Fix snapshot rotation failure on remote filesystems

Snapshots with read-only permissions (from chmod -w at creation) and
internal dirs with restrictive modes (e.g. /etc at 555) prevented
rm -rf from deleting old snapshots during rotation. This caused
cascading mv failures and silent rotation breakage.

- Add chmod -R u+w before rm -rf of oldest snapshot
- Clean up orphan snapshots beyond retention count
- Add error checking on rm, mv, and cp -al operations

1 files changed, 22 insertions, 3 deletions

diff --git a/rsyncshot b/rsyncshot
index 5b5820b..8194d20 100755
--- a/rsyncshot
+++ b/rsyncshot
@@ -940,9 +940,24 @@ fi
 log "Rotating snapshots..."
 
 # --- Delete oldest snapshot if it exceeds retention count ---
+# Restore write permission recursively first — snapshots contain directories
+# preserved with their original permissions (e.g. /etc dirs with mode 555),
+# and chmod -w (applied at creation) removes owner write on the top level.
+# Without u+w, rm -rf fails on remote filesystems where we run as a normal user.
 if run_cmd "[ -d '$BASE_PATH/$TYPE.$MAX' ]"; then
     log "Deleting oldest snapshot: $TYPE.$MAX"
-    run_cmd "$RM -rf '$BASE_PATH/$TYPE.$MAX'"
+    run_cmd "chmod -R u+w '$BASE_PATH/$TYPE.$MAX'"
+    if ! run_cmd "$RM -rf '$BASE_PATH/$TYPE.$MAX'"; then
+        error "Snapshot rotation failed: could not delete $TYPE.$MAX"
+    fi
+fi
+
+# --- Clean up orphan snapshot beyond retention (from previous failures) ---
+BEYOND=$((MAX+1))
+if run_cmd "[ -d '$BASE_PATH/$TYPE.$BEYOND' ]"; then
+    log "Cleaning up orphaned snapshot: $TYPE.$BEYOND"
+    run_cmd "chmod -R u+w '$BASE_PATH/$TYPE.$BEYOND'"
+    run_cmd "$RM -rf '$BASE_PATH/$TYPE.$BEYOND'"
 fi
 
 # --- Rotate existing snapshots (newest to oldest to avoid overwriting) ---
@@ -950,7 +965,9 @@ for (( start=$((MAX)); start>=0; start-- )); do
     end=$((start+1))
     if run_cmd "[ -d '$BASE_PATH/$TYPE.$start' ]"; then
         log "Rotating: $TYPE.$start -> $TYPE.$end"
-        run_cmd "$MV '$BASE_PATH/$TYPE.$start' '$BASE_PATH/$TYPE.$end'"
+        if ! run_cmd "$MV '$BASE_PATH/$TYPE.$start' '$BASE_PATH/$TYPE.$end'"; then
+            error "Snapshot rotation failed: could not move $TYPE.$start to $TYPE.$end"
+        fi
     fi
 done
 
@@ -962,7 +979,9 @@ run_cmd "touch '$BASE_PATH/latest'"
 # This is instant and uses no additional disk space for unchanged files.
 # Only files that differ between snapshots consume extra space.
 log "Creating new snapshot: $TYPE.0"
-run_cmd "$CP -al '$BASE_PATH/latest' '$BASE_PATH/$TYPE.0'"
+if ! run_cmd "$CP -al '$BASE_PATH/latest' '$BASE_PATH/$TYPE.0'"; then
+    error "Snapshot creation failed: could not hard-link latest to $TYPE.0"
+fi
 
 # --- Make snapshot read-only to prevent accidental modification ---
 run_cmd "chmod -w '$BASE_PATH/$TYPE.0'"