From: Ming Lei ming.lei@redhat.com
[ Upstream commit 7db304375e11741e5940f9bc549155035bfb4dc1 ]
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 asml.silence@gmail.com Signed-off-by: Ming Lei ming.lei@redhat.com Reviewed-by: Pavel Begunkov asml.silence@gmail.com Link: https://lore.kernel.org/r/20210821150751.1290434-1-ming.lei@redhat.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- 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 0361c48c9cb0..43aaa3566431 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -3286,6 +3286,12 @@ 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; @@ -3340,7 +3346,7 @@ 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; }