Hello,
a machine booted with Linux 6.6.23 up to 6.6.32:
writing /dev/zero with dd on a mounted cifs share with vers=1.0 or vers=2.0 slows down drastically in my setup after writing approx. 46GB of data.
The whole machine gets unresponsive as it was under very high IO load. It pings but opening a new ssh session needs too much time. I can stop the dd (ctrl-c) and after a few minutes the machine is fine again.
cifs with vers=3.1.1 seems to be fine with 6.6.32. Linux 6.10-rc3 is fine with vers=1.0 and vers=2.0.
Bisected down to:
cifs-fix-writeback-data-corruption.patch which is: Upstream commit f3dc1bdb6b0b0693562c7c54a6c28bafa608ba3c and linux-stable commit e45deec35bf7f1f4f992a707b2d04a8c162f2240
Reverting this patch on 6.6.32 fixes the problem for me.
Thomas