Struct RootItem

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#[repr(C, packed(1))]
pub struct RootItem {
Show 25 fields pub inode: InodeItem, pub generation: U64, pub root_dirid: U64, pub bytenr: U64, pub byte_limit: U64, pub bytes_used: U64, pub last_snapshot: U64, pub flags: U64, pub refs: U32, pub drop_progress: Key, pub drop_level: u8, pub level: u8, pub generation_v2: U64, pub uuid: UuidBytes, pub parent_uuid: UuidBytes, pub received_uuid: UuidBytes, pub ctransid: U64, pub otransid: U64, pub stransid: U64, pub rtransid: U64, pub ctime: Time, pub otime: Time, pub stime: Time, pub rtime: Time, pub _unused: [u64; 8],
}
Expand description

Defines the location and parameters of the root of a b-tree.

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§inode: InodeItem§generation: U64§root_dirid: U64§bytenr: U64§byte_limit: U64

Currently unused. Always 0.

§bytes_used: U64

Currently unused.

§last_snapshot: U64

The transaction ID of the last transaction that created a snapshot of this root.

§flags: U64§refs: U32

Only 0 or 1. Historically contained a reference count.

§drop_progress: Key

Contains the key of the last dropped item during subvolume removal or relocation.

Value will be zeroed out otherwise.

§drop_level: u8

The tree level of the node referenced in drop_progress.

§level: u8

The height of this root’s tree.

§generation_v2: U64

Value to help determine whether this root has been modified by an older btrfs implementation.

If the value is equal to generation, the fields below are valid. Otherwise, this indicates the fields are invalid but recoverable.

§uuid: UuidBytes

The subvolume’s UUID.

§parent_uuid: UuidBytes

The parent’s subvolume UUID.

This is used during send/receive.

§received_uuid: UuidBytes

The received UUID.

This is used during send/receive.

§ctransid: U64

The transaction ID of the last transaction that modified the tree.

Note: some operations like internal caches or relocation will not update this value.

§otransid: U64

The transaction ID of the transaction that created the tree.

§stransid: U64

The transaction ID for the transaction that sent this subvolume.

This value is non-zero for a received subvolume.

§rtransid: U64

The transaction ID for the transaction that received this subvolume.

This value is non-zero for a received subvolume.

§ctime: Time

The timestamp of the ctransid.

§otime: Time

The timestamp of the otransid.

§stime: Time

The timestamp of the stransid.

§rtime: Time

The timestamp of the rtransid.

§_unused: [u64; 8]

Currently unused. Reserved for future use.

Trait Implementations§

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impl Clone for RootItem

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fn clone(&self) -> RootItem

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl Debug for RootItem

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fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more
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impl FromBytes for RootItem

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fn mut_from_bytes( source: &mut [u8], ) -> Result<&mut Self, ConvertError<AlignmentError<&mut [u8], Self>, SizeError<&mut [u8], Self>, Infallible>>
where Self: IntoBytes + KnownLayout,

Interprets the given source as a &mut Self. Read more
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fn mut_from_prefix( source: &mut [u8], ) -> Result<(&mut Self, &mut [u8]), ConvertError<AlignmentError<&mut [u8], Self>, SizeError<&mut [u8], Self>, Infallible>>
where Self: IntoBytes + KnownLayout,

Interprets the prefix of the given source as a &mut Self without copying. Read more
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fn mut_from_suffix( source: &mut [u8], ) -> Result<(&mut [u8], &mut Self), ConvertError<AlignmentError<&mut [u8], Self>, SizeError<&mut [u8], Self>, Infallible>>
where Self: IntoBytes + KnownLayout,

Interprets the suffix of the given source as a &mut Self without copying. Read more
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fn mut_from_prefix_with_elems( source: &mut [u8], count: usize, ) -> Result<(&mut Self, &mut [u8]), ConvertError<AlignmentError<&mut [u8], Self>, SizeError<&mut [u8], Self>, Infallible>>
where Self: IntoBytes + KnownLayout<PointerMetadata = usize>,

Interprets the prefix of the given source as a &mut Self with DST length equal to count. Read more
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fn mut_from_suffix_with_elems( source: &mut [u8], count: usize, ) -> Result<(&mut [u8], &mut Self), ConvertError<AlignmentError<&mut [u8], Self>, SizeError<&mut [u8], Self>, Infallible>>
where Self: IntoBytes + KnownLayout<PointerMetadata = usize>,

Interprets the suffix of the given source as a &mut Self with DST length equal to count. Read more
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fn read_from_bytes(source: &[u8]) -> Result<Self, SizeError<&[u8], Self>>
where Self: Sized,

Reads a copy of Self from the given source. Read more
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fn read_from_prefix( source: &[u8], ) -> Result<(Self, &[u8]), SizeError<&[u8], Self>>
where Self: Sized,

Reads a copy of Self from the prefix of the given source. Read more
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fn read_from_suffix( source: &[u8], ) -> Result<(&[u8], Self), SizeError<&[u8], Self>>
where Self: Sized,

Reads a copy of Self from the suffix of the given source. Read more
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impl FromZeros for RootItem

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fn zero(&mut self)

Overwrites self with zeros. Read more
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fn new_zeroed() -> Self
where Self: Sized,

Creates an instance of Self from zeroed bytes. Read more
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impl IntoBytes for RootItem

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fn as_mut_bytes(&mut self) -> &mut [u8]
where Self: FromBytes,

Gets the bytes of this value mutably. Read more
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impl KnownLayout for RootItem
where [u64; 8]: KnownLayout,

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type PointerMetadata = <[u64; 8] as KnownLayout>::PointerMetadata

The type of metadata stored in a pointer to Self. Read more
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impl TryFromBytes for RootItem

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fn try_mut_from_bytes( bytes: &mut [u8], ) -> Result<&mut Self, ConvertError<AlignmentError<&mut [u8], Self>, SizeError<&mut [u8], Self>, ValidityError<&mut [u8], Self>>>
where Self: KnownLayout + IntoBytes,

Attempts to interpret the given source as a &mut Self without copying. Read more
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fn try_mut_from_prefix( source: &mut [u8], ) -> Result<(&mut Self, &mut [u8]), ConvertError<AlignmentError<&mut [u8], Self>, SizeError<&mut [u8], Self>, ValidityError<&mut [u8], Self>>>
where Self: KnownLayout + IntoBytes,

Attempts to interpret the prefix of the given source as a &mut Self. Read more
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fn try_mut_from_suffix( source: &mut [u8], ) -> Result<(&mut [u8], &mut Self), ConvertError<AlignmentError<&mut [u8], Self>, SizeError<&mut [u8], Self>, ValidityError<&mut [u8], Self>>>
where Self: KnownLayout + IntoBytes,

Attempts to interpret the suffix of the given source as a &mut Self. Read more
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fn try_mut_from_bytes_with_elems( source: &mut [u8], count: usize, ) -> Result<&mut Self, ConvertError<AlignmentError<&mut [u8], Self>, SizeError<&mut [u8], Self>, ValidityError<&mut [u8], Self>>>
where Self: KnownLayout<PointerMetadata = usize> + IntoBytes,

Attempts to interpret the given source as a &mut Self with a DST length equal to count. Read more
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fn try_mut_from_prefix_with_elems( source: &mut [u8], count: usize, ) -> Result<(&mut Self, &mut [u8]), ConvertError<AlignmentError<&mut [u8], Self>, SizeError<&mut [u8], Self>, ValidityError<&mut [u8], Self>>>
where Self: KnownLayout<PointerMetadata = usize> + IntoBytes,

Attempts to interpret the prefix of the given source as a &mut Self with a DST length equal to count. Read more
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fn try_mut_from_suffix_with_elems( source: &mut [u8], count: usize, ) -> Result<(&mut [u8], &mut Self), ConvertError<AlignmentError<&mut [u8], Self>, SizeError<&mut [u8], Self>, ValidityError<&mut [u8], Self>>>
where Self: KnownLayout<PointerMetadata = usize> + IntoBytes,

Attempts to interpret the suffix of the given source as a &mut Self with a DST length equal to count. Read more
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fn try_read_from_bytes( source: &[u8], ) -> Result<Self, ConvertError<Infallible, SizeError<&[u8], Self>, ValidityError<&[u8], Self>>>
where Self: Sized,

Attempts to read the given source as a Self. Read more
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fn try_read_from_prefix( source: &[u8], ) -> Result<(Self, &[u8]), ConvertError<Infallible, SizeError<&[u8], Self>, ValidityError<&[u8], Self>>>
where Self: Sized,

Attempts to read a Self from the prefix of the given source. Read more
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fn try_read_from_suffix( source: &[u8], ) -> Result<(&[u8], Self), ConvertError<Infallible, SizeError<&[u8], Self>, ValidityError<&[u8], Self>>>
where Self: Sized,

Attempts to read a Self from the suffix of the given source. Read more
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impl Copy for RootItem

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impl Unaligned for RootItem

Auto Trait Implementations§

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> CloneToUninit for T
where T: Clone,

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unsafe fn clone_to_uninit(&self, dest: *mut u8)

🔬This is a nightly-only experimental API. (clone_to_uninit)
Performs copy-assignment from self to dest. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.