On Sat, Aug 29, 2020 at 7:08 PM OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx> 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); > reada_blocks = ra_pages << (PAGE_SHIFT - sb->s_blocksize_bits + 1); I don't think we should work-around this here. What device is this on? Something like the below may help. diff --git a/block/blk-core.c b/block/blk-core.c index d9d632639bd1..10c08ac50697 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -539,6 +539,7 @@ struct request_queue *blk_alloc_queue(int node_id) goto fail_stats; q->backing_dev_info->ra_pages = VM_READAHEAD_PAGES; + q->backing_dev_info->io_pages = VM_READAHEAD_PAGES; q->backing_dev_info->capabilities = BDI_CAP_CGROUP_WRITEBACK; q->node = node_id; -- Jens Axboe
