fs: new API for handling inode->i_version
Add a documentation blob that explains what the i_version field is, how
it is expected to work, and how it is currently implemented by various
filesystems.
We already have inode_inc_iversion. Add several other functions for
manipulating and accessing the i_version counter. For now, the
implementation is trivial and basically works the way that all of the
open-coded i_version accesses work today.
Future patches will convert existing users of i_version to use the new
API, and then convert the backend implementation to do things more
efficiently.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 2ef8aca..aa452c9 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -43,6 +43,7 @@
#include <linux/uuid.h>
#include <linux/btrfs.h>
#include <linux/uaccess.h>
+#include <linux/iversion.h>
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"