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 0ED3D9460; Tue, 15 Jul 2025 05:24:44 +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=1752557086; cv=none; b=pX8HbnEsQT52eAS/whpGrxb0fJx5RJGCIN/hyqvkFp+/KntNezdpcYu3+1eNDYRF+IWw00Y6YJpiYxxvpbi5+1YjVIEt0gBSlRO4N4vU5sAnWI2pVukT2ITwBEuQblWsrvcYxmzKfl1eTDLPn929kkdtxTYyYVFs3F4EaYoVotg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752557086; c=relaxed/simple; bh=Y8QDFCLNe7huxVz/T2FtbyuCf7tVqCtXCDHmrvgYseM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=AjDTQzT6ITY7KnL1mq9V2ROoo+uIJ2ZNqKsPgY3aJdd9QDjG0iFkZ6URiABf1/6iIGEmXPDcU/H1HIQ3dUR3ywdkwnURexfGjqNDZDKxksWFY8ejL+hGcPg5NMuOZuiDyXLlXzj8MQtrrtWnHAOHh8/0vCpPK867Ehi/PNGqeSA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=kQS/lahF; 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="kQS/lahF" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 92989C4CEE3; Tue, 15 Jul 2025 05:24:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1752557084; bh=Y8QDFCLNe7huxVz/T2FtbyuCf7tVqCtXCDHmrvgYseM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=kQS/lahFX1CrZjmtX9is+pM96MWVMFMX5jW9i7mlTkF19O6zm+9uiKcDK5TG/XsQg t9aO1sBJ/fJp6jmnr5W6AAttL472j0tygLrUjjWbeFyxr7/tF31v/bX4WiqsGNyOnH HOUs23bUddApYDFGz+vN3hxwL6uQD7G3maxbqM+lJ2sTPvDji2z5PBPrheXfdl9s54 Cic0/C7k6optol5Pma+vfLvwmM8hCCSmgAgTtzShOQdxLH5dZCbhKS61T6Zqwsamp/ cWkCricgQj3Gc66Ers5F8CuUziOeuZ2nKV6VoXVXgez14u1qm40yvB6vqxPI/imtz0 1J1rZ5q69GO/w== Date: Mon, 14 Jul 2025 22:24:44 -0700 From: "Darrick J. Wong" To: Brian Foster Cc: linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org, linux-mm@kvack.org, hch@infradead.org, willy@infradead.org Subject: Re: [PATCH v3 7/7] xfs: error tag to force zeroing on debug kernels Message-ID: <20250715052444.GP2672049@frogsfrogsfrogs> References: <20250714204122.349582-1-bfoster@redhat.com> <20250714204122.349582-8-bfoster@redhat.com> Precedence: bulk X-Mailing-List: linux-fsdevel@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: <20250714204122.349582-8-bfoster@redhat.com> On Mon, Jul 14, 2025 at 04:41:22PM -0400, Brian Foster wrote: > iomap_zero_range() has to cover various corner cases that are > difficult to test on production kernels because it is used in fairly > limited use cases. For example, it is currently only used by XFS and > mostly only in partial block zeroing cases. > > While it's possible to test most of these functional cases, we can > provide more robust test coverage by co-opting fallocate zero range > to invoke zeroing of the entire range instead of the more efficient > block punch/allocate sequence. Add an errortag to occasionally > invoke forced zeroing. > > Signed-off-by: Brian Foster > Reviewed-by: Christoph Hellwig > --- > fs/xfs/libxfs/xfs_errortag.h | 4 +++- > fs/xfs/xfs_error.c | 3 +++ > fs/xfs/xfs_file.c | 26 ++++++++++++++++++++------ > 3 files changed, 26 insertions(+), 7 deletions(-) > > diff --git a/fs/xfs/libxfs/xfs_errortag.h b/fs/xfs/libxfs/xfs_errortag.h > index a53c5d40e084..33ca3fc2ca88 100644 > --- a/fs/xfs/libxfs/xfs_errortag.h > +++ b/fs/xfs/libxfs/xfs_errortag.h > @@ -65,7 +65,8 @@ > #define XFS_ERRTAG_WRITE_DELAY_MS 43 > #define XFS_ERRTAG_EXCHMAPS_FINISH_ONE 44 > #define XFS_ERRTAG_METAFILE_RESV_CRITICAL 45 > -#define XFS_ERRTAG_MAX 46 > +#define XFS_ERRTAG_FORCE_ZERO_RANGE 46 > +#define XFS_ERRTAG_MAX 47 > > /* > * Random factors for above tags, 1 means always, 2 means 1/2 time, etc. > @@ -115,5 +116,6 @@ > #define XFS_RANDOM_WRITE_DELAY_MS 3000 > #define XFS_RANDOM_EXCHMAPS_FINISH_ONE 1 > #define XFS_RANDOM_METAFILE_RESV_CRITICAL 4 > +#define XFS_RANDOM_FORCE_ZERO_RANGE 4 > > #endif /* __XFS_ERRORTAG_H_ */ > diff --git a/fs/xfs/xfs_error.c b/fs/xfs/xfs_error.c > index dbd87e137694..00c0c391c329 100644 > --- a/fs/xfs/xfs_error.c > +++ b/fs/xfs/xfs_error.c > @@ -64,6 +64,7 @@ static unsigned int xfs_errortag_random_default[] = { > XFS_RANDOM_WRITE_DELAY_MS, > XFS_RANDOM_EXCHMAPS_FINISH_ONE, > XFS_RANDOM_METAFILE_RESV_CRITICAL, > + XFS_RANDOM_FORCE_ZERO_RANGE, > }; > > struct xfs_errortag_attr { > @@ -183,6 +184,7 @@ XFS_ERRORTAG_ATTR_RW(wb_delay_ms, XFS_ERRTAG_WB_DELAY_MS); > XFS_ERRORTAG_ATTR_RW(write_delay_ms, XFS_ERRTAG_WRITE_DELAY_MS); > XFS_ERRORTAG_ATTR_RW(exchmaps_finish_one, XFS_ERRTAG_EXCHMAPS_FINISH_ONE); > XFS_ERRORTAG_ATTR_RW(metafile_resv_crit, XFS_ERRTAG_METAFILE_RESV_CRITICAL); > +XFS_ERRORTAG_ATTR_RW(force_zero_range, XFS_ERRTAG_FORCE_ZERO_RANGE); > > static struct attribute *xfs_errortag_attrs[] = { > XFS_ERRORTAG_ATTR_LIST(noerror), > @@ -230,6 +232,7 @@ static struct attribute *xfs_errortag_attrs[] = { > XFS_ERRORTAG_ATTR_LIST(write_delay_ms), > XFS_ERRORTAG_ATTR_LIST(exchmaps_finish_one), > XFS_ERRORTAG_ATTR_LIST(metafile_resv_crit), > + XFS_ERRORTAG_ATTR_LIST(force_zero_range), > NULL, > }; > ATTRIBUTE_GROUPS(xfs_errortag); > diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c > index 0b41b18debf3..c865f9555b77 100644 > --- a/fs/xfs/xfs_file.c > +++ b/fs/xfs/xfs_file.c > @@ -27,6 +27,8 @@ > #include "xfs_file.h" > #include "xfs_aops.h" > #include "xfs_zone_alloc.h" > +#include "xfs_error.h" > +#include "xfs_errortag.h" > > #include > #include > @@ -1269,13 +1271,25 @@ xfs_falloc_zero_range( > if (error) > return error; > > - error = xfs_free_file_space(XFS_I(inode), offset, len, ac); > - if (error) > - return error; > + /* > + * Zero range implements a full zeroing mechanism but is only used in > + * limited situations. It is more efficient to allocate unwritten > + * extents than to perform zeroing here, so use an errortag to randomly > + * force zeroing on DEBUG kernels for added test coverage. > + */ > + if (XFS_TEST_ERROR(false, XFS_I(inode)->i_mount, > + XFS_ERRTAG_FORCE_ZERO_RANGE)) { > + error = xfs_zero_range(XFS_I(inode), offset, len, ac, NULL); Isn't this basically the ultra slow version fallback version of FALLOC_FL_WRITE_ZEROES ? --D > + } else { > + error = xfs_free_file_space(XFS_I(inode), offset, len, ac); > + if (error) > + return error; > > - len = round_up(offset + len, blksize) - round_down(offset, blksize); > - offset = round_down(offset, blksize); > - error = xfs_alloc_file_space(XFS_I(inode), offset, len); > + len = round_up(offset + len, blksize) - > + round_down(offset, blksize); > + offset = round_down(offset, blksize); > + error = xfs_alloc_file_space(XFS_I(inode), offset, len); > + } > if (error) > return error; > return xfs_falloc_setsize(file, new_size); > -- > 2.50.0 > >