direct-io: add flag to allow aio writes beyond i_size
Some filesystems can handle direct I/O writes beyond i_size safely,
so allow them to opt into receiving them.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
diff --git a/fs/direct-io.c b/fs/direct-io.c
index 160a548..a701752 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -1194,13 +1194,19 @@
}
/*
- * For file extending writes updating i_size before data
- * writeouts complete can expose uninitialized blocks. So
- * even for AIO, we need to wait for i/o to complete before
- * returning in this case.
+ * For file extending writes updating i_size before data writeouts
+ * complete can expose uninitialized blocks in dumb filesystems.
+ * In that case we need to wait for I/O completion even if asked
+ * for an asynchronous write.
*/
- dio->is_async = !is_sync_kiocb(iocb) && !((rw & WRITE) &&
- (end > i_size_read(inode)));
+ if (is_sync_kiocb(iocb))
+ dio->is_async = false;
+ else if (!(dio->flags & DIO_ASYNC_EXTEND) &&
+ (rw & WRITE) && end > i_size_read(inode))
+ dio->is_async = false;
+ else
+ dio->is_async = true;
+
dio->inode = inode;
dio->rw = rw;