = 1
	},
};

void __init btrfs_props_init(void)
{
	int i;

	hash_init(prop_handlers_ht);

	for (i = 0; i < ARRAY_SIZE(prop_handlers); i++) {
		struct prop_handler *p = &prop_handlers[i];
		u64 h = btrfs_name_hash(p->xattr_name, strlen(p->xattr_name));

		hash_add(prop_handlers_ht, &p->node, h);
	}
}

static const struct hlist_head *find_prop_handlers_by_hash(const u64 hash)
{
	struct hlist_head *h;

	h = &prop_handlers_ht[hash_min(hash, BTRFS_PROP_HANDLERS_HT_BITS)];
	if (hlist_empty(h))
		return NULL;

	return h;
}

static const struct prop_handler *
find_prop_handler(const char *name,
		  const struct hlist_head *handlers)
{
	struct prop_handler *h;

	if (!handlers) {
		u64 hash = btrfs_name_hash(name, strlen(name));

		handlers = find_prop_handlers_by_hash(hash);
		if (!handlers)
			return NULL;
	}

	hlist_for_each_entry(h, handlers, node)
		if (!strcmp(h->xattr_name, name))
			return h;

	return NULL;
}

static int __btrfs_set_prop(struct btrfs_trans_handle *trans,
			    struct inode *inode,
			    const char *name,
			    const char *value,
			    size_t value_len,
			    int flags)
{
	const struct prop_handler *handler;
	int ret;

	if (strlen(name) <= XATTR_BTRFS_PREFIX_LEN)
		return -EINVAL;

	handler = find_prop_handler(name, NULL);
	if (!handler)
		return -EINVAL;

	if (value_len == 0) {
		ret = __btrfs_setxattr(trans, inode, handler->xattr_name,
				       NULL, 0, flags);
		if (ret)
			return ret;

		ret = handler->apply(inode, NULL, 0);
		ASSERT(ret == 0);

		return ret;
	}

	ret = handler->validate(value, value_len);
	if (ret)
		return ret;
	ret = __btrfs_setxattr(trans, inode, handler->xattr_name,
			       value, value_len, flags);
	if (ret)
		return ret;
	ret = handler->apply(inode, value, value_len);
	if (ret) {
		__btrfs_setxattr(trans, inode, handler->xattr_name,
				 NULL, 0, flags);
		return ret;
	}

	set_bit(BTRFS_INODE_HAS_PROPS, &BTRFS_I(inode)->runtime_flags);

	return 0;
}

int btrfs_set_prop(struct inode *inode,
		   const char *name,
		   const char *value,
		   size_t value_len,
		   int flags)
{
	return __btrfs_set_prop(NULL, inode, name, value, value_len, flags);
}

static int iterate_object_props(struct btrfs_root *root,
				struct btrfs_path *path,
				u64 objectid,
				void (*iterator)(void *,
						 const struct prop_handler *,
						 const char *,
						 size_t),
				void *ctx)
{
	int ret;
	char *name_buf = NULL;
	char *value_buf = NULL;
	int name_buf_len = 0;
	int value_buf_len = 0;

	while (1) {
		struct btrfs_key key;
		struct btrfs_dir_item *di;
		struct extent_buffer *leaf;
		u32 total_len, cur, this_len;
		int slot;
		const struct hlist_head *handlers;

		slot = path->slots[0];
		leaf = path->nodes[0];

		if (slot >= btrfs_header_nritems(leaf)) {
			ret = btrfs_next_leaf(root, path);
			if (ret < 0)
				goto out;
			else if (ret > 0)
				break;
			continue;
		}

		btrfs_item_key_to_cpu(leaf, &key, slot);
		if (key.objectid != objectid)
			break;
		if (key.type != BTRFS_XATTR_ITEM_KEY)
			break;

		handlers = find_prop_handlers_by_hash(key.offset);
		if (!handlers)
			goto next_slot;

		di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
		cur = 0;
		total_len = btrfs_item_size_nr(leaf, slot);

		while (cur < total_len) {
			u32 name_len = btrfs_dir_name_len(leaf, di);
			u32 data_len = btrfs_dir_data_len(leaf, di);
			unsigned long name_ptr, data_ptr;
			const struct prop_handler *handler;

			this_len = sizeof(*di) + name_len + data_len;
			name_ptr = (unsigned long)(di + 1);
			data_ptr = name_ptr + name_len;

			if (name_len <= XATTR_BTRFS_PREFIX_LEN ||
			    memcmp_extent_buffer(leaf, XATTR_BTRFS_PREFIX,
						 name_ptr,
						 XATTR_BTRFS_PREFIX_LEN))
				goto next_dir_item;

			if (name_len >= name_buf_len) {
				kfree(name_buf);
				name_buf_len = name_len + 1;
				name_buf = kmalloc(name_buf_len, GFP_NOFS);
				if (!name_buf) {
					ret = -ENOMEM;
					goto out;
				}
			}
			read_extent_buffer(leaf, name_buf, name_ptr, name_len);
			name_buf[name_len] = '\0';

			handler = find_prop_handler(name_buf, handlers);
			if (!handler)
				goto next_dir_item;

			if (data_len > value_buf_len) {
				kfree(value_buf);
				value_buf_len = data_len;
				value_buf = kmalloc(data_len, GFP_NOFS);
				if (!value_buf) {
					ret = -ENOMEM;
					goto out;
				}
			}
			read_extent_buffer(leaf, value_buf, data_ptr, data_len);

			iterator(ctx, handler, value_buf, data_len);
next_dir_item:
			cur += this_len;
			di = (struct btrfs_dir_item *)((char *) di + this_len);
		}

next_slot:
		path->slots[0]++;
	}

	ret = 0;
out:
	btrfs_release_path(path);
	kfree(name_buf);
	kfree(value_buf);

	return ret;
}

static void inode_prop_iterator(void *ctx,
				const struct prop_handler *handler,
				const char *value,
				size_t len)
{
	struct inode *inode = ctx;
	struct btrfs_root *root = BTRFS_I(inode)->root;
	int ret;

	ret = handler->apply(inode, value, len);
	if (unlikely(ret))
		btrfs_warn(root->fs_info,
			   "error applying prop %s to ino %llu (root %llu): %d",
			   handler->xattr_name, btrfs_ino(inode),
			   root->root_key.objectid, ret);
	else
		set_bit(BTRFS_INODE_HAS_PROPS, &BTRFS_I(inode)->runtime_flags);
}

int btrfs_load_inode_props(struct inode *inode, struct btrfs_path *path)
{
	struct btrfs_root *root = BTRFS_I(inode)->root;
	u64 ino = btrfs_ino(inode);
	int ret;

	ret = iterate_object_props(root, path, ino, inode_prop_iterator, inode);

	return ret;
}

static int inherit_props(struct btrfs_trans_handle *trans,
			 struct inode *inode,
			 struct inode *parent)
{
	struct btrfs_root *root = BTRFS_I(inode)->root;
	int ret;
	int i;

	if (!test_bit(BTRFS_INODE_HAS_PROPS,
		      &BTRFS_I(parent)->runtime_flags))
		return 0;

	for (i = 0; i < ARRAY_SIZE(prop_handlers); i++) {
		const struct prop_handler *h = &prop_handlers[i];
		const char *value;
		u64 num_bytes;

		if (!h->inheritable)
			continue;

		value = h->extract(parent);
		if (!value)
			continue;

		num_bytes = btrfs_calc_trans_metadata_size(root, 1);
		ret = btrfs_block_rsv_add(root, trans->block_rsv,
					  num_bytes, BTRFS_RESERVE_NO_FLUSH);
		if (ret)
			goto out;
		ret = __btrfs_set_prop(trans, inode, h->xattr_name,
				       value, strlen(value), 0);
		btrfs_block_rsv_release(root, trans->block_rsv, num_bytes);
		if (ret)
			goto out;
	}
	ret = 0;
out:
	return ret;
}

int btrfs_inode_inherit_props(struct btrfs_trans_handle *trans,
			      struct inode *inode,
			      struct inode *dir)
{
	if (!dir)
		return 0;

	return inherit_props(trans, inode, dir);
}

int btrfs_subvol_inherit_props(struct btrfs_trans_handle *trans,
			       struct btrfs_root *root,
			       struct btrfs_root *parent_root)
{
	struct btrfs_key key;
	struct inode *parent_inode, *child_inode;
	int ret;

	key.objectid = BTRFS_FIRST_FREE_OBJECTID;
	key.type = BTRFS_INODE_ITEM_KEY;
	key.offset = 0;

	parent_inode = btrfs_iget(parent_root->fs_info->sb, &key,
				  parent_root, NULL);
	if (IS_ERR(parent_inode))
		return PTR_ERR(parent_inode);

	child_inode = btrfs_iget(root->fs_info->sb, &key, root, NULL);
	if (IS_ERR(child_inode)) {
		iput(parent_inode);
		return PTR_ERR(child_inode);
	}

	ret = inherit_props(trans, child_inode, parent_inode);
	iput(child_inode);
	iput(parent_inode);

	return ret;
}

static int prop_compression_validate(const char *value, size_t len)
{
	if (!strncmp("lzo", value, len))
		return 0;
	else if (!strncmp("zlib", value, len))
		return 0;

	return -EINVAL;
}

static int prop_compression_apply(struct inode *inode,
				  const char *value,
				  size_t len)
{
	int type;

	if (len == 0) {
		BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
		BTRFS_I(inode)->flags &= ~BTRFS_INODE_COMPRESS;
		BTRFS_I(inode)->force_compress = BTRFS_COMPRESS_NONE;

		return 0;
	}

	if (!strncmp("lzo", value, len))
		type = BTRFS_COMPRESS_LZO;
	else if (!strncmp("zlib", value, len))
		type = BTRFS_COMPRESS_ZLIB;
	else
		return -EINVAL;

	BTRFS_I(inode)->flags &= ~BTRFS_INODE_NOCOMPRESS;
	BTRFS_I(inode)->flags |= BTRFS_INODE_COMPRESS;
	BTRFS_I(inode)->force_compress = type;

	return 0;
}

static const char *prop_compression_extract(struct inode *inode)
{
	switch (BTRFS_I(inode)->force_compress) {
	case BTRFS_COMPRESS_ZLIB:
		return "zlib";
	case BTRFS_COMPRESS_LZO:
		return "lzo";
	}

	return NULL;
}
Commit	Line	Data
63541927 FDBM	1	/*
	2	* Copyright (C) 2014 Filipe David Borba Manana <fdmanana@gmail.com>
	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/hashtable.h>
	20	#include "props.h"
	21	#include "btrfs_inode.h"
	22	#include "hash.h"
	23	#include "transaction.h"
	24	#include "xattr.h"
	25
	26	#define BTRFS_PROP_HANDLERS_HT_BITS 8
	27	static DEFINE_HASHTABLE(prop_handlers_ht, BTRFS_PROP_HANDLERS_HT_BITS);
	28
	29	struct prop_handler {
	30	struct hlist_node node;
	31	const char *xattr_name;
	32	int (validate)(const char value, size_t len);
	33	int (apply)(struct inode inode, const char *value, size_t len);
	34	const char (extract)(struct inode *inode);
	35	int inheritable;
	36	};
	37
	38	static int prop_compression_validate(const char *value, size_t len);
	39	static int prop_compression_apply(struct inode *inode,
	40	const char *value,
	41	size_t len);
	42	static const char prop_compression_extract(struct inode inode);
	43
	44	static struct prop_handler prop_handlers[] = {
	45	{
	46	.xattr_name = XATTR_BTRFS_PREFIX "compression",
	47	.validate = prop_compression_validate,
	48	.apply = prop_compression_apply,
	49	.extract = prop_compression_extract,
	50	.inheritable = 1
	51	},
63541927 FDBM	52	};
	53
	54	void __init btrfs_props_init(void)
	55	{
619ed392	56	int i;
63541927 FDBM	57
	58	hash_init(prop_handlers_ht);
	59
619ed392 BL	60	for (i = 0; i < ARRAY_SIZE(prop_handlers); i++) {
619ed392 BL	61	struct prop_handler *p = &prop_handlers[i];
63541927 FDBM	62	u64 h = btrfs_name_hash(p->xattr_name, strlen(p->xattr_name));
	63
	64	hash_add(prop_handlers_ht, &p->node, h);
	65	}
	66	}
	67
	68	static const struct hlist_head *find_prop_handlers_by_hash(const u64 hash)
	69	{
	70	struct hlist_head *h;
	71
	72	h = &prop_handlers_ht[hash_min(hash, BTRFS_PROP_HANDLERS_HT_BITS)];
	73	if (hlist_empty(h))
	74	return NULL;
	75
	76	return h;
	77	}
	78
	79	static const struct prop_handler *
	80	find_prop_handler(const char *name,
	81	const struct hlist_head *handlers)
	82	{
	83	struct prop_handler *h;
	84
	85	if (!handlers) {
	86	u64 hash = btrfs_name_hash(name, strlen(name));
	87
	88	handlers = find_prop_handlers_by_hash(hash);
	89	if (!handlers)
	90	return NULL;
	91	}
	92
	93	hlist_for_each_entry(h, handlers, node)
	94	if (!strcmp(h->xattr_name, name))
	95	return h;
	96
	97	return NULL;
	98	}
	99
	100	static int __btrfs_set_prop(struct btrfs_trans_handle *trans,
	101	struct inode *inode,
	102	const char *name,
	103	const char *value,
	104	size_t value_len,
	105	int flags)
	106	{
	107	const struct prop_handler *handler;
	108	int ret;
	109
	110	if (strlen(name) <= XATTR_BTRFS_PREFIX_LEN)
	111	return -EINVAL;
	112
	113	handler = find_prop_handler(name, NULL);
	114	if (!handler)
	115	return -EINVAL;
	116
	117	if (value_len == 0) {
	118	ret = __btrfs_setxattr(trans, inode, handler->xattr_name,
	119	NULL, 0, flags);
	120	if (ret)
	121	return ret;
	122
	123	ret = handler->apply(inode, NULL, 0);
	124	ASSERT(ret == 0);
	125
126	return ret;
127	}
128
129	ret = handler->validate(value, value_len);
130	if (ret)
131	return ret;
132	ret = __btrfs_setxattr(trans, inode, handler->xattr_name,
133	value, value_len, flags);
134	if (ret)
135	return ret;
136	ret = handler->apply(inode, value, value_len);
137	if (ret) {
138	__btrfs_setxattr(trans, inode, handler->xattr_name,
139	NULL, 0, flags);
140	return ret;
141	}
142
143	set_bit(BTRFS_INODE_HAS_PROPS, &BTRFS_I(inode)->runtime_flags);
144
145	return 0;
146	}
147
148	int btrfs_set_prop(struct inode *inode,
149	const char *name,
150	const char *value,
151	size_t value_len,
152	int flags)
153	{
154	return __btrfs_set_prop(NULL, inode, name, value, value_len, flags);
155	}
156
157	static int iterate_object_props(struct btrfs_root *root,
158	struct btrfs_path *path,
159	u64 objectid,
160	void (iterator)(void ,
161	const struct prop_handler *,
162	const char *,
163	size_t),
164	void *ctx)
165	{
166	int ret;
167	char *name_buf = NULL;
168	char *value_buf = NULL;
169	int name_buf_len = 0;
170	int value_buf_len = 0;
171
172	while (1) {
173	struct btrfs_key key;
174	struct btrfs_dir_item *di;
175	struct extent_buffer *leaf;
176	u32 total_len, cur, this_len;
177	int slot;
178	const struct hlist_head *handlers;
179
180	slot = path->slots[0];
181	leaf = path->nodes[0];
182
183	if (slot >= btrfs_header_nritems(leaf)) {
184	ret = btrfs_next_leaf(root, path);
185	if (ret < 0)
186	goto out;
187	else if (ret > 0)
188	break;
189	continue;
190	}
191
192	btrfs_item_key_to_cpu(leaf, &key, slot);
193	if (key.objectid != objectid)
194	break;
195	if (key.type != BTRFS_XATTR_ITEM_KEY)
196	break;
197
198	handlers = find_prop_handlers_by_hash(key.offset);
199	if (!handlers)
200	goto next_slot;
201
202	di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
203	cur = 0;
204	total_len = btrfs_item_size_nr(leaf, slot);
205
206	while (cur < total_len) {
207	u32 name_len = btrfs_dir_name_len(leaf, di);
208	u32 data_len = btrfs_dir_data_len(leaf, di);
209	unsigned long name_ptr, data_ptr;
210	const struct prop_handler *handler;
211
212	this_len = sizeof(*di) + name_len + data_len;
213	name_ptr = (unsigned long)(di + 1);
214	data_ptr = name_ptr + name_len;
215
216	if (name_len <= XATTR_BTRFS_PREFIX_LEN \|\|
217	memcmp_extent_buffer(leaf, XATTR_BTRFS_PREFIX,
218	name_ptr,
219	XATTR_BTRFS_PREFIX_LEN))
220	goto next_dir_item;
221
222	if (name_len >= name_buf_len) {
223	kfree(name_buf);
224	name_buf_len = name_len + 1;
225	name_buf = kmalloc(name_buf_len, GFP_NOFS);
226	if (!name_buf) {
227	ret = -ENOMEM;
228	goto out;
229	}
230	}
231	read_extent_buffer(leaf, name_buf, name_ptr, name_len);
232	name_buf[name_len] = '\0';
233
234	handler = find_prop_handler(name_buf, handlers);
235	if (!handler)
236	goto next_dir_item;
237
238	if (data_len > value_buf_len) {
239	kfree(value_buf);
240	value_buf_len = data_len;
241	value_buf = kmalloc(data_len, GFP_NOFS);
242	if (!value_buf) {
243	ret = -ENOMEM;
244	goto out;
245	}
246	}
247	read_extent_buffer(leaf, value_buf, data_ptr, data_len);
248
249	iterator(ctx, handler, value_buf, data_len);
250	next_dir_item:
251	cur += this_len;
252	di = (struct btrfs_dir_item )((char ) di + this_len);
253	}
254
255	next_slot:
256	path->slots[0]++;
257	}
258
259	ret = 0;
260	out:
261	btrfs_release_path(path);
262	kfree(name_buf);
263	kfree(value_buf);
264
265	return ret;
266	}
267
268	static void inode_prop_iterator(void *ctx,
269	const struct prop_handler *handler,
270	const char *value,
271	size_t len)
272	{
273	struct inode *inode = ctx;
274	struct btrfs_root *root = BTRFS_I(inode)->root;
275	int ret;
276
277	ret = handler->apply(inode, value, len);
278	if (unlikely(ret))
279	btrfs_warn(root->fs_info,
280	"error applying prop %s to ino %llu (root %llu): %d",
281	handler->xattr_name, btrfs_ino(inode),
282	root->root_key.objectid, ret);
283	else
284	set_bit(BTRFS_INODE_HAS_PROPS, &BTRFS_I(inode)->runtime_flags);
285	}
286
287	int btrfs_load_inode_props(struct inode inode, struct btrfs_path path)
288	{
289	struct btrfs_root *root = BTRFS_I(inode)->root;
290	u64 ino = btrfs_ino(inode);
291	int ret;
292
293	ret = iterate_object_props(root, path, ino, inode_prop_iterator, inode);
294
295	return ret;
296	}
297
298	static int inherit_props(struct btrfs_trans_handle *trans,
299	struct inode *inode,
300	struct inode *parent)
301	{
63541927 FDBM	302	struct btrfs_root *root = BTRFS_I(inode)->root;
63541927 FDBM	303	int ret;
619ed392	304	int i;
63541927 FDBM	305
	306	if (!test_bit(BTRFS_INODE_HAS_PROPS,
	307	&BTRFS_I(parent)->runtime_flags))
	308	return 0;
	309
619ed392 BL	310	for (i = 0; i < ARRAY_SIZE(prop_handlers); i++) {
619ed392 BL	311	const struct prop_handler *h = &prop_handlers[i];
63541927 FDBM	312	const char *value;
	313	u64 num_bytes;
	314
	315	if (!h->inheritable)
	316	continue;
	317
	318	value = h->extract(parent);
	319	if (!value)
	320	continue;
	321
	322	num_bytes = btrfs_calc_trans_metadata_size(root, 1);
	323	ret = btrfs_block_rsv_add(root, trans->block_rsv,
	324	num_bytes, BTRFS_RESERVE_NO_FLUSH);
	325	if (ret)
	326	goto out;
	327	ret = __btrfs_set_prop(trans, inode, h->xattr_name,
	328	value, strlen(value), 0);
	329	btrfs_block_rsv_release(root, trans->block_rsv, num_bytes);
	330	if (ret)
	331	goto out;
	332	}
	333	ret = 0;
	334	out:
	335	return ret;
	336	}
	337
	338	int btrfs_inode_inherit_props(struct btrfs_trans_handle *trans,
	339	struct inode *inode,
	340	struct inode *dir)
	341	{
	342	if (!dir)
	343	return 0;
	344
	345	return inherit_props(trans, inode, dir);
	346	}
	347
	348	int btrfs_subvol_inherit_props(struct btrfs_trans_handle *trans,
	349	struct btrfs_root *root,
	350	struct btrfs_root *parent_root)
	351	{
	352	struct btrfs_key key;
	353	struct inode parent_inode, child_inode;
	354	int ret;
	355
	356	key.objectid = BTRFS_FIRST_FREE_OBJECTID;
	357	key.type = BTRFS_INODE_ITEM_KEY;
	358	key.offset = 0;
	359
	360	parent_inode = btrfs_iget(parent_root->fs_info->sb, &key,
	361	parent_root, NULL);
	362	if (IS_ERR(parent_inode))
	363	return PTR_ERR(parent_inode);
	364
	365	child_inode = btrfs_iget(root->fs_info->sb, &key, root, NULL);
	366	if (IS_ERR(child_inode)) {
	367	iput(parent_inode);
	368	return PTR_ERR(child_inode);
	369	}
	370
	371	ret = inherit_props(trans, child_inode, parent_inode);
	372	iput(child_inode);
	373	iput(parent_inode);
	374
	375	return ret;
376	}
377
378	static int prop_compression_validate(const char *value, size_t len)
379	{
380	if (!strncmp("lzo", value, len))
381	return 0;
382	else if (!strncmp("zlib", value, len))
383	return 0;
384
385	return -EINVAL;
386	}
387
388	static int prop_compression_apply(struct inode *inode,
389	const char *value,
390	size_t len)
391	{
392	int type;
393
394	if (len == 0) {
395	BTRFS_I(inode)->flags \|= BTRFS_INODE_NOCOMPRESS;
396	BTRFS_I(inode)->flags &= ~BTRFS_INODE_COMPRESS;
397	BTRFS_I(inode)->force_compress = BTRFS_COMPRESS_NONE;
398
399	return 0;
400	}
401
402	if (!strncmp("lzo", value, len))
403	type = BTRFS_COMPRESS_LZO;
404	else if (!strncmp("zlib", value, len))
405	type = BTRFS_COMPRESS_ZLIB;
406	else
407	return -EINVAL;
408
409	BTRFS_I(inode)->flags &= ~BTRFS_INODE_NOCOMPRESS;
410	BTRFS_I(inode)->flags \|= BTRFS_INODE_COMPRESS;
411	BTRFS_I(inode)->force_compress = type;
412
413	return 0;
414	}
415
416	static const char prop_compression_extract(struct inode inode)
417	{
418	switch (BTRFS_I(inode)->force_compress) {
419	case BTRFS_COMPRESS_ZLIB:
420	return "zlib";
421	case BTRFS_COMPRESS_LZO:
422	return "lzo";
423	}
424
425	return NULL;
426	}
e8c9f186 DS	427
e8c9f186 DS	428