On 01/03/2013 12:45 PM, Nikos Chantziaras wrote: > On 03/01/13 15:51, Duane wrote: >> On 01/02/2013 04:45 PM, Nikos Chantziaras wrote: >>> On 02/01/13 22:49, Duane wrote: >>>> Qt 4.8 on Linux TinyCore or Fedora. >>>> >>>> I have a function to back up some files to a usb stick. I've had >>>> complaints from users that the files are sometime not copied. It looks >>>> like they're removing the usb stick before the standard sync cycle. If >>>> I call sync from my copy routine this works but it hangs the system >>>> waiting for sync to complete. >>>> >>>> If I mount the usb stick with -o sync, this also solves my problem but >>>> it also hangs the system. >>>> [...] >>> >>> Once QFile::flush() is called, the data is sent to the OS. From there, >>> it's up to the system what to do with the data. Users need to unmount >>> the stick before removing it. If they don't want to do that, then they >>> need to set up their system such that it mounts the USB stick >>> synchronously by default. It's either that or unmount first. >>> [...] >> >> This device is a "controller" with a touch screen and no access to a >> terminal where the user can enter anything. I would have to add >> something to the gui to unmount the device but I think this would be >> more or less the same as calling sync when the copying is done. > > Keep in mind that if you're not mounting synchronously by default, then > removing the stick without unmounting it can lead to filesystem > corruption and inconsistencies. > > The fact that it's a USB stick doesn't matter. The only thing that > matters is that a non-synchronous filesystem is being removed while it's > still live.
Yes, the first thing that I tried was to change the mount to synchronous. It solves the problem but what it does is a bit strange. I have a loop that I copy N files. After all N are copied, it gets synced which makes the system non-responsive for some amount of time. I would prefer it to sync them on each copy. _______________________________________________ Interest mailing list Interest@qt-project.org http://lists.qt-project.org/mailman/listinfo/interest
