I'm not sure I follow, but I'll take your word for it. Is it your opinion, then, that if I upgrade to 2.6.19.2 it will fix my problem?
Jonas Jyrki Jaakkola wrote: > From latest 2.6.19.2 kernel change log: > > "[PATCH] VM: Fix nasty and subtle race in shared mmap'ed page writeback > > The VM layer (on the face of it, fairly reasonably) expected that when > it does a ->writepage() call to the filesystem, it would write out the > full page at that point in time. Especially since it had earlier marked > the whole page dirty with "set_page_dirty()". > > But that isn't actually the case: ->writepage() does not actually write > a page, it writes the parts of the page that have been explicitly marked > dirty before, *and* that had not got written out for other reasons since > the last time we told it they were dirty. > > That last caveat is the important one. > > Which _most_ of the time ends up being the whole page (since we had > called "set_page_dirty()" on the page earlier), but if the filesystem > had done any dirty flushing of its own (for example, to honor some > internal write ordering guarantees), it might end up doing only a > partial page IO (or none at all) when ->writepage() is actually called. > > That is the correct thing in general (since we actually often _want_ > only the known-dirty parts of the page to be written out), but the > shared dirty page handling had implicitly forgotten about these details, > and had a number of cases where it was doing just the "->writepage()" > part, without telling the low-level filesystem that the whole page might > have been re-dirtied as part of being mapped writably into user space. > > Since most of the time the FS did actually write out the full page, we > didn't notice this for a loong time, and this needed some really odd > patterns to trigger. But it caused occasional corruption with rtorrent > and with the Debian "apt" database, because both use shared mmaps to > update the end result." > > This could be the cause for the problem. > > Jyrki Jaakkola > > ------------------------------------------------------------------------- > Take Surveys. Earn Cash. Influence the Future of IT > Join SourceForge.net's Techsay panel and you'll get the chance to share your > opinions on IT & business topics through brief surveys - and earn cash > http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV > _______________________________________________ > User-mode-linux-user mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/user-mode-linux-user ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ User-mode-linux-user mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/user-mode-linux-user
