On Mon 14-09-09 21:42:43, Jens Axboe wrote: > On Mon, Sep 14 2009, Jens Axboe wrote: > > On Mon, Sep 14 2009, Christoph Hellwig wrote: > > > On Mon, Sep 14, 2009 at 03:33:07PM +0200, Jan Kara wrote: > > > > On Mon 14-09-09 11:36:33, Jens Axboe wrote: > > > > > bdi_start_writeback() is currently split into two paths, one for > > > > > WB_SYNC_NONE and one for WB_SYNC_ALL. Add bdi_sync_writeback() > > > > > for WB_SYNC_ALL writeback and let bdi_start_writeback() handle > > > > > only WB_SYNC_NONE. > > > > What I don't like about this patch is that if somebody sets up > > > > writeback_control with WB_SYNC_ALL mode set and then submits it to disk via > > > > bdi_start_writeback() it will just silently convert his writeback to an > > > > asynchronous one. > > > > So I'd maybe leave setting of sync_mode to the caller and just WARN_ON if > > > > it does not match the purpose of the function... > > > > > > Or initialize the wb entirely inside these functions. For the sync case > > > we really only need a superblock as argument, and for writeback it's > > > bdi + nr_pages. And also make sure they consistenly return void as > > > no one cares about the return value. > > > > Yes, I thought about doing that and like that better than the warning. > > Just pass in the needed args and allocate+fill the wbc on stack. I'll > > make that change. > > That works out much better, imho: > > http://git.kernel.dk/?p=linux-2.6-block.git;a=commit;h=270c12655d7d11e234d335a8ab0540c02c034b66 Yeah, the code looks better. BTW, how about converting also bdi_writeback_all() to get superblock and nr_pages as an argument? Currently it seems to be the only place "above" flusher thread which uses wbc and it's just constructed in the callers of bdi_writeback_all() and then disassembled inside the function... Honza -- Jan Kara <jack@xxxxxxx> SUSE Labs, CR -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
