blkid: add bcache support

URL: https://bugs.gentoo.org/508596
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

util-linux/volume_id/bcache.c

@@ -0,0 +1,110 @@
+/*
+ * Copyright (C) 2013 Rolf Fokkens <rolf@fokkens.nl>
+ *
+ * This file may be redistributed under the terms of the
+ * GNU Lesser General Public License.
+ *
+ * Based on code fragments from bcache-tools by Kent Overstreet:
+ * http://evilpiepirate.org/git/bcache-tools.git
+ */
+
+//kbuild:lib-$(CONFIG_FEATURE_VOLUMEID_BCACHE) += bcache.o
+
+//config:
+//config:config FEATURE_VOLUMEID_BCACHE
+//config:	bool "bcache filesystem"
+//config:	default y
+//config:	depends on VOLUMEID
+//config:	help
+//config:	  TODO
+//config:
+
+#include "volume_id_internal.h"
+
+#define SB_LABEL_SIZE      32
+#define SB_JOURNAL_BUCKETS 256U
+
+static const char bcache_magic[] = {
+	0xc6, 0x85, 0x73, 0xf6, 0x4e, 0x1a, 0x45, 0xca,
+	0x82, 0x65, 0xf5, 0x7f, 0x48, 0xba, 0x6d, 0x81
+};
+
+struct bcache_super_block {
+	uint64_t		csum;
+	uint64_t		offset;	/* sector where this sb was written */
+	uint64_t		version;
+
+	uint8_t			magic[16];
+
+	uint8_t			uuid[16];
+	union {
+		uint8_t		set_uuid[16];
+		uint64_t	set_magic;
+	};
+	uint8_t			label[SB_LABEL_SIZE];
+
+	uint64_t		flags;
+	uint64_t		seq;
+	uint64_t		pad[8];
+
+	union {
+	struct {
+		/* Cache devices */
+		uint64_t	nbuckets;	/* device size */
+
+		uint16_t	block_size;	/* sectors */
+		uint16_t	bucket_size;	/* sectors */
+
+		uint16_t	nr_in_set;
+		uint16_t	nr_this_dev;
+	};
+	struct {
+		/* Backing devices */
+		uint64_t	data_offset;
+
+		/*
+		 * block_size from the cache device section is still used by
+		 * backing devices, so don't add anything here until we fix
+		 * things to not need it for backing devices anymore
+		 */
+	};
+	};
+
+	uint32_t		last_mount;	/* time_t */
+
+	uint16_t		first_bucket;
+	union {
+		uint16_t	njournal_buckets;
+		uint16_t	keys;
+	};
+	uint64_t		d[SB_JOURNAL_BUCKETS];	/* journal buckets */
+};
+
+/* magic string */
+#define BCACHE_SB_MAGIC     bcache_magic
+/* magic string len */
+#define BCACHE_SB_MAGIC_LEN sizeof (bcache_magic)
+/* super block offset */
+#define BCACHE_SB_OFF       0x1000
+/* supper block offset in kB */
+#define BCACHE_SB_KBOFF     (BCACHE_SB_OFF >> 10)
+/* magic string offset within super block */
+#define BCACHE_SB_MAGIC_OFF offsetof (struct bcache_super_block, magic)
+
+int FAST_FUNC volume_id_probe_bcache(struct volume_id *id /*,uint64_t off*/)
+{
+	struct bcache_super_block *sb;
+
+	sb = volume_id_get_buffer(id, BCACHE_SB_OFF, sizeof(*sb));
+	if (sb == NULL)
+		return -1;
+
+	if (memcmp(sb->magic, BCACHE_SB_MAGIC, BCACHE_SB_MAGIC_LEN) != 0)
+		return -1;
+
+	volume_id_set_label_string(id, sb->label, SB_LABEL_SIZE);
+	volume_id_set_uuid(id, sb->uuid, UUID_DCE);
+	IF_FEATURE_BLKID_TYPE(id->type = "bcache";)
+
+	return 0;
+}

util-linux/volume_id/volume_id.c

@@ -107,6 +107,9 @@ static const probe_fptr fs1[] = {
 #if ENABLE_FEATURE_VOLUMEID_XFS
 	volume_id_probe_xfs,
 #endif
+#if ENABLE_FEATURE_VOLUMEID_BCACHE
+	volume_id_probe_bcache,
+#endif
 };
 
 /* fill buffer with maximum */

util-linux/volume_id/volume_id_internal.h

@@ -169,6 +169,8 @@ int FAST_FUNC volume_id_probe_linux_raid(struct volume_id *id /*,uint64_t off*/,
 
 /* FS */
 
+int FAST_FUNC volume_id_probe_bcache(struct volume_id *id /*,uint64_t off*/);
+
 int FAST_FUNC volume_id_probe_btrfs(struct volume_id *id /*,uint64_t off*/);
 
 int FAST_FUNC volume_id_probe_cramfs(struct volume_id *id /*,uint64_t off*/);