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>

1 files changed, 14 insertions, 4 deletions

diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index f5bc54dccecb..3523b895eb4b 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -35,6 +35,7 @@
 #include "delegation.h"
 #include "internal.h"
 #include "iostat.h"
+#include "fscache.h"
 
 #define NFSDBG_FACILITY         NFSDBG_FILE
 
@@ -413,7 +414,7 @@ static int nfs_write_end(struct file *file, struct address_space *mapping,
  * Partially or wholly invalidate a page
  * - Release the private state associated with a page if undergoing complete
  *   page invalidation
- * - Called if either PG_private or PG_private_2 is set on the page
+ * - Called if either PG_private or PG_fscache is set on the page
  * - Caller holds page lock
  */
 static void nfs_invalidate_page(struct page *page, unsigned long offset)
@@ -424,11 +425,13 @@ static void nfs_invalidate_page(struct page *page, unsigned long offset)
                 return;
         /* Cancel any unstarted writes on this page */
         nfs_wb_page_cancel(page->mapping->host, page);
+
+        nfs_fscache_invalidate_page(page, page->mapping->host);
 }
 
 /*
  * Attempt to release the private state associated with a page
- * - Called if either PG_private or PG_private_2 is set on the page
+ * - Called if either PG_private or PG_fscache is set on the page
  * - Caller holds page lock
  * - Return true (may release page) or false (may not)
  */
@@ -437,24 +440,28 @@ static int nfs_release_page(struct page *page, gfp_t gfp)
         dfprintk(PAGECACHE, "NFS: release_page(%p)\n", page);
 
         /* If PagePrivate() is set, then the page is not freeable */
-        return 0;
+        if (PagePrivate(page))
+                return 0;
+        return nfs_fscache_release_page(page, gfp);
 }
 
 /*
  * Attempt to clear the private state associated with a page when an error
  * occurs that requires the cached contents of an inode to be written back or
  * destroyed
- * - Called if either PG_private or PG_private_2 is set on the page
+ * - Called if either PG_private or fscache is set on the page
  * - Caller holds page lock
  * - Return 0 if successful, -error otherwise
  */
 static int nfs_launder_page(struct page *page)
 {
         struct inode *inode = page->mapping->host;
+        struct nfs_inode *nfsi = NFS_I(inode);
 
         dfprintk(PAGECACHE, "NFS: launder_page(%ld, %llu)\n",
                 inode->i_ino, (long long)page_offset(page));
 
+        nfs_fscache_wait_on_page_write(nfsi, page);
         return nfs_wb_page(inode, page);
 }
 
@@ -491,6 +498,9 @@ static int nfs_vm_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
                 filp->f_mapping->host->i_ino,
                 (long long)page_offset(page));
 
+        /* make sure the cache has finished storing the page */
+        nfs_fscache_wait_on_page_write(NFS_I(dentry->d_inode), page);
+
         lock_page(page);
         mapping = page->mapping;
         if (mapping != dentry->d_inode->i_mapping)