From: Oleg Nesterov <oleg@redhat.com>
To: Karl Mehltretter <kmehltretter@gmail.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
Christian Brauner <brauner@kernel.org>, Jan Kara <jack@suse.cz>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] super: remember whether freeze holds writer rwsems
Date: Thu, 3 Sep 2026 14:44:19 +0200 [thread overview]
Message-ID: <aplro1ObQ5YNZT6R@redhat.com> (raw)
In-Reply-To: <20260903060855.4610-1-kmehltretter@gmail.com>
On 09/03, Karl Mehltretter wrote:
>
> Record whether a successful freeze acquired the writer rwsems and use that
> state during thaw instead of re-sampling SB_RDONLY.
Looks correct at first glance, but I leave this to other reviewers,
I don't understand fs/ enough.
> Tested with a test-only KUnit case in x86_64 QEMU on linux-next
> 32b6ef9a5d0e (next-20260902). It freezes a writable ramfs, sets SB_RDONLY,
> thaws it, and calls sb_start_write_trylock(). The call fails without this
> patch and succeeds with it.
But I am curious, how exactly did you test this?
ramfs_ops doesn't have ->freeze_fs or ->freeze_super, so
ioctl_fsfreeze() should fail?
And how it is possible to remount with -ro, reconfigure_super() should
see sb->s_writers.frozen != SB_UNFROZEN ?
Oleg.
next prev parent reply other threads:[~2026-09-03 12:44 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-03 6:08 [PATCH] super: remember whether freeze holds writer rwsems Karl Mehltretter
2026-09-03 10:40 ` Jan Kara
2026-09-03 19:50 ` Karl Mehltretter
2026-09-04 9:31 ` Jan Kara
2026-09-03 12:44 ` Oleg Nesterov [this message]
2026-09-03 19:36 ` Karl Mehltretter
2026-09-03 21:43 ` Oleg Nesterov
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