Theodore Ts'o <tytso@xxxxxxx> wrote: > So what this means is that on 32-bit systems, if we have a userspace > program which isn't using the Largefile-enabled, and it opens a file > which is larger than can be addressed with a 32-bit off_t, it can get > surprised and possibly cause data loss. Good point. I was initially thinking that 32-bit userspace on a 64-bit system would have O_LARGEFILE automatically enabled - but I guess it'll trap through the compat entry points which avoid that. That said, fanotify and xfs_open_by_handle() will both automatically set O_LARGEFILE irrespectively of the 32-bitness of the original caller. Further, path-based truncate() makes no checks based on file-largeness, unlike ftruncate(). > Is this something we are willing to live with? After all, there was a > originally a really good reason for the O_LARGEFILE flag in the first > place, and it was primarily about making sure that a non-LARGEFILE > capable program would hard fail on the open, instead of after it had > trashed the user's data. Okay, that seems reasonable - but it still leaves truncate() dangling. I'm not sure there's a good answer to that, though. > Was there a reason that motivated this change, other than just an > clean up? Overlayfs and one or two other places need to potentially apply O_LARGEFILE to the things that they do on behalf of userspace - but other than suppressing some size checks, it seems to be ignored by the filesystems and the VM. I vaguely seem to remember that at one point there were still filesystems that couldn't handle large files and would reject such opens - but they appear to all have been fixed. David _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
