LXR linux/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 <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