Wrapfs: main header file

Signed-off-by: Erez Zadok <ezk@cs.sunysb.edu>

diff --git a/fs/wrapfs/wrapfs.h b/fs/wrapfs/wrapfs.h
new file mode 100644 (file)
index 0000000..1e7fcb6
--- /dev/null
+++ b/fs/wrapfs/wrapfs.h
@@ -0,0 +1,203 @@
+/*
+ * Copyright (c) 1998-2010 Erez Zadok
+ * Copyright (c) 2009     Shrikar Archak
+ * Copyright (c) 2003-2010 Stony Brook University
+ * Copyright (c) 2003-2010 The Research Foundation of SUNY
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef _WRAPFS_H_
+#define _WRAPFS_H_
+
+#include <linux/dcache.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/mount.h>
+#include <linux/namei.h>
+#include <linux/seq_file.h>
+#include <linux/smp_lock.h>
+#include <linux/statfs.h>
+#include <linux/fs_stack.h>
+#include <linux/magic.h>
+#include <linux/uaccess.h>
+
+/* the file system name */
+#define WRAPFS_NAME "wrapfs"
+
+/* wrapfs root inode number */
+#define WRAPFS_ROOT_INO     1
+
+/* useful for tracking code reachability */
+#define UDBG printk("DBG:%s:%s:%d\n", __FILE__, __func__, __LINE__)
+
+/* operations vectors defined in specific files */
+extern const struct file_operations wrapfs_main_fops;
+extern const struct file_operations wrapfs_dir_fops;
+extern const struct inode_operations wrapfs_main_iops;
+extern const struct inode_operations wrapfs_dir_iops;
+extern const struct inode_operations wrapfs_symlink_iops;
+extern const struct super_operations wrapfs_sops;
+extern const struct dentry_operations wrapfs_dops;
+extern const struct address_space_operations wrapfs_aops, wrapfs_dummy_aops;
+extern const struct vm_operations_struct wrapfs_vm_ops;
+
+extern int wrapfs_init_inode_cache(void);
+extern void wrapfs_destroy_inode_cache(void);
+extern int wrapfs_init_dentry_cache(void);
+extern void wrapfs_destroy_dentry_cache(void);
+extern int new_dentry_private_data(struct dentry *dentry);
+extern void free_dentry_private_data(struct dentry *dentry);
+extern int init_lower_nd(struct nameidata *nd, unsigned int flags);
+extern void release_lower_nd(struct nameidata *nd, int err);
+extern struct dentry *wrapfs_lookup(struct inode *dir, struct dentry *dentry,
+                                   struct nameidata *nd);
+extern int wrapfs_interpose(struct dentry *dentry, struct super_block *sb,
+                           struct path *lower_path);
+
+/* file private data */
+struct wrapfs_file_info {
+       struct file *lower_file;
+       const struct vm_operations_struct *lower_vm_ops;
+};
+
+/* wrapfs inode data in memory */
+struct wrapfs_inode_info {
+       struct inode *lower_inode;
+       struct inode vfs_inode;
+};
+
+/* wrapfs dentry data in memory */
+struct wrapfs_dentry_info {
+       spinlock_t lock;        /* protects lower_path */
+       struct path lower_path;
+};
+
+/* wrapfs super-block data in memory */
+struct wrapfs_sb_info {
+       struct super_block *lower_sb;
+};
+
+/*
+ * inode to private data
+ *
+ * Since we use containers and the struct inode is _inside_ the
+ * wrapfs_inode_info structure, WRAPFS_I will always (given a non-NULL
+ * inode pointer), return a valid non-NULL pointer.
+ */
+static inline struct wrapfs_inode_info *WRAPFS_I(const struct inode *inode)
+{
+       return container_of(inode, struct wrapfs_inode_info, vfs_inode);
+}
+
+/* dentry to private data */
+#define WRAPFS_D(dent) ((struct wrapfs_dentry_info *)(dent)->d_fsdata)
+
+/* superblock to private data */
+#define WRAPFS_SB(super) ((struct wrapfs_sb_info *)(super)->s_fs_info)
+
+/* file to private Data */
+#define WRAPFS_F(file) ((struct wrapfs_file_info *)((file)->private_data))
+
+/* file to lower file */
+static inline struct file *wrapfs_lower_file(const struct file *f)
+{
+       return WRAPFS_F(f)->lower_file;
+}
+
+static inline void wrapfs_set_lower_file(struct file *f, struct file *val)
+{
+       WRAPFS_F(f)->lower_file = val;
+}
+
+/* inode to lower inode. */
+static inline struct inode *wrapfs_lower_inode(const struct inode *i)
+{
+       return WRAPFS_I(i)->lower_inode;
+}
+
+static inline void wrapfs_set_lower_inode(struct inode *i, struct inode *val)
+{
+       WRAPFS_I(i)->lower_inode = val;
+}
+
+/* superblock to lower superblock */
+static inline struct super_block *wrapfs_lower_super(
+       const struct super_block *sb)
+{
+       return WRAPFS_SB(sb)->lower_sb;
+}
+
+static inline void wrapfs_set_lower_super(struct super_block *sb,
+                                         struct super_block *val)
+{
+       WRAPFS_SB(sb)->lower_sb = val;
+}
+
+/* path based (dentry/mnt) macros */
+static inline void pathcpy(struct path *dst, const struct path *src)
+{
+       dst->dentry = src->dentry;
+       dst->mnt = src->mnt;
+}
+/* Returns struct path.  Caller must path_put it. */
+static inline void wrapfs_get_lower_path(const struct dentry *dent,
+                                        struct path *lower_path)
+{
+       spin_lock(&WRAPFS_D(dent)->lock);
+       pathcpy(lower_path, &WRAPFS_D(dent)->lower_path);
+       path_get(lower_path);
+       spin_unlock(&WRAPFS_D(dent)->lock);
+       return;
+}
+static inline void wrapfs_put_lower_path(const struct dentry *dent,
+                                        struct path *lower_path)
+{
+       path_put(lower_path);
+       return;
+}
+static inline void wrapfs_set_lower_path(const struct dentry *dent,
+                                        struct path *lower_path)
+{
+       spin_lock(&WRAPFS_D(dent)->lock);
+       pathcpy(&WRAPFS_D(dent)->lower_path, lower_path);
+       spin_unlock(&WRAPFS_D(dent)->lock);
+       return;
+}
+static inline void wrapfs_reset_lower_path(const struct dentry *dent)
+{
+       spin_lock(&WRAPFS_D(dent)->lock);
+       WRAPFS_D(dent)->lower_path.dentry = NULL;
+       WRAPFS_D(dent)->lower_path.mnt = NULL;
+       spin_unlock(&WRAPFS_D(dent)->lock);
+       return;
+}
+static inline void wrapfs_put_reset_lower_path(const struct dentry *dent)
+{
+       struct path lower_path;
+       spin_lock(&WRAPFS_D(dent)->lock);
+       pathcpy(&lower_path, &WRAPFS_D(dent)->lower_path);
+       WRAPFS_D(dent)->lower_path.dentry = NULL;
+       WRAPFS_D(dent)->lower_path.mnt = NULL;
+       spin_unlock(&WRAPFS_D(dent)->lock);
+       path_put(&lower_path);
+       return;
+}
+
+/* locking helpers */
+static inline struct dentry *lock_parent(struct dentry *dentry)
+{
+       struct dentry *dir = dget_parent(dentry);
+       mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
+       return dir;
+}
+
+static inline void unlock_dir(struct dentry *dir)
+{
+       mutex_unlock(&dir->d_inode->i_mutex);
+       dput(dir);
+}
+#endif /* not _WRAPFS_H_ */