Hello, On Mon 14-01-19 11:30:11, Jan Kara wrote: > On Mon 14-01-19 01:33:30, Kevin Weidemann wrote: > > this is RE the patch 8515b9edf7a0c9dcf1ad218ccc783700db217336 (Upstream > > commit a9ad01bc759df79b0012f43ee52164391e31cd96) in 4.18.20. > > > > I have an issue with UDF. I used to be able to create a UDF fs in a way > > that is very similar to this: > > > > `# mkudffs --label=.... -m dvd -b 512 /dev/mapper/cryptdev1` > > > > I used to proceed mounting it, noticing it got mounted as readonly > > (because the accesstype of the udf fs is readonly (as decided per -m > > dvd)), so I remounted it as rw and then was able to fill it with data.[1] > > > > Now, this doesn't work anymore since the last time I did that. I figured > > out it must have to do with the commit mentioned above. All I get now, > > during a remount-as-rw attempt, is: > > `cannot remount /dev/mapper/cryptdev1 read-write, is write-protected`. > > > > I am not sure if this counts as a regression, because I see the point in > > not only auto-mounting such filesystems as readonly, but also preventing > > remounting as rw, however it breaks my use case. > > > > However, I noticed the following, too: > > case A) when having a "readonly udf" on a readwrite device, the > > filesystem mounts as readonly (old behavior) and also prevents remounting > > as rw (new behavior) > > This works as intended. > > > case B) when having a "readwrite udf" on a readonly device, the > > filesystem mounts as readwrite (!), but the writes end up being invisibly > > discarded > > That's a bug. I'll fix it. Thanks for reporting this! I have checked this and it works for me as designed: (none):~# mount -t udf /dev/ubdb /mnt mount: block device /dev/ubdb is write-protected, mounting read-only UDF-fs: warning (device ubdb): udf_load_vrs: No anchor found UDF-fs: Scanning with blocksize 512 failed UDF-fs: warning (device ubdb): udf_load_vrs: No anchor found UDF-fs: Scanning with blocksize 1024 failed UDF-fs: INFO Mounting volume 'LinuxUDF', timestamp 2017/01/20 10:17 (1000) So if the block device is read-only, you will get only read only mount. Also remount read-write gets prevented: (none):~# mount -o remount,rw /mnt/ mount: block device /dev/ubdb is write-protected, mounting read-only Or with more recent util-linux (2.31.1): (none):/ # mount -t udf /dev/ubdb /mnt UDF-fs: warning (device ubdb): udf_load_vrs: No anchor found UDF-fs: Scanning with blocksize 512 failed UDF-fs: warning (device ubdb): udf_load_vrs: No anchor found UDF-fs: Scanning with blocksize 1024 failed UDF-fs: INFO Mounting volume 'LinuxUDF', timestamp 2017/01/20 10:17 (1000) mount: /mnt: WARNING: device write-protected, mounted read-only. and remount: (none):/ # mount -o remount,rw /mnt mount: /mnt: cannot remount /dev/ubdb read-write, is write-protected. The kernel is 5.0-rc3. What kernel were you testing with? Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
