The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From de1b0ee490eafdf65fac9eef9925391a8369f2dc Mon Sep 17 00:00:00 2001

From: Jens Axboe axboe@kernel.dk Date: Mon, 31 Aug 2020 11:20:02 -0600 Subject: [PATCH] block: ensure bdi->io_pages is always initialized

If a driver leaves the limit settings as the defaults, then we don't initialize bdi->io_pages. This means that file systems may need to work around bdi->io_pages == 0, which is somewhat messy.

Initialize the default value just like we do for ->ra_pages.

Cc: stable@vger.kernel.org Fixes: 9491ae4aade6 ("mm: don't cap request size based on read-ahead setting") Reported-by: OGAWA Hirofumi hirofumi@mail.parknet.co.jp Reviewed-by: Christoph Hellwig hch@lst.de Signed-off-by: Jens Axboe axboe@kernel.dk

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;