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authorDavid Howells <dhowells@redhat.com>2009-04-03 16:42:36 +0100
committerDavid Howells <dhowells@redhat.com>2009-04-03 16:42:36 +0100
commit266cf658efcf6ac33541a46740f74f50c79d2b6b (patch)
tree5c83b0879892d509e598dfd54be3ba3679ecd348 /mm/filemap.c
parent03fb3d2af96c2783c3a5bc03f3d984cf422f0e69 (diff)
downloadconfigs-266cf658efcf6ac33541a46740f74f50c79d2b6b.tar.gz
FS-Cache: Recruit a page flags for cache management
Recruit a page flag to aid in cache management. The following extra flag is defined: (1) PG_fscache (PG_private_2) The marked page is backed by a local cache and is pinning resources in the cache driver. If PG_fscache is set, then things that checked for PG_private will now also check for that. This includes things like truncation and page invalidation. The function page_has_private() had been added to make the checks for both PG_private and PG_private_2 at the same time. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Steve Dickson <steved@redhat.com> Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Tested-by: Daire Byrne <Daire.Byrne@framestore.com>
Diffstat (limited to 'mm/filemap.c')
-rw-r--r--mm/filemap.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/mm/filemap.c b/mm/filemap.c
index 126d3973b3d..cbc5772e717 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2463,6 +2463,9 @@ EXPORT_SYMBOL(generic_file_aio_write);
* (presumably at page->private). If the release was successful, return `1'.
* Otherwise return zero.
*
+ * This may also be called if PG_fscache is set on a page, indicating that the
+ * page is known to the local caching routines.
+ *
* The @gfp_mask argument specifies whether I/O may be performed to release
* this page (__GFP_IO), and whether the call may block (__GFP_WAIT & __GFP_FS).
*