xref: /linux/drivers/md/bcache/features.c (revision cf21f328fcafacf4f96e7a30ef9dceede1076378)
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 
13 struct feature {
14 	int		compat;
15 	unsigned int	mask;
16 	const char	*string;
17 };
18 
19 static 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 
56 int 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 
63 int 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 
70 int 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