Re: "data=writeback" and TRIM don't get along

[Eric Sandeen <sandeen@redhat.com>]

Nebojsa Trpkovic wrote:
> Hello.
> 
> TRIM command issued to SSD doesn't work with this mount options:
> 
> ============================
> rootfs / rootfs rw 0 0
> /dev/root / ext4
> rw,noatime,commit=100,barrier=0,nobh,stripe=128,data=writeback,discard 0 0
> proc /proc proc rw,nosuid,nodev,noexec,relatime 0 0
> rc-svcdir /lib64/rc/init.d tmpfs
> rw,nosuid,nodev,noexec,relatime,size=1024k,mode=755 0 0
> sysfs /sys sysfs rw,nosuid,nodev,noexec,relatime 0 0
> udev /dev tmpfs rw,nosuid,relatime,size=10240k,mode=755 0 0
> devpts /dev/pts devpts rw,nosuid,noexec,relatime,gid=5,mode=620 0 0
> shm /dev/shm tmpfs rw,nosuid,nodev,noexec,relatime 0 0
> ============================

How does it fail?

> Removing "data=writeback" option from /etc/fstab and from rootflags in
> kernel boot options results in TRIM working just like it should.
> 
> So, the question is:
> 
> Is this "data=writeback" and TRIM incompatibility a bug or a feature? :)

Surely a bug.  :)  If you can provide details we'll look into it.
(perhaps it's obvious on first try but still worth saying exactly
what problematic behavior you saw, when reporting a bug you
encountered)

Thanks,
-Eric