[PATCH 1/2] i_version update - vfs part

[Cordenner jean noel <jean-noel.cordenner@bull.net>]

Hi, 

This is an update of the i_version patch. 
The i_version field is a 64bit counter that is set on every inode 
creation and that is incremented every time the inode data is modified 
(similarly to the "ctime" time-stamp). 
The aim is to fulfill a NFSv4 requirement for rfc3530: 
"5.5.  Mandatory Attributes - Definitions 
Name        #    DataType   Access   Description 
___________________________________________________________________ 
change        3    uint64       READ     A value created by the 
        server that the client can use to determine if file 
        data, directory contents or attributes of the object 
        have been modified.  The servermay return the object's 
        time_metadata attribute for this attribute's value but 
        only if the filesystem object can not be updated more 
        frequently than the resolution of time_metadata. 
"

This first part deals with adding a flag in the super block and incrementing the i_version in the vfs.

Signed-off-by: Jean Noel Cordenner <jean-noel.cordenner@bull.net>
--- 
 fs/inode.c         |   23 +++++++++++++++++++++++
 fs/libfs.c         |   12 ++++++++++++
 include/linux/fs.h |    3 +++
 3 files changed, 38 insertions(+)

Index: linux-2.6.23-rc8-ext4-i_version/fs/inode.c
===================================================================
--- linux-2.6.23-rc8-ext4-i_version.orig/fs/inode.c	2007-09-26 14:41:41.000000000 +0200
+++ linux-2.6.23-rc8-ext4-i_version/fs/inode.c	2007-10-05 16:14:41.000000000 +0200
@@ -1216,6 +1216,24 @@
 EXPORT_SYMBOL(touch_atime);
 
 /**
+ *	inode_inc_iversion	-	increments i_version
+ *	@inode: inode that need to be updated
+ *
+ *	Every time the inode is modified, the i_version field
+ *	will be incremented.
+ *	The filesystem has to be mounted with i_version flag
+ *
+ */
+
+void inode_inc_iversion(struct inode *inode)
+{
+	spin_lock(&inode->i_lock);
+	inode->i_version++;
+	spin_unlock(&inode->i_lock);
+}
+EXPORT_SYMBOL(inode_inc_iversion);
+
+/**
  *	file_update_time	-	update mtime and ctime time
  *	@file: file accessed
  *
@@ -1249,6 +1267,11 @@
 		sync_it = 1;
 	}
 
+	if (IS_I_VERSION(inode)) {
+		inode_inc_iversion(inode);
+		sync_it = 1;
+	}
+
 	if (sync_it)
 		mark_inode_dirty_sync(inode);
 }
Index: linux-2.6.23-rc8-ext4-i_version/fs/libfs.c
===================================================================
--- linux-2.6.23-rc8-ext4-i_version.orig/fs/libfs.c	2007-07-09 01:32:17.000000000 +0200
+++ linux-2.6.23-rc8-ext4-i_version/fs/libfs.c	2007-09-26 14:51:08.000000000 +0200
@@ -255,6 +255,10 @@
 	struct inode *inode = old_dentry->d_inode;
 
 	inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
+	if (IS_I_VERSION(inode)) {
+		inode_inc_iversion(inode);
+		inode_inc_iversion(dir);
+	}
 	inc_nlink(inode);
 	atomic_inc(&inode->i_count);
 	dget(dentry);
@@ -287,6 +291,10 @@
 	struct inode *inode = dentry->d_inode;
 
 	inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
+	if (IS_I_VERSION(inode)) {
+		inode_inc_iversion(inode);
+		inode_inc_iversion(dir);
+	}
 	drop_nlink(inode);
 	dput(dentry);
 	return 0;
@@ -323,6 +331,10 @@
 
 	old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime =
 		new_dir->i_mtime = inode->i_ctime = CURRENT_TIME;
+	if (IS_I_VERSION(old_dir)) {
+		inode_inc_iversion(old_dir);
+		inode_inc_iversion(new_dir);
+	}
 
 	return 0;
 }
Index: linux-2.6.23-rc8-ext4-i_version/include/linux/fs.h
===================================================================
--- linux-2.6.23-rc8-ext4-i_version.orig/include/linux/fs.h	2007-09-26 14:46:15.000000000 +0200
+++ linux-2.6.23-rc8-ext4-i_version/include/linux/fs.h	2007-09-26 14:51:08.000000000 +0200
@@ -123,6 +123,7 @@
 #define MS_SLAVE	(1<<19)	/* change to slave */
 #define MS_SHARED	(1<<20)	/* change to shared */
 #define MS_RELATIME	(1<<21)	/* Update atime relative to mtime/ctime. */
+#define MS_I_VERSION	(1<<22)	/* Update inode i_version field */
 #define MS_ACTIVE	(1<<30)
 #define MS_NOUSER	(1<<31)
 
@@ -172,6 +173,7 @@
 					((inode)->i_flags & (S_SYNC|S_DIRSYNC)))
 #define IS_MANDLOCK(inode)	__IS_FLG(inode, MS_MANDLOCK)
 #define IS_NOATIME(inode)   __IS_FLG(inode, MS_RDONLY|MS_NOATIME)
+#define IS_I_VERSION(inode)	__IS_FLG(inode, MS_I_VERSION)
 
 #define IS_NOQUOTA(inode)	((inode)->i_flags & S_NOQUOTA)
 #define IS_APPEND(inode)	((inode)->i_flags & S_APPEND)
@@ -1284,6 +1286,7 @@
 	mark_inode_dirty(inode);
 }
 
+extern void inode_inc_iversion(struct inode *inode);
 extern void touch_atime(struct vfsmount *mnt, struct dentry *dentry);
 static inline void file_accessed(struct file *file)
 {


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