[pbs-devel] [RFC proxmox-backup] backup/backup_info: ignore vanished backup dirs during listing

[Dominik Csapak <d.csapak@proxmox.com>]

this had the effect that that a snapshot listing errored out when called
during a prune action

we now ignore such errors and simply return no files

also add some context for the error if one happens

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
---
maybe we also want to filter such snapshots out one level higher?
so that we do not show 'empty' snapshots

 src/backup/backup_info.rs | 28 ++++++++++++++++++++++------
 1 file changed, 22 insertions(+), 6 deletions(-)

diff --git a/src/backup/backup_info.rs b/src/backup/backup_info.rs
index 5ff1a6f8..dba3fea5 100644
--- a/src/backup/backup_info.rs
+++ b/src/backup/backup_info.rs
@@ -1,4 +1,7 @@
-use crate::tools;
+use crate::tools::{
+    self,
+    fs::FileIterOps,
+};
 
 use anyhow::{bail, format_err, Error};
 use std::os::unix::io::RawFd;
@@ -339,11 +342,24 @@ impl BackupInfo {
 fn list_backup_files<P: ?Sized + nix::NixPath>(dirfd: RawFd, path: &P) -> Result<Vec<String>, Error> {
     let mut files = vec![];
 
-    tools::scandir(dirfd, path, &BACKUP_FILE_REGEX, |_, filename, file_type| {
-        if file_type != nix::dir::Type::File { return Ok(()); }
-        files.push(filename.to_owned());
-        Ok(())
-    })?;
+    match tools::fs::read_subdir(dirfd, path) {
+        Ok(iter) => {
+            for entry in iter.filter_file_name_regex(&BACKUP_FILE_REGEX) {
+                let entry = entry?;
+                let file_type = entry.file_type().ok_or_else(|| format_err!("unable to detect file type"))?;
+                if file_type == nix::dir::Type::File {
+                    // ok because we filtered with BACKUP_FILE_REGEX
+                    let filename = unsafe { entry.file_name_utf8_unchecked() };
+                    files.push(filename.to_owned());
+                }
+            }
+        },
+        Err(nix::Error::Sys(errno)) if errno == nix::errno::Errno::ENOENT => {
+            // ignore vanished backup dirs
+            eprintln!("backup dir vanished during listing");
+        },
+        Err(err) => bail!("error listing backup files: {}", err),
+    }
 
     Ok(files)
 }
-- 
2.20.1