linux-ext4 - Re: [PATCH v2 00/24] ext4: enable block size larger than page size

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Message-ID: <21efa577-a577-48ce-a82b-bce446539fba@huawei.com>
Date: Wed, 12 Nov 2025 14:27:19 +0800
From: Baokun Li <libaokun1@...wei.com>
To: Theodore Ts'o <tytso@....edu>
CC: <linux-ext4@...r.kernel.org>, <adilger.kernel@...ger.ca>, <jack@...e.cz>,
	<linux-kernel@...r.kernel.org>, <kernel@...kajraghav.com>,
	<mcgrof@...nel.org>, <ebiggers@...nel.org>, <willy@...radead.org>,
	<yi.zhang@...wei.com>, <yangerkun@...wei.com>, <chengzhihao1@...wei.com>,
	Baokun Li <libaokun@...weicloud.com>, Baokun Li <libaokun1@...wei.com>,
	"Darrick J. Wong" <djwong@...nel.org>
Subject: Re: [PATCH v2 00/24] ext4: enable block size larger than page size

On 2025-11-12 12:02, Theodore Ts'o wrote:
> On Wed, Nov 12, 2025 at 10:19:06AM +0800, Baokun Li wrote:
>> I am using a slightly older version of xfstests, and when running the
>> 64k tests I also encountered similar failures. The cover letter stated
>> "no Oops" for the 64k tests rather than "no new failures," meaning that
>> some cases did fail, but no severe issues such as BUG_ON or softlock
>> were observed.
> Sorry, I misread your cover letter.  It's good you are seeing similar
> failures.

Sorry, my description wasn’t clear enough.

>
>
> On Wed, Nov 12, 2025 at 10:49:19AM +0800, Baokun Li wrote:
>> I checked the code of the swapon syscall in mm/swapfile.c, and currently
>> the swapfile does not support LBS. Therefore, some failing test cases can
>> be filtered out based on this.
> Ah, OK. What's happening is with XFS the swap tests are being skipped
> automatically if the swapon fails.  From _require_scratch_swapfils:
>
> 	*)
> 		if ! swapon "$SCRATCH_MNT/swap" >/dev/null 2>&1; then
> 			_scratch_unmount
> 			_notrun "swapfiles are not supported"
> 		fi
> 		;;
>
>
> But ext4 has different logic:
>
> 	# ext* has supported all variants of swap files since their
> 	# introduction, so swapon should not fail.
>
> << famous last words >>
😄
>
> 	case "$FSTYP" in
> 	ext2|ext3|ext4)
> 		if ! swapon "$SCRATCH_MNT/swap" >/dev/null 2>&1; then
> 			if _check_s_dax "$SCRATCH_MNT/swap" 1 >/dev/null; then
> 				_scratch_unmount
> 				_notrun "swapfiles are not supported"
> 			else
> 				_scratch_unmount
> 				_fail "swapon failed for $FSTYP"
> 			fi
> 		fi
> 		;;
>
>
> I guess we could add logic to _require_scratch_swapfile in common/rc
> to also _notrun if swapon fails and block size is greater that page
> size.  Or I might just add an exclusion in my test appliance runner
> for now for all tests in group swap.

Darrick’s reply in another thread has already made a similar change,
so we can apply that patch first for testing.


Cheers,
Baokun