ecryptfs team mailing list archive

[CowboyTim <tim__aerts@xxxxxxxxxxx>]

@Tom

I might not be good at making my point sometimes, but you clearly sum
things up very good. Way better than I do.

@Aryeh

In Ext3, too many applications use fsync, I think that was from the ext2
day-and-era, where not syncing could lead to corrupt filesystems, not
just empty files. Same with ufs on solaris - what a PITA that that
sometimes can be. FAT on usbsticks is even always synced for that
reason.

Even gvim does it, firefox too (actually sqlite3). Sometimes I get
frustrated by the performance problems when copying a large file, and
not being able to surf, that I do kill -9 (firefox hangs forever - fsync
is a blocking call). However on the open-temp+fsync+rename, the rename
won't happen anymore, as the kill -9 is handled right after the fsync(),
hence, no new file. If it would have taken the sheer 1s to complete,
nobody is going to kill -9, you'd be too late, the new file is there.

Under ext4, things will improve as Theodore pointed out. However, fsync
means real I/O,  and harddisks are just painfully slow, where stupid
applications fsync-ing too much can and will hurt a machine's
performance while not solving the problem of durability. That problem
can just best be solved by atomicity with a rename - given the order
stays correct.

Atomicity is a simple performance friendly solution to fsync() for me on
a journaled filesystem.

-- 
Ext4 data loss
https://bugs.launchpad.net/bugs/317781
You received this bug notification because you are a member of eCryptfs,
which is subscribed to ecryptfs-utils in ubuntu.

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