From 985b71db17506c668e5a9bd9fc700c95640dc191 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Thu, 29 Apr 2021 22:55:24 -0700 Subject: [PATCH] iomap: use filemap_range_needs_writeback() for O_DIRECT reads For reads, use the better variant of checking for the need to call filemap_write_and_wait_range() when doing O_DIRECT. This avoids falling back to the slow path for IOCB_NOWAIT, if there are no pages to wait for (or write out). Link: https://lkml.kernel.org/r/20210224164455.1096727-4-axboe@kernel.dk Signed-off-by: Jens Axboe Reviewed-by: Jan Kara Cc: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/iomap/direct-io.c | 24 ++++++++++++++++-------- 1 file changed, 16 insertions(+), 8 deletions(-) diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c index bdd0d89bbf0a..9398b8c31323 100644 --- a/fs/iomap/direct-io.c +++ b/fs/iomap/direct-io.c @@ -487,12 +487,28 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, if (pos >= dio->i_size) goto out_free_dio; + if (iocb->ki_flags & IOCB_NOWAIT) { + if (filemap_range_needs_writeback(mapping, pos, end)) { + ret = -EAGAIN; + goto out_free_dio; + } + iomap_flags |= IOMAP_NOWAIT; + } + if (iter_is_iovec(iter)) dio->flags |= IOMAP_DIO_DIRTY; } else { iomap_flags |= IOMAP_WRITE; dio->flags |= IOMAP_DIO_WRITE; + if (iocb->ki_flags & IOCB_NOWAIT) { + if (filemap_range_has_page(mapping, pos, end)) { + ret = -EAGAIN; + goto out_free_dio; + } + iomap_flags |= IOMAP_NOWAIT; + } + /* for data sync or sync, we need sync completion processing */ if (iocb->ki_flags & IOCB_DSYNC) dio->flags |= IOMAP_DIO_NEED_SYNC; @@ -507,14 +523,6 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, dio->flags |= IOMAP_DIO_WRITE_FUA; } - if (iocb->ki_flags & IOCB_NOWAIT) { - if (filemap_range_has_page(mapping, pos, end)) { - ret = -EAGAIN; - goto out_free_dio; - } - iomap_flags |= IOMAP_NOWAIT; - } - if (dio_flags & IOMAP_DIO_OVERWRITE_ONLY) { ret = -EAGAIN; if (pos >= dio->i_size || pos + count > dio->i_size)