From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 98CD6125AC; Tue, 13 Aug 2024 14:40:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723560005; cv=none; b=mnYWOPE9lRdCQGJq2Kpp4C+WYnaU+AX0Y6j015VOP8bc1YzHpT8fYaio2FEYmCleRcmgD06gzt+b/+wt0LZMl2+IMYDQASD5qglkE0S/WpU1E0fE9LOCOtlBlJJWbVJYtXx4405/FZrjn6h/gSmLl5ptT/AecWRJPt+wJMnya88= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723560005; c=relaxed/simple; bh=SdIe+xJItG6ZuNwa0Em9ah2j1AjQv8knZayRK+shvD4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=iIU+8IWYJV8yWDOFDMCYsJFb0rSYfUiGpGVsA6Lc3HsK9GBl2VPxEYbP+dvYs1kJ/yA+PMqgiLoVdrXdKPYDjEuJG8KooPjCP7St0mrmSIchAeJVMdFrytJY83hbal62eSHhSkECQCqGT9rHQKs+lHWtOPcNJBH0E2STw9a8biU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=FDoVrv6h; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="FDoVrv6h" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2D2E4C4AF09; Tue, 13 Aug 2024 14:40:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1723560005; bh=SdIe+xJItG6ZuNwa0Em9ah2j1AjQv8knZayRK+shvD4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=FDoVrv6h5N0jaeIel/7klS/8Lt1d0lw1PAkc2dL6MuVOWulGr1b9ZAI+GMNr/2U6p p64rw17XcPV6P7/kd8rjb0kLWnXmFsINseuz3doEMAi0kD87CPMX5vsbgrBWF0LnU8 002K1xyemZdjbYwSy+R/Y/GeLtzl38buAe9+Tyx/hTgoFLRPr8UIHttHlg1tQiSsOc psYhHhoHDqsrntZNYPE8gSZMk4wFupf5d49o2huTztPO45tkcumCckl2bobEFTDRcN l8GIjY44nxxXvBRch1cxMxjzDRj7KFbNoCIIpIwCgmzdXVdx5rKnhdwxUNCEWjQnfR c4f5Xui7Hzerw== Date: Tue, 13 Aug 2024 07:40:04 -0700 From: "Darrick J. Wong" To: Christoph Hellwig Cc: Zorro Lang , fstests@vger.kernel.org, linux-xfs@vger.kernel.org Subject: Re: [PATCH 2/5] add a new min_dio_alignment helper Message-ID: <20240813144004.GD6047@frogsfrogsfrogs> References: <20240813073527.81072-1-hch@lst.de> <20240813073527.81072-3-hch@lst.de> Precedence: bulk X-Mailing-List: linux-xfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240813073527.81072-3-hch@lst.de> On Tue, Aug 13, 2024 at 09:35:01AM +0200, Christoph Hellwig wrote: > Add a new C program to find the minimum direct I/O alignment. This > uses the statx stx_dio_offset_align field if provided, then falls > back to the BLKSSZGET ioctl for block backed file systems and finally > the page size. It is intended as a more capable replacement for the > _min_dio_alignment bash helper. > > Signed-off-by: Christoph Hellwig > --- > src/Makefile | 2 +- > src/min_dio_alignment.c | 66 +++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 67 insertions(+), 1 deletion(-) > create mode 100644 src/min_dio_alignment.c > > diff --git a/src/Makefile b/src/Makefile > index 559209be9..b3da59a0e 100644 > --- a/src/Makefile > +++ b/src/Makefile > @@ -34,7 +34,7 @@ LINUX_TARGETS = xfsctl bstat t_mtab getdevicesize preallo_rw_pattern_reader \ > attr_replace_test swapon mkswap t_attr_corruption t_open_tmpfiles \ > fscrypt-crypt-util bulkstat_null_ocount splice-test chprojid_fail \ > detached_mounts_propagation ext4_resize t_readdir_3 splice2pipe \ > - uuid_ioctl t_snapshot_deleted_subvolume fiemap-fault > + uuid_ioctl t_snapshot_deleted_subvolume fiemap-fault min_dio_alignment > > EXTRA_EXECS = dmerror fill2attr fill2fs fill2fs_check scaleread.sh \ > btrfs_crc32c_forged_name.py popdir.pl popattr.py \ > diff --git a/src/min_dio_alignment.c b/src/min_dio_alignment.c > new file mode 100644 > index 000000000..c3345bfb2 > --- /dev/null > +++ b/src/min_dio_alignment.c > @@ -0,0 +1,66 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Copyright (c) 2024 Christoph Hellwig > + */ > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include "statx.h" > + > +static int min_dio_alignmenent(const char *mntpnt, const char *devname) min_dio_alignment > +{ > + struct statx stx = { }; > + struct stat st; > + int fd; > + > + /* > + * If the file system supports STATX_DIOALIGN, use the dio_offset_align > + * member, as that reports exactly the information that we are asking > + * for. > + * > + * STATX_DIOALIGN is only reported on regular files, so use O_TMPFILE > + * to create one without leaving a trace. > + */ > + fd = open(mntpnt, O_TMPFILE | O_RDWR | O_EXCL, 0600); > + if (fd >= 0 && > + xfstests_statx(fd, "", AT_EMPTY_PATH, STATX_DIOALIGN, &stx) == 0 && > + (stx.stx_mask & STATX_DIOALIGN)) > + return stx.stx_dio_offset_align; > + > + /* > + * If we are on a block device and no explicit aligned is reported, use > + * the logical block size as a guestimate. > + */ > + if (stat(devname, &st) == 0 && S_ISBLK(st.st_mode)) { > + int dev_fd = open(devname, O_RDONLY); > + int logical_block_size; > + > + if (dev_fd > 0 && > + fstat(dev_fd, &st) == 0 && > + S_ISBLK(st.st_mode) && > + ioctl(dev_fd, BLKSSZGET, &logical_block_size)) { > + return logical_block_size; > + } > + } > + > + /* > + * No support for STATX_DIOALIGN and not a block device: > + * default to PAGE_SIZE. Should we try DIOINFO here as a second to last gasp? --D > + */ > + return getpagesize(); > +} > + > +int main(int argc, char **argv) > +{ > + if (argc != 3) { > + fprintf(stderr, "usage: %s mountpoint devicename\n", argv[0]); > + exit(1); > + } > + > + printf("%d\n", min_dio_alignmenent(argv[1], argv[2])); > + exit(0); > +} > -- > 2.43.0 > >