Add btrfs detection to libblkid, now that the disk format should be
recognizable in the future.
# misc/blkid /tmp/fsfile
/tmp/fsfile: LABEL="mylabel" UUID="102b07f0-0e79-4b42-8a4e-1dde418bbe6d" TYPE="btrfs"
Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
---
Index: e2fsprogs/lib/blkid/probe.c
===================================================================
--- e2fsprogs.orig/lib/blkid/probe.c
+++ e2fsprogs/lib/blkid/probe.c
@@ -1293,6 +1293,22 @@ static int probe_lvm2(struct blkid_probe
return 0;
}
+
+static int probe_btrfs(struct blkid_probe *probe,
+ struct blkid_magic *id,
+ unsigned char *buf)
+{
+ struct btrfs_super_block *bs;
+ const char *label = 0;
+
+ bs = (struct btrfs_super_block *)buf;
+
+ if (strlen(bs->label))
+ label = bs->label;
+ blkid_set_tag(probe->dev, "LABEL", label, sizeof(bs->label));
+ set_uuid(probe->dev, bs->fsid, 0);
+ return 0;
+}
/*
* Various filesystem magics that we can check for. Note that kboff and
* sboff are in kilobytes and bytes respectively. All magics are in
@@ -1386,6 +1402,7 @@ static struct blkid_magic type_array[] =
{ "lvm2pv", 0, 0x018, 8, "LVM2 001", probe_lvm2 },
{ "lvm2pv", 1, 0x018, 8, "LVM2 001", probe_lvm2 },
{ "lvm2pv", 1, 0x218, 8, "LVM2 001", probe_lvm2 },
+ { "btrfs", 64, 0x40, 8, "_BHRfS_M", probe_btrfs },
{ NULL, 0, 0, 0, NULL, NULL }
};
Index: e2fsprogs/lib/blkid/probe.h
===================================================================
--- e2fsprogs.orig/lib/blkid/probe.h
+++ e2fsprogs/lib/blkid/probe.h
@@ -621,6 +621,110 @@ struct lvm2_pv_label_header {
__u8 pv_uuid[LVM2_ID_LEN];
} __attribute__ ((packed));
+
+/*
+ * this is a very generous portion of the super block, giving us
+ * room to translate 14 chunks with 3 stripes each.
+ */
+#define BTRFS_SYSTEM_CHUNK_ARRAY_SIZE 2048
+#define BTRFS_LABEL_SIZE 256
+#define BTRFS_UUID_SIZE 16
+#define BTRFS_FSID_SIZE 16
+#define BTRFS_CSUM_SIZE 32
+
+struct btrfs_dev_item {
+ /* the internal btrfs device id */
+ __u64 devid;
+
+ /* size of the device */
+ __u64 total_bytes;
+
+ /* bytes used */
+ __u64 bytes_used;
+
+ /* optimal io alignment for this device */
+ __u32 io_align;
+
+ /* optimal io width for this device */
+ __u32 io_width;
+
+ /* minimal io size for this device */
+ __u32 sector_size;
+
+ /* type and info about this device */
+ __u64 type;
+
+ /* expected generation for this device */
+ __u64 generation;
+
+ /*
+ * starting byte of this partition on the device,
+ * to allowr for stripe alignment in the future
+ */
+ __u64 start_offset;
+
+ /* grouping information for allocation decisions */
+ __u32 dev_group;
+
+ /* seek speed 0-100 where 100 is fastest */
+ __u8 seek_speed;
+
+ /* bandwidth 0-100 where 100 is fastest */
+ __u8 bandwidth;
+
+ /* btrfs generated uuid for this device */
+ __u8 uuid[BTRFS_UUID_SIZE];
+
+ /* uuid of FS who owns this device */
+ __u8 fsid[BTRFS_UUID_SIZE];
+} __attribute__ ((__packed__));
+
+/*
+ * the super block basically lists the main trees of the FS
+ * it currently lacks any block count etc etc
+ */
+struct btrfs_super_block {
+ __u8 csum[BTRFS_CSUM_SIZE];
+ /* the first 3 fields must match struct btrfs_header */
+ __u8 fsid[BTRFS_FSID_SIZE]; /* FS specific uuid */
+ __u64 bytenr; /* this block number */
+ __u64 flags;
+
+ /* allowed to be different from the btrfs_header from here own down */
+ __u64 magic;
+ __u64 generation;
+ __u64 root;
+ __u64 chunk_root;
+ __u64 log_root;
+
+ /* this will help find the new super based on the log root */
+ __u64 log_root_transid;
+ __u64 total_bytes;
+ __u64 bytes_used;
+ __u64 root_dir_objectid;
+ __u64 num_devices;
+ __u32 sectorsize;
+ __u32 nodesize;
+ __u32 leafsize;
+ __u32 stripesize;
+ __u32 sys_chunk_array_size;
+ __u64 chunk_root_generation;
+ __u64 compat_flags;
+ __u64 compat_ro_flags;
+ __u64 incompat_flags;
+ __u16 csum_type;
+ __u8 root_level;
+ __u8 chunk_root_level;
+ __u8 log_root_level;
+ struct btrfs_dev_item dev_item;
+
+ char label[BTRFS_LABEL_SIZE];
+
+ /* future expansion */
+ __u64 reserved[32];
+ __u8 sys_chunk_array[BTRFS_SYSTEM_CHUNK_ARRAY_SIZE];
+} __attribute__ ((__packed__));
+
/*
* Byte swap functions
*/
--
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