On Wed, Nov 21, 2018 at 06:48:18PM +0100, Jean-Christophe Guillain wrote: > Hi, > > I see a strange behaviour when playing with the metadata_csum parameter of ext4. > (I use a Debian Stretch, with a kernel 4.9.0-8-amd64 #1 SMP Debian 4.9.110-3+deb9u6 (2018-10-08) x86_64 GNU/Linux) > > How to reproduce : > > * I enable metada checksum : OK > root@test# tune2fs -O metadata_csum /dev/my_vol > tune2fs 1.43.4 (31-Jan-2017) > Enabling checksums could take some time. > Proceed anyway (or wait 5 seconds) ? (y,N) y > > * I check : Checksum enabled > root@test# tune2fs -l /dev/my_vol > tune2fs 1.43.4 (31-Jan-2017) > Filesystem volume name: <none> > [...] > Journal backup: inode blocks > Checksum type: crc32c > Checksum: 0xb0e3a180 > > * I change filesystem UUID : OK > root@test# tune2fs -U random /dev/my_vol > tune2fs 1.43.4 (31-Jan-2017) > Setting UUID on a checksummed filesystem could take some time. > Proceed anyway (or wait 5 seconds) ? (y,N) y > > * I disable metadata checksum : OK > root@test# tune2fs -O ^metadata_csum /dev/my_vol > tune2fs 1.43.4 (31-Jan-2017) > Disabling checksums could take some time. > Proceed anyway (or wait 5 seconds) ? (y,N) y > > * I change filesystem UUID : It looks like metada checksum still is enabled > root@test# tune2fs -U random /dev/my_vol > tune2fs 1.43.4 (31-Jan-2017) > Setting UUID on a checksummed filesystem could take some time. > Proceed anyway (or wait 5 seconds) ? (y,N) y > > * I fsck the filesystem to see if it could fix this. > root@test# e2fsck -f /dev/my_vol > 2fsck 1.43.4 (31-Jan-2017) > Pass 1: Checking inodes, blocks, and sizes > Pass 2: Checking directory structure > Pass 3: Checking directory connectivity > Pass 4: Checking reference counts > Pass 5: Checking group summary information > /dev/my_vol: 16303/3932160 files (0.9% non-contiguous), 1829950/15728640 blocks > > * I check : metadata checksum looks like disabled > root@test# tune2fs -l /dev/my_vol tune2fs 1.43.4 (31-Jan-2017) > Filesystem volume name: <none> > [...] > Journal backup: inode blocks > > * I change filesystem UUID : It looks like metada checksum still is enabled > root@test# tune2fs -U random /dev/my_vol > tune2fs 1.43.4 (31-Jan-2017) > Setting UUID on a checksummed filesystem could take some time. > Proceed anyway (or wait 5 seconds) ? (y,N) y > > Is it a bug ? Yes. > How can I actually disable this parameter ? I think you have to turn off the metadata_csum_seed feature, but tbh tune2fs really shouldn't pester about !metadata_csum,metadata_csum_seed filesystems... --D > Best regards, > jC Guillain > > > -- IMPORTANT NOTICE: > > The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you. >
