> -----Original Message----- > From: systemd-devel <systemd-devel-bounces@xxxxxxxxxxxxxxxxxxxxx> On > Behalf Of Krister Johansen > Sent: Tuesday, November 19, 2024 12:14 AM > To: Lennart Poettering <lennart@xxxxxxxxxxxxxx> > Cc: util-linux@xxxxxxxxxxxxxxx; Karel Zak <kzak@xxxxxxxxxx>; systemd- > devel@xxxxxxxxxxxxxxxxxxxxx; David Reaver <me@xxxxxxxxxxxxxxx>; > Theodore Ts'o <tytso@xxxxxxx> > 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.
