1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Feature set bits and string conversion.
4 * Inspired by ext4's features compat/incompat/ro_compat related code.
5 *
6 * Copyright 2020 Coly Li <colyli@suse.de>
7 *
8 */
9#include "bcache_ondisk.h"
10#include "bcache.h"
11#include "features.h"
12
13struct feature {
14 int compat;
15 unsigned int mask;
16 const char *string;
17};
18
19static struct feature feature_list[] = {
20 {BCH_FEATURE_INCOMPAT, BCH_FEATURE_INCOMPAT_LOG_LARGE_BUCKET_SIZE,
21 "large_bucket"},
22 {0, 0, NULL },
23};
24
25#define compose_feature_string(type) \
26({ \
27 struct feature *f; \
28 bool first = true; \
29 \
30 for (f = &feature_list[0]; f->compat != 0; f++) { \
31 if (f->compat != BCH_FEATURE_ ## type) \
32 continue; \
33 if (BCH_HAS_ ## type ## _FEATURE(&c->cache->sb, f->mask)) { \
34 if (first) { \
35 out += snprintf(out, buf + size - out, \
36 "["); \
37 } else { \
38 out += snprintf(out, buf + size - out, \
39 " ["); \
40 } \
41 } else if (!first) { \
42 out += snprintf(out, buf + size - out, " "); \
43 } \
44 \
45 out += snprintf(out, buf + size - out, "%s", f->string);\
46 \
47 if (BCH_HAS_ ## type ## _FEATURE(&c->cache->sb, f->mask)) \
48 out += snprintf(out, buf + size - out, "]"); \
49 \
50 first = false; \
51 } \
52 if (!first) \
53 out += snprintf(out, buf + size - out, "\n"); \
54})
55
56int bch_print_cache_set_feature_compat(struct cache_set *c, char *buf, int size)
57{
58 char *out = buf;
59 compose_feature_string(COMPAT);
60 return out - buf;
61}
62
63int bch_print_cache_set_feature_ro_compat(struct cache_set *c, char *buf, int size)
64{
65 char *out = buf;
66 compose_feature_string(RO_COMPAT);
67 return out - buf;
68}
69
70int bch_print_cache_set_feature_incompat(struct cache_set *c, char *buf, int size)
71{
72 char *out = buf;
73 compose_feature_string(INCOMPAT);
74 return out - buf;
75}
76

source code of linux/drivers/md/bcache/features.c