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>

1 files changed, 5 insertions, 0 deletions

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 9941dc8342df..ea21d18d8e79 100644
--- 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);