To reproduce:

Install hjfs on an mp system. Do things (sysupdate; cd /sys/src && mk install; etc.). Files become corrupt.

This is not observed on single cpu systems.

found a missing BDELWRI mark in newentry() with some debug code (not commited) checking clean buffers for modification in putbuf().

got tons of:

hjfs: putbuf cleancrc mismatch, dev /tmp/test.hjfs, block 3241, type dentry, op 0, getbuf caller 0x6648, putbuf caller 0x678

commited fix in r53664686c2ca

rebuild the kernel on the fixed hjfs with NPROC=4 and compared the resulting bootfs.paq in my /boot/bootfs.paq, there was no corruption. can anyone verify this please?

newentry() could allocate dentry that still had loc pointing to it. the following commit fixes the NPROC build problems for me: r6467d5bdfc43

please rebuild and verify.