zfs_prune: reset sc.nr_to_scan

sc.nr_to_scan is an input to super_cache_clean (via shrinker->scan_objects), used to set the number of objects to scan in the various caches. However super_cache_scan also modifies sc.nr_to_scan, so when used in a loop we need to reset sc.nr_to_scan back to our desired nr_to_scan for the next iteration. Issue discovered and solution suggested by Tenzin Lhakhang @tlhakhan. Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Chris Dunlop <[email protected]> Issue openzfs#12433 Closes openzfs#12908
truenas · Jan 18, 2022 · a0c70ee · a0c70ee
1 parent d43236a
commit a0c70ee
Showing 1 changed file with 5 additions and 0 deletions.
diff --git a/module/os/linux/zfs/zfs_vfsops.c b/module/os/linux/zfs/zfs_vfsops.c
@@ -1295,6 +1295,11 @@ zfs_prune(struct super_block *sb, unsigned long nr_to_scan, int *objects)
 		*objects = 0;
 		for_each_online_node(sc.nid) {
 			*objects += (*shrinker->scan_objects)(shrinker, &sc);
+			/*
+			 * reset sc.nr_to_scan, modified by
+			 * scan_objects == super_cache_scan
+			 */
+			sc.nr_to_scan = nr_to_scan;
 		}
 	} else {
 			*objects = (*shrinker->scan_objects)(shrinker, &sc);