[PATCH 1 of 2] Stackfs: Introduce stackfs_copy_{attr,inode}_*

[Josef "Jeff" Sipek <jsipek@cs.sunysb.edu>]

From: Josef "Jeff" Sipek <jsipek@cs.sunysb.edu>

The following patch introduces several stackfs_copy_* functions which allow
stackable filesystems (such as eCryptfs and Unionfs) to easily copy over
(currently only) inode attributes. This prevents code duplication and allows
for code reuse.

Signed-off-by: Josef "Jeff" Sipek <jsipek@cs.sunysb.edu>

---

1 file changed, 65 insertions(+)
include/linux/stack_fs.h |   65 ++++++++++++++++++++++++++++++++++++++++++++++

diff --git a/include/linux/stack_fs.h b/include/linux/stack_fs.h
new file mode 100644
--- /dev/null
+++ b/include/linux/stack_fs.h
@@ -0,0 +1,65 @@
+#ifndef _LINUX_STACK_FS_H
+#define _LINUX_STACK_FS_H
+
+/* This file defines generic functions used primarily by stackable
+ * filesystems
+ */
+
+static inline void stackfs_copy_inode_size(struct inode *dst,
+					   const struct inode *src)
+{
+	i_size_write(dst, i_size_read((struct inode *)src));
+	dst->i_blocks = src->i_blocks;
+}
+
+static inline void stackfs_copy_attr_atime(struct inode *dest,
+					   const struct inode *src)
+{
+	dest->i_atime = src->i_atime;
+}
+
+static inline void stackfs_copy_attr_times(struct inode *dest,
+					   const struct inode *src)
+{
+	dest->i_atime = src->i_atime;
+	dest->i_mtime = src->i_mtime;
+	dest->i_ctime = src->i_ctime;
+}
+
+static inline void stackfs_copy_attr_timesizes(struct inode *dest,
+					       const struct inode *src)
+{
+	dest->i_atime = src->i_atime;
+	dest->i_mtime = src->i_mtime;
+	dest->i_ctime = src->i_ctime;
+	stackfs_copy_inode_size(dest, src);
+}
+
+static inline void __stackfs_copy_attr_all(struct inode *dest,
+					   const struct inode *src,
+					   int (*get_nlinks)(struct inode *))
+{
+	if (!get_nlinks)
+		dest->i_nlink = src->i_nlink;
+	else
+		dest->i_nlink = get_nlinks(dest);
+
+	dest->i_mode = src->i_mode;
+	dest->i_uid = src->i_uid;
+	dest->i_gid = src->i_gid;
+	dest->i_rdev = src->i_rdev;
+	dest->i_atime = src->i_atime;
+	dest->i_mtime = src->i_mtime;
+	dest->i_ctime = src->i_ctime;
+	dest->i_blkbits = src->i_blkbits;
+	dest->i_flags = src->i_flags;
+}
+
+static inline void stackfs_copy_attr_all(struct inode *dest,
+					 const struct inode *src)
+{
+	__stackfs_copy_attr_all(dest, src, NULL);
+}
+
+#endif /* _LINUX_STACK_FS_H */
+