[K42-discussion] Volatile directories and revalidation patch

[Dilma DaSilva]

This patch has been applied.

Patrick Bozeman writes:
 > This patch probably could have been split into a few pieces, but they 
 > are somewhat intertwined.   Let me know if you want it broken up.  The 
 > patch provides 3 things:
 > 
 > 1) Provides a FileInfoVirtFSDirVolatile class.  This class is actually a 
 > combo of static and dynamic directory functionality.  It has 
 > FileInfoVirtFSDirStatic as its base class, so it is possible to add 
 > static files and perform lookups on them using the static dir methods.  
 > However, it overrides key methods such as directory enumeration and 
 > object lookup.  For such methods, it first calls the static dir method 
 > and then a dynamic method implemented by derived classes.  This is of 
 > course useful for directories such as /proc that has a mix of static and 
 > dynamic content, and for directories like /proc/<pid>/fd that have only 
 > dynamic content.
 > 
 > 2) getRecLen was moved from a static function in FileInfoVirtFS.C to a 
 > static member function of FileInfoVirtFSDirBase.  This enables derived 
 > classes outside of this compilation unit to call it (e.g. the derived 
 > classes used in the procfs server.)
 > 
 > 3)  Provides isStale() and shouldRevalidate() methods to the 
 > FileInfoVirtFSDir class hierarchy and calls them from 
 > ServerFileDirVirtFS  to check and potentially trigger revalidation.   
 > This causes revalidation to occur before a stale object gets used rather 
 > than after as was the case before this change.  (And it largely avoids 
 > the bug from my previous email.)
 > 
 > People may have stylistic issues with part number 1 of the patch. Let me 
 > know what you think.