[LU-5309] The `zfs userspace` command is broken on Lustre-ZFS-OST datasets

• Type: Bug
• Resolution: Cannot Reproduce
• Priority: Minor
• Affects Version/s: Lustre 2.4.2
• Labels: llnl
• Severity: 3
• Assignee: Nathaniel Clark
• Reporter: Prakash Surya (Inactive)

Description

It looks as though the zfs userspace command is completely broken on at least one of our ZFS datasets backing a Lustre OST running a Lustre 2.4.2 based release.

Here's what zfs list shows:

# pilsner1 /root > zfs list -t all
NAME                          USED  AVAIL  REFER  MOUNTPOINT
pilsner1                     17.3T  46.9T    30K  /pilsner1
pilsner1/lsd-ost0            17.3T  46.9T  15.9T  /pilsner1/lsd-ost0
pilsner1/lsd-ost0@17jun2014  1.39T      -  10.6T  -

And here's what zfs userspace shows:

# pilsner1 /root > zfs userspace pilsner1/lsd-ost0@17jun2014
TYPE        NAME         USED  QUOTA                                            
POSIX User  <omitted>   21.5K   none                                               
POSIX User  <omitted>    118M   none                                               
POSIX User  <omitted>   6.49G   none                                               
POSIX User  <omitted>   72.1M   none                                               
POSIX User  <omitted>    725M   none

This is clearly broken, and according to Matt Ahrens:

<+mahrens> prakash: yeah, that pbpaste output looks wrong.  All the "REFER" space should be accounted for by "zfs userspace"

Additionally, running that command on the dataset itself (as opposed to a snapshot) fails with an error:

# pilsner1 /root > zfs userspace pilsner1/lsd-ost0          
cannot get used/quota for pilsner1/lsd-ost0: dataset is busy

This is not the case for filesystems mounted through the ZPL.