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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 "messages.h"
8#include "props.h"
9#include "btrfs_inode.h"
10#include "transaction.h"
11#include "ctree.h"
12#include "xattr.h"
13#include "compression.h"
14#include "space-info.h"
15#include "fs.h"
16#include "accessors.h"
17#include "super.h"
18
19#define BTRFS_PROP_HANDLERS_HT_BITS 8
20static DEFINE_HASHTABLE(prop_handlers_ht, BTRFS_PROP_HANDLERS_HT_BITS);
21
22struct prop_handler {
23 struct hlist_node node;
24 const char *xattr_name;
25 int (*validate)(const struct btrfs_inode *inode, const char *value,
26 size_t len);
27 int (*apply)(struct inode *inode, const char *value, size_t len);
28 const char *(*extract)(struct inode *inode);
29 bool (*ignore)(const struct btrfs_inode *inode);
30 int inheritable;
31};
32
33static const struct hlist_head *find_prop_handlers_by_hash(const u64 hash)
34{
35 struct hlist_head *h;
36
37 h = &prop_handlers_ht[hash_min(hash, BTRFS_PROP_HANDLERS_HT_BITS)];
38 if (hlist_empty(h))
39 return NULL;
40
41 return h;
42}
43
44static const struct prop_handler *
45find_prop_handler(const char *name,
46 const struct hlist_head *handlers)
47{
48 struct prop_handler *h;
49
50 if (!handlers) {
51 u64 hash = btrfs_name_hash(name, strlen(name));
52
53 handlers = find_prop_handlers_by_hash(hash);
54 if (!handlers)
55 return NULL;
56 }
57
58 hlist_for_each_entry(h, handlers, node)
59 if (!strcmp(h->xattr_name, name))
60 return h;
61
62 return NULL;
63}
64
65int btrfs_validate_prop(const struct btrfs_inode *inode, const char *name,
66 const char *value, size_t value_len)
67{
68 const struct prop_handler *handler;
69
70 if (strlen(name) <= XATTR_BTRFS_PREFIX_LEN)
71 return -EINVAL;
72
73 handler = find_prop_handler(name, NULL);
74 if (!handler)
75 return -EINVAL;
76
77 if (value_len == 0)
78 return 0;
79
80 return handler->validate(inode, value, value_len);
81}
82
83/*
84 * Check if a property should be ignored (not set) for an inode.
85 *
86 * @inode: The target inode.
87 * @name: The property's name.
88 *
89 * The caller must be sure the given property name is valid, for example by
90 * having previously called btrfs_validate_prop().
91 *
92 * Returns: true if the property should be ignored for the given inode
93 * false if the property must not be ignored for the given inode
94 */
95bool btrfs_ignore_prop(const struct btrfs_inode *inode, const char *name)
96{
97 const struct prop_handler *handler;
98
99 handler = find_prop_handler(name, NULL);
100 ASSERT(handler != NULL);
101
102 return handler->ignore(inode);
103}
104
105int btrfs_set_prop(struct btrfs_trans_handle *trans, struct inode *inode,
106 const char *name, const char *value, size_t value_len,
107 int flags)
108{
109 const struct prop_handler *handler;
110 int ret;
111
112 handler = find_prop_handler(name, NULL);
113 if (!handler)
114 return -EINVAL;
115
116 if (value_len == 0) {
117 ret = btrfs_setxattr(trans, inode, handler->xattr_name,
118 NULL, 0, flags);
119 if (ret)
120 return ret;
121
122 ret = handler->apply(inode, NULL, 0);
123 ASSERT(ret == 0);
124
125 return ret;
126 }
127
128 ret = btrfs_setxattr(trans, inode, handler->xattr_name, value,
129 value_len, flags);
130 if (ret)
131 return ret;
132 ret = handler->apply(inode, value, value_len);
133 if (ret) {
134 btrfs_setxattr(trans, inode, handler->xattr_name, NULL,
135 0, flags);
136 return ret;
137 }
138
139 set_bit(BTRFS_INODE_HAS_PROPS, &BTRFS_I(inode)->runtime_flags);
140
141 return 0;
142}
143
144static int iterate_object_props(struct btrfs_root *root,
145 struct btrfs_path *path,
146 u64 objectid,
147 void (*iterator)(void *,
148 const struct prop_handler *,
149 const char *,
150 size_t),
151 void *ctx)
152{
153 int ret;
154 char *name_buf = NULL;
155 char *value_buf = NULL;
156 int name_buf_len = 0;
157 int value_buf_len = 0;
158
159 while (1) {
160 struct btrfs_key key;
161 struct btrfs_dir_item *di;
162 struct extent_buffer *leaf;
163 u32 total_len, cur, this_len;
164 int slot;
165 const struct hlist_head *handlers;
166
167 slot = path->slots[0];
168 leaf = path->nodes[0];
169
170 if (slot >= btrfs_header_nritems(leaf)) {
171 ret = btrfs_next_leaf(root, path);
172 if (ret < 0)
173 goto out;
174 else if (ret > 0)
175 break;
176 continue;
177 }
178
179 btrfs_item_key_to_cpu(leaf, &key, slot);
180 if (key.objectid != objectid)
181 break;
182 if (key.type != BTRFS_XATTR_ITEM_KEY)
183 break;
184
185 handlers = find_prop_handlers_by_hash(key.offset);
186 if (!handlers)
187 goto next_slot;
188
189 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
190 cur = 0;
191 total_len = btrfs_item_size(leaf, slot);
192
193 while (cur < total_len) {
194 u32 name_len = btrfs_dir_name_len(leaf, di);
195 u32 data_len = btrfs_dir_data_len(leaf, di);
196 unsigned long name_ptr, data_ptr;
197 const struct prop_handler *handler;
198
199 this_len = sizeof(*di) + name_len + data_len;
200 name_ptr = (unsigned long)(di + 1);
201 data_ptr = name_ptr + name_len;
202
203 if (name_len <= XATTR_BTRFS_PREFIX_LEN ||
204 memcmp_extent_buffer(leaf, XATTR_BTRFS_PREFIX,
205 name_ptr,
206 XATTR_BTRFS_PREFIX_LEN))
207 goto next_dir_item;
208
209 if (name_len >= name_buf_len) {
210 kfree(name_buf);
211 name_buf_len = name_len + 1;
212 name_buf = kmalloc(name_buf_len, GFP_NOFS);
213 if (!name_buf) {
214 ret = -ENOMEM;
215 goto out;
216 }
217 }
218 read_extent_buffer(leaf, name_buf, name_ptr, name_len);
219 name_buf[name_len] = '\0';
220
221 handler = find_prop_handler(name_buf, handlers);
222 if (!handler)
223 goto next_dir_item;
224
225 if (data_len > value_buf_len) {
226 kfree(value_buf);
227 value_buf_len = data_len;
228 value_buf = kmalloc(data_len, GFP_NOFS);
229 if (!value_buf) {
230 ret = -ENOMEM;
231 goto out;
232 }
233 }
234 read_extent_buffer(leaf, value_buf, data_ptr, data_len);
235
236 iterator(ctx, handler, value_buf, data_len);
237next_dir_item:
238 cur += this_len;
239 di = (struct btrfs_dir_item *)((char *) di + this_len);
240 }
241
242next_slot:
243 path->slots[0]++;
244 }
245
246 ret = 0;
247out:
248 btrfs_release_path(path);
249 kfree(name_buf);
250 kfree(value_buf);
251
252 return ret;
253}
254
255static void inode_prop_iterator(void *ctx,
256 const struct prop_handler *handler,
257 const char *value,
258 size_t len)
259{
260 struct inode *inode = ctx;
261 struct btrfs_root *root = BTRFS_I(inode)->root;
262 int ret;
263
264 ret = handler->apply(inode, value, len);
265 if (unlikely(ret))
266 btrfs_warn(root->fs_info,
267 "error applying prop %s to ino %llu (root %llu): %d",
268 handler->xattr_name, btrfs_ino(BTRFS_I(inode)),
269 root->root_key.objectid, ret);
270 else
271 set_bit(BTRFS_INODE_HAS_PROPS, &BTRFS_I(inode)->runtime_flags);
272}
273
274int btrfs_load_inode_props(struct inode *inode, struct btrfs_path *path)
275{
276 struct btrfs_root *root = BTRFS_I(inode)->root;
277 u64 ino = btrfs_ino(BTRFS_I(inode));
278
279 return iterate_object_props(root, path, ino, inode_prop_iterator, inode);
280}
281
282static int prop_compression_validate(const struct btrfs_inode *inode,
283 const char *value, size_t len)
284{
285 if (!btrfs_inode_can_compress(inode))
286 return -EINVAL;
287
288 if (!value)
289 return 0;
290
291 if (btrfs_compress_is_valid_type(value, len))
292 return 0;
293
294 if ((len == 2 && strncmp("no", value, 2) == 0) ||
295 (len == 4 && strncmp("none", value, 4) == 0))
296 return 0;
297
298 return -EINVAL;
299}
300
301static int prop_compression_apply(struct inode *inode, const char *value,
302 size_t len)
303{
304 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
305 int type;
306
307 /* Reset to defaults */
308 if (len == 0) {
309 BTRFS_I(inode)->flags &= ~BTRFS_INODE_COMPRESS;
310 BTRFS_I(inode)->flags &= ~BTRFS_INODE_NOCOMPRESS;
311 BTRFS_I(inode)->prop_compress = BTRFS_COMPRESS_NONE;
312 return 0;
313 }
314
315 /* Set NOCOMPRESS flag */
316 if ((len == 2 && strncmp("no", value, 2) == 0) ||
317 (len == 4 && strncmp("none", value, 4) == 0)) {
318 BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
319 BTRFS_I(inode)->flags &= ~BTRFS_INODE_COMPRESS;
320 BTRFS_I(inode)->prop_compress = BTRFS_COMPRESS_NONE;
321
322 return 0;
323 }
324
325 if (!strncmp("lzo", value, 3)) {
326 type = BTRFS_COMPRESS_LZO;
327 btrfs_set_fs_incompat(fs_info, COMPRESS_LZO);
328 } else if (!strncmp("zlib", value, 4)) {
329 type = BTRFS_COMPRESS_ZLIB;
330 } else if (!strncmp("zstd", value, 4)) {
331 type = BTRFS_COMPRESS_ZSTD;
332 btrfs_set_fs_incompat(fs_info, COMPRESS_ZSTD);
333 } else {
334 return -EINVAL;
335 }
336
337 BTRFS_I(inode)->flags &= ~BTRFS_INODE_NOCOMPRESS;
338 BTRFS_I(inode)->flags |= BTRFS_INODE_COMPRESS;
339 BTRFS_I(inode)->prop_compress = type;
340
341 return 0;
342}
343
344static bool prop_compression_ignore(const struct btrfs_inode *inode)
345{
346 /*
347 * Compression only has effect for regular files, and for directories
348 * we set it just to propagate it to new files created inside them.
349 * Everything else (symlinks, devices, sockets, fifos) is pointless as
350 * it will do nothing, so don't waste metadata space on a compression
351 * xattr for anything that is neither a file nor a directory.
352 */
353 if (!S_ISREG(inode->vfs_inode.i_mode) &&
354 !S_ISDIR(inode->vfs_inode.i_mode))
355 return true;
356
357 return false;
358}
359
360static const char *prop_compression_extract(struct inode *inode)
361{
362 switch (BTRFS_I(inode)->prop_compress) {
363 case BTRFS_COMPRESS_ZLIB:
364 case BTRFS_COMPRESS_LZO:
365 case BTRFS_COMPRESS_ZSTD:
366 return btrfs_compress_type2str(BTRFS_I(inode)->prop_compress);
367 default:
368 break;
369 }
370
371 return NULL;
372}
373
374static struct prop_handler prop_handlers[] = {
375 {
376 .xattr_name = XATTR_BTRFS_PREFIX "compression",
377 .validate = prop_compression_validate,
378 .apply = prop_compression_apply,
379 .extract = prop_compression_extract,
380 .ignore = prop_compression_ignore,
381 .inheritable = 1
382 },
383};
384
385int btrfs_inode_inherit_props(struct btrfs_trans_handle *trans,
386 struct inode *inode, struct inode *parent)
387{
388 struct btrfs_root *root = BTRFS_I(inode)->root;
389 struct btrfs_fs_info *fs_info = root->fs_info;
390 int ret;
391 int i;
392 bool need_reserve = false;
393
394 if (!test_bit(BTRFS_INODE_HAS_PROPS,
395 &BTRFS_I(parent)->runtime_flags))
396 return 0;
397
398 for (i = 0; i < ARRAY_SIZE(prop_handlers); i++) {
399 const struct prop_handler *h = &prop_handlers[i];
400 const char *value;
401 u64 num_bytes = 0;
402
403 if (!h->inheritable)
404 continue;
405
406 if (h->ignore(BTRFS_I(inode)))
407 continue;
408
409 value = h->extract(parent);
410 if (!value)
411 continue;
412
413 /*
414 * This is not strictly necessary as the property should be
415 * valid, but in case it isn't, don't propagate it further.
416 */
417 ret = h->validate(BTRFS_I(inode), value, strlen(value));
418 if (ret)
419 continue;
420
421 /*
422 * Currently callers should be reserving 1 item for properties,
423 * since we only have 1 property that we currently support. If
424 * we add more in the future we need to try and reserve more
425 * space for them. But we should also revisit how we do space
426 * reservations if we do add more properties in the future.
427 */
428 if (need_reserve) {
429 num_bytes = btrfs_calc_insert_metadata_size(fs_info, 1);
430 ret = btrfs_block_rsv_add(fs_info, trans->block_rsv,
431 num_bytes,
432 BTRFS_RESERVE_NO_FLUSH);
433 if (ret)
434 return ret;
435 }
436
437 ret = btrfs_setxattr(trans, inode, h->xattr_name, value,
438 strlen(value), 0);
439 if (!ret) {
440 ret = h->apply(inode, value, strlen(value));
441 if (ret)
442 btrfs_setxattr(trans, inode, h->xattr_name,
443 NULL, 0, 0);
444 else
445 set_bit(BTRFS_INODE_HAS_PROPS,
446 &BTRFS_I(inode)->runtime_flags);
447 }
448
449 if (need_reserve) {
450 btrfs_block_rsv_release(fs_info, trans->block_rsv,
451 num_bytes, NULL);
452 if (ret)
453 return ret;
454 }
455 need_reserve = true;
456 }
457
458 return 0;
459}
460
461int __init btrfs_props_init(void)
462{
463 int i;
464
465 for (i = 0; i < ARRAY_SIZE(prop_handlers); i++) {
466 struct prop_handler *p = &prop_handlers[i];
467 u64 h = btrfs_name_hash(p->xattr_name, strlen(p->xattr_name));
468
469 hash_add(prop_handlers_ht, &p->node, h);
470 }
471 return 0;
472}
473