block_dev: support RFW_NOWAIT on block device nodes

All support is already there in the generic code, we just need to wire
it up.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 9941dc8..ea21d18 100644 (file)
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1739,6 +1739,8 @@ static int blkdev_open(struct inode * inode, struct file * filp)
         */
        filp->f_flags |= O_LARGEFILE;
 
+       filp->f_mode |= FMODE_NOWAIT;
+
        if (filp->f_flags & O_NDELAY)
                filp->f_mode |= FMODE_NDELAY;
        if (filp->f_flags & O_EXCL)
@@ -1891,6 +1893,9 @@ ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from)
        if (iocb->ki_pos >= size)
                return -ENOSPC;
 
+       if ((iocb->ki_flags & (IOCB_NOWAIT | IOCB_DIRECT)) == IOCB_NOWAIT)
+               return -EOPNOTSUPP;
+
        iov_iter_truncate(from, size - iocb->ki_pos);
 
        blk_start_plug(&plug);