On one system, there was bdi->io_pages==0. This seems to be the bug of a driver somewhere, and should fix it though. Anyway, it is better to avoid the divide-by-zero Oops. So this check it. Signed-off-by: OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> --- fs/fat/fatent.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/fat/fatent.c b/fs/fat/fatent.c index f7e3304..98a1c4f 100644 --- a/fs/fat/fatent.c 2020-08-30 06:52:47.251564566 +0900 +++ b/fs/fat/fatent.c 2020-08-30 06:54:05.838319213 +0900 @@ -660,7 +660,7 @@ static void fat_ra_init(struct super_blo if (fatent->entry >= ent_limit) return; - if (ra_pages > sb->s_bdi->io_pages) + if (sb->s_bdi->io_pages && ra_pages > sb->s_bdi->io_pages) ra_pages = rounddown(ra_pages, sb->s_bdi->io_pages); reada_blocks = ra_pages << (PAGE_SHIFT - sb->s_blocksize_bits + 1); _ -- OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx>
