NFS: FS-Cache page management
FS-Cache page management for NFS. This includes hooking the releasing and
invalidation of pages marked with PG_fscache (aka PG_private_2) and waiting for
completion of the write-to-cache flag (PG_fscache_write aka PG_owner_priv_2).
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: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Daire Byrne <Daire.Byrne@framestore.com>
diff --git a/fs/nfs/fscache.c b/fs/nfs/fscache.c
index e3816eb..f673d35 100644
--- a/fs/nfs/fscache.c
+++ b/fs/nfs/fscache.c
@@ -19,6 +19,7 @@
#include <linux/seq_file.h>
#include "internal.h"
+#include "iostat.h"
#include "fscache.h"
#define NFSDBG_FACILITY NFSDBG_FSCACHE
@@ -328,3 +329,55 @@
}
nfs_fscache_inode_unlock(inode);
}
+
+/*
+ * Release the caching state associated with a page, if the page isn't busy
+ * interacting with the cache.
+ * - Returns true (can release page) or false (page busy).
+ */
+int nfs_fscache_release_page(struct page *page, gfp_t gfp)
+{
+ struct nfs_inode *nfsi = NFS_I(page->mapping->host);
+ struct fscache_cookie *cookie = nfsi->fscache;
+
+ BUG_ON(!cookie);
+
+ if (fscache_check_page_write(cookie, page)) {
+ if (!(gfp & __GFP_WAIT))
+ return 0;
+ fscache_wait_on_page_write(cookie, page);
+ }
+
+ if (PageFsCache(page)) {
+ dfprintk(FSCACHE, "NFS: fscache releasepage (0x%p/0x%p/0x%p)\n",
+ cookie, page, nfsi);
+
+ fscache_uncache_page(cookie, page);
+ nfs_add_fscache_stats(page->mapping->host,
+ NFSIOS_FSCACHE_PAGES_UNCACHED, 1);
+ }
+
+ return 1;
+}
+
+/*
+ * Release the caching state associated with a page if undergoing complete page
+ * invalidation.
+ */
+void __nfs_fscache_invalidate_page(struct page *page, struct inode *inode)
+{
+ struct nfs_inode *nfsi = NFS_I(inode);
+ struct fscache_cookie *cookie = nfsi->fscache;
+
+ BUG_ON(!cookie);
+
+ dfprintk(FSCACHE, "NFS: fscache invalidatepage (0x%p/0x%p/0x%p)\n",
+ cookie, page, nfsi);
+
+ fscache_wait_on_page_write(cookie, page);
+
+ BUG_ON(!PageLocked(page));
+ fscache_uncache_page(cookie, page);
+ nfs_add_fscache_stats(page->mapping->host,
+ NFSIOS_FSCACHE_PAGES_UNCACHED, 1);
+}
