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 992E839879; Wed, 14 Aug 2024 05:12:28 +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=1723612349; cv=none; b=qbqDacP97gyHj5IYBULBXqNyXhLQFIOfLXQ9YDsL9ZANTXpZ4s6s1RcG5HtTmdQ+L0A/89LzOfqa0/7XyLyRmfMU0yLr2VH8mhCyiZLol5wpnwID4nDUgIop/Y7oLesyuEa/3JOnVu6JkAtm/ivcSqcWcmY1NcuKooBepAEAO+Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723612349; c=relaxed/simple; bh=Inla43+pi/44Nhb5T/nwC5IJ9GX/L5QYMTS/FVfyoPI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=tN9s93HyCR6HGjiJ2+SYCIaXiCQZ/Nyt1I8Mk7Hq9CoNwBVWaVOym9/aPP1gxLGToEXp9dCWaxQNmYWGw1x21a5aasV9JnBTQGDwQ4uhXHtqtEVPeSWGkooT2aT6AqTzKdvgtGTtdsE3W/024/87jxKpD6b3JwrficmbE0ffMNM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=SA/QQerg; 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="SA/QQerg" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E22E1C32786; Wed, 14 Aug 2024 05:12:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1723612348; bh=Inla43+pi/44Nhb5T/nwC5IJ9GX/L5QYMTS/FVfyoPI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=SA/QQerg71Ju3qDAkz68EBDJuwl2Kh4Z3rHAfPURo1md94eJK/8fgg9XuJLI12o75 5xq49Lr7CfZwlDwbyklvBc/XOPPR54fz3mFjiTT/DGSBGk4ErLpyL2MHYtNqMx9vh/ /uKCRHSHY+oB65aD6pQgfSsgnrpwrH3Ft0vwAg7dWBgA79VPB7VmOQjGD25NMH3+Oc 76dwKPIuZK/mLPWZZmdXNEWXMqd7IexZSOc39iT3LtyIALnVt3VbZw+iHAtukjTUxG XX4+p1ibBVt2maQpg9r6SP5vN9FkTi7ftNkSsjmIQUjCV/Q0Wtay3aReNConnlVq+b p3DQ6HqYZRCCQ== Date: Tue, 13 Aug 2024 22:12:27 -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: <20240814051227.GC865349@frogsfrogsfrogs> References: <20240814045232.21189-1-hch@lst.de> <20240814045232.21189-3-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: <20240814045232.21189-3-hch@lst.de> On Wed, Aug 14, 2024 at 06:52:11AM +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 Looks good now, Reviewed-by: Darrick J. Wong --D > --- > .gitignore | 1 + > src/Makefile | 2 +- > src/min_dio_alignment.c | 66 +++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 68 insertions(+), 1 deletion(-) > create mode 100644 src/min_dio_alignment.c > > diff --git a/.gitignore b/.gitignore > index 97c7e0014..36083e9d3 100644 > --- a/.gitignore > +++ b/.gitignore > @@ -207,6 +207,7 @@ tags > /src/log-writes/replay-log > /src/perf/*.pyc > /src/fiemap-fault > +/src/min_dio_alignment > > # Symlinked files > /tests/generic/035.out > 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..131f60236 > --- /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_alignment(const char *mntpnt, const char *devname) > +{ > + 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. > + */ > + 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_alignment(argv[1], argv[2])); > + exit(0); > +} > -- > 2.43.0 > >