f2fs: Add error handling for negative returns from do_garbage_collect

The function do_garbage_collect can return a value less than 0 due
to f2fs_cp_error being true or page allocation failure, as a result
of calling f2fs_get_sum_page. However, f2fs_gc does not account for
such cases, which could potentially lead to an abnormal total_freed
and thus cause subsequent code to behave unexpectedly. Given that
an f2fs_cp_error is irrecoverable, and considering that
do_garbage_collect already retries page allocation errors through
its call to f2fs_get_sum_page->f2fs_get_meta_page_retry, any error
reported by do_garbage_collect should immediately terminate the
current GC.

Signed-off-by: Yongpeng Yang <yangyongpeng1@oppo.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Author: Yongpeng Yang

fs/f2fs/gc.c

@@ -1865,6 +1865,9 @@ int f2fs_gc(struct f2fs_sb_info *sbi, struct f2fs_gc_control *gc_control)
 
 	seg_freed = do_garbage_collect(sbi, segno, &gc_list, gc_type,
 				gc_control->should_migrate_blocks);
+	if (seg_freed < 0)
+		goto stop;
+
 	total_freed += seg_freed;
 
 	if (seg_freed == f2fs_usable_segs_in_sec(sbi, segno)) {