[PATCH] allow strictatime to be set as a global default

[Mandeep Sandhu]

Looks good to me.

To test the real waters....you should send it to the lists you
mentioned (or whatever the maintainers script tells you).

Good luck,
-mandeep


On Sat, Dec 19, 2015 at 1:41 PM, Raymond Jennings <shentino at gmail.com> wrote:
> How does this version look?
>
> (the other delta for the other file was untouched)
>
> Any chance it is ready to post to the big list (presumably fs with a cc to
> lkml)?
>
> diff --git a/fs/Kconfig b/fs/Kconfig
> index 6ce72d8..122a993 100644
> --- a/fs/Kconfig
> +++ b/fs/Kconfig
> @@ -4,6 +4,20 @@
>
>  menu "File systems"
>
> +config DEFAULT_STRICTATIME
> + bool "Use strictatime by default"
> + default n
> + help
> +  Use strictatime as a default mount option.
> +
> +  Relatime became the default in 2007 to reduce I/O load on block devices.
> +
> +  Enabling this option will restore historic behavior and provide perfectly
> +  accurate atimes, but the increase in write load may reduce performance
> +  and shorten the life of the block device.
> +
> +  If unsure, say N.
> +
>  # Use unaligned word dcache accesses
>  config DCACHE_WORD_ACCESS
>         bool
>
> On Fri, Dec 18, 2015 at 2:21 PM, Mandeep Sandhu
> <mandeepsandhu.chd at gmail.com> wrote:
>>
>> Ah yes...now it makes sense! :)
>>
>> The current 'word of caution' (about increased I/O load on block
>> devices), seems mild IMHO. Maybe we should we have a stricter
>> warning...something like enabling this option might be harmful to the
>> life of your block device (due to excessive writes) and will also lead
>> to reduced performance?
>>
>> HTH,
>> -mandeep
>>
>>
>> On Fri, Dec 18, 2015 at 2:12 PM, Raymond Jennings <shentino at gmail.com>
>> wrote:
>> > On Fri, Dec 18, 2015 at 10:50 AM, Mandeep Sandhu
>> > <mandeepsandhu.chd at gmail.com> wrote:
>> >>
>> >> You've removed the strictatime option altogether. So how does that
>> >> satisfy people who _do_ want it?
>> >
>> >
>> > ...actually it looks like I was an idiot and got my diff backwards when
>> > I
>> > pulled it out of git :P
>> >
>> > Here's the correct version.
>> >
>> > diff --git a/fs/Kconfig b/fs/Kconfig
>> > index 6ce72d8..4b917eb 100644
>> > --- a/fs/Kconfig
>> > +++ b/fs/Kconfig
>> > @@ -4,6 +4,17 @@
>> >
>> > menu "File systems"
>> >
>> > +config DEFAULT_STRICTATIME
>> > +       bool "Use strictatime by default"
>> > +       default n
>> > +       help
>> > +         Use strictatime as a default mount option.
>> > +
>> > +         Strictatime preserves ancient historic behavior of keeping the
>> > atime field always up to date.
>> > +         However, it was changed in 2007 to relatime to reduce I/O load
>> > on
>> > block devices.
>> > +
>> > +         If unsure, say N.
>> > +
>> > # Use unaligned word dcache accesses
>> > config DCACHE_WORD_ACCESS
>> >        bool
>> > diff --git a/fs/namespace.c b/fs/namespace.c
>> > index 0570729..48e7c15 100644
>> > --- a/fs/namespace.c
>> > +++ b/fs/namespace.c
>> > @@ -2680,9 +2680,15 @@ long do_mount(const char *dev_name, const char
>> > __user
>> > *dir_name,
>> >         if (retval)
>> >                 goto dput_out;
>> >
>> > -       /* Default to relatime unless overriden */
>> > +#ifdef CONFIG_DEFAULT_STRICTATIME
>> > +       /* Default to strictatime unless overridden */
>> > +       if (flags & MS_RELATIME)
>> > +               mnt_flags |= MNT_RELATIME;
>> > +#else
>> > +       /* Default to relatime unless overridden */
>> >         if (!(flags & MS_NOATIME))
>> >                 mnt_flags |= MNT_RELATIME;
>> > +#endif
>> >
>> >
>> >         /* Separate the per-mountpoint flags */
>> >         if (flags & MS_NOSUID)
>> >
>> >
>> >
>
>