Re: -o remount,rw not possible?

[Jari Ruusu <jariruusu@xxxxxxxxxxxxxxxxxxxxx>]

Christian Kujau wrote:
> i'm using loop-aes for quite a while now and from time to time i had to
> remount device-backed loop-aes partitions. eg. a normally r/o mounted
> backup partition would become a r/w. i did this like so:
> 
> $ mount -o remount,rw /data
> 
> when i try this now, mount comes back with
> 
> mount: block device /dev/hda1 is write-protected, mounting read-only
> 
> i don't know exactly when it stopped working (but i'm pretty sure it
> worked a month ago or so). upgrading to the latest loop-aes/ciphers
> package did not help.
> 
> my setup:
> 
> root@sheep:~# losetup -a
> /dev/loop5: [0805]:173 (/dev/hda1) encryption=twofish128 multi-key read-only
                                                                     ^^^^^^^^^
> /dev/loop6: [0805]:380 (/dev/sda8) encryption=AES128 multi-key
> /dev/loop7: [0805]:389 (/dev/sdb1) encryption=twofish128 multi-key read-only
                                                                     ^^^^^^^^^
When loop was set up, it was set up in "hard" read-only mode, IOW, loop
driver would not permit any writes to reach underlying device. rw mount is
doomed to fail on such read-only loop device. Loop code in loop-AES has
worked like that for long time, years IIRC. OTOH, if VFS is now opening
about-to-rw-mount devices without FMODE_WRITE set, then something is broken
in VFS.

The fix is to do the initial loop mount rw, or to set up loop using losetup
but no -r option passed losetup.

-- 
Jari Ruusu  1024R/3A220F51 5B 4B F9 BB D3 3F 52 E9  DB 1D EB E3 24 0E A9 DD

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