Hi Juergen, Thank you for the feedback.
2014-05-08 10:12 GMT+02:00 Juergen Borleis <[email protected]>: > Hi Guillermo, > > On Wednesday 07 May 2014 19:22:33 Guillermo Rodriguez Garcia wrote: >> I wanted to use the noatime option for the jffs2 filesystem that is used in >> the default ptxdist / mini2440 configuration, and found the following >> problem: >> >> I first tried to modify /env/config in barebox to pass rootflags=noatime in >> the kernel bootargs parameter. >> >> This results in a kernel panic: >> >> jffs2: Error: unrecognized mount option 'noatime' or missing value >> [...] >> No filesystem could mount root, tried: jffs2 >> Kernel panic - not syncing: VFS: Unable to mount root fs on >> unknown-block(31,3) >> >> However, if I boot normally (with the default bootargs) and then remount >> the jffs2 filesystem with noatime, it works fine: >> >> $ mount -o remount,noatime / > > What 'mount' command implementation do you use? > root@mini2440:~ mount -V mount from util-linux 2.23.1 (libmount 2.23.0: debug, assert) > http://lists.infradead.org/pipermail/linux-mtd/2011-September/037975.html That issue does not seem to apply here: root@mini2440:~ mount -o remount,anything / jffs2: Error: unrecognized mount option 'anything' or missing value mount: / not mounted or bad option In some cases useful info is found in syslog - try dmesg | tail or so. root@mini2440:~ mount -o remount,noatime / root@mini2440:~ cat /etc/mtab rootfs / rootfs rw 0 0 /dev/root / jffs2 rw,noatime 0 0 devtmpfs /dev devtmpfs rw,relatime,size=30656k,nr_inodes=7664,mode=755 0 0 none /proc proc rw,relatime 0 0 none /tmp tmpfs rw,relatime 0 0 none /sys sysfs rw,relatime 0 0 debugfs /sys/kernel/debug debugfs rw,relatime 0 0 none /var/log tmpfs rw,relatime,mode=755 0 0 none /var/run tmpfs rw,relatime,mode=755 0 0 none /var/lock tmpfs rw,relatime,mode=755 0 0 none /var/tmp tmpfs rw,relatime 0 0 devpts /dev/pts devpts rw,relatime,mode=600 0 0 > >> I am puzzled by this as according to the documentation [1], the rootflags >> argument "allows you to give options pertaining to the mounting of the >> root filesystem just as you would to the mount program". >> >> Looks like a kernel bug to me, but on the other hand it seems so obvious >> that perhaps I am overlooking something. > > Or simply a missunderstanding. JFFS2 seems not updating the access time > itself. That's good to know, however noatime is a generic mount option, not a filesystem specific option. It is checked here: http://lxr.free-electrons.com/source/fs/namespace.c?v=3.2#L2315 You can use it with any filesystem. If JFFS2 does not support the atime attribute (I have not found any authoritative reference stating this), then it would make no difference, but it should still be possible to specify it. Also if it is accepted by mount it should also be accepted by rootflags, as the description of rootflags specifically says that it allows you to "give options pertaining to the mounting of the root filesystem just as you would to the mount program" I still think this is a bug (either in the implementation or in the documentation..) What do you think? Guillermo Rodriguez Garcia [email protected]
