Re: [PATCH v2] 9p: fix i_size update race in getattr with writeback caching

[David Howells]

Christian Schoenebeck <linux_oss@xxxxxxxxxxxxx> wrote:

> For cache=loose I couldn't reproduce, but with cache=mmap I could reproduce
> data corruption, folio writeback hangup and the following error message:
> 
> [   60.847671] [append] R=134d: No submit

Can you get me some tracing?  If you can turn on:

echo 65536 >/sys/kernel/tracing/buffer_size_kb
echo 1 > /sys/kernel/tracing/events/netfs/netfs_read/enable
echo 1 > /sys/kernel/tracing/events/netfs/netfs_write/enable
echo 1 > /sys/kernel/tracing/events/netfs/netfs_rreq/enable
echo 1 > /sys/kernel/tracing/events/netfs/netfs_sreq/enable
echo 1 > /sys/kernel/tracing/events/netfs/netfs_failure/enable

run the test to generate the issue, then get the trace:

cat /sys/kernel/tracing/trace | bzip2 -9 >trace.txt

and grab whatever it said in dmesg, particularly if it mentions R=<hex-number>.

Thanks,
David