On Sun, Aug 30, 2020 at 09:59:41AM +0900, OGAWA Hirofumi wrote: > 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); Wait, rounddown? ->io_pages is supposed to be the maximum number of pages to readahead. Shouldn't this be max() instead of rounddown()?
