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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2014 Filipe David Borba Manana <fdmanana@gmail.com>
4 */
5
6#include <linux/hashtable.h>
7#include "props.h"
8#include "btrfs_inode.h"
9#include "transaction.h"
10#include "ctree.h"
11#include "xattr.h"
12#include "compression.h"
13
14#define BTRFS_PROP_HANDLERS_HT_BITS 8
15static DEFINE_HASHTABLE(prop_handlers_ht, BTRFS_PROP_HANDLERS_HT_BITS);
16
17struct prop_handler {
18 struct hlist_node node;
19 const char *xattr_name;
20 int (*validate)(const char *value, size_t len);
21 int (*apply)(struct inode *inode, const char *value, size_t len);
22 const char *(*extract)(struct inode *inode);
23 int inheritable;
24};
25
26static const struct hlist_head *find_prop_handlers_by_hash(const u64 hash)
27{
28 struct hlist_head *h;
29
30 h = &prop_handlers_ht[hash_min(hash, BTRFS_PROP_HANDLERS_HT_BITS)];
31 if (hlist_empty(h))
32 return NULL;
33
34 return h;
35}
36
37static const struct prop_handler *
38find_prop_handler(const char *name,
39 const struct hlist_head *handlers)
40{
41 struct prop_handler *h;
42
43 if (!handlers) {
44 u64 hash = btrfs_name_hash(name, strlen(name));
45
46 handlers = find_prop_handlers_by_hash(hash);
47 if (!handlers)
48 return NULL;
49 }
50
51 hlist_for_each_entry(h, handlers, node)
52 if (!strcmp(h->xattr_name, name))
53 return h;
54
55 return NULL;
56}
57
58int btrfs_validate_prop(const char *name, const char *value, size_t value_len)
59{
60 const struct prop_handler *handler;
61
62 if (strlen(name) <= XATTR_BTRFS_PREFIX_LEN)
63 return -EINVAL;
64
65 handler = find_prop_handler(name, NULL);
66 if (!handler)
67 return -EINVAL;
68
69 if (value_len == 0)
70 return 0;
71
72 return handler->validate(value, value_len);
73}
74
75int btrfs_set_prop(struct btrfs_trans_handle *trans, struct inode *inode,
76 const char *name, const char *value, size_t value_len,
77 int flags)
78{
79 const struct prop_handler *handler;
80 int ret;
81
82 handler = find_prop_handler(name, NULL);
83 if (!handler)
84 return -EINVAL;
85
86 if (value_len == 0) {
87 ret = btrfs_setxattr(trans, inode, handler->xattr_name,
88 NULL, 0, flags);
89 if (ret)
90 return ret;
91
92 ret = handler->apply(inode, NULL, 0);
93 ASSERT(ret == 0);
94
95 return ret;
96 }
97
98 ret = btrfs_setxattr(trans, inode, handler->xattr_name, value,
99 value_len, flags);
100 if (ret)
101 return ret;
102 ret = handler->apply(inode, value, value_len);
103 if (ret) {
104 btrfs_setxattr(trans, inode, handler->xattr_name, NULL,
105 0, flags);
106 return ret;
107 }
108
109 set_bit(BTRFS_INODE_HAS_PROPS, &BTRFS_I(inode)->runtime_flags);
110
111 return 0;
112}
113
114static int iterate_object_props(struct btrfs_root *root,
115 struct btrfs_path *path,
116 u64 objectid,
117 void (*iterator)(void *,
118 const struct prop_handler *,
119 const char *,
120 size_t),
121 void *ctx)
122{
123 int ret;
124 char *name_buf = NULL;
125 char *value_buf = NULL;
126 int name_buf_len = 0;
127 int value_buf_len = 0;
128
129 while (1) {
130 struct btrfs_key key;
131 struct btrfs_dir_item *di;
132 struct extent_buffer *leaf;
133 u32 total_len, cur, this_len;
134 int slot;
135 const struct hlist_head *handlers;
136
137 slot = path->slots[0];
138 leaf = path->nodes[0];
139
140 if (slot >= btrfs_header_nritems(leaf)) {
141 ret = btrfs_next_leaf(root, path);
142 if (ret < 0)
143 goto out;
144 else if (ret > 0)
145 break;
146 continue;
147 }
148
149 btrfs_item_key_to_cpu(leaf, &key, slot);
150 if (key.objectid != objectid)
151 break;
152 if (key.type != BTRFS_XATTR_ITEM_KEY)
153 break;
154
155 handlers = find_prop_handlers_by_hash(key.offset);
156 if (!handlers)
157 goto next_slot;
158
159 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
160 cur = 0;
161 total_len = btrfs_item_size_nr(leaf, slot);
162
163 while (cur < total_len) {
164 u32 name_len = btrfs_dir_name_len(leaf, di);
165 u32 data_len = btrfs_dir_data_len(leaf, di);
166 unsigned long name_ptr, data_ptr;
167 const struct prop_handler *handler;
168
169 this_len = sizeof(*di) + name_len + data_len;
170 name_ptr = (unsigned long)(di + 1);
171 data_ptr = name_ptr + name_len;
172
173 if (name_len <= XATTR_BTRFS_PREFIX_LEN ||
174 memcmp_extent_buffer(leaf, XATTR_BTRFS_PREFIX,
175 name_ptr,
176 XATTR_BTRFS_PREFIX_LEN))
177 goto next_dir_item;
178
179 if (name_len >= name_buf_len) {
180 kfree(name_buf);
181 name_buf_len = name_len + 1;
182 name_buf = kmalloc(name_buf_len, GFP_NOFS);
183 if (!name_buf) {
184 ret = -ENOMEM;
185 goto out;
186 }
187 }
188 read_extent_buffer(leaf, name_buf, name_ptr, name_len);
189 name_buf[name_len] = '\0';
190
191 handler = find_prop_handler(name_buf, handlers);
192 if (!handler)
193 goto next_dir_item;
194
195 if (data_len > value_buf_len) {
196 kfree(value_buf);
197 value_buf_len = data_len;
198 value_buf = kmalloc(data_len, GFP_NOFS);
199 if (!value_buf) {
200 ret = -ENOMEM;
201 goto out;
202 }
203 }
204 read_extent_buffer(leaf, value_buf, data_ptr, data_len);
205
206 iterator(ctx, handler, value_buf, data_len);
207next_dir_item:
208 cur += this_len;
209 di = (struct btrfs_dir_item *)((char *) di + this_len);
210 }
211
212next_slot:
213 path->slots[0]++;
214 }
215
216 ret = 0;
217out:
218 btrfs_release_path(path);
219 kfree(name_buf);
220 kfree(value_buf);
221
222 return ret;
223}
224
225static void inode_prop_iterator(void *ctx,
226 const struct prop_handler *handler,
227 const char *value,
228 size_t len)
229{
230 struct inode *inode = ctx;
231 struct btrfs_root *root = BTRFS_I(inode)->root;
232 int ret;
233
234 ret = handler->apply(inode, value, len);
235 if (unlikely(ret))
236 btrfs_warn(root->fs_info,
237 "error applying prop %s to ino %llu (root %llu): %d",
238 handler->xattr_name, btrfs_ino(BTRFS_I(inode)),
239 root->root_key.objectid, ret);
240 else
241 set_bit(BTRFS_INODE_HAS_PROPS, &BTRFS_I(inode)->runtime_flags);
242}
243
244int btrfs_load_inode_props(struct inode *inode, struct btrfs_path *path)
245{
246 struct btrfs_root *root = BTRFS_I(inode)->root;
247 u64 ino = btrfs_ino(BTRFS_I(inode));
248 int ret;
249
250 ret = iterate_object_props(root, path, ino, inode_prop_iterator, inode);
251
252 return ret;
253}
254
255static int prop_compression_validate(const char *value, size_t len)
256{
257 if (!value)
258 return 0;
259
260 if (btrfs_compress_is_valid_type(value, len))
261 return 0;
262
263 return -EINVAL;
264}
265
266static int prop_compression_apply(struct inode *inode, const char *value,
267 size_t len)
268{
269 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
270 int type;
271
272 if (len == 0) {
273 BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
274 BTRFS_I(inode)->flags &= ~BTRFS_INODE_COMPRESS;
275 BTRFS_I(inode)->prop_compress = BTRFS_COMPRESS_NONE;
276
277 return 0;
278 }
279
280 if (!strncmp("lzo", value, 3)) {
281 type = BTRFS_COMPRESS_LZO;
282 btrfs_set_fs_incompat(fs_info, COMPRESS_LZO);
283 } else if (!strncmp("zlib", value, 4)) {
284 type = BTRFS_COMPRESS_ZLIB;
285 } else if (!strncmp("zstd", value, 4)) {
286 type = BTRFS_COMPRESS_ZSTD;
287 btrfs_set_fs_incompat(fs_info, COMPRESS_ZSTD);
288 } else {
289 return -EINVAL;
290 }
291
292 BTRFS_I(inode)->flags &= ~BTRFS_INODE_NOCOMPRESS;
293 BTRFS_I(inode)->flags |= BTRFS_INODE_COMPRESS;
294 BTRFS_I(inode)->prop_compress = type;
295
296 return 0;
297}
298
299static const char *prop_compression_extract(struct inode *inode)
300{
301 switch (BTRFS_I(inode)->prop_compress) {
302 case BTRFS_COMPRESS_ZLIB:
303 case BTRFS_COMPRESS_LZO:
304 case BTRFS_COMPRESS_ZSTD:
305 return btrfs_compress_type2str(BTRFS_I(inode)->prop_compress);
306 default:
307 break;
308 }
309
310 return NULL;
311}
312
313static struct prop_handler prop_handlers[] = {
314 {
315 .xattr_name = XATTR_BTRFS_PREFIX "compression",
316 .validate = prop_compression_validate,
317 .apply = prop_compression_apply,
318 .extract = prop_compression_extract,
319 .inheritable = 1
320 },
321};
322
323static int inherit_props(struct btrfs_trans_handle *trans,
324 struct inode *inode,
325 struct inode *parent)
326{
327 struct btrfs_root *root = BTRFS_I(inode)->root;
328 struct btrfs_fs_info *fs_info = root->fs_info;
329 int ret;
330 int i;
331 bool need_reserve = false;
332
333 if (!test_bit(BTRFS_INODE_HAS_PROPS,
334 &BTRFS_I(parent)->runtime_flags))
335 return 0;
336
337 for (i = 0; i < ARRAY_SIZE(prop_handlers); i++) {
338 const struct prop_handler *h = &prop_handlers[i];
339 const char *value;
340 u64 num_bytes = 0;
341
342 if (!h->inheritable)
343 continue;
344
345 value = h->extract(parent);
346 if (!value)
347 continue;
348
349 /*
350 * This is not strictly necessary as the property should be
351 * valid, but in case it isn't, don't propagate it futher.
352 */
353 ret = h->validate(value, strlen(value));
354 if (ret)
355 continue;
356
357 /*
358 * Currently callers should be reserving 1 item for properties,
359 * since we only have 1 property that we currently support. If
360 * we add more in the future we need to try and reserve more
361 * space for them. But we should also revisit how we do space
362 * reservations if we do add more properties in the future.
363 */
364 if (need_reserve) {
365 num_bytes = btrfs_calc_insert_metadata_size(fs_info, 1);
366 ret = btrfs_block_rsv_add(root, trans->block_rsv,
367 num_bytes, BTRFS_RESERVE_NO_FLUSH);
368 if (ret)
369 return ret;
370 }
371
372 ret = btrfs_setxattr(trans, inode, h->xattr_name, value,
373 strlen(value), 0);
374 if (!ret) {
375 ret = h->apply(inode, value, strlen(value));
376 if (ret)
377 btrfs_setxattr(trans, inode, h->xattr_name,
378 NULL, 0, 0);
379 else
380 set_bit(BTRFS_INODE_HAS_PROPS,
381 &BTRFS_I(inode)->runtime_flags);
382 }
383
384 if (need_reserve) {
385 btrfs_block_rsv_release(fs_info, trans->block_rsv,
386 num_bytes, NULL);
387 if (ret)
388 return ret;
389 }
390 need_reserve = true;
391 }
392
393 return 0;
394}
395
396int btrfs_inode_inherit_props(struct btrfs_trans_handle *trans,
397 struct inode *inode,
398 struct inode *dir)
399{
400 if (!dir)
401 return 0;
402
403 return inherit_props(trans, inode, dir);
404}
405
406int btrfs_subvol_inherit_props(struct btrfs_trans_handle *trans,
407 struct btrfs_root *root,
408 struct btrfs_root *parent_root)
409{
410 struct super_block *sb = root->fs_info->sb;
411 struct inode *parent_inode, *child_inode;
412 int ret;
413
414 parent_inode = btrfs_iget(sb, BTRFS_FIRST_FREE_OBJECTID, parent_root);
415 if (IS_ERR(parent_inode))
416 return PTR_ERR(parent_inode);
417
418 child_inode = btrfs_iget(sb, BTRFS_FIRST_FREE_OBJECTID, root);
419 if (IS_ERR(child_inode)) {
420 iput(parent_inode);
421 return PTR_ERR(child_inode);
422 }
423
424 ret = inherit_props(trans, child_inode, parent_inode);
425 iput(child_inode);
426 iput(parent_inode);
427
428 return ret;
429}
430
431void __init btrfs_props_init(void)
432{
433 int i;
434
435 for (i = 0; i < ARRAY_SIZE(prop_handlers); i++) {
436 struct prop_handler *p = &prop_handlers[i];
437 u64 h = btrfs_name_hash(p->xattr_name, strlen(p->xattr_name));
438
439 hash_add(prop_handlers_ht, &p->node, h);
440 }
441}
442