blkid: add bcache support

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

3 files changed, 115 insertions, 0 deletions

diff --git a/util-linux/volume_id/bcache.c b/util-linux/volume_id/bcache.c
new file mode 100644
index 000000000..648e44de5
--- /dev/null
+++ b/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;
+}
diff --git a/util-linux/volume_id/volume_id.c b/util-linux/volume_id/volume_id.c
index 5c459a0e2..3f71e0084 100644
--- a/util-linux/volume_id/volume_id.c
+++ b/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 */
diff --git a/util-linux/volume_id/volume_id_internal.h b/util-linux/volume_id/volume_id_internal.h
index 6e2dbd7bb..3061ac4d5 100644
--- a/util-linux/volume_id/volume_id_internal.h
+++ b/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*/);