On Fri, May 20, 2016 at 05:45:12AM +0200, Adam Borowski wrote: > (Only btrfs currently implements dedupe_file_range.) > > Instead of checking the mode of the file descriptor, let's check whether > it could have been opened rw. This allows fixing failures when deduping > a live system: anyone trying to exec a file currently being deduped gets > ETXTBSY. > > Issuing this ioctl on a ro file was already allowed for root/cap. > > Signed-off-by: Adam Borowski <kilobyte@xxxxxxxxxx> Hi Adam, this patch seems reasonable to me but I have to admit to being worried about 'unintended consequences'. I poked around the code in fs/ for a bit and saw mostly checks against file open mode. It might be that dedupe is a special case due to the potential for longer running operations, but theoretically you'd see the same problem if trying to exec against a file being cloned too, correct? If that's the case then I wonder how this issue gets solved for other ioctls. --Mark -- Mark Fasheh -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
