On 05/03/2014 10:32 PM, Ivan Shapovalov wrote:
On Saturday 03 May 2014 at 22:21:58, Edward Shishkin wrote:
TBH, I have never looked at the deallocation paths in reiser4: everything
worked fine there.. BTW, why not to use atom's delete_set to discard
things? Could you please take a look?
[...]
Blocks used for the journal (wander.c) are deallocated without BA_DEFER
set
and thus they never hit delete_set. However, we want to discard these.
This happens in error paths. Don't be so scrupulous ;)
I don't think so:
- wander.c:485
dealloc_tx_list() <- reiser4_write_logs()
- wander.c:505
dealloc_wmap_actor() <- dealloc_wmap() <- reiser4_write_logs()
Yep, indeed.
I don't completely understand this special case of wandered blocks.
Also I don't see where wandered blocks are deallocated after journal
replay (as journal is not needed any more): it can be a possible leak
of disk space after system crashes..
Once we understand it, I think we'll able to re-use the delete_set for
discard needs.
Edward.
Also users will use copy-on-write transaction model for their SSDs(*),
and in this mode journals are tiny: they contain only system blocks.
In short, there is nothing to discard..
(*) http://marc.info/?l=reiserfs-devel&m=139449965000686&w=2
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