On Wed, Mar 07, 2018 at 11:08:56AM -0500, Theodore Y. Ts'o wrote: > This is where it's critcal to understand that the "tune2fs -o" changes > the *default* mount options. The key in the comment is the anything > different from the *filesystem* defaults (that is, the defaults of the > particular ext4 file system, as opposed to the global defaults). The > idea is that /proc/mounts, and /etc/mtab shows the options string that > if used in /etc/fstab, or in the mount command line, will replicate > the current mount option state. Furthermore, that /proc/mounts is the > minimal set of mount option strings. One more question about this. Trying to use tune2fs -E mount_opts to set some default options, and can't figure out how to enter two options at once. Doing: tune2fs -E mount_opts=nodelalloc,nouser_xattr /dev/sda3 gives the error: tune2fs 1.43.4 (31-Jan-2017) Bad options specified. Extended options are separated by commas, and may take an argument which is set off by an equals ('=') sign. Valid extended options are: clear_mmp hash_alg=<hash algorithm> mount_opts=<extended default mount options> stride=<RAID per-disk chunk size in blocks> stripe_width=<RAID stride*data disks in blocks> test_fs ^test_fs Apparently it gets confused by the , in the argument to mount_opts. Unfortunately , happens to be the separator required by ext4 for that field. So how does one use it? Sure in this case I can set one with -o and the other with -E, but in general there seems to be a small problem here, probably only in user space though. Seems tune2fs needs some change in how it deals with extended options that contain commas. -- Len Sorensen