[pacman-dev] Strange (critical) bug with checkspace

[Dan McGee]

On Sun, Feb 19, 2012 at 9:25 PM, Nagy Gabor <ngaba at bibl.u-szeged.hu> wrote:
> Hi!
>
> I've run into the following bug:
> $ df -h
> Filesystem      Size  Used Avail Use% Mounted on
> rootfs           44G   30G   13G  71% /
> /dev            501M     0  501M   0% /dev
> /run            503M  276K  503M   1% /run
> /dev/sda3        44G   30G   13G  71% /
> none            503M     0  503M   0% /dev/shm
> /dev/sda1        30G   29G  1.6G  95% /c
> /dev/sr0        4.2G  4.2G     0 100% /e
>
> [Don't laugh at my mountpoints.]
>
> $ sudo pacman -Su
> ...
> Total Installed Size:   900.93 MiB
> Net Upgrade Size:       139.47 MiB
> ...
> error: Partition /e is mounted read only
> error: not enough free disk space
> error: failed to commit transaction (not enough free disk space)
> Errors occurred, no packages were upgraded.
>
> What?! I think none of our packages wants to write to /e/...
No, but the packages you were installing *did* want to write to /etc,
and we fail hard because we apparently prefix match and don't make
sure it ends in a directory separator. Working on a fix, will submit a
patch soon.

This is 100% reproducible: mkdir /e; mount something ro there, `pacman
-S libao` or any other package that installs something in /etc.

> I've tried
> with both pacman 4.0.2-1 and pacman-git, the result is the same. I've
> also tried with "pacman -S randompkg", that worked fine. I don't want
> to umount /e, because I am afraid of the fact that I might not be able
> to reproduce this bug any more...
>
> The relevant part of --debug log says nothing:
> [04:19:41] debug: checking available disk space
> [04:19:41] debug: mountpoint: /sys
> [04:19:41] debug: mountpoint: /run
> [04:19:41] debug: mountpoint: /root/.gvfs
> [04:19:41] debug: mountpoint: /proc
> [04:19:41] debug: mountpoint: /e
> [04:19:41] debug: mountpoint: /dev/shm
> [04:19:41] debug: mountpoint: /dev/pts
> [04:19:41] debug: mountpoint: /dev
> [04:19:41] debug: mountpoint: /c
> [04:19:41] debug: mountpoint: /
> [04:19:41] debug: mountpoint: /
> [04:19:41] error: Partition /e is mounted read only
> [04:19:41] debug: partition /, needed 3897, cushion 5121, free 3727796
> [04:19:41] debug: returning error 7 from _alpm_check_diskspace : not enough free disk space
> [04:19:41] error: not enough free disk space
> [04:19:41] error: failed to commit transaction (not enough free disk space)
> [04:19:41] debug: unregistering database 'local'
>
> NG
>