On Thu, Sep 15, 2016 at 11:36:14AM +0200, Marcin Mirosław wrote:

Hi!
I was playing with fs without tiering. I was using it for tmp dir for
compilation. Next I changed in sys:
echo crc64 > options/data_checksum
echo crc64 > options/metadata_checksum
echo crc64 > options/str_hash

After a couple of minutes I got:
[ 8372.574346] bcache (dm-10): IO error on dm-10 for checksum error
[ 8372.680196] bcache (dm-10): IO error on dm-10 for checksum error
[ 8464.361860] bcache (dm-10): IO error on dm-10 for checksum error
[ 8466.146966] bcache (dm-10): IO error on dm-10 for checksum error
[ 8466.995095] bcache (dm-10): IO error on dm-10 for checksum error
[ 8469.199749] bcache (dm-10): IO error on dm-10 for checksum error
[ 8469.441408] bcache (dm-10): IO error on dm-10 for checksum error
[ 8469.722676] bcache (dm-10): IO error on dm-10 for checksum error
[ 8469.827055] bcache (dm-10): IO error on dm-10 for checksum error
[ 8470.038869] bcache (dm-10): IO error on dm-10 for checksum error
[ 8470.236663] bcache (dm-10): IO error on dm-10 for checksum error
[ 8470.427094] bcache (dm-10): IO error on dm-10 for checksum error
[ 8472.030519] bcache (dm-10): IO error on dm-10 for checksum error
[ 8473.098820] bcache (dm-10): IO error on dm-10 for checksum error
[ 8916.491297] bcache (dm-10): IO error on dm-10 for checksum error
[ 8916.715057] bcache (dm-10): IO error on dm-10 for checksum error
[ 8916.715111] bcache (dm-10): too many IO errors on dm-10, setting
filesystem RO
[ 8916.733056] bcache (dm-10): IO error on dm-10 for checksum error
[ 8916.733125] bcache (dm-10): dm-10 read only
[ 8916.733161] bcache (dm-10): too many IO errors on dm-10, setting
device RO
[ 8916.988286] bcache (dm-10): IO error: read only
[ 8916.988545] bcache (dm-10): IO error: read only


Is this due to changing str_hash?

Damn, you're finding all the bugs :)

I'm trying to reproduce it. It's probably due to changing data_checksum though,
not str_hash (and changing all of those at runtime should definitely work! just
neglected to test that, it seems...)