Re: [pbs-devel] [PATCH proxmox-backup v3 07/24] api2: removable datastore creation

[Christian Ebner <c.ebner@proxmox.com>]

On 4/9/24 12:59, Hannes Laimer wrote:
> Signed-off-by: Hannes Laimer <h.laimer@proxmox.com>
> ---
>   src/api2/config/datastore.rs | 52 ++++++++++++++++++++++++++++++++++--
>   1 file changed, 50 insertions(+), 2 deletions(-)
> 
> diff --git a/src/api2/config/datastore.rs b/src/api2/config/datastore.rs
> index 3081e1f4..0194d7d4 100644
> --- a/src/api2/config/datastore.rs
> +++ b/src/api2/config/datastore.rs
> @@ -8,7 +8,7 @@ use serde_json::Value;
>   use proxmox_router::{http_bail, Permission, Router, RpcEnvironment, RpcEnvironmentType};
>   use proxmox_schema::{api, param_bail, ApiType};
>   use proxmox_section_config::SectionConfigData;
> -use proxmox_sys::{task_warn, WorkerTaskContext};
> +use proxmox_sys::{task_log, task_warn, WorkerTaskContext};
>   use proxmox_uuid::Uuid;
>   
>   use pbs_api_types::{
> @@ -20,7 +20,8 @@ use pbs_config::BackupLockGuard;
>   use pbs_datastore::chunk_store::ChunkStore;
>   
>   use crate::api2::admin::{
> -    prune::list_prune_jobs, sync::list_sync_jobs, verify::list_verification_jobs,
> +    datastore::do_mount_device, prune::list_prune_jobs, sync::list_sync_jobs,
> +    verify::list_verification_jobs,
>   };
>   use crate::api2::config::prune::{delete_prune_job, do_create_prune_job};
>   use crate::api2::config::sync::delete_sync_job;
> @@ -72,6 +73,31 @@ pub(crate) fn do_create_datastore(
>       datastore: DataStoreConfig,
>       worker: Option<&dyn WorkerTaskContext>,
>   ) -> Result<(), Error> {
> +    if datastore.backing_device.is_some() {
> +        let mut mount_point: PathBuf = PathBuf::from(&datastore.path);

There is no need for the additional type annotation, the type is already 
given by the return type of the `PathBuf::from()`.

> +
> +        let default_options = proxmox_sys::fs::CreateOptions::new();
> +        proxmox_sys::fs::create_path(
> +            &mount_point,
> +            Some(default_options.clone()),
> +            Some(default_options),
> +        )?;
> +        do_mount_device(None, config.clone(), datastore.clone(), worker)?;
> +
> +        mount_point.push(".chunks");
> +        if mount_point.is_dir() {
> +            config.set_data(&datastore.name, "datastore", &datastore)?;
> +            pbs_config::datastore::save_config(&config)?;
> +            if let Some(worker) = worker {
> +                task_log!(
> +                    worker,
> +                    "created removable datastore, chunkstore already exists"
> +                );
> +                return Ok(());
> +            }
> +        }

If `.chunks` already exists on the mounted datastore, but it is not a 
directory, then I guess something is off. Can and should this be handled 
early, or is this already fully covered by the `ChunkStore::create` call 
later on?

> +    }
> +
>       let path: PathBuf = datastore.path.clone().into();
>   
>       let tuning: DatastoreTuning = serde_json::from_value(
> @@ -122,6 +148,28 @@ pub fn create_datastore(
>           param_bail!("name", "datastore '{}' already exists.", config.name);
>       }
>   
> +    if let Some(uuid) = &config.backing_device {
> +        let already_used_by = section_config
> +            .sections
> +            .iter()
> +            .flat_map(|(datastore_name, (_, config))| {
> +                config
> +                    .as_object()
> +                    .and_then(|cfg| cfg.get("backing-device"))
> +                    .and_then(|backing_device| backing_device.as_str())
> +                    .filter(|&device_uuid| device_uuid == uuid)
> +                    .map(|_| datastore_name)
> +            })
> +            .next();
> +
> +        if let Some(datastore_name) = already_used_by {
> +            param_bail!(
> +                "backing-device",
> +                "device already in use by datastore '{datastore_name}'",
> +            );
> +        }
> +    }
> +
>       let auth_id: Authid = rpcenv.get_auth_id().unwrap().parse()?;
>       let to_stdout = rpcenv.env_type() == RpcEnvironmentType::CLI;
>