From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 036F0385D89; Wed, 1 Jul 2026 17:07:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782925635; cv=none; b=gKRxHzsxndjAV23hd1099vzsie4362Y/CMNU6WVMufR7JzsPl9IZlSPPdyCWxX/2Ouv8eXHA08vFcu9QJJq/IW9L7X2YHYZMNlc6vcn9+B4SxE8xQIzEpbPeUs4aMgQWktZsIOlwrLuAqfqvEkB6HbwViqlbAHIbuamOyKdIbp4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782925635; c=relaxed/simple; bh=3iisFyUjd5BnT25bYG8Yi8RdLOCy3g9Jmhn0Ujipl1Y=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=e4lsOdHv5Kng5FuWE35XjdW4rLZySUIKJb/lqjpvw7rsck4g6YOfVMh3wX2t+BzeaZHRaPZAw7iHHjhMvrgp9lBekqA6XK+Nv3om7fTHoF60+dQby5jQ/3aDZN7+D2gvoLtCnIZJSvb5YnxbNv9zkau4szFp0gUL7773h7hEZnI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=AGHmrzkn; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="AGHmrzkn" Received: by smtp.kernel.org (Postfix) with UTF8SMTPSA id 820C61F000E9; Wed, 1 Jul 2026 17:07:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1782925633; bh=09HWxDVeypl9bxp+WG1vrJ1WtSL6U/JuJK1E737LUCA=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=AGHmrzknDfNiq8VGRsyT1WFe2XL3uXXaXIZCL1ui2djLdJIfnfHuKxEU5syp72KCh qyw1hcOzqCvu2hcXWvuASMVwcOvjBB5yIjrYbGUHX4hdpo6UTXoHGaraxCIpWMGD1Q P9ruQ8vDAbzuTw0vM/87Ch1imZyFfR5kGZlDtNDA0XR1l3pFlt2+jT8/FTgt7T1amF DK6cAPHT4dhE3+JKGwEgPW9uHZ/qDRQ9N0Jp8uYAlBC5sW7eydUQNJkWnd+ueuDNr9 c/0Jtb1npDKnM4thmBgtBFOpo4PtB444XJwEC5ky+GhOwrv2BwLANruV8uHOedK5Uw 1i9rzrCEqUExA== Date: Wed, 1 Jul 2026 10:07:13 -0700 From: "Darrick J. Wong" To: Anand Jain Cc: fstests@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, zlang@redhat.com, hch@infradead.org Subject: Re: [PATCH v7 01/11] fstests: add _loop_image_create_clone() helper Message-ID: <20260701170713.GE6517@frogsfrogsfrogs> References: <421c7cdd5aae27b99d04dddf08c5d9df79c2f790.1781694879.git.asj@kernel.org> Precedence: bulk X-Mailing-List: linux-btrfs@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: <421c7cdd5aae27b99d04dddf08c5d9df79c2f790.1781694879.git.asj@kernel.org> On Wed, Jun 17, 2026 at 07:20:28PM +0800, Anand Jain wrote: > Introduce _loop_image_create_clone() and _loop_image_destroy() to mkfs an > image file and clone it to another image file, and attach a loop device to > them. And its destroy part. > > Signed-off-by: Anand Jain > --- > common/rc | 63 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 63 insertions(+) > > diff --git a/common/rc b/common/rc > index 79189e7e6e94..d7e3e0bdfb1e 100644 > --- a/common/rc > +++ b/common/rc > @@ -1520,6 +1520,69 @@ _scratch_resvblks() > esac > } > > +# Create a small loop image, run an optional tuning function ($2) on it, > +# clone it, and attach both to loop devices, returned in ($1). > +# Args: > +# $1: Nameref to return the array of allocated loop devices [base, clone]. > +# $2: Optional callback function to tune the base filesystem before cloning. > +_loop_image_create_clone() > +{ > + local -n _ret=$1 > + local pre_clone_tune_func="$2" > + local img_file=$TEST_DIR/${seq}.img > + local img_file_clone=$TEST_DIR/${seq}_clone.img > + local size=$(_small_fs_size_mb 128) # Smallest possible > + local loop_devs > + > + # Since we copy the block device image, we keep its size small. > + _require_fs_space $TEST_DIR $((size * 1024)) > + > + _create_file_sized $((size * 1024 * 1024)) $img_file || > + _fail "Failed: Create $img_file $size" > + > + loop_devs=$(_create_loop_device $img_file) > + _ret=($loop_devs) > + > + case $FSTYP in > + xfs) > + _mkfs_dev "-s size=4096" ${loop_devs[0]} Not sure why you pass two separate cli arguments as a quoted string, but my guess is it "doesn't matter" because _try_mkfs_dev uses $* unquoted, which separates them again. I HATE BASH. > + ;; > + btrfs) > + _mkfs_dev ${loop_devs[0]} And while I'm whining: ^^^^^^^^^^^^^^^ actually should be quoted. Not that fstests is at all good at getting this right. > + ;; > + *) > + _mkfs_dev ${loop_devs[0]} > + ;; > + esac > + > + # Only execute if the function argument is not empty > + if [ -n "$pre_clone_tune_func" ]; then > + $pre_clone_tune_func ${loop_devs[0]} > + fi > + > + sync ${loop_devs[0]} > + cp $img_file $img_file_clone What if cp doesn't create a reflink copy? Can we fill up the $TEST_DIR despite having checked it for sufficient free space? Especially on filesystems that don't support sparse holes? > + > + loop_devs="$loop_devs $(_create_loop_device $img_file_clone)" > + > + _ret=($loop_devs) Hmm. Should this function return nonzero if any part of the clone creation fails? Or are callers expected to notice that _ret only has one element? --D > +} > + > +# Teardown loop devices and delete their underlying backing image files. > +# Accepts a list of loop device paths (e.g., /dev/loop0 /dev/loop1). > +_loop_image_destroy() > +{ > + for d in "$@"; do > + # Retrieve the path of the backing file > + local f=$(losetup --noheadings --output BACK-FILE $d) > + > + # Detach the loop device from the backing file > + _destroy_loop_device "$d" > + > + # Clean up the backing disk image file > + [ -n "$f" ] && rm -f "$f" > + done > +} > > # Repair scratch filesystem. Returns 0 if the FS is good to go (either no > # errors found or errors were fixed) and nonzero otherwise; also spits out > -- > 2.43.0 > >