How does something enter the CLEAN2 state?

[Stephen R. van den Berg]

While browsing the code, I was trying to figure out when something enters the CLEAN2 state.

Maybe I'm not looking right, but I can't seem to find it.

Any pointers?

[Archie Cobbs]

The states are not stored explicitly with the cache entries; instead they are "inferred" based on other bits in the structure.

This is how:

#define ENTRY_GET_STATE(entry)  (ENTRY_IN_LIST(entry) ?                             \
                                   ((entry)->dirty ? DIRTY :                        \
                                      ((entry)->verify ? CLEAN2 : CLEAN)) :         \
                                    ((entry)->timeout == READING_TIMEOUT ?          \
                                      ((entry)->verify ? READING2 : READING) :      \
                                      (entry)->dirty ? WRITING2 : WRITING))

So you can see that a cache entry is in state CLEAN2 when it is in the clean list and entry->verify is true. This happens on line 398 of block_cache.c.

-Archie