From: "Windl, Ulrich" <u.windl@ukr.de>
To: Krister Johansen <kjlx@templeofstupid.com>,
Lennart Poettering <lennart@poettering.net>
Cc: "util-linux@vger.kernel.org" <util-linux@vger.kernel.org>,
Karel Zak <kzak@redhat.com>,
"systemd-devel@lists.freedesktop.org"
<systemd-devel@lists.freedesktop.org>,
David Reaver <me@davidreaver.com>, Theodore Ts'o <tytso@mit.edu>
Subject: RE: [EXT] Re: [systemd-devel] [PATCH] libblkid: fix spurious ext superblock checksum mismatches
Date: Tue, 19 Nov 2024 08:19:54 +0000 [thread overview]
Message-ID: <246892aea2ef4119bb2b0b248c720737@ukr.de> (raw)
In-Reply-To: <20241118231352.GC1885@templeofstupid.com>
> -----Original Message-----
> From: systemd-devel <systemd-devel-bounces@lists.freedesktop.org> On
> Behalf Of Krister Johansen
> Sent: Tuesday, November 19, 2024 12:14 AM
> To: Lennart Poettering <lennart@poettering.net>
> Cc: util-linux@vger.kernel.org; Karel Zak <kzak@redhat.com>; systemd-
> devel@lists.freedesktop.org; David Reaver <me@davidreaver.com>;
> Theodore Ts'o <tytso@mit.edu>
> Subject: [EXT] Re: [systemd-devel] [PATCH] libblkid: fix spurious ext
> superblock checksum mismatches
>
...
> I may have done a poor job of explaining this. This is ext writing its
> own superblock from the kernel, but reads seeing an potentially
> inconsistent view of that write. O_DIRECT causes us to seralize with
> the locks ext4 holds when it writes the superblock, which prevents the
> read from observing a partial update.
>
> It's not necessarily the partitioning tools causing this, but any
> filesystem level udpdate that modifies the contents of the superblock.
As I wrote before: I don't think the needless O_DIRECT fixes things some other code broke.
next prev parent reply other threads:[~2024-11-19 8:21 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-11-18 20:35 [PATCH] libblkid: fix spurious ext superblock checksum mismatches Krister Johansen
2024-11-18 22:36 ` [systemd-devel] " Lennart Poettering
2024-11-18 23:13 ` Krister Johansen
2024-11-19 8:19 ` Windl, Ulrich [this message]
2024-11-19 8:15 ` [EXT] " Windl, Ulrich
2024-11-19 17:49 ` Theodore Ts'o
2024-11-19 23:59 ` Krister Johansen
2024-11-20 6:07 ` Theodore Ts'o
2024-11-21 10:44 ` Karel Zak
2024-11-21 15:55 ` Theodore Ts'o
2024-11-22 8:54 ` Krister Johansen
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