On Wed, Jun 20, 2018 at 12:53 PM, David Howells <[email protected]> wrote:
> Arnd Bergmann <[email protected]> wrote:
>
>> which avoids the y2038 overflow
>
> No it doesn't. The AFS protocol is limited.
>
>> + time64_t mtime_client; /* last time client changed
>> data */
>> + time64_t mtime_server; /* last time server changed
>> data */
>> ...
>> - time_t creation; /* volume creation time */
>> + time64_t creation; /* volume creation time */
>
> Unless you can change the AFS protocol, this is a waste of memory. It might
> be better to change them to u32 as they are protocol values rather than system
> values.
AFS uses 'unsigned' seconds, right? What I was trying to say there is
that with the patch, the 32-bit overflow gets moved from 2038 to 2106, so at
least the nearer problem is solved.
On 64-bit machines, we already waste a little memory here, the usual
tradeoff I took was to use time64_t for all time storage when possible for
clarity reasons, but that is easily changed if you prefer.
>> - inode->i_ctime.tv_sec = get_seconds();
>> - inode->i_ctime.tv_nsec = 0;
>> - inode->i_atime = inode->i_mtime = inode->i_ctime;
>> + inode->i_ctime = inode->i_atime = inode->i_mtime = current_time(inode);
>
> Surely, the tv_nsec should be zero since anything else cannot be represented
> in the AFS protocol.
current_time() truncates the nanoseconds to the granularity of the filesystem.
Since AFS doesn't set s_time_gran, it gets the default 1000000000 value
leads to tv_nsec being zero. Once Deepa's patch to truncate the tv_sec
range lands, it will also ensure that this is within the range (this is less
of a problem for setting the current time than it is for utimensat() which
can set arbitrary future timestamps of course).
> I will grant, however, I should be consistently using them as unsigned values.
>
> Note that the answers to the above may change if and when I start supporting
> the YFS protocol extensions, but for the AFS protocol, this is simply not
> there.
Ok, good to know this exists.
Arnd
_______________________________________________
Y2038 mailing list
[email protected]
https://lists.linaro.org/mailman/listinfo/y2038
