On Thu, 2015-06-25 at 17:55 +0800, Dongsheng Yang wrote: > On 06/24/2015 08:33 AM, Dave Chinner wrote: > > On Tue, Jun 23, 2015 at 01:44:00PM +0300, Artem Bityutskiy wrote: > >> On Tue, 2015-06-23 at 17:55 +0800, Dongsheng Yang wrote: > >>> In short, I think force_atime to ubifs is the choice from my opinion. > >> > >> So will we end up with this: > >> > >> -o - no atime support > >> -o atime - no atime support > >> -o noatime - same, no atime support > >> -o force_atime - full atime support > >> -o relatime - relative atime support > >> -o lazyatime - lazy atime support > > > >> IOW, atime/noatime mount options have no effect on UBIFS. To have full > >> atime support - people have to use "force_atime". And then the rest of > >> the standard options are supported. > > > > That's the exact semantics of the standard -o strictatime option. > > See the mount(8) man page: > > > > strictatime > > Allows to explicitly requesting full atime updates. > > This makes it possible for kernel to defaults to > > relatime or noatime but still allow userspace to > > override it. For more details about the default system > > mount options see /proc/mounts. > > > > It's passed down to the kernel via the MS_STRICTATIME flag. All > > you need to do is make ubifs aware of this flag... > > Hi Dave, thanx for your suggestiong, but sorry, it's a little confusing > to me :(. I do not know the history, but IIUC, this is what Dave's hint translates to for UBIFS: -o - default behavior (no atime) -o atime - default behavior (no atime) -o noatime - default behavior (no atime) -o strictatime - full atime support -o relatime - relative atime support -o lazyatime - lazy atime support Is this logical from user's perspective? No, but this is a standard "hack", not an UBIFS-only "hack", so we are fine. "force_atime" that you are suggesting would be UBIFS-only hack, which is not as fine as a standard and documented "hack". IOW, atime/noatime are the "don't use" options, they are ignored and every file-system is free to use its own defaults, be that noatime or relatime or strictatime. If you want to tell the FS what to do, use strictatime/relatime/lazyatime. Does it make sense? -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
