ecryptfs team mailing list archive

[Aryeh Gregor <Simetrical+launchpad@xxxxxxxxx>]

@CowBoyTim

Power failure during fsync() will result in a half-written file, but
that's why the correct sequence is

1) Create new temp file
2) Write to new temp file
3) fsync() new temp file
4) rename() over old file

If there's a power failure before or during step 3, the temp file will
be partially written or not at all, but you'll still have the old data
intact.  A power failure during step 4 is no problem due to journaling.
Therefore this really does give 100% assurance of durability, unless of
course the hardware fails.  But "it's not perfect, therefore it's
worthless" is flawed logic anyway.

-- 
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: Fix Committed
Status in ecryptfs-utils in Ubuntu Jaunty: Invalid
Status in linux in Ubuntu Jaunty: Fix Committed

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