From patchwork Fri Sep 25 20:36:38 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Goldwyn Rodrigues X-Patchwork-Id: 11800723 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 099091580 for ; Fri, 25 Sep 2020 20:37:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E88EB20838 for ; Fri, 25 Sep 2020 20:37:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728996AbgIYUhF (ORCPT ); Fri, 25 Sep 2020 16:37:05 -0400 Received: from mx2.suse.de ([195.135.220.15]:37590 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727495AbgIYUhE (ORCPT ); Fri, 25 Sep 2020 16:37:04 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 4346BABBD; Fri, 25 Sep 2020 20:37:02 +0000 (UTC) From: Goldwyn Rodrigues To: linux-btrfs@vger.kernel.org Cc: Goldwyn Rodrigues Subject: [PATCH] btrfs: Calculate num_pages, reserve_bytes once in btrfs_buffered_write() Date: Fri, 25 Sep 2020 15:36:38 -0500 Message-Id: <20200925203638.28890-1-rgoldwyn@suse.de> X-Mailer: git-send-email 2.26.2 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org From: Goldwyn Rodrigues Cleanup. write_bytes can change in btrfs_check_nocow_lock(). Calculate variables such as num_pages and reserve_bytes once we are sure of the value of write_bytes so there is no need to re-calculate. Signed-off-by: Goldwyn Rodrigues Reviewed-by: Josef Bacik --- fs/btrfs/file.c | 34 ++++++++++++---------------------- 1 file changed, 12 insertions(+), 22 deletions(-) diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index 038e0afaf3d0..7695988fdba3 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -1648,8 +1648,7 @@ static noinline ssize_t btrfs_buffered_write(struct kiocb *iocb, size_t write_bytes = min(iov_iter_count(i), nrptrs * (size_t)PAGE_SIZE - offset); - size_t num_pages = DIV_ROUND_UP(write_bytes + offset, - PAGE_SIZE); + size_t num_pages; size_t reserve_bytes; size_t dirty_pages; size_t copied; @@ -1657,8 +1656,6 @@ static noinline ssize_t btrfs_buffered_write(struct kiocb *iocb, size_t num_sectors; int extents_locked; - WARN_ON(num_pages > nrptrs); - /* * Fault pages before locking them in prepare_pages * to avoid recursive lock @@ -1670,35 +1667,28 @@ static noinline ssize_t btrfs_buffered_write(struct kiocb *iocb, only_release_metadata = false; sector_offset = pos & (fs_info->sectorsize - 1); - reserve_bytes = round_up(write_bytes + sector_offset, - fs_info->sectorsize); extent_changeset_release(data_reserved); ret = btrfs_check_data_free_space(BTRFS_I(inode), &data_reserved, pos, write_bytes); if (ret < 0) { + /* + * If we don't have to cow at the offset, reserve + * metadata only. write_bytes may get smaller + * than requested here. + */ if (btrfs_check_nocow_lock(BTRFS_I(inode), pos, - &write_bytes) > 0) { - /* - * For nodata cow case, no need to reserve - * data space. - */ + &write_bytes) > 0) only_release_metadata = true; - /* - * our prealloc extent may be smaller than - * write_bytes, so scale down. - */ - num_pages = DIV_ROUND_UP(write_bytes + offset, - PAGE_SIZE); - reserve_bytes = round_up(write_bytes + - sector_offset, - fs_info->sectorsize); - } else { + else break; - } } + num_pages = DIV_ROUND_UP(write_bytes + offset, PAGE_SIZE); + WARN_ON(num_pages > nrptrs); + reserve_bytes = round_up(write_bytes + sector_offset, + fs_info->sectorsize); WARN_ON(reserve_bytes == 0); ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode), reserve_bytes);