On 8/15/11 12:54 PM, 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. > > 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. > > 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). Well, just my $0.02, I won't fight it. One thing I do want, though, is to be able to look at logs and know what mode we're running in. I guess we do print all specified options, so those in the know, will know that delalloc is off if data=journal is on. But I think we could use some consistency here at least: [root@inode ~]# mount -o data=journal,dioread_nolock /dev/sdb5 /mnt/test [root@inode ~]# /* YAY it worked! */ [root@inode ~]# dmesg | tail ... [269530.183245] EXT4-fs (sdb5): Ignoring delalloc option - requested data journaling mode [269530.191170] EXT4-fs (sdb5): Ignoring dioread_nolock option - requested data journaling mode /* boo it didn't work */ Better hit that one too, I guess, and any other option which disables another default ... (honestly, I think it'd be better to fail the mount in cases like this if conflicting options are specified). -Eric -Eric -- 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
