[OpenWrt-Devel] [PATCH fstools] libblkid-tiny: add btrfs probe info

[Daniel Golle]

This only adds the magic for btrfs to show btrfs volumes in
block detect.

In order to properly support btrfs with more than one device and avoid
trying to mount the same device group once for each instance we have to
make sure that only one device per group will be mounted (btrfs then
automatically detects all other devices of the group).
For unmounting, the opposite should be applied: umount if called for
any of the devices in a mounted device group, unmount the filesystem.

Signed-off-by: Daniel Golle <daniel at makrotopia.org>
---
 libblkid-tiny/btrfs.c         | 92 +++++++++++++++++++++++++++++++++++++++++++
 libblkid-tiny/libblkid-tiny.c |  1 +
 2 files changed, 93 insertions(+)
 create mode 100644 libblkid-tiny/btrfs.c

diff --git a/libblkid-tiny/btrfs.c b/libblkid-tiny/btrfs.c
new file mode 100644
index 0000000..a95bd21
--- /dev/null
+++ b/libblkid-tiny/btrfs.c
@@ -0,0 +1,92 @@
+/*
+ * Copyright (C) 2009 Karel Zak <kzak at redhat.com>
+ *
+ * This file may be redistributed under the terms of the
+ * GNU Lesser General Public License.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <stdint.h>
+
+#include "superblocks.h"
+
+struct btrfs_super_block {
+	uint8_t csum[32];
+	uint8_t fsid[16];
+	uint64_t bytenr;
+	uint64_t flags;
+	uint8_t magic[8];
+	uint64_t generation;
+	uint64_t root;
+	uint64_t chunk_root;
+	uint64_t log_root;
+	uint64_t log_root_transid;
+	uint64_t total_bytes;
+	uint64_t bytes_used;
+	uint64_t root_dir_objectid;
+	uint64_t num_devices;
+	uint32_t sectorsize;
+	uint32_t nodesize;
+	uint32_t leafsize;
+	uint32_t stripesize;
+	uint32_t sys_chunk_array_size;
+	uint64_t chunk_root_generation;
+	uint64_t compat_flags;
+	uint64_t compat_ro_flags;
+	uint64_t incompat_flags;
+	uint16_t csum_type;
+	uint8_t root_level;
+	uint8_t chunk_root_level;
+	uint8_t log_root_level;
+	struct btrfs_dev_item {
+		uint64_t devid;
+		uint64_t total_bytes;
+		uint64_t bytes_used;
+		uint32_t io_align;
+		uint32_t io_width;
+		uint32_t sector_size;
+		uint64_t type;
+		uint64_t generation;
+		uint64_t start_offset;
+		uint32_t dev_group;
+		uint8_t seek_speed;
+		uint8_t bandwidth;
+		uint8_t uuid[16];
+		uint8_t fsid[16];
+	} __attribute__ ((__packed__)) dev_item;
+	uint8_t label[256];
+} __attribute__ ((__packed__));
+
+static int probe_btrfs(blkid_probe pr, const struct blkid_idmag *mag)
+{
+	struct btrfs_super_block *bfs;
+
+	bfs = blkid_probe_get_sb(pr, mag, struct btrfs_super_block);
+	if (!bfs)
+		return errno ? -errno : 1;
+
+	if (*bfs->label)
+		blkid_probe_set_label(pr,
+				(unsigned char *) bfs->label,
+				sizeof(bfs->label));
+
+	blkid_probe_set_uuid(pr, bfs->fsid);
+	blkid_probe_set_uuid_as(pr, bfs->dev_item.uuid, "UUID_SUB");
+
+	return 0;
+}
+
+const struct blkid_idinfo btrfs_idinfo =
+{
+	.name		= "btrfs",
+	.usage		= BLKID_USAGE_FILESYSTEM,
+	.probefunc	= probe_btrfs,
+	.minsz		= 1024 * 1024,
+	.magics		=
+	{
+	  { .magic = "_BHRfS_M", .len = 8, .sboff = 0x40, .kboff = 64 },
+	  { NULL }
+	}
+};
diff --git a/libblkid-tiny/libblkid-tiny.c b/libblkid-tiny/libblkid-tiny.c
index a01a43e..570cd73 100644
--- a/libblkid-tiny/libblkid-tiny.c
+++ b/libblkid-tiny/libblkid-tiny.c
@@ -167,6 +167,7 @@ static const struct blkid_idinfo *idinfos[] =
 	&jffs2_idinfo,
 	&hfsplus_idinfo,
 	&hfs_idinfo,
+	&btrfs_idinfo,
 };
 
 int probe_block(char *block, struct blkid_struct_probe *pr)
-- 
2.2.1
_______________________________________________
openwrt-devel mailing list
openwrt-devel at lists.openwrt.org
https://lists.openwrt.org/cgi-bin/mailman/listinfo/openwrt-devel