Re: reiser4 mkfs, cryptcompress, tail packing, etc.

[Gordan Bobic <gordan@bobich.net>]

On 08/24/2010 06:47 PM, Edward Shishkin wrote:

>> Also, is there a nolog option on reiser4 as there is on reiserfs?
>
> no sorry, currently reiser4 transaction manager can not be switched off.

Is there a way to use an external journal and point it at a different 
device (e.g. ramdisk/tmpfs), and force fsck on unclean shutdown instead?

>> Another question (not sure if it is specifically related to reiser4 or
>> generic) is about compressed hard-linked DLLs and mmap. Specifically,
>> if a .so is hard-linked in two places, dynamically linking to each
>> instance causes both to be mmapped to the same memory since they'll
>> have the same inode, and that means the memory is only used once. How
>> does this work if the .so is compressed? Does it all still work the
>> same, with the decompressed file being in a single mmap for both
>> dynamically linked instances?
>
> Works as usual: when populating address space by readpage(s) data are
> read from disk and decompressed.
> If page gets dirty, then its data will be compressed in flush time and
> written to disk.

What about the hard-link issue I mentioned? If two hard-links point to 
the same inode with a compressed shared library, will it work as 
expected and only map the file into shared memory once even if both .so 
files are dyna-linked by different running binaries?

Gordan