From 7db304375e11741e5940f9bc549155035bfb4dc1 Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Sat, 21 Aug 2021 23:07:51 +0800 Subject: [PATCH] io_uring: retry in case of short read on block device In case of buffered reading from block device, when short read happens, we should retry to read more, otherwise the IO will be completed partially, for example, the following fio expects to read 2MB, but it can only read 1M or less bytes: fio --name=onessd --filename=/dev/nvme0n1 --filesize=2M \ --rw=randread --bs=2M --direct=0 --overwrite=0 --numjobs=1 \ --iodepth=1 --time_based=0 --runtime=2 --ioengine=io_uring \ --registerfiles --fixedbufs --gtod_reduce=1 --group_reporting Fix the issue by allowing short read retry for block device, which sets FMODE_BUF_RASYNC really. Fixes: 9a173346bd9e ("io_uring: fix short read retries for non-reg files") Cc: Pavel Begunkov Signed-off-by: Ming Lei Reviewed-by: Pavel Begunkov Link: https://lore.kernel.org/r/20210821150751.1290434-1-ming.lei@redhat.com Signed-off-by: Jens Axboe --- fs/io_uring.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 473a977c79792..364e77d5fe6ce 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -3382,6 +3382,12 @@ static inline int io_iter_do_read(struct io_kiocb *req, struct iov_iter *iter) return -EINVAL; } +static bool need_read_all(struct io_kiocb *req) +{ + return req->flags & REQ_F_ISREG || + S_ISBLK(file_inode(req->file)->i_mode); +} + static int io_read(struct io_kiocb *req, unsigned int issue_flags) { struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs; @@ -3436,7 +3442,7 @@ static int io_read(struct io_kiocb *req, unsigned int issue_flags) } else if (ret == -EIOCBQUEUED) { goto out_free; } else if (ret <= 0 || ret == io_size || !force_nonblock || - (req->flags & REQ_F_NOWAIT) || !(req->flags & REQ_F_ISREG)) { + (req->flags & REQ_F_NOWAIT) || !need_read_all(req)) { /* read all, failed, already did sync or don't want to retry */ goto done; } -- 2.30.2