libblkid: DRBD support for blkid

DRBD is the Distributed Replicated Block Device, a replication service for low
level block devices.

The attached patch provides libblkid detection for v08 type drbd devices
(v08 is the current one).

[kzak@redhat.com: - port to libblkid 2.17
                  - use BLKID_USAGE_RAID flag
                  - remove BLKID_IDINFO_TOLERANT flag
                  - note that DRBD is supported since kernel v2.6.33-rc1]

Signed-off-by: Bastian Friedrich <bastian.friedrich@collax.com>
Signed-off-by: Karel Zak <kzak@redhat.com>

1 files changed, 106 insertions, 0 deletions

diff --git a/shlibs/blkid/src/superblocks/drbd.c b/shlibs/blkid/src/superblocks/drbd.c
new file mode 100644
index 000000000..e0bbb4d66
--- /dev/null
+++ b/shlibs/blkid/src/superblocks/drbd.c
@@ -0,0 +1,106 @@
+/*
+ * Copyright (C) 2009 by Bastian Friedrich <bastian.friedrich@collax.com>
+ *
+ * This file may be redistributed under the terms of the
+ * GNU Lesser General Public License.
+ *
+ * defines, structs taken from drbd source; file names represent drbd source
+ * files.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <ctype.h>
+#include <inttypes.h>
+
+#include "superblocks.h"
+
+/*
+ * drbd/linux/drbd.h
+ */
+#define DRBD_MAGIC 0x83740267
+
+/*
+ * user/drbdmeta.c
+ * We only support v08 for now
+ */
+#define DRBD_MD_MAGIC_08 (DRBD_MAGIC+4)
+
+/*
+ * drbd/linux/drbd.h
+ */
+enum drbd_uuid_index {
+	UI_CURRENT,
+	UI_BITMAP,
+	UI_HISTORY_START,
+	UI_HISTORY_END,
+	UI_SIZE,		/* nl-packet: number of dirty bits */
+	UI_FLAGS,		/* nl-packet: flags */
+	UI_EXTENDED_SIZE	/* Everything. */
+};
+
+/*
+ * user/drbdmeta.c
+ * Minor modifications wrt. types
+ */
+struct md_on_disk_08 {
+	uint64_t la_sect;         /* last agreed size. */
+	uint64_t uuid[UI_SIZE];   /* UUIDs */
+	uint64_t device_uuid;
+	uint64_t reserved_u64_1;
+	uint32_t flags;
+	uint32_t magic;
+	uint32_t md_size_sect;
+	int32_t  al_offset;       /* signed sector offset to this block */
+	uint32_t al_nr_extents;   /* important for restoring the AL */
+	int32_t  bm_offset;       /* signed sector offset to the bitmap, from here */
+	uint32_t bm_bytes_per_bit;
+	uint32_t reserved_u32[4];
+
+	char reserved[8 * 512 - (8*(UI_SIZE+3)+4*11)];
+};
+
+
+static int probe_drbd(blkid_probe pr, const struct blkid_idmag *mag)
+{
+	struct md_on_disk_08 *md;
+	off_t off;
+
+	off = pr->size - sizeof(*md);
+
+	/* Small devices cannot be drbd (?) */
+	if (pr->size < 0x10000)
+		return -1;
+
+	md = (struct md_on_disk_08 *)
+		blkid_probe_get_buffer(pr,
+		off,
+		sizeof(struct md_on_disk_08));
+
+
+	if (be32_to_cpu(md->magic) != DRBD_MD_MAGIC_08)
+		return -1;
+
+	/*
+	 * DRBD does not have "real" uuids; the following resembles DRBD's
+	 * notion of uuids (64 bit, see struct above)
+	 */
+	blkid_probe_sprintf_uuid(pr,
+		(unsigned char *) &md->device_uuid, sizeof(md->device_uuid),
+		"0x%" PRIx64, be64_to_cpu(md->device_uuid));
+
+	blkid_probe_set_version(pr, "v08");
+
+	return 0;
+}
+
+const struct blkid_idinfo drbd_idinfo =
+{
+	.name		= "drbd",
+	.usage		= BLKID_USAGE_RAID,
+	.probefunc	= probe_drbd,
+	.magics		= BLKID_NONE_MAGIC
+};
+