On Tue, 2007-07-31 at 21:25 +0100, David Howells wrote: > diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h > index 209d3a4..eaf9854 100644 > --- a/include/linux/page-flags.h > +++ b/include/linux/page-flags.h > @@ -83,19 +83,24 @@ > #define PG_private 11 /* If pagecache, has fs-private data */ > > #define PG_writeback 12 /* Page is under writeback */ > +#define PG_owner_priv_2 13 /* Owner use. If pagecache, fs may use */ > #define PG_compound 14 /* Part of a compound page */ > #define PG_swapcache 15 /* Swap page: swp_entry_t in private */ > > #define PG_mappedtodisk 16 /* Has blocks allocated on-disk */ > #define PG_reclaim 17 /* To be reclaimed asap */ > +#define PG_owner_priv_3 18 /* Owner use. If pagecache, fs may use */ > #define PG_buddy 19 /* Page is free, on buddy lists */ > > /* PG_readahead is only used for file reads; PG_reclaim is only for writes */ > #define PG_readahead PG_reclaim /* Reminder to do async read-ahead */ > > -/* PG_owner_priv_1 users should have descriptive aliases */ > +/* PG_owner_priv_1/2/3 users should have descriptive aliases */ > #define PG_checked PG_owner_priv_1 /* Used by some filesystems */ > #define PG_pinned PG_owner_priv_1 /* Xen pinned pagetable */ > +#define PG_fscache PG_owner_priv_2 /* Backed by local cache */ > +#define PG_fscache_write PG_owner_priv_3 /* Writing to local cache */ > + > +/** > + * page_has_private - Determine if page has private stuff > + * @page: The page to be checked > + * > + * Determine if a page has private stuff, indicating that release routines > + * should be invoked upon it. > + */ > +#define page_has_private(page) \ > + ((page)->flags & ((1 << PG_private) | \ > + (1 << PG_fscache))) > + Not sure its a good idea to overload page_has_private() with an overloadable page-flag. What if some future FS wants to use PG_owner_priv_2 for other purposes? Obviously filesystems cannot use these two page-flags if they want to be compatible with FS-cache, but need all filesystems be? (also, ouch! - 2 pageflags) - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
