[Unionfs] How to enable debugging

[Erez Zadok]

In message <47E24C7F.9020302 at expires-20080606.gate.mooo.com>, Klaus Fuerstberger writes:
> Hi,
> 
> I want to enable debugging in unionfs-2.2.4_for_2.6.24.2, but it does 
> not work.
> 
> CONFIG_UNION_FS=m
> CONFIG_UNION_FS_XATTR=y
> CONFIG_UNION_FS_DEBUG=y
> 
> This is, how I want to enable debug:
> mount -t unionfs -o dirs=/tmp/aaa=rw:/tmp/bbb=ro,debug=1 unionfs /tmp/ccc
> 
> But I get:
> unionfs: unrecognized option 'debug'
> 
> ~# modinfo unionfs
> filename:       /lib/modules/2.6.24.2-alix-i586/kernel/fs/unionfs/unionfs.ko
> license:        GPL
> description:    Unionfs 2.2.4 (for 2.6.24.2) 
> (http://unionfs.filesystems.org)
> author:         Erez Zadok, Filesystems and Storage Lab, Stony Brook 
> University (http://www.fsl.cs.sunysb.edu)
> depends:
> vermagic:       2.6.24.2-alix-i586 mod_unload 586

There's no debug options to turn on at mount time: you just need to compile
with debugging on, as you've done above, and Unionfs will printk some
additional messages if/when needed.

> I got a warning when compiling the kernel with enabled debugging. Mabe 
> its important:
>   CC [M]  fs/unionfs/debug.o
> fs/unionfs/debug.c: In function '__unionfs_check_dentry':
> fs/unionfs/debug.c:172: warning: passing argument 1 of 'd_deleted' 
> discards qualifiers from pointer target type

Klaus, I'm unable to reproduce this compile warning with several of my
setups.  Are you using a vanilla 2.6.24 kernel or one modified somehow?  If
it's not a vanilla kernel, please send me all other patches you've applied
on top of the vanilla kernel.

Also, what version of g/cc are you using (gcc -v).

> Thanks!
> Klaus

Thanks,
Erez.