drivers/md/bcache/features.c

   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 <[email protected]>
   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 }