[pbs-devel] [PATCH proxmox-backup 1/1] api: datastore: fix cache store creation when reusing s3 backend

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

Commit 3cc3c10d ("datastore: mark store as in-use by setting marker
on s3 backend") introduced the marker object on datastores used by
another instance. The check was however flawed as it made the local
chunk store creation dependent on the s3 client instantiation.

Therefore, instead factor out the DatastoreBackendType determination,
use that for the check and never assume the local cache store to
be pre-existing.

Also, since contents from the s3 store are refreshed anyway, local
contents in the cache store will be removed, except chunks which
are now cleaned up on create.

Fixes: 3cc3c10d ("datastore: mark store as in-use by setting marker on s3 backend")
Signed-off-by: Christian Ebner <c.ebner@proxmox.com>
---
 src/api2/config/datastore.rs | 119 +++++++++++++++++++----------------
 1 file changed, 64 insertions(+), 55 deletions(-)

diff --git a/src/api2/config/datastore.rs b/src/api2/config/datastore.rs
index f7b852cb7..d24323152 100644
--- a/src/api2/config/datastore.rs
+++ b/src/api2/config/datastore.rs
@@ -131,57 +131,54 @@ pub(crate) fn do_create_datastore(
             .parse_property_string(datastore.tuning.as_deref().unwrap_or(""))?,
     )?;
 
-    let mut backend_s3_client = None;
-    if let Some(ref backend_config) = datastore.backend {
-        let backend_config: DatastoreBackendConfig = backend_config.parse()?;
-        match backend_config.ty.unwrap_or_default() {
-            DatastoreBackendType::Filesystem => (),
-            DatastoreBackendType::S3 => {
-                if !overwrite_in_use {
-                    let s3_client_id = backend_config
-                        .client
-                        .as_ref()
-                        .ok_or_else(|| format_err!("missing required client"))?;
-                    let bucket = backend_config
-                        .bucket
-                        .clone()
-                        .ok_or_else(|| format_err!("missing required bucket"))?;
-                    let (config, _config_digest) =
-                        pbs_config::s3::config().context("failed to get s3 config")?;
-                    let config: S3ClientConf = config
-                        .lookup(S3_CFG_TYPE_ID, s3_client_id)
-                        .with_context(|| format!("no '{s3_client_id}' in config"))?;
-                    let options = S3ClientOptions::from_config(
-                        config.config,
-                        config.secret_key,
-                        bucket,
-                        datastore.name.to_owned(),
-                    );
-                    let s3_client = S3Client::new(options).context("failed to create s3 client")?;
-
-                    let object_key = S3ObjectKey::try_from(S3_DATASTORE_IN_USE_MARKER)
-                        .context("failed to generate s3 object key")?;
-                    if let Some(response) =
-                        proxmox_async::runtime::block_on(s3_client.get_object(object_key.clone()))
-                            .context("failed to get in-use marker from bucket")?
-                    {
-                        let content = proxmox_async::runtime::block_on(response.content.collect())
-                            .unwrap_or_default();
-                        let content =
-                            String::from_utf8(content.to_bytes().to_vec()).unwrap_or_default();
-                        let in_use: InUseContent =
-                            serde_json::from_str(&content).unwrap_or_default();
-                        if let Some(hostname) = in_use.hostname {
-                            bail!("Bucket already contains datastore in use by host {hostname}");
-                        } else {
-                            bail!("Bucket already contains datastore in use");
-                        }
-                    }
-                    backend_s3_client = Some(Arc::new(s3_client));
+    let backend_config: DatastoreBackendConfig =
+        datastore.backend.as_deref().unwrap_or("").parse()?;
+    let backend_type = backend_config.ty.unwrap_or_default();
+    let backend_s3_client = if backend_type == DatastoreBackendType::S3 {
+        let s3_client_id = backend_config
+            .client
+            .as_ref()
+            .ok_or_else(|| format_err!("missing required client"))?;
+        let bucket = backend_config
+            .bucket
+            .clone()
+            .ok_or_else(|| format_err!("missing required bucket"))?;
+        let (config, _config_digest) =
+            pbs_config::s3::config().context("failed to get s3 config")?;
+        let config: S3ClientConf = config
+            .lookup(S3_CFG_TYPE_ID, s3_client_id)
+            .with_context(|| format!("no '{s3_client_id}' in config"))?;
+        let options = S3ClientOptions::from_config(
+            config.config,
+            config.secret_key,
+            bucket,
+            datastore.name.to_owned(),
+        );
+        let s3_client = S3Client::new(options).context("failed to create s3 client")?;
+
+        if !overwrite_in_use {
+            let object_key = S3ObjectKey::try_from(S3_DATASTORE_IN_USE_MARKER)
+                .context("failed to generate s3 object key")?;
+            if let Some(response) =
+                proxmox_async::runtime::block_on(s3_client.get_object(object_key.clone()))
+                    .context("failed to get in-use marker from bucket")?
+            {
+                let content = proxmox_async::runtime::block_on(response.content.collect())
+                    .unwrap_or_default();
+                let content = String::from_utf8(content.to_bytes().to_vec()).unwrap_or_default();
+                let in_use: InUseContent = serde_json::from_str(&content).unwrap_or_default();
+                if let Some(hostname) = in_use.hostname {
+                    bail!("Bucket already contains datastore in use by host {hostname}");
+                } else {
+                    bail!("Bucket already contains datastore in use");
                 }
             }
         }
-    }
+
+        Some(Arc::new(s3_client))
+    } else {
+        None
+    };
 
     let unmount_guard = if datastore.backing_device.is_some() {
         do_mount_device(datastore.clone())?;
@@ -190,7 +187,7 @@ pub(crate) fn do_create_datastore(
         UnmountGuard::new(None)
     };
 
-    let chunk_store = if reuse_datastore && backend_s3_client.is_none() {
+    let chunk_store = if reuse_datastore && backend_type == DatastoreBackendType::Filesystem {
         ChunkStore::verify_chunkstore(&path).and_then(|_| {
             // Must be the only instance accessing and locking the chunk store,
             // dropping will close all other locks from this process on the lockfile as well.
@@ -201,12 +198,24 @@ pub(crate) fn do_create_datastore(
             )
         })?
     } else {
-        if let Ok(dir) = std::fs::read_dir(&path) {
-            for file in dir {
-                let name = file?.file_name();
-                let name = name.to_str();
-                if !name.is_some_and(|name| name.starts_with('.') || name == "lost+found") {
-                    bail!("datastore path not empty");
+        if !reuse_datastore && backend_type == DatastoreBackendType::Filesystem {
+            if let Ok(dir) = std::fs::read_dir(&path) {
+                for file in dir {
+                    let name = file?.file_name();
+                    let name = name.to_str();
+                    if !name.is_some_and(|name| name.starts_with('.') || name == "lost+found") {
+                        bail!("datastore path not empty");
+                    }
+                }
+            }
+        }
+        if reuse_datastore && backend_type == DatastoreBackendType::S3 {
+            let chunks_path = path.join(".chunks");
+            if let Err(err) = std::fs::remove_dir_all(&chunks_path) {
+                if err.kind() != std::io::ErrorKind::NotFound {
+                    return Err(err).with_context(|| {
+                        format!("failed to remove pre-existing chunks in {chunks_path:?}")
+                    });
                 }
             }
         }
-- 
2.47.2



_______________________________________________
pbs-devel mailing list
pbs-devel@lists.proxmox.com
https://lists.proxmox.com/cgi-bin/mailman/listinfo/pbs-devel