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NetBSD 6.1.5 - man page for puffs_flush (netbsd section 3)

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PUFFS_FLUSH(3)			   BSD Library Functions Manual 		   PUFFS_FLUSH(3)

     puffs_flush -- puffs kernel cache flushing and invalidation routines

     library ``libpuffs''

     #include <puffs.h>

     puffs_inval_namecache_dir(struct puffs_usermount *pu, puffs_cookie_t cookie);

     puffs_inval_namecache_all(struct puffs_usermount *pu);

     puffs_inval_pagecache_node(struct puffs_usermount *pu, puffs_cookie_t cookie);

     puffs_inval_pagecache_node_range(struct puffs_usermount *pu, puffs_cookie_t cookie,
	 off_t start, off_t end);

     puffs_flush_pagecache_node(struct puffs_usermount *pu, puffs_cookie_t cookie);

     puffs_flush_pagecache_node_range(struct puffs_usermount *pu, puffs_cookie_t cookie,
	 off_t start, off_t end);

     These routines are used inform the kernel that any information it might have cached is no
     longer valid.  puffs_inval_namecache_dir() invalidates the name cache for a given directory.
     The argument cookie should describe an existing and valid directory cookie for the file sys-
     tem.  Similarly, puffs_inval_namecache_all() invalidates the name cache for the entire file
     system (this routine might go away).

     The cached pages (file contents) for a regular file described by cookie are invalidated
     using puffs_inval_pagecache_node().  A specific range can be invalidated using
     puffs_inval_pagecache_node_range() for a platform specific page level granularity.  The off-
     set start will be truncated to a page boundary while end will be rounded up to the next page
     boundary.	As a special case, specifying 0 as end will invalidate all contents from start to
     the end of the file.

     It is especially important to note that these routines will not only invalidate data in the
     "read cache", but also data in the "write back" cache (conceptually speaking; in reality
     they are the same cache), which has not yet been flushed to the file server.  Therefore any
     unflushed data will be lost.

     The counterparts of the invalidation routines are the flushing routines
     puffs_flush_pagecache_node() and puffs_flush_pagecache_node_range(), which force unwritten
     data from the kernel page cache to be written.  For the flush range version, the same range
     rules as with the invalidation routine apply.  The data is flushed asynchronously, i.e. if
     the routine returns successfully, all the caller knows is that the data has been queued for


BSD					  April 7, 2007 				      BSD
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