bcachefs: avoid overflowing LRU_TIME_BITS for cached data lru

Kent Overstreet · Kent Overstreet · commit 9482f3b05332 · 2024-08-16T12:46:40.000-04:00
Reported-by: syzbot+510b0b28f8e6de64d307@syzkaller.appspotmail.com
Signed-off-by: Kent Overstreet &lt;kent.overstreet@linux.dev&gt;
diff --git a/fs/bcachefs/alloc_background.h b/fs/bcachefs/alloc_background.h
@@ -150,7 +150,9 @@ static inline void alloc_data_type_set(struct bch_alloc_v4 *a, enum bch_data_typ
 
 static inline u64 alloc_lru_idx_read(struct bch_alloc_v4 a)
 {
-	return a.data_type == BCH_DATA_cached ? a.io_time[READ] : 0;
+	return a.data_type == BCH_DATA_cached
+		? a.io_time[READ] & LRU_TIME_MAX
+		: 0;
 }
 
 #define DATA_TYPES_MOVABLE		\

Original file line number	Diff line number	Diff line change
`@@ -150,7 +150,9 @@ static inline void alloc_data_type_set(struct bch_alloc_v4 *a, enum bch_data_typ`
`150`	`150`
`151`	`151`	`static inline u64 alloc_lru_idx_read(struct bch_alloc_v4 a)`
`152`	`152`	`{`
`153`		`- return a.data_type == BCH_DATA_cached ? a.io_time[READ] : 0;`
	`153`	`+ return a.data_type == BCH_DATA_cached`
	`154`	`+ ? a.io_time[READ] & LRU_TIME_MAX`
	`155`	`+ : 0;`
`154`	`156`	`}`
`155`	`157`
`156`	`158`	`#define DATA_TYPES_MOVABLE \`