• David Howells's avatar
    afs: Overhaul cell database management · 989782dc
    David Howells authored
    Overhaul the way that the in-kernel AFS client keeps track of cells in the
    following manner:
    
     (1) Cells are now held in an rbtree to make walking them quicker and RCU
         managed (though this is probably overkill).
    
     (2) Cells now have a manager work item that:
    
         (A) Looks after fetching and refreshing the VL server list.
    
         (B) Manages cell record lifetime, including initialising and
         	 destruction.
    
         (B) Manages cell record caching whereby threads are kept around for a
         	 certain time after last use and then destroyed.
    
         (C) Manages the FS-Cache index cookie for a cell.  It is not permitted
         	 for a cookie to be in use twice, so we have to be careful to not
         	 allow a new cell record to exist at the same time as an old record
         	 of the same name.
    
     (3) Each AFS network namespace is given a manager work item that manages
         the cells within it, maintaining a single timer to prod cells into
         updating their DNS records.
    
         This uses the reduce_timer() facility to make the timer expire at the
         soonest timed event that needs happening.
    
     (4) When a module is being unloaded, cells and cell managers are now
         counted out using dec_after_work() to make sure the module text is
         pinned until after the data structures have been cleaned up.
    
     (5) Each cell's VL server list is now protected by a seqlock rather than a
         semaphore.
    Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
    989782dc
proc.c 15.3 KB