From: Christoph Hellwig <hch@lst.de>
To: Dave Chinner <dgc@kernel.org>
Cc: Hans Holmberg <hans.holmberg@wdc.com>,
Carlos Maiolino <cem@kernel.org>,
Dave Chinner <david@fromorbit.com>,
"Darrick J . Wong" <djwong@kernel.org>,
Christoph Hellwig <hch@lst.de>,
Damien Le Moal <dlemoal@kernel.org>,
linux-xfs@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH v2] xfs: start gc on zonegc_low_space attribute updates
Date: Thu, 26 Mar 2026 07:08:40 +0100 [thread overview]
Message-ID: <20260326060840.GA23733@lst.de> (raw)
In-Reply-To: <acSfSmE_IBjWl_cR@dread>
On Thu, Mar 26, 2026 at 01:51:54PM +1100, Dave Chinner wrote:
> > - Added a new helper to wake up the gc thread in stead of unparking it,
> > which is required to make this work properly.
> > - Added protection against races with unmounts as sysfs gets torn down
> > after the zone info struct is freed. This also avoids unneded
> > wakeups during remount.
>
> Isn't that a deadlock vector?
>
> i.e. unmount takes s_umount, concurrently userspace writes a new
> value to sysfs file. sysfs file write blocks on s_umount, unmount
> blocks holding s_umount waiting for sysfs file reference count to go
> to zero to destroy it?
Given that the code does a trylock it should not.
next prev parent reply other threads:[~2026-03-26 6:08 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-25 12:43 [PATCH v2] xfs: start gc on zonegc_low_space attribute updates Hans Holmberg
2026-03-25 15:22 ` Darrick J. Wong
2026-03-26 9:33 ` Hans Holmberg
2026-03-26 0:50 ` Damien Le Moal
2026-03-26 2:51 ` Dave Chinner
2026-03-26 6:08 ` Christoph Hellwig [this message]
2026-03-26 6:10 ` Christoph Hellwig
2026-03-30 15:10 ` Carlos Maiolino
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