* The method vm_cache_remove_consumer() and the page daemon used to get

a reference to a by them not yet referenced cache was not correct.
  They only incremented the reference count, but a vnode cache reference
  includes also a vnode reference. In case of the page daemon this would
  cause vnode references to be lost (causing bug #1465).
* The page daemon used an unsafe method to access a yet unreferenced
  page cache. There was nothing that prevented the cache from being
  deleted while the page daemon tried to get a reference. The
  vm_page::cache field is now protected by the page cache table
  spinlock, too, which the new function
  vm_cache_acquire_page_cache_ref(), used by the page daemon, also
  acquires while trying to get the reference.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@22208 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/private/kernel/vm_cache.h

@@ -23,6 +23,7 @@ status_t vm_cache_init(struct kernel_args *args);
 vm_cache *vm_cache_create(vm_store *store);
 void vm_cache_acquire_ref(vm_cache *cache);
 void vm_cache_release_ref(vm_cache *cache);
+vm_cache *vm_cache_acquire_page_cache_ref(vm_page *page);
 vm_page *vm_cache_lookup_page(vm_cache *cache, off_t page);
 void vm_cache_insert_page(vm_cache *cache, vm_page *page, off_t offset);
 void vm_cache_remove_page(vm_cache *cache, vm_page *page);