btrfs_cli/inspect/
min_dev_size.rs

1use crate::{Format, Runnable, util::human_bytes};
2use anyhow::{Context, Result};
3use clap::Parser;
4use std::{fs::File, os::unix::io::AsFd, path::PathBuf};
5
6/// Print the minimum size a device can be shrunk to.
7///
8/// Returns the minimum size in bytes that the specified device can be
9/// resized to without losing data. The device id 1 is used by default.
10/// Requires CAP_SYS_ADMIN.
11#[derive(Parser, Debug)]
12pub struct MinDevSizeCommand {
13    /// Specify the device id to query
14    #[arg(long = "id", default_value = "1")]
15    devid: u64,
16
17    /// Path to a file or directory on the btrfs filesystem
18    path: PathBuf,
19}
20
21impl Runnable for MinDevSizeCommand {
22    fn run(&self, _format: Format, _dry_run: bool) -> Result<()> {
23        let file = File::open(&self.path).with_context(|| {
24            format!("failed to open '{}'", self.path.display())
25        })?;
26
27        let size = btrfs_uapi::device::device_min_size(
28            file.as_fd(),
29            self.devid,
30        )
31        .with_context(|| {
32            format!(
33                "failed to determine min device size for devid {} on '{}'",
34                self.devid,
35                self.path.display()
36            )
37        })?;
38
39        println!("{} bytes ({})", size, human_bytes(size));
40        Ok(())
41    }
42}
btrfs_cli/inspect/min_dev_size.rs

btrfs_cli/inspect/
min_dev_size.rs
