On Fri, Aug 29, 2014 at 3:56 PM, Theodore Ts'o <tytso@xxxxxxx> wrote: > On Fri, Aug 29, 2014 at 10:33:05AM -0500, Eric Sandeen wrote: >> >> > Is there a reason why noatime can't be set as a default mount option? Thinking of all these USB connected devices where it would be handy. >> >> I haven't looked, but I'm guessing it's because noatime is a >> vfs-level switch, and by the time the ext4 superblock is getting >> read and processed during mount, that chance has passed. > > Yes, and this is also the cause of this user complaint/bug: > > https://bugzilla.kernel.org/show_bug.cgi?id=61601 > > There was some discussion at the kernel summit by Andy Lutomirski to > create new mount system call with sane parsing, and Al Viro wasn't > totally against that idea. If we do go forward with some of the ideas > that was tossed about, this would be something else that would be a > nice thing to fix at the same time. > > The whole distinction between VFS-level mount options (which are > parsed in userspace and passed down into the kernel using bits in a > bitfield) and file system-level mount options (which is parsed by the > kernel and passed in from userspace as a string) is just nasty. > > What I would suggest is that all mount options would be passed all the > way down to the file system, and then there would be a library > function to handle common VFS-level mount options that would be called > by the file system's mount option handling code. > To clarify: do you mean that per-superblock options would all be strings and would all get passed down to the fs? If so, I like it. I think that whatever corresponds to MNT_READONLY shouldn't be passed down to the filesystem or necessarily specified when loading the filesystem at all. But MNT_READONLY is a very different thing than "ro". --Andy -- 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
