> i guess you are talking about getpages with PGO_LOCKED, right?
> i think it's acceptable to add "never allocate new pages"
> to the definition of PGO_LOCKED so that you don't need to check
> finger prints in that case.  i believe it's already true for all in-tree
> filesystems.  (please confirm.)

i withdraw this because filesystems are free to read-in pages
without explicit requests from upper layers.
eg. when aligning i/o range to block boundaries.
 
YAMAMOTO Takashi