27 May, 2011

1 commit

  • This third patch of eight in this cleancache series provides
    the core code for cleancache that interfaces between the hooks in
    VFS and individual filesystems and a cleancache backend. It also
    includes build and config patches.

    Two new files are added: mm/cleancache.c and include/linux/cleancache.h.

    Note that CONFIG_CLEANCACHE can default to on; in systems that do
    not provide a cleancache backend, all hooks devolve to a simple
    check of a global enable flag, so performance impact should
    be negligible but can be reduced to zero impact if config'ed off.
    However for this first commit, it defaults to off.

    Details and a FAQ can be found in Documentation/vm/cleancache.txt

    Credits: Cleancache_ops design derived from Jeremy Fitzhardinge
    design for tmem

    [v8: dan.magenheimer@oracle.com: fix exportfs call affecting btrfs]
    [v8: akpm@linux-foundation.org: use static inline function, not macro]
    [v7: dan.magenheimer@oracle.com: cleanup sysfs and remove cleancache prefix]
    [v6: JBeulich@novell.com: robustly handle buggy fs encode_fh actor definition]
    [v5: jeremy@goop.org: clean up global usage and static var names]
    [v5: jeremy@goop.org: simplify init hook and any future fs init changes]
    [v5: hch@infradead.org: cleaner non-global interface for ops registration]
    [v4: adilger@sun.com: interface must support exportfs FS's]
    [v4: hch@infradead.org: interface must support 64-bit FS on 32-bit kernel]
    [v3: akpm@linux-foundation.org: use one ops struct to avoid pointer hops]
    [v3: akpm@linux-foundation.org: document and ensure PageLocked reqts are met]
    [v3: ngupta@vflare.org: fix success/fail codes, change funcs to void]
    [v2: viro@ZenIV.linux.org.uk: use sane types]
    Signed-off-by: Dan Magenheimer
    Reviewed-by: Jeremy Fitzhardinge
    Reviewed-by: Konrad Rzeszutek Wilk
    Acked-by: Al Viro
    Acked-by: Andrew Morton
    Acked-by: Nitin Gupta
    Acked-by: Minchan Kim
    Acked-by: Andreas Dilger
    Acked-by: Jan Beulich
    Cc: Matthew Wilcox
    Cc: Nick Piggin
    Cc: Mel Gorman
    Cc: Rik Van Riel
    Cc: Chris Mason
    Cc: Ted Ts'o
    Cc: Mark Fasheh
    Cc: Joel Becker

    Dan Magenheimer