f2fs: fix infinite loop in __insert_extent_tree()

When we get wrong extent info data, and look up extent_node in rb tree,
it will cause infinite loop (CONFIG_F2FS_CHECK_FS=n). Avoiding this by
return NULL and print some kernel messages in that case.

Signed-off-by: wangzijie <[email protected]>
Reviewed-by: Chao Yu <[email protected]>
Signed-off-by: Jaegeuk Kim <[email protected]>

Author: wangzijie

fs/f2fs/extent_cache.c

@@ -604,7 +604,13 @@ static struct extent_node *__insert_extent_tree(struct f2fs_sb_info *sbi,
 			p = &(*p)->rb_right;
 			leftmost = false;
 		} else {
+			f2fs_err_ratelimited(sbi, "%s: corrupted extent, type: %d, "
+				"extent node in rb tree [%u, %u, %u], age [%llu, %llu], "
+				"extent node to insert [%u, %u, %u], age [%llu, %llu]",
+				__func__, et->type, en->ei.fofs, en->ei.blk, en->ei.len, en->ei.age,
+				en->ei.last_blocks, ei->fofs, ei->blk, ei->len, ei->age, ei->last_blocks);
 			f2fs_bug_on(sbi, 1);
+			return NULL;
 		}
 	}