Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / fs / fscache / netfs.c

diff --git a/kernel/fs/fscache/netfs.c b/kernel/fs/fscache/netfs.c
new file mode 100644 (file)
index 0000000..6d941f5
--- /dev/null
+++ b/kernel/fs/fscache/netfs.c
@@ -0,0 +1,104 @@
+/* FS-Cache netfs (client) registration
+ *
+ * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#define FSCACHE_DEBUG_LEVEL COOKIE
+#include <linux/module.h>
+#include <linux/slab.h>
+#include "internal.h"
+
+static LIST_HEAD(fscache_netfs_list);
+
+/*
+ * register a network filesystem for caching
+ */
+int __fscache_register_netfs(struct fscache_netfs *netfs)
+{
+       struct fscache_netfs *ptr;
+       int ret;
+
+       _enter("{%s}", netfs->name);
+
+       INIT_LIST_HEAD(&netfs->link);
+
+       /* allocate a cookie for the primary index */
+       netfs->primary_index =
+               kmem_cache_zalloc(fscache_cookie_jar, GFP_KERNEL);
+
+       if (!netfs->primary_index) {
+               _leave(" = -ENOMEM");
+               return -ENOMEM;
+       }
+
+       /* initialise the primary index cookie */
+       atomic_set(&netfs->primary_index->usage, 1);
+       atomic_set(&netfs->primary_index->n_children, 0);
+       atomic_set(&netfs->primary_index->n_active, 1);
+
+       netfs->primary_index->def               = &fscache_fsdef_netfs_def;
+       netfs->primary_index->parent            = &fscache_fsdef_index;
+       netfs->primary_index->netfs_data        = netfs;
+       netfs->primary_index->flags             = 1 << FSCACHE_COOKIE_ENABLED;
+
+       atomic_inc(&netfs->primary_index->parent->usage);
+       atomic_inc(&netfs->primary_index->parent->n_children);
+
+       spin_lock_init(&netfs->primary_index->lock);
+       INIT_HLIST_HEAD(&netfs->primary_index->backing_objects);
+
+       /* check the netfs type is not already present */
+       down_write(&fscache_addremove_sem);
+
+       ret = -EEXIST;
+       list_for_each_entry(ptr, &fscache_netfs_list, link) {
+               if (strcmp(ptr->name, netfs->name) == 0)
+                       goto already_registered;
+       }
+
+       list_add(&netfs->link, &fscache_netfs_list);
+       ret = 0;
+
+       pr_notice("Netfs '%s' registered for caching\n", netfs->name);
+
+already_registered:
+       up_write(&fscache_addremove_sem);
+
+       if (ret < 0) {
+               netfs->primary_index->parent = NULL;
+               __fscache_cookie_put(netfs->primary_index);
+               netfs->primary_index = NULL;
+       }
+
+       _leave(" = %d", ret);
+       return ret;
+}
+EXPORT_SYMBOL(__fscache_register_netfs);
+
+/*
+ * unregister a network filesystem from the cache
+ * - all cookies must have been released first
+ */
+void __fscache_unregister_netfs(struct fscache_netfs *netfs)
+{
+       _enter("{%s.%u}", netfs->name, netfs->version);
+
+       down_write(&fscache_addremove_sem);
+
+       list_del(&netfs->link);
+       fscache_relinquish_cookie(netfs->primary_index, 0);
+
+       up_write(&fscache_addremove_sem);
+
+       pr_notice("Netfs '%s' unregistered from caching\n",
+                 netfs->name);
+
+       _leave("");
+}
+EXPORT_SYMBOL(__fscache_unregister_netfs);