I've been cooking a very simple patch that hopefully gives both sides of the "great strictatime war" what they want with minimal pain. I sent it through kernelnewbies for a basic review and got some polish on irc.
---- Signed-off-by: Raymond Jennings <[email protected]> Reviewed-by: Mandeep Sandhu <[email protected]> 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 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) ---------- Forwarded message ---------- From: Mandeep Sandhu <[email protected]> Subject: Re: [PATCH] allow strictatime to be set as a global default Date: Sat, 19 Dec 2015 17:25:37 -0800 To: Raymond Jennings <[email protected]> Cc: kernelnewbies <[email protected]> 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 <[email protected]> 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 > <[email protected]> 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 >> <[email protected]> >> wrote: >> > On Fri, Dec 18, 2015 at 10:50 AM, Mandeep Sandhu >> > <[email protected]> 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) >> > >> > >> > > > _______________________________________________ Kernelnewbies mailing list [email protected] http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
