NFS: Invalidate FsCache page flags when cache removed

Invalidate the FsCache page flags on the pages belonging to an inode when the
cache backing that NFS inode is removed.

This allows a live cache to be withdrawn.

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, 40 insertions, 0 deletions

diff --git a/fs/nfs/fscache-index.c b/fs/nfs/fscache-index.c
index 7bc54acb7b00..a119b5691e7c 100644
--- a/fs/nfs/fscache-index.c
+++ b/fs/nfs/fscache-index.c
@@ -253,6 +253,45 @@ enum fscache_checkaux nfs_fscache_inode_check_aux(void *cookie_netfs_data,
 }
 
 /*
+ * Indication from FS-Cache that the cookie is no longer cached
+ * - This function is called when the backing store currently caching a cookie
+ *   is removed
+ * - The netfs should use this to clean up any markers indicating cached pages
+ * - This is mandatory for any object that may have data
+ */
+static void nfs_fscache_inode_now_uncached(void *cookie_netfs_data)
+{
+        struct nfs_inode *nfsi = cookie_netfs_data;
+        struct pagevec pvec;
+        pgoff_t first;
+        int loop, nr_pages;
+
+        pagevec_init(&pvec, 0);
+        first = 0;
+
+        dprintk("NFS: nfs_inode_now_uncached: nfs_inode 0x%p\n", nfsi);
+
+        for (;;) {
+                /* grab a bunch of pages to unmark */
+                nr_pages = pagevec_lookup(&pvec,
+                                          nfsi->vfs_inode.i_mapping,
+                                          first,
+                                          PAGEVEC_SIZE - pagevec_count(&pvec));
+                if (!nr_pages)
+                        break;
+
+                for (loop = 0; loop < nr_pages; loop++)
+                        ClearPageFsCache(pvec.pages[loop]);
+
+                first = pvec.pages[nr_pages - 1]->index + 1;
+
+                pvec.nr = nr_pages;
+                pagevec_release(&pvec);
+                cond_resched();
+        }
+}
+
+/*
  * Define the inode object for FS-Cache.  This is used to describe an inode
  * object to fscache_acquire_cookie().  It is keyed by the NFS file handle for
  * an inode.
@@ -268,4 +307,5 @@ const struct fscache_cookie_def nfs_fscache_inode_object_def = {
         .get_attr       = nfs_fscache_inode_get_attr,
         .get_aux        = nfs_fscache_inode_get_aux,
         .check_aux      = nfs_fscache_inode_check_aux,
+        .now_uncached   = nfs_fscache_inode_now_uncached,
 };