On Monday 02 June 2014 09:07:00 Theodore Ts'o wrote: > Yes, there are some ongoing dicussions about changing the post-2038 > encoding of the timestamp in ext4, which is why this hasn't been fixed > yet. The main thing that's been missing is time for me to review the > patches, and a good way of writing regression tests that will work (or > at least not fail) on build environments with a 32-bit time_t and > 32-bit-only capable versions of functions such as gmtime(3). > > And given current discussions, I may want to think about some kind of > superblock flag to allow the use of a 32-bit unsigned encoding for > file systems using a 128-byte inode, with a way of setting that flag > after scanning the file system to make sure there are no times that > are previous to January 1, 1970. (Or more generally, allow any epoch > to be defined using a 64-bit time_t offset stored in the superblock...) FWIW, I've gone through the other file system implementations once more. The most common pattern I've encountered is to have a read_inode function with inode->i_mtime = le32_to_cpu(raw_inode->mtime); which results in interpreting the time as 'signed' on 32-bit kernels, but as 'unsigned' on 64-bit kernels. This could have been done intentionally to extend the valid time range to 2106 on 64-bit kernels, but it seems more likely that the code was written with no thought given to 64-bit time_t at all. I see this pattern on p9fs (old protocol only), afs, bfs, ceph, efs, freevxfs, hpfs, jffs2, jfs, minix, nfsv2/v3 (this was clearly intentional and is spelled out in the RFC), qnx4, qnx6, reiserfs, squashfs, sysv, and ufs (protocol version 1 only). The other behavior I see is to treat the on-disk 32-bit value as signed on both 32-bit and 64-bit kernels: inode->i_mtime = (signed)le32_to_cpu(raw_inode->mtime); this seems to be done intentionally in all cases, to maintain compatibility between 32-bit and 64-bit kernels, but it's relatively rare: exofs, ext2/3/4 (good old inodes) and xfs are the only ones doing this. In case of ext2/3/4, the sign handlign was introduced here: http://www.spinics.net/lists/linux-ext4/msg01758.html exofs and xfs seem to have done it like this for all of git history. Arnd _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
