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

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Message-ID: <20251112052327.GL196358@frogsfrogsfrogs>
Date: Tue, 11 Nov 2025 21:23:27 -0800
From: "Darrick J. Wong" <djwong@...nel.org>
To: Theodore Ts'o <tytso@....edu>
Cc: Baokun Li <libaokun1@...wei.com>, 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>
Subject: Re: [PATCH v2 00/24] ext4: enable block size larger than page size

On Tue, Nov 11, 2025 at 11:02:20PM -0500, 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.
> 
> 
> 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.

https://lore.kernel.org/fstests/176169820051.1433624.4158113392739761085.stgit@frogsfrogsfrogs/T/#u

Hm?

--D

> 
> 						- Ted
>