ceph: increment/decrement dio counter on async requests

Ceph can in some cases issue an async DIO request, in which case we can
end up calling ceph_end_io_direct before the I/O is actually complete.
That may allow buffered operations to proceed while DIO requests are
still in flight.

Fix this by incrementing the i_dio_count when issuing an async DIO
request, and decrement it when tearing down the aio_req.

Fixes: 321fe13c9398 ("ceph: add buffered/direct exclusionary locking for reads and writes")
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 06efeaf..8de6339 100644 (file)
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -753,6 +753,9 @@ static void ceph_aio_complete(struct inode *inode,
        if (!atomic_dec_and_test(&aio_req->pending_reqs))
                return;
 
+       if (aio_req->iocb->ki_flags & IOCB_DIRECT)
+               inode_dio_end(inode);
+
        ret = aio_req->error;
        if (!ret)
                ret = aio_req->total_len;
@@ -1091,6 +1094,7 @@ ceph_direct_read_write(struct kiocb *iocb, struct iov_iter *iter,
                                              CEPH_CAP_FILE_RD);
 
                list_splice(&aio_req->osd_reqs, &osd_reqs);
+               inode_dio_begin(inode);
                while (!list_empty(&osd_reqs)) {
                        req = list_first_entry(&osd_reqs,
                                               struct ceph_osd_request,