ovl: allocate an ovl_inode struct

We need some more space to store overlay inode data in memory,
so allocate overlay inodes from a slab of struct ovl_inode.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

diff --git a/fs/overlayfs/ovl_entry.h b/fs/overlayfs/ovl_entry.h
index 34bc4a9f5c61d95f049b3f34ccd0de243aa27ddd..553727df886c5604f49411cbd6ac39550a41fa23 100644 (file)
--- a/fs/overlayfs/ovl_entry.h
+++ b/fs/overlayfs/ovl_entry.h
@@ -58,3 +58,12 @@ static inline struct dentry *ovl_upperdentry_dereference(struct ovl_entry *oe)
 {
        return lockless_dereference(oe->__upperdentry);
 }
+
+struct ovl_inode {
+       struct inode vfs_inode;
+};
+
+static inline struct ovl_inode *OVL_I(struct inode *inode)
+{
+       return container_of(inode, struct ovl_inode, vfs_inode);
+}

diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 4882ffb37baead1c4da41684158d22cbe58e5353..ed916018fe1a76f427e2abcdbcbca2f76735fc54 100644 (file)
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -165,6 +165,27 @@ static const struct dentry_operations ovl_reval_dentry_operations = {
        .d_weak_revalidate = ovl_dentry_weak_revalidate,
 };
 
+static struct kmem_cache *ovl_inode_cachep;
+
+static struct inode *ovl_alloc_inode(struct super_block *sb)
+{
+       struct ovl_inode *oi = kmem_cache_alloc(ovl_inode_cachep, GFP_KERNEL);
+
+       return &oi->vfs_inode;
+}
+
+static void ovl_i_callback(struct rcu_head *head)
+{
+       struct inode *inode = container_of(head, struct inode, i_rcu);
+
+       kmem_cache_free(ovl_inode_cachep, OVL_I(inode));
+}
+
+static void ovl_destroy_inode(struct inode *inode)
+{
+       call_rcu(&inode->i_rcu, ovl_i_callback);
+}
+
 static void ovl_put_super(struct super_block *sb)
 {
        struct ovl_fs *ufs = sb->s_fs_info;
@@ -263,12 +284,14 @@ static int ovl_remount(struct super_block *sb, int *flags, char *data)
 }
 
 static const struct super_operations ovl_super_operations = {
+       .alloc_inode    = ovl_alloc_inode,
+       .destroy_inode  = ovl_destroy_inode,
+       .drop_inode     = generic_delete_inode,
        .put_super      = ovl_put_super,
        .sync_fs        = ovl_sync_fs,
        .statfs         = ovl_statfs,
        .show_options   = ovl_show_options,
        .remount_fs     = ovl_remount,
-       .drop_inode     = generic_delete_inode,
 };
 
 enum {
@@ -1038,14 +1061,43 @@ static struct file_system_type ovl_fs_type = {
 };
 MODULE_ALIAS_FS("overlay");
 
+static void ovl_inode_init_once(void *foo)
+{
+       struct ovl_inode *oi = foo;
+
+       inode_init_once(&oi->vfs_inode);
+}
+
 static int __init ovl_init(void)
 {
-       return register_filesystem(&ovl_fs_type);
+       int err;
+
+       ovl_inode_cachep = kmem_cache_create("ovl_inode",
+                                            sizeof(struct ovl_inode), 0,
+                                            (SLAB_RECLAIM_ACCOUNT|
+                                             SLAB_MEM_SPREAD|SLAB_ACCOUNT),
+                                            ovl_inode_init_once);
+       if (ovl_inode_cachep == NULL)
+               return -ENOMEM;
+
+       err = register_filesystem(&ovl_fs_type);
+       if (err)
+               kmem_cache_destroy(ovl_inode_cachep);
+
+       return err;
 }
 
 static void __exit ovl_exit(void)
 {
        unregister_filesystem(&ovl_fs_type);
+
+       /*
+        * Make sure all delayed rcu free inodes are flushed before we
+        * destroy cache.
+        */
+       rcu_barrier();
+       kmem_cache_destroy(ovl_inode_cachep);
+
 }
 
 module_init(ovl_init);