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#41 — Cannot store ecryptfs backend on zfs-fuse

State Unconfirmed
Version: 0.6.0
Area Functionality
Issue type Bug
Severity Medium
Submitted by Stephen Paul Weber
Submitted on May 15, 2010
Responsible Seth Heeren
Target release:
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Last modified on May 27, 2011
I am running Ubuntu with the ecryptfs ~/Private folder. If the backend storage for this (~/.Private) is stored on a zfs-fuse partition, then writing to any file in ~/Private causes that file to become zero-length.

I have temporarily fixed this by putting the data elsewhere and making ~/.Private a symlink.
Added by (anonymous) on May 21, 2010 08:43 PM
Reproduced.

No analysis available

Diagnosis:

. "never" worked (not on 0.5.0)
. low prio: not frequently used and workaround exists

Consider filing against ecryptfs as they should be better equipped to start debugging this
Added by (anonymous) on Jun 02, 2010 05:09 PM
Works for me.



# zfs list | grep Priva
sctank2/Users/mmm/.Private 95,2M 7,62G 95,2M /sctank2/Users/mmm/.Private

# mount | grep Private
sctank2/Users/mmm/.Private on /sctank2/Users/mmm/.Private type fuse (rw,allow_other)
/home/mmm/.Private on /home/mmm/Private type ecryptfs (ecryptfs_sig=xyazz,ecryptfs_fnek_sig=kjaskdjasjsd,ecryptfs_cipher=aes,ecryptfs_key_bytes=16)

# ls -la /home/mmm/ | grep Private
drwxr-xr-x 4 mmm mmm 7 12-08 22:40 Private
lrwxrwxrwx 1 mmm mmm 31 12-08 22:40 .Private -> /sctank2/Users/mmm/.Private
#


Fully functional.
Added by (anonymous) on Jun 02, 2010 05:20 PM
OH, tested it again. Indeed there is small but important problem on writing. After creating file, writing data and closing file on first time, it is zero length. But opening it again, writing something and closing make it work.

$ ls -l README
-rw-r--r-- 1 mmm mmm 2339 04-16 02:59 README

$ cp ./README ~/Private/

$ ls -l ~/Private/README
-rw-r--r-- 1 mmm mmm 0 06-03 00:17 /home/mmm/Private/README

$ cp ./README ~/Private/
cp: cannot create regular file `/home/mmm/Private/README': Input/output error

$ ls -l ~/Private/README
-rw-r--r-- 1 mmm mmm 0 06-03 00:17 /home/mmm/Private/README

$ echo 1 >> ~/Private/README

$ ls -l ~/Private/README
-rw-r--r-- 1 mmm mmm 2 06-03 00:17 /home/mmm/Private/README

$ cp ./README ~/Private/

$ ls -l ~/Private/README
-rw-r--r-- 1 mmm mmm 2339 06-03 00:19 /home/mmm/Private/README


$ md5sum README /home/mmm/Private/README
5f5ee41185d8641241bfea06cfcefca6 README
5f5ee41185d8641241bfea06cfcefca6 /home/mmm/Private/README

And now this is strange.

Added by Seth Heeren on Jun 02, 2010 05:24 PM
Responsible manager: (UNASSIGNED) → sgheeren
Thanks for adding this insight!

Finally something to go on in terms of further analysis.

I'm thinking there is something inherently fuse-on-fuse-on-fuse going on there. Well, I'll find some time later since this is definitely not going to make 0.6.9 at this point
Added by (anonymous) on May 27, 2011 03:46 PM
A possible workaround is to use encfs over zfs-fuse. This combination works for me.