Struct btrfs_diskformat::Chunk
source · #[repr(C, packed)]pub struct Chunk {
pub length: U64<LE>,
pub owner: U64<LE>,
pub stripe_len: U64<LE>,
pub type: U64<LE>,
pub io_align: U32<LE>,
pub io_width: U32<LE>,
pub sector_size: U32<LE>,
pub num_stripes: U16<LE>,
pub sub_stripes: U16<LE>,
pub stripe: Stripe,
}
Expand description
This structure contains the mapping from a virtualized usable byte range within the backing
storage to a set of one or more stripes on individual backing devices. In addition to the
mapping, hints on optimal I/O parameters for this chunk. It is associated with CHUNK_ITEM
.
Although the structure definition only contains one stripe member, CHUNK_ITEM
contain as
many struct Stripe
structures as specified in the num_stripes
and sub_stripes
fields.
Fields
length: U64<LE>
The size of this chunk, in bytes.
owner: U64<LE>
The object ID of the root referencing this chunk. This is always the ID of an extent root.
stripe_len: U64<LE>
The replication stripe length.
type: U64<LE>
Flags indicating allocation type and replication policy.
io_align: U32<LE>
The optimal I/O alignment for this chunk.
io_width: U32<LE>
The optimal I/O width for this chunk.
sector_size: U32<LE>
The minimal I/O size for this chunk.
num_stripes: U16<LE>
The number of replication stripes.
sub_stripes: U16<LE>
The number of sub-stripes. This is only used for RAID-10.
stripe: Stripe
The first of one or more stripes that map to device extents.