[feature] 1: custom fs, 2: custom lock. 3: use DB interface

[izouxv]

hi
add 3 features

1. Custom fs
2. Custom lock
3. db use interface to replace db struct

thank you

[roseduan]

Please open a issue to discuss why you want to do this, and how do you do it.

[izouxv]

Please open a issue to discuss why you want to do this, and how do you do it.

#313

[roseduan]

Thanks, issue : #313