[linux.git] / fs / btrfs / props.c

/*
 * Copyright (C) 2014 Filipe David Borba Manana <[email protected]>
 *
 * 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"
#include "compression.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(BTRFS_I(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(BTRFS_I(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;
	struct btrfs_fs_info *fs_info = root->fs_info;
	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(fs_info, 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(fs_info, 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 super_block *sb = root->fs_info->sb;
	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(sb, &key, parent_root, NULL);
	if (IS_ERR(parent_inode))
		return PTR_ERR(parent_inode);

	child_inode = btrfs_iget(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 <[email protected]>
	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"
ebb8765b	25	#include "compression.h"
63541927 FDBM	26
	27	#define BTRFS_PROP_HANDLERS_HT_BITS 8
	28	static DEFINE_HASHTABLE(prop_handlers_ht, BTRFS_PROP_HANDLERS_HT_BITS);
	29
	30	struct prop_handler {
	31	struct hlist_node node;
	32	const char *xattr_name;
	33	int (validate)(const char value, size_t len);
	34	int (apply)(struct inode inode, const char *value, size_t len);
	35	const char (extract)(struct inode *inode);
	36	int inheritable;
	37	};
	38
	39	static int prop_compression_validate(const char *value, size_t len);
	40	static int prop_compression_apply(struct inode *inode,
	41	const char *value,
	42	size_t len);
	43	static const char prop_compression_extract(struct inode inode);
	44
	45	static struct prop_handler prop_handlers[] = {
	46	{
	47	.xattr_name = XATTR_BTRFS_PREFIX "compression",
	48	.validate = prop_compression_validate,
	49	.apply = prop_compression_apply,
	50	.extract = prop_compression_extract,
	51	.inheritable = 1
	52	},
63541927 FDBM	53	};
	54
	55	void __init btrfs_props_init(void)
	56	{
619ed392	57	int i;
63541927 FDBM	58
	59	hash_init(prop_handlers_ht);
	60
619ed392 BL	61	for (i = 0; i < ARRAY_SIZE(prop_handlers); i++) {
619ed392 BL	62	struct prop_handler *p = &prop_handlers[i];
63541927 FDBM	63	u64 h = btrfs_name_hash(p->xattr_name, strlen(p->xattr_name));
	64
	65	hash_add(prop_handlers_ht, &p->node, h);
	66	}
	67	}
	68
	69	static const struct hlist_head *find_prop_handlers_by_hash(const u64 hash)
	70	{
	71	struct hlist_head *h;
	72
	73	h = &prop_handlers_ht[hash_min(hash, BTRFS_PROP_HANDLERS_HT_BITS)];
	74	if (hlist_empty(h))
	75	return NULL;
	76
	77	return h;
	78	}
	79
	80	static const struct prop_handler *
	81	find_prop_handler(const char *name,
	82	const struct hlist_head *handlers)
	83	{
	84	struct prop_handler *h;
	85
	86	if (!handlers) {
	87	u64 hash = btrfs_name_hash(name, strlen(name));
	88
	89	handlers = find_prop_handlers_by_hash(hash);
	90	if (!handlers)
	91	return NULL;
	92	}
	93
	94	hlist_for_each_entry(h, handlers, node)
	95	if (!strcmp(h->xattr_name, name))
	96	return h;
	97
	98	return NULL;
	99	}
	100
	101	static int __btrfs_set_prop(struct btrfs_trans_handle *trans,
	102	struct inode *inode,
	103	const char *name,
	104	const char *value,
	105	size_t value_len,
	106	int flags)
	107	{
	108	const struct prop_handler *handler;
	109	int ret;
	110
	111	if (strlen(name) <= XATTR_BTRFS_PREFIX_LEN)
	112	return -EINVAL;
	113
	114	handler = find_prop_handler(name, NULL);
	115	if (!handler)
	116	return -EINVAL;
	117
	118	if (value_len == 0) {
	119	ret = __btrfs_setxattr(trans, inode, handler->xattr_name,
	120	NULL, 0, flags);
	121	if (ret)
	122	return ret;
	123
	124	ret = handler->apply(inode, NULL, 0);
	125	ASSERT(ret == 0);
	126
127	return ret;
128	}
129
130	ret = handler->validate(value, value_len);
131	if (ret)
132	return ret;
133	ret = __btrfs_setxattr(trans, inode, handler->xattr_name,
134	value, value_len, flags);
135	if (ret)
136	return ret;
137	ret = handler->apply(inode, value, value_len);
138	if (ret) {
139	__btrfs_setxattr(trans, inode, handler->xattr_name,
140	NULL, 0, flags);
141	return ret;
142	}
143
144	set_bit(BTRFS_INODE_HAS_PROPS, &BTRFS_I(inode)->runtime_flags);
145
146	return 0;
147	}
148
149	int btrfs_set_prop(struct inode *inode,
150	const char *name,
151	const char *value,
152	size_t value_len,
153	int flags)
154	{
155	return __btrfs_set_prop(NULL, inode, name, value, value_len, flags);
156	}
157
158	static int iterate_object_props(struct btrfs_root *root,
159	struct btrfs_path *path,
160	u64 objectid,
161	void (iterator)(void ,
162	const struct prop_handler *,
163	const char *,
164	size_t),
165	void *ctx)
166	{
167	int ret;
168	char *name_buf = NULL;
169	char *value_buf = NULL;
170	int name_buf_len = 0;
171	int value_buf_len = 0;
172
173	while (1) {
174	struct btrfs_key key;
175	struct btrfs_dir_item *di;
176	struct extent_buffer *leaf;
177	u32 total_len, cur, this_len;
178	int slot;
179	const struct hlist_head *handlers;
180
181	slot = path->slots[0];
182	leaf = path->nodes[0];
183
184	if (slot >= btrfs_header_nritems(leaf)) {
185	ret = btrfs_next_leaf(root, path);
186	if (ret < 0)
187	goto out;
188	else if (ret > 0)
189	break;
190	continue;
191	}
192
193	btrfs_item_key_to_cpu(leaf, &key, slot);
194	if (key.objectid != objectid)
195	break;
196	if (key.type != BTRFS_XATTR_ITEM_KEY)
197	break;
198
199	handlers = find_prop_handlers_by_hash(key.offset);
200	if (!handlers)
201	goto next_slot;
202
203	di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
204	cur = 0;
205	total_len = btrfs_item_size_nr(leaf, slot);
206
207	while (cur < total_len) {
208	u32 name_len = btrfs_dir_name_len(leaf, di);
209	u32 data_len = btrfs_dir_data_len(leaf, di);
210	unsigned long name_ptr, data_ptr;
211	const struct prop_handler *handler;
212
213	this_len = sizeof(*di) + name_len + data_len;
214	name_ptr = (unsigned long)(di + 1);
215	data_ptr = name_ptr + name_len;
216
217	if (name_len <= XATTR_BTRFS_PREFIX_LEN \|\|
218	memcmp_extent_buffer(leaf, XATTR_BTRFS_PREFIX,
219	name_ptr,
220	XATTR_BTRFS_PREFIX_LEN))
221	goto next_dir_item;
222
223	if (name_len >= name_buf_len) {
224	kfree(name_buf);
225	name_buf_len = name_len + 1;
226	name_buf = kmalloc(name_buf_len, GFP_NOFS);
227	if (!name_buf) {
228	ret = -ENOMEM;
229	goto out;
230	}
231	}
232	read_extent_buffer(leaf, name_buf, name_ptr, name_len);
233	name_buf[name_len] = '\0';
234
235	handler = find_prop_handler(name_buf, handlers);
236	if (!handler)
237	goto next_dir_item;
238
239	if (data_len > value_buf_len) {
240	kfree(value_buf);
241	value_buf_len = data_len;
242	value_buf = kmalloc(data_len, GFP_NOFS);
243	if (!value_buf) {
244	ret = -ENOMEM;
245	goto out;
246	}
247	}
248	read_extent_buffer(leaf, value_buf, data_ptr, data_len);
249
250	iterator(ctx, handler, value_buf, data_len);
251	next_dir_item:
252	cur += this_len;
253	di = (struct btrfs_dir_item )((char ) di + this_len);
254	}
255
256	next_slot:
257	path->slots[0]++;
258	}
259
260	ret = 0;
261	out:
262	btrfs_release_path(path);
263	kfree(name_buf);
264	kfree(value_buf);
265
266	return ret;
267	}
268
269	static void inode_prop_iterator(void *ctx,
270	const struct prop_handler *handler,
271	const char *value,
272	size_t len)
273	{
274	struct inode *inode = ctx;
275	struct btrfs_root *root = BTRFS_I(inode)->root;
276	int ret;
277
278	ret = handler->apply(inode, value, len);
279	if (unlikely(ret))
280	btrfs_warn(root->fs_info,
281	"error applying prop %s to ino %llu (root %llu): %d",
4a0cc7ca	282	handler->xattr_name, btrfs_ino(BTRFS_I(inode)),
63541927 FDBM	283	root->root_key.objectid, ret);
	284	else
	285	set_bit(BTRFS_INODE_HAS_PROPS, &BTRFS_I(inode)->runtime_flags);
	286	}
	287
	288	int btrfs_load_inode_props(struct inode inode, struct btrfs_path path)
	289	{
	290	struct btrfs_root *root = BTRFS_I(inode)->root;
4a0cc7ca	291	u64 ino = btrfs_ino(BTRFS_I(inode));
63541927 FDBM	292	int ret;
	293
	294	ret = iterate_object_props(root, path, ino, inode_prop_iterator, inode);
	295
	296	return ret;
	297	}
	298
	299	static int inherit_props(struct btrfs_trans_handle *trans,
	300	struct inode *inode,
	301	struct inode *parent)
	302	{
63541927	303	struct btrfs_root *root = BTRFS_I(inode)->root;
2ff7e61e	304	struct btrfs_fs_info *fs_info = root->fs_info;
63541927	305	int ret;
619ed392	306	int i;
63541927 FDBM	307
	308	if (!test_bit(BTRFS_INODE_HAS_PROPS,
	309	&BTRFS_I(parent)->runtime_flags))
	310	return 0;
	311
619ed392 BL	312	for (i = 0; i < ARRAY_SIZE(prop_handlers); i++) {
619ed392 BL	313	const struct prop_handler *h = &prop_handlers[i];
63541927 FDBM	314	const char *value;
	315	u64 num_bytes;
	316
	317	if (!h->inheritable)
	318	continue;
	319
	320	value = h->extract(parent);
	321	if (!value)
	322	continue;
	323
2ff7e61e	324	num_bytes = btrfs_calc_trans_metadata_size(fs_info, 1);
63541927 FDBM	325	ret = btrfs_block_rsv_add(root, trans->block_rsv,
	326	num_bytes, BTRFS_RESERVE_NO_FLUSH);
	327	if (ret)
	328	goto out;
	329	ret = __btrfs_set_prop(trans, inode, h->xattr_name,
	330	value, strlen(value), 0);
2ff7e61e	331	btrfs_block_rsv_release(fs_info, trans->block_rsv, num_bytes);
63541927 FDBM	332	if (ret)
	333	goto out;
	334	}
	335	ret = 0;
	336	out:
	337	return ret;
	338	}
	339
	340	int btrfs_inode_inherit_props(struct btrfs_trans_handle *trans,
	341	struct inode *inode,
	342	struct inode *dir)
	343	{
	344	if (!dir)
	345	return 0;
	346
	347	return inherit_props(trans, inode, dir);
	348	}
	349
	350	int btrfs_subvol_inherit_props(struct btrfs_trans_handle *trans,
	351	struct btrfs_root *root,
	352	struct btrfs_root *parent_root)
	353	{
bd6c57dd	354	struct super_block *sb = root->fs_info->sb;
63541927 FDBM	355	struct btrfs_key key;
	356	struct inode parent_inode, child_inode;
	357	int ret;
	358
	359	key.objectid = BTRFS_FIRST_FREE_OBJECTID;
	360	key.type = BTRFS_INODE_ITEM_KEY;
	361	key.offset = 0;
	362
bd6c57dd	363	parent_inode = btrfs_iget(sb, &key, parent_root, NULL);
63541927 FDBM	364	if (IS_ERR(parent_inode))
	365	return PTR_ERR(parent_inode);
	366
bd6c57dd	367	child_inode = btrfs_iget(sb, &key, root, NULL);
63541927 FDBM	368	if (IS_ERR(child_inode)) {
	369	iput(parent_inode);
	370	return PTR_ERR(child_inode);
	371	}
	372
	373	ret = inherit_props(trans, child_inode, parent_inode);
	374	iput(child_inode);
	375	iput(parent_inode);
	376
	377	return ret;
	378	}
	379
	380	static int prop_compression_validate(const char *value, size_t len)
	381	{
	382	if (!strncmp("lzo", value, len))
	383	return 0;
	384	else if (!strncmp("zlib", value, len))
	385	return 0;
	386
	387	return -EINVAL;
	388	}
	389
	390	static int prop_compression_apply(struct inode *inode,
	391	const char *value,
	392	size_t len)
	393	{
	394	int type;
	395
	396	if (len == 0) {
	397	BTRFS_I(inode)->flags \|= BTRFS_INODE_NOCOMPRESS;
	398	BTRFS_I(inode)->flags &= ~BTRFS_INODE_COMPRESS;
	399	BTRFS_I(inode)->force_compress = BTRFS_COMPRESS_NONE;
	400
	401	return 0;
	402	}
	403
	404	if (!strncmp("lzo", value, len))
	405	type = BTRFS_COMPRESS_LZO;
	406	else if (!strncmp("zlib", value, len))
	407	type = BTRFS_COMPRESS_ZLIB;
	408	else
	409	return -EINVAL;
	410
	411	BTRFS_I(inode)->flags &= ~BTRFS_INODE_NOCOMPRESS;
	412	BTRFS_I(inode)->flags \|= BTRFS_INODE_COMPRESS;
	413	BTRFS_I(inode)->force_compress = type;
	414
	415	return 0;
	416	}
	417
	418	static const char prop_compression_extract(struct inode inode)
	419	{
	420	switch (BTRFS_I(inode)->force_compress) {
	421	case BTRFS_COMPRESS_ZLIB:
	422	return "zlib";
	423	case BTRFS_COMPRESS_LZO:
	424	return "lzo";
	425	}
	426
	427	return NULL;
	428	}
e8c9f186 DS	429
e8c9f186 DS	430