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-rw-r--r--drivers/md/bcache/features.c75
1 files changed, 75 insertions, 0 deletions
diff --git a/drivers/md/bcache/features.c b/drivers/md/bcache/features.c
new file mode 100644
index 0000000000..634922c560
--- /dev/null
+++ b/drivers/md/bcache/features.c
@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Feature set bits and string conversion.
+ * Inspired by ext4's features compat/incompat/ro_compat related code.
+ *
+ * Copyright 2020 Coly Li <colyli@suse.de>
+ *
+ */
+#include "bcache_ondisk.h"
+#include "bcache.h"
+#include "features.h"
+
+struct feature {
+ int compat;
+ unsigned int mask;
+ const char *string;
+};
+
+static struct feature feature_list[] = {
+ {BCH_FEATURE_INCOMPAT, BCH_FEATURE_INCOMPAT_LOG_LARGE_BUCKET_SIZE,
+ "large_bucket"},
+ {0, 0, NULL },
+};
+
+#define compose_feature_string(type) \
+({ \
+ struct feature *f; \
+ bool first = true; \
+ \
+ for (f = &feature_list[0]; f->compat != 0; f++) { \
+ if (f->compat != BCH_FEATURE_ ## type) \
+ continue; \
+ if (BCH_HAS_ ## type ## _FEATURE(&c->cache->sb, f->mask)) { \
+ if (first) { \
+ out += snprintf(out, buf + size - out, \
+ "["); \
+ } else { \
+ out += snprintf(out, buf + size - out, \
+ " ["); \
+ } \
+ } else if (!first) { \
+ out += snprintf(out, buf + size - out, " "); \
+ } \
+ \
+ out += snprintf(out, buf + size - out, "%s", f->string);\
+ \
+ if (BCH_HAS_ ## type ## _FEATURE(&c->cache->sb, f->mask)) \
+ out += snprintf(out, buf + size - out, "]"); \
+ \
+ first = false; \
+ } \
+ if (!first) \
+ out += snprintf(out, buf + size - out, "\n"); \
+})
+
+int bch_print_cache_set_feature_compat(struct cache_set *c, char *buf, int size)
+{
+ char *out = buf;
+ compose_feature_string(COMPAT);
+ return out - buf;
+}
+
+int bch_print_cache_set_feature_ro_compat(struct cache_set *c, char *buf, int size)
+{
+ char *out = buf;
+ compose_feature_string(RO_COMPAT);
+ return out - buf;
+}
+
+int bch_print_cache_set_feature_incompat(struct cache_set *c, char *buf, int size)
+{
+ char *out = buf;
+ compose_feature_string(INCOMPAT);
+ return out - buf;
+}