[LU-14135] lfs df --pool incorrectly iterates over every FS when no path is provided

• Status: Open
• Project: Lustre
• Affects Version/s: Upstream
• Type: Bug
• Priority: Minor
• Reporter: Quentin Bouget
• Assignee: WC Triage
• Resolution: Unresolved
• Severity: 3

Description

Having several Lustre filesystems mounted on the same node will result in lfs df --pool ... misbehaving and reporting either the same information multiple times (if the same FS is mounted multiple times), or printing error messages.

$ lfs getname
fs0-abcdefabcdefabcd /mnt/fs0
fs1-abcdefabcdefabcd /mnt/fs1
$ lfs pool_list /mnt/fs0
Pools from fs0:
fs0.pool0
$ lfs df --pool fs0.pool0
<normal output>
filesystem name incorrect

Looking at the implementation of lfs df in lustre/utils/lfs.c I think what is happening is pretty straightforward: since no path is provided, lfs df assumes it should iterate on all available Lustre FS, diregarding the fact that the poolname provided on the command line points at a specific FS.

Note that the behaviour of iterating on all the filesystems returned by llapi_search_mounts() is not entirely correct anyway, as multiple bind mounts are reported as separate filesystems (which makes the output confusing).

Iterating on the FS names would be better.