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Message-ID: <500F1F42.5010209@redhat.com> Date: Tue, 24 Jul 2012 17:18:42 -0500 From: Eric Sandeen <sandeen@...hat.com> To: ext4 development <linux-ext4@...r.kernel.org> CC: Jan Kara <jack@...e.cz> Subject: Re: [PATCH] jbd2: don't write superblock when unmounting an ro filesystem On 7/24/12 5:05 PM, Eric Sandeen wrote: > This sequence: > > # truncate --size=65536 fsfile > # losetup --offset 65536 /dev/loop0 fsfile > # mkfs.ext4 /dev/loop0 > # losetup -d /dev/loop0 > # mount -o loop,ro,offset=65536 fsfile mnt/ > # umount mnt > # dmesg | tail > > results in an IO error when unmounting the RO filesystem: > > [ 312.386074] SELinux: initialized (dev loop1, type ext4), uses xattr > [ 318.020828] Buffer I/O error on device loop1, logical block 196608 > [ 318.027024] lost page write due to I/O error on loop1 > [ 318.032088] JBD2: Error -5 detected when updating journal superblock for loop1-8. > > This behavior changed with: > > commit 24bcc89c7e7c64982e6192b4952a0a92379fc341 > Author: Jan Kara <jack@...e.cz> > Date: Tue Mar 13 15:41:04 2012 -0400 > > jbd2: split updating of journal superblock and marking journal empty > > which lost some of the magic in jbd2_journal_update_superblock() which > used to test for a journal with no outstanding transactions. > > I'm not sure if the following is quite the right approach, but it fixes > it for me. > > Signed-off-by: Eric Sandeen <sandeen@...hat.com> > --- > > p.s. no idea why this only happens if I use a loop device with an offset! PEBKAC. no-offset ro loop mount does the same. -Eric -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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