If CONFIG_NETFS_DEBUG is enabled, the FS-Cache facility and NETFS support can have runtime debugging enabled by adjusting the value in::
/sys/module/netfs/parameters/debug
This is a bitmask of debugging streams to enable:
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BIT VALUE STREAM POINT
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0 1 Cache management Function entry trace
1 2 Function exit trace
2 4 General
3 8 Cookie management Function entry trace
4 16 Function exit trace
5 32 General
6-8 (Not used)
9 512 I/O operation management Function entry trace
10 1024 Function exit trace
11 2048 General ```text
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The appropriate set of values should be OR’d together and the result written to the control file. For example::
echo $((1|8|512)) >/sys/module/netfs/parameters/debug
will turn on all function entry debugging. ```