md/bcache/features.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * Feature set bits and string conversion.
0004  * Inspired by ext4's features compat/incompat/ro_compat related code.
0005  *
0006  * Copyright 2020 Coly Li <colyli@suse.de>
0007  *
0008  */
0009 #include "bcache_ondisk.h"
0010 #include "bcache.h"
0011 #include "features.h"
0012
0013 struct feature {
0014     int     compat;
0015     unsigned int    mask;
0016     const char  *string;
0017 };
0018
0019 static struct feature feature_list[] = {
0020     {BCH_FEATURE_INCOMPAT, BCH_FEATURE_INCOMPAT_LOG_LARGE_BUCKET_SIZE,
0021         "large_bucket"},
0022     {0, 0, NULL },
0023 };
0024
0025 #define compose_feature_string(type)                \
0026 ({                                  \
0027     struct feature *f;                      \
0028     bool first = true;                      \
0029                                     \
0030     for (f = &feature_list[0]; f->compat != 0; f++) {       \
0031         if (f->compat != BCH_FEATURE_ ## type)          \
0032             continue;                   \
0033         if (BCH_HAS_ ## type ## _FEATURE(&c->cache->sb, f->mask)) { \
0034             if (first) {                    \
0035                 out += snprintf(out, buf + size - out,  \
0036                         "[");   \
0037             } else {                    \
0038                 out += snprintf(out, buf + size - out,  \
0039                         " [");          \
0040             }                       \
0041         } else if (!first) {                    \
0042             out += snprintf(out, buf + size - out, " ");    \
0043         }                           \
0044                                     \
0045         out += snprintf(out, buf + size - out, "%s", f->string);\
0046                                     \
0047         if (BCH_HAS_ ## type ## _FEATURE(&c->cache->sb, f->mask))   \
0048             out += snprintf(out, buf + size - out, "]");    \
0049                                     \
0050         first = false;                      \
0051     }                               \
0052     if (!first)                         \
0053         out += snprintf(out, buf + size - out, "\n");       \
0054 })
0055
0056 int bch_print_cache_set_feature_compat(struct cache_set *c, char *buf, int size)
0057 {
0058     char *out = buf;
0059     compose_feature_string(COMPAT);
0060     return out - buf;
0061 }
0062
0063 int bch_print_cache_set_feature_ro_compat(struct cache_set *c, char *buf, int size)
0064 {
0065     char *out = buf;
0066     compose_feature_string(RO_COMPAT);
0067     return out - buf;
0068 }
0069
0070 int bch_print_cache_set_feature_incompat(struct cache_set *c, char *buf, int size)
0071 {
0072     char *out = buf;
0073     compose_feature_string(INCOMPAT);
0074     return out - buf;
0075 }