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Build Identifier: 

xfs_scrub -n -v /home
EXPERIMENTAL xfs_scrub program in use! Use at your own risk!
Phase 1: Find filesystem geometry.
/home: using 24 threads to scrub.
Info: /home: Kernel metadata scrub facility not detected.
Info: /home: Kernel metadata scrubbing facility is not available.
Info: /home: Scrub aborted after phase 1.
/home: errors found: 1


Reproducible: Always

Steps to Reproduce:
1. As root (or via sudo) run 'xfs_scrub -n -v (xfs mounted directory)
I.e. xfs_scrub -n -v /home
Actual Results:  
flash:~ # xfs_scrub -n -v /home
EXPERIMENTAL xfs_scrub program in use! Use at your own risk!
Phase 1: Find filesystem geometry.
/home: using 24 threads to scrub.
Info: /home: Kernel metadata scrub facility not detected.
Info: /home: Kernel metadata scrubbing facility is not available.
Info: /home: Scrub aborted after phase 1.
/home: errors found: 1


Expected Results:  
I expect xfs_scrub to execute properly.

This happens on at least two of my XFS mounted partitions.  Here is the
xfs_info from two partitions where this fails to run:
flash:~ # xfs_info /home
meta-data=/dev/sdb1              isize=256    agcount=169, agsize=7247920 blks
         =                       sectsz=512   attr=2, projid32bit=0
         =                       crc=0        finobt=0, sparse=0, rmapbt=0
         =                       reflink=0
data     =                       bsize=4096   blocks=1220702785, imaxpct=5
         =                       sunit=16     swidth=32 blks
naming   =version 2              bsize=4096   ascii-ci=0, ftype=0
log      =internal log           bsize=4096   blocks=32768, version=2
         =                       sectsz=512   sunit=16 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0
/home is mounted on a hardware RAID6 controller

flash:~ # xfs_info /
meta-data=/dev/nvme0n1p2         isize=512    agcount=4, agsize=19661056 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=1        finobt=0, sparse=0, rmapbt=0
         =                       reflink=0
data     =                       bsize=4096   blocks=78644224, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0, ftype=1
log      =internal log           bsize=4096   blocks=38400, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0
/ is mounted on a Samsung 970 Pro NVME drive
rpm -q xfsprogs
xfsprogs-4.15.0-lp151.7.3.1.x86_64
uname -a
Linux flash 4.12.14-lp151.28.10-default #1 SMP Sat Jul 13 17:59:31 UTC 2019
(0ab03b7) x86_64 x86_64 x86_64 GNU/Linux