ecryptfs team mailing list archive

[Theodore Ts'o <tytso@xxxxxxx>]

So a couple of things, since this has gone totally out of control.

First of all, ZFS also has delayed allocation (also called "allocate on
flush").   That means it will suffer similar issues if you crash without
doing an f*sync(), and the page cache hasn't been flushed out yet.
Solaris partisans will probably say, "But Solaris is so reliable, it
doesn't crash", which is an acceptable response.   It's true of Linux
too, but apparently Ubuntu has too many unstable proprietary drivers.
:-)

Secondly, you can turn off delayed allocation for ext4.   If you mount
the filesystem with the nodelalloc mount option, you will basically get
the old ext3 behaviour with data=ordered.  You will also lose many of
the performance gains of ext4, and the files will tend to be more
fragmented as a result, but if you have crappy drivers, and you're
convinced your system will randomly crash, that may be your best move.
Personally, that's not the Linux I use, but I'm not using proprietary
drivers.

As far as including the 3 queued-for-2.6.30 patches in question, they
are very low-risk, so I think it's fair for Ubuntu to consider including
them; if not, and if you don't have confidence about the stability if
your kernel, probably your best bet is to just include nodelalloc as a
default mount option for now, or patch ext4 to use nodelalloc as a the
default, and allow people who want delayed allocation to request it via
a mount option delalloc.   This used to be the default, until we were
confident with the delalloc code.

Finally, I'll note that Fedora folks haven't really been complaining
about this, so far as I know.  Which should make people ask the
question, "why is Ubuntu different"?

-- 
Ext4 data loss
https://bugs.launchpad.net/bugs/317781
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Status in “ecryptfs-utils” source package in Ubuntu: Invalid
Status in “linux” source package in Ubuntu: Confirmed
Status in ecryptfs-utils in Ubuntu Jaunty: Invalid
Status in linux in Ubuntu Jaunty: Confirmed

Bug description:
I recently installed Kubuntu Jaunty on a new drive, using Ext4 for all my data.

The first time i had this problem was a few days ago when after a power loss ktimetracker's config file was replaced by a 0 byte version . No idea if anything else was affected.. I just noticed ktimetracker right away.

Today, I was experimenting with some BIOS settings that made the system crash right after loading the desktop. After a clean reboot pretty much any file written to by any application (during the previous boot) was 0 bytes.
For example Plasma and some of the KDE core config files were reset. Also some of my MySQL databases were killed...

My EXT4 partitions all use the default settings with no performance tweaks. Barriers on, extents on, ordered data mode..

I used Ext3 for 2 years and I never had any problems after power losses or system crashes.

Jaunty has all the recent updates except for the kernel that i don't upgrade because of bug #315006

ProblemType: Bug
Architecture: amd64
DistroRelease: Ubuntu 9.04
NonfreeKernelModules: nvidia
Package: linux-image-2.6.28-4-generic 2.6.28-4.6
ProcCmdLine: root=UUID=81942248-db70-46ef-97df-836006aad399 ro rootfstype=ext4 vga=791 all_generic_ide elevator=anticipatory
ProcEnviron:
 LANGUAGE=
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.28-4.6-generic
SourcePackage: linux