On Fri, Nov 04, 2016 at 10:21:18AM -0600, Christoph Hellwig wrote: > This adds a full fledget direct I/O implementation using the iomap > interface. Full fledged in this case means all features are supported: > AIO, vectored I/O, any iov_iter type including kernel pointers, bvecs > and pipes, support for hole filling and async apending writes. It does > not mean supporting all the warts of the old generic code. We expect > i_rwsem to be held over the duration of the call, and we expect to > maintain i_dio_count ourselves, and we pass on any kinds of mapping > to the file system for now. > > The algorithm used is very simple: We use iomap_apply to iterate over > the range of the I/O, and then we use the new bio_iov_iter_get_pages > helper to lock down the user range for the size of the extent. > bio_iov_iter_get_pages can currently lock down twice as many pages as > the old direct I/O code did, which means that we will have a better > batch factor for everything but overwrites of badly fragmented files. > > Signed-off-by: Christoph Hellwig <hch@xxxxxx> Reviewed-by: Kent Overstreet <kent.overstreet@xxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
