bin/56690: tar hangs extracting base.tar.xz on v7fs

[abs%absd.org@localhost]

>Number:         56690
>Category:       bin
>Synopsis:       tar hangs extracting base.tar.xz on v7fs
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    bin-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Feb 05 22:10:00 +0000 2022
>Originator:     David Brownlee
>Release:        NetBSD 9.99.92
>Organization:
none
>Environment:
NetBSD forsaken.absd.org 9.99.92 NetBSD 9.99.92 (GENERIC) #0: Mon Jan 24 16:56:26 GMT 2022  abs%iris.absd.org@localhost:/home/netbsd/src/sys/arch/amd64/compile/obj/GENERIC amd64

>Description:
Attempting to extract a NetBSD base.tar.xz onto a 2GB v7fs filesystem mounted via vnd0 hangs

First attempt hung on
./libdata/firmware/if_bwfm/brcmfmac43602-pcie.bin

Second and subsequent attempt hangs on
./lib/libc.so.12.220

Removing all files and restarting returns to hanging on brcmfmac43602-pcie.bin

Extracting rescue.tar.xz works fine (and a subsequent chroot /altroot /rescue/sh works)
>How-To-Repeat:
dd if=/dev/zero of=/tmp/fs bs=1m count=2048
newfs_v7fs -F -s 4194304 /tmp/fs
vndconfig vnd0 /tmp/fs
mount_v7fs /dev/vnd0d /altroot
tar xvzpf -C /altroot .../base.tar.xz
<watch hang>

hit ^C and try again

Running an rsync of /usr/X11R7 onto /altroot/usr/X11R7 also gives indications of a broken fs:

# ls /altroot/usr/X11R7/lib/X11/fonts
.uuid     75dpi     Speedo    Type1     encodings misc
100dpi    CID       TTF       cyrillic  local     util
# du /altroot/usr/X11R7/lib/X11/fonts
24647   /altroot/usr/X11R7/lib/X11/fonts/100dpi
du: fts_read: No such file or directory
7# ls -alsd /altroot/usr/X11R7/lib/X11/fonts/75dpi
6 drwxr-xr-x  2 root  wheel  6608 Feb  5 21:48 /altroot/usr/X11R7/lib/X11/fonts/75dpi
# du /altroot/usr/X11R7/lib/X11/fonts/75dpi
du: fts_read: No such file or directory
94# ls -als /altroot/usr/X11R7/lib/X11/fonts/75dpi| wc -l
     414

>Fix: