On Wed, Mar 15, 2017 at 04:51:02PM -0500, Goldwyn Rodrigues wrote: > From: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx> > > Find out if the write will trigger a wait due to writeback. If yes, > return -EAGAIN. > > This introduces a new function filemap_range_has_page() which > returns true if the file's mapping has a page within the range > mentioned. > > Return -EINVAL for buffered AIO: there are multiple causes of > delay such as page locks, dirty throttling logic, page loading > from disk etc. which cannot be taken care of. Also, this patch only touches the write path; we have a similar call to write_and_wait_range() in generic_file_read_iter(). Actually, why do we even have that? Why can't we satisfy an O_DIRECT read from the cache?
