[PATCH 3/3] iomap: use filemap_range_needs_writeback() for O_DIRECT reads
From: Jens Axboe <axboe@kernel.dk>
Date: 2021-02-09 02:31:29
Also in:
linux-fsdevel
Subsystem:
filesystems (vfs and infrastructure), filesystems [iomap], the rest · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds
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). Signed-off-by: Jens Axboe <axboe@kernel.dk> --- fs/iomap/direct-io.c | 23 +++++++++++++++-------- 1 file changed, 15 insertions(+), 8 deletions(-)
diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
index 933f234d5bec..5b111d1635ab 100644
--- a/fs/iomap/direct-io.c
+++ b/fs/iomap/direct-io.c@@ -458,9 +458,24 @@ __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; + } + flags |= IOMAP_NOWAIT; + } if (iter_is_iovec(iter)) dio->flags |= IOMAP_DIO_DIRTY; } else { + if (iocb->ki_flags & IOCB_NOWAIT) { + if (filemap_range_has_page(mapping, pos, end)) { + ret = -EAGAIN; + goto out_free_dio; + } + flags |= IOMAP_NOWAIT; + } + flags |= IOMAP_WRITE; dio->flags |= IOMAP_DIO_WRITE;
@@ -478,14 +493,6 @@ __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; - } - flags |= IOMAP_NOWAIT; - } - ret = filemap_write_and_wait_range(mapping, pos, end); if (ret) goto out_free_dio;
--
2.30.0