On 09/01/2008, Anton Salikhmetov <[EMAIL PROTECTED]> wrote: > Since no reaction in LKML was recieved for this message it seemed > logical to suggest closing the bug #2645 as "WONTFIX": > > http://bugzilla.kernel.org/show_bug.cgi?id=2645#c15 > > However, the reporter of the bug, Jacob Oestergaard, insisted the > solution to be resubmitted once more: >
Good idea. The bug is real and should be fixed IMHO. ... > This bug causes backup systems to *miss* changed files. > > This bug does cause data loss in common real-world deployments (I gave an > example with a database when posting the bug, but this affects the data from > all mmap using applications with common backup systems). > Not just backup systems, but any application that relies on mtime being correctly updated will be bitten by this. > Silent exclusion from backups is very very nasty. > Agreed. In fact if mtime is not reliable (which it is not) one could argue that we might as well not update it at all, ever. But I think we can all agree that just fixing it (as your patch does) is a lot better. > Please comment on my solution or commit it if it's acceptable in its > present form. > I've only looked briefly at your patch but it seems resonable. I'll try to do some testing with it later. Thank you for working on this long standing bug. ... > > I would like to propose my solution for the bug #2645 from the kernel bug > > tracker: > > > > http://bugzilla.kernel.org/show_bug.cgi?id=2645 > > > > The Open Group defines the behavior of the mmap() function as follows. > > > > The st_ctime and st_mtime fields of a file that is mapped with MAP_SHARED > > and PROT_WRITE shall be marked for update at some point in the interval > > between a write reference to the mapped region and the next call to msync() > > with MS_ASYNC or MS_SYNC for that portion of the file by any process. > > If there is no such call and if the underlying file is modified as a result > > of a write reference, then these fields shall be marked for update at some > > time after the write reference. > > > > The above citation was taken from the following link: > > > > http://www.opengroup.org/onlinepubs/009695399/functions/mmap.html > > ... I agree that our current behaviour is certainly not what the standard (sensibly) requires. -- Jesper Juhl <[EMAIL PROTECTED]> Don't top-post http://www.catb.org/~esr/jargon/html/T/top-post.html Plain text mails only, please http://www.expita.com/nomime.html -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
