btrfs_diskformat/core/
dev_item.rs

1use {
2    crate::UuidBytes,
3    byteorder::LE,
4    static_assertions::const_assert_eq,
5    zerocopy::{AsBytes, FromBytes, Unaligned, U32, U64},
6};
7
8/// Represents a complete block device.
9#[derive(Copy, Clone, Debug, AsBytes, FromBytes, Unaligned)]
10#[repr(C, packed)]
11pub struct DevItem {
12    /// The internal btrfs device ID.
13    ///
14    /// This should match the devid found in the filesystem's list of devices.
15    pub devid: U64<LE>,
16
17    /// The size of the device.
18    pub total_bytes: U64<LE>,
19
20    /// The bytes in use by the filesystem on the device.
21    pub bytes_used: U64<LE>,
22
23    /// The optimal I/O alignment for this device.
24    pub io_align: U32<LE>,
25
26    /// The optimal I/O width for this device.
27    pub io_width: U32<LE>,
28
29    /// The minimum I/O size for this device.
30    pub sector_size: U32<LE>,
31
32    /// The type and info for this device.
33    pub r#type: U64<LE>,
34
35    /// The expected generation for this device.
36    pub generation: U64<LE>,
37
38    /// The starting byte of this partition on the device, to allow for stripe
39    /// alignment.
40    pub start_offset: U64<LE>,
41
42    /// Grouping information for allocation decisions.
43    pub dev_group: U32<LE>,
44
45    /// The seek speed of the device on a scale from 0 to 100, where 100 is the
46    /// fastest.
47    pub seek_speed: u8,
48
49    /// The bandwidth of the device on a scale from 0 to 100, where 100 is the
50    /// fastest.
51    pub bandwith: u8,
52
53    /// The generated UUID for this device.
54    pub uuid: UuidBytes,
55
56    /// The UUID of the filesystem that owns this device.
57    pub fsid: UuidBytes,
58}
59const_assert_eq!(core::mem::size_of::<DevItem>(), 98);
btrfs_diskformat/core/dev_item.rs

btrfs_diskformat/core/
dev_item.rs
