On Mon, 15 Aug 2011, Ted Ts'o wrote: > On Mon, Aug 15, 2011 at 10:59:02AM -0500, Eric Sandeen wrote: > > > > The giant behavior-options switch in ext4 is confusing enough; if enabling > > one option disables another default option, I think that explicitly stating > > it in the logs is useful. Doing so silently just covers up the behavior. > > > > If users are unhappy with the message, it's probably more because of > > the fact of the matter, and not because of the presentation of the fact. :) > > Most users probably have no idea what "delalloc" actually means. So > when they get a message that saying that data=journalled has disabled > delalloc, it could easily be seen as noise. I was moved to do it > because I got tired of seeing the message over, and over, and over > again when running xfstests. So the actual users of data=journal does not care all that much about it apparently. If the information for some of the users is "noise" than be it, there is a lot of "noise" in the logs but it is useful for people who do understand it, or to people who can search for it. > > Maybe an improvement would be (1) to document what data=journal > implies in the Documentation/filesystems/ext4.txt, (2) change the > message to explicitly say "delayed allocation" instead of "delalloc" > (although many people won't have any idea what "delayed allocation" > means either), and (3) make it a printk_once thing. That information actually already is in Documentation/filesystems/ext4.txt but not in the Options section. However important is to have this information in mount man page, because that is where usually users go for info right ? I like the "delayed allocation" version of the warning, but I do not think we should do it with printk_once as it seems even more confusing to me. > > I guess I don't agree with the fundamental presumption which is that > users should be looking at the dmesg output to understand what various > things mean, and if they didn't explicitly specify delalloc, why > should we complain about the fact that both delalloc and data=journal > were specified (when in fact it wasn't specified). Yeah, we should probably say that we are "disabling delayed allocation". > > - Ted > Thanks! -Lukas -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
