[pbs-devel] [PATCH proxmox-backup] garbage_collection: only ignore 'missing chunk' errors

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

with the fix for #2909 (improving handling missing chunks), we
changed from bailing to warning during a garbage collection when
updating the atime of a chunk.

but, updating the atime can not only fail when the chunk is missing,
but also on other occasions, e.g. no permissions or more importantly,
no space left on the device. in that case, the atime of a valid and used
chunk cannot be updated, and the second sweep of the gc will remove that chunk.
[0] is a real world example of that happening.

instead, only warn on really missin chunks, and bail on all other
errors.

0: https://forum.proxmox.com/threads/pbs-server-full-two-days-later-almost-empty.83274/

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
---
this can easily be tested by marking a chunk immutable with 'chattr +i <chunk>'
before that patch, the worker will warn and going over to the second phase,
with this patch, we will abort the gc

 src/backup/datastore.rs | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/src/backup/datastore.rs b/src/backup/datastore.rs
index fae7ff25..f8298ae8 100644
--- a/src/backup/datastore.rs
+++ b/src/backup/datastore.rs
@@ -445,13 +445,12 @@ impl DataStore {
             worker.check_abort()?;
             tools::fail_on_shutdown()?;
             let digest = index.index_digest(pos).unwrap();
-            if let Err(err) = self.chunk_store.touch_chunk(digest) {
+            if !self.chunk_store.cond_touch_chunk(digest, false)? {
                 crate::task_warn!(
                     worker,
-                    "warning: unable to access chunk {}, required by {:?} - {}",
+                    "warning: unable to access non-existant chunk {}, required by {:?}",
                     proxmox::tools::digest_to_hex(digest),
                     file_name,
-                    err,
                 );
 
                 // touch any corresponding .bad files to keep them around, meaning if a chunk is
-- 
2.20.1