What were you trying to do that didn't work?

If an nfs filesystem is mounted between iterations of nfsiostat outputting statistics, nfsiostat will die with a KeyError while attempting to reference the new mountpoint in the 'old' dict:

Traceback (most recent call last):
  File "/usr/sbin/nfsiostat", line 670, in <module>
    iostat_command(prog)
  File "/usr/sbin/nfsiostat", line 638, in iostat_command
    print_iostat_summary(old_mountstats, mountstats, devices, sample_time, options)
  File "/usr/sbin/nfsiostat", line 478, in print_iostat_summary
    if "fstype autofs" not in str(old[device]):
KeyError: '/mnt/server'

What is the impact of this issue to you?

Customer is unable to execute nfsiostat with multiple iterations, since autofs may mount nfs filesystems between iterations of statistics.

Please provide the package NVR for which the bug is seen:

nfs-utils-2.3.3-59.el8.x86_64

nfs-utils-2.5.4-25.el9.x86_64

How reproducible is this bug?:

easy, steps provided

Steps to reproduce

at least one nfs filesytem must be mounted initially

in terminal 1, ensure that the to-be-mounted filesystem is not already mounted, then start nfsiostat with a 15-second delay between iterations, and outputting 2 iterations:

# umount /mnt/server2
# nfsiostat 15 2

in terminal 2, within the 15-second delay, mount the second nfs filesystem at that mountpoint:

# mount server2:/exports /mnt/server2

after the 15-second delay, nfsiostat will read the mounstats file and attempt to filter the mounts to determine the intersection of old and new mounts. Currently, nfsiostat accounts for filesystems becoming unmounted between iterations, but does not account for new nfs mounts.

Expected results

nfsiostat handles newly-mounted filesystems just like it does during the first iteration

Actual results

nfsiostat dies with a KeyError due to old[device] not existing