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