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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#include "compression.h"
26
27#define BTRFS_PROP_HANDLERS_HT_BITS 8
28static DEFINE_HASHTABLE(prop_handlers_ht, BTRFS_PROP_HANDLERS_HT_BITS);
29
30struct 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
39static int prop_compression_validate(const char *value, size_t len);
40static int prop_compression_apply(struct inode *inode,
41 const char *value,
42 size_t len);
43static const char *prop_compression_extract(struct inode *inode);
44
45static 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 },
53};
54
55void __init btrfs_props_init(void)
56{
57 int i;
58
59 hash_init(prop_handlers_ht);
60
61 for (i = 0; i < ARRAY_SIZE(prop_handlers); i++) {
62 struct prop_handler *p = &prop_handlers[i];
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
69static 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
80static const struct prop_handler *
81find_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
101static 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
149int 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
158static 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);
251next_dir_item:
252 cur += this_len;
253 di = (struct btrfs_dir_item *)((char *) di + this_len);
254 }
255
256next_slot:
257 path->slots[0]++;
258 }
259
260 ret = 0;
261out:
262 btrfs_release_path(path);
263 kfree(name_buf);
264 kfree(value_buf);
265
266 return ret;
267}
268
269static 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",
282 handler->xattr_name, btrfs_ino(inode),
283 root->root_key.objectid, ret);
284 else
285 set_bit(BTRFS_INODE_HAS_PROPS, &BTRFS_I(inode)->runtime_flags);
286}
287
288int btrfs_load_inode_props(struct inode *inode, struct btrfs_path *path)
289{
290 struct btrfs_root *root = BTRFS_I(inode)->root;
291 u64 ino = btrfs_ino(inode);
292 int ret;
293
294 ret = iterate_object_props(root, path, ino, inode_prop_iterator, inode);
295
296 return ret;
297}
298
299static int inherit_props(struct btrfs_trans_handle *trans,
300 struct inode *inode,
301 struct inode *parent)
302{
303 struct btrfs_root *root = BTRFS_I(inode)->root;
304 int ret;
305 int i;
306
307 if (!test_bit(BTRFS_INODE_HAS_PROPS,
308 &BTRFS_I(parent)->runtime_flags))
309 return 0;
310
311 for (i = 0; i < ARRAY_SIZE(prop_handlers); i++) {
312 const struct prop_handler *h = &prop_handlers[i];
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}
428
429