Struct BlockDevBuilder 

pub struct BlockDevBuilder<S: State = Empty> { /* private fields */ }

Use builder syntax to set the inputs and finish with build().

Implementations

impl<S: State> BlockDevBuilder<S>

pub fn build(self) -> BlockDev

where S: IsComplete,

Finish building and return the requested object

pub fn driver(self, value: String) -> BlockDevBuilder<SetDriver<S>>

where S::Driver: IsUnset,

Required.

Specifies the block driver to use for the given node.

pub fn node_name(self, value: String) -> BlockDevBuilder<SetNodeName<S>>

where S::NodeName: IsUnset,

Optional (Some / Option setters).

This defines the name of the block driver node by which it will be referenced later. The name must be unique, i.e. it must not match the name of a different block driver node, or (if you use -drive as well) the ID of a drive.

If no node name is specified, it is automatically generated. The generated node name is not intended to be predictable and changes between QEMU invocations. For the top level, an explicit node name must be specified.

pub fn maybe_node_name( self, value: Option<String>, ) -> BlockDevBuilder<SetNodeName<S>>

where S::NodeName: IsUnset,

Optional (Some / Option setters).

This defines the name of the block driver node by which it will be referenced later. The name must be unique, i.e. it must not match the name of a different block driver node, or (if you use -drive as well) the ID of a drive.

If no node name is specified, it is automatically generated. The generated node name is not intended to be predictable and changes between QEMU invocations. For the top level, an explicit node name must be specified.

pub fn discard(self, value: IgnoreUnmap) -> BlockDevBuilder<SetDiscard<S>>

where S::Discard: IsUnset,

Optional (Some / Option setters).

discard is one of “ignore” (or “off”) or “unmap” (or “on”) and controls whether discard (also known as trim or unmap) requests are ignored or passed to the filesystem. Some machine types may not support discard requests.

pub fn maybe_discard( self, value: Option<IgnoreUnmap>, ) -> BlockDevBuilder<SetDiscard<S>>

where S::Discard: IsUnset,

Optional (Some / Option setters).

discard is one of “ignore” (or “off”) or “unmap” (or “on”) and controls whether discard (also known as trim or unmap) requests are ignored or passed to the filesystem. Some machine types may not support discard requests.

pub fn cache_direct(self, value: OnOff) -> BlockDevBuilder<SetCacheDirect<S>>

where S::CacheDirect: IsUnset,

Optional (Some / Option setters).

The host page cache can be avoided with cache.direct=on. This will attempt to do disk IO directly to the guest’s memory. QEMU may still perform an internal copy of the data.

pub fn maybe_cache_direct( self, value: Option<OnOff>, ) -> BlockDevBuilder<SetCacheDirect<S>>

where S::CacheDirect: IsUnset,

Optional (Some / Option setters).

The host page cache can be avoided with cache.direct=on. This will attempt to do disk IO directly to the guest’s memory. QEMU may still perform an internal copy of the data.

pub fn cache_no_flush(self, value: OnOff) -> BlockDevBuilder<SetCacheNoFlush<S>>

where S::CacheNoFlush: IsUnset,

Optional (Some / Option setters).

In case you don’t care about data integrity over host failures, you can use cache.no-flush=on. This option tells QEMU that it never needs to write any data to the disk but can instead keep things in cache. If anything goes wrong, like your host losing power, the disk storage getting disconnected accidentally, etc. your image will most probably be rendered unusable.

pub fn maybe_cache_no_flush( self, value: Option<OnOff>, ) -> BlockDevBuilder<SetCacheNoFlush<S>>

where S::CacheNoFlush: IsUnset,

Optional (Some / Option setters).

In case you don’t care about data integrity over host failures, you can use cache.no-flush=on. This option tells QEMU that it never needs to write any data to the disk but can instead keep things in cache. If anything goes wrong, like your host losing power, the disk storage getting disconnected accidentally, etc. your image will most probably be rendered unusable.

pub fn read_only(self, value: OnOff) -> BlockDevBuilder<SetReadOnly<S>>

where S::ReadOnly: IsUnset,

Optional (Some / Option setters).

Open the node read-only. Guest write attempts will fail.

Note that some block drivers support only read-only access, either generally or in certain configurations. In this case, the default value read-only=off does not work and the option must be specified explicitly.

pub fn maybe_read_only( self, value: Option<OnOff>, ) -> BlockDevBuilder<SetReadOnly<S>>

where S::ReadOnly: IsUnset,

Optional (Some / Option setters).

Open the node read-only. Guest write attempts will fail.

Note that some block drivers support only read-only access, either generally or in certain configurations. In this case, the default value read-only=off does not work and the option must be specified explicitly.

pub fn auto_read_only(self, value: OnOff) -> BlockDevBuilder<SetAutoReadOnly<S>>

where S::AutoReadOnly: IsUnset,

Optional (Some / Option setters).

If auto-read-only=on is set, QEMU may fall back to read-only usage even when read-only=off is requested, or even switch between modes as needed, e.g. depending on whether the image file is writable or whether a writing user is attached to the node.

pub fn maybe_auto_read_only( self, value: Option<OnOff>, ) -> BlockDevBuilder<SetAutoReadOnly<S>>

where S::AutoReadOnly: IsUnset,

Optional (Some / Option setters).

If auto-read-only=on is set, QEMU may fall back to read-only usage even when read-only=off is requested, or even switch between modes as needed, e.g. depending on whether the image file is writable or whether a writing user is attached to the node.

pub fn force_share(self, value: OnOff) -> BlockDevBuilder<SetForceShare<S>>

where S::ForceShare: IsUnset,

Optional (Some / Option setters).

Override the image locking system of QEMU by forcing the node to utilize weaker shared access for permissions where it would normally request exclusive access. When there is the potential for multiple instances to have the same file open (whether this invocation of QEMU is the first or the second instance), both instances must permit shared access for the second instance to succeed at opening the file.

Enabling force-share=on requires read-only=on.

pub fn maybe_force_share( self, value: Option<OnOff>, ) -> BlockDevBuilder<SetForceShare<S>>

where S::ForceShare: IsUnset,

Optional (Some / Option setters).

Override the image locking system of QEMU by forcing the node to utilize weaker shared access for permissions where it would normally request exclusive access. When there is the potential for multiple instances to have the same file open (whether this invocation of QEMU is the first or the second instance), both instances must permit shared access for the second instance to succeed at opening the file.

Enabling force-share=on requires read-only=on.

pub fn detect_zeroes( self, value: OnOffUnmap, ) -> BlockDevBuilder<SetDetectZeroes<S>>

where S::DetectZeroes: IsUnset,

Optional (Some / Option setters).

detect-zeroes is “off”, “on” or “unmap” and enables the automatic conversion of plain zero writes by the OS to driver specific optimized zero write commands. You may even choose “unmap” if discard is set to “unmap” to allow a zero write to be converted to an unmap operation.

pub fn maybe_detect_zeroes( self, value: Option<OnOffUnmap>, ) -> BlockDevBuilder<SetDetectZeroes<S>>

where S::DetectZeroes: IsUnset,

Optional (Some / Option setters).

detect-zeroes is “off”, “on” or “unmap” and enables the automatic conversion of plain zero writes by the OS to driver specific optimized zero write commands. You may even choose “unmap” if discard is set to “unmap” to allow a zero write to be converted to an unmap operation.

pub fn driver_opts( self, value: HashMap<String, String>, ) -> BlockDevBuilder<SetDriverOpts<S>>

where S::DriverOpts: IsUnset,

Optional (Some / Option setters).

pub fn maybe_driver_opts( self, value: Option<HashMap<String, String>>, ) -> BlockDevBuilder<SetDriverOpts<S>>

where S::DriverOpts: IsUnset,

Optional (Some / Option setters).