Struct devices::virtio::fs::Config

pub struct Config {

    pub timeout: Duration,
    pub negative_timeout: Duration,
    pub cache_policy: CachePolicy,
    pub writeback: bool,
    pub rewrite_security_xattrs: bool,
    pub ascii_casefold: bool,
    pub privileged_quota_uids: Vec<uid_t>,
    pub use_dax: bool,
    pub posix_acl: bool,
    pub max_dynamic_perm: usize,
    pub max_dynamic_xattr: usize,
    pub security_ctx: bool,
    pub ugid_map: Vec<PermissionData>,
}

Options that configure the behavior of the file system.

Fields

timeout: Duration

How long the FUSE client should consider directory entries and file/directory attributes to be valid. This value corresponds to entry_timeout and attr_timeout in libfuse’s fuse_config, but we use the same value for the two.

If the contents of a directory or the attributes of a file or directory can only be modified by the FUSE client (i.e., the file system has exclusive access), then this should be a large value. The default value for this option is 5 seconds.

negative_timeout: Duration

How long the FUSE client can cache negative lookup results. If a file lookup fails, the client can assume the file doesn’t exist until the timeout and won’t send lookup. The value 0 means that negative lookup shouldn’t be cached.

If the contents of a directory can only be modified by the FUSE client (i.e., the file system has exclusive access), then this should be a large value. The default value for this option is 0 seconds (= no negative cache).

cache_policy: CachePolicy

The caching policy the file system should use. See the documentation of CachePolicy for more details.

writeback: bool

Whether the file system should enabled writeback caching. This can improve performance as it allows the FUSE client to cache and coalesce multiple writes before sending them to the file system. However, enabling this option can increase the risk of data corruption if the file contents can change without the knowledge of the FUSE client (i.e., the server does NOT have exclusive access). Additionally, the file system should have read access to all files in the directory it is serving as the FUSE client may send read requests even for files opened with O_WRONLY.

Therefore callers should only enable this option when they can guarantee that: 1) the file system has exclusive access to the directory and 2) the file system has read permissions for all files in that directory.

The default value for this option is false.

rewrite_security_xattrs: bool

Controls whether security.* xattrs (except for security.selinux) are re-written. When this is set to true, the server will add a “user.virtiofs” prefix to xattrs in the security namespace. Setting these xattrs requires CAP_SYS_ADMIN in the namespace where the file system was mounted and since the server usually runs in an unprivileged user namespace, it’s unlikely to have that capability.

The default value for this option is false.

ascii_casefold: bool

Use case-insensitive lookups for directory entries (ASCII only).

The default value for this option is false.

privileged_quota_uids: Vec<uid_t>

use_dax: bool

Use DAX for shared files.

Enabling DAX can improve performance for frequently accessed files by mapping regions of the file directly into the VM’s memory region, allowing direct access with the cost of slightly increased latency the first time the file is accessed. Additionally, since the mapping is shared directly from the host kernel’s file cache, enabling DAX can improve performance even when the cache policy is Never.

The default value for this option is false.

posix_acl: bool

Enable support for POSIX acls.

Enable POSIX acl support for the shared directory. This requires that the underlying file system also supports POSIX acls.

The default value for this option is true.

max_dynamic_perm: usize

max_dynamic_xattr: usize

security_ctx: bool

ugid_map: Vec<PermissionData>

Trait Implementations

impl Clone for Config

fn clone(&self) -> Config

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Config

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

Formats the value using the given formatter.

impl Default for Config

fn default() -> Self

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for Config

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl FromArgValue for Config

fn from_arg_value(value: &str) -> Result<Self, String>

Construct the type from a commandline value, returning an error string on failure.

impl PartialEq for Config

fn eq(&self, other: &Config) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for Config

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Eq for Config

impl StructuralPartialEq for Config