vfs: Add 64 bit i_version support

The i_version field of the inode is changed to be a 64-bit 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.
This first part concerns the vfs, it converts the 32-bit i_version in
the generic inode to a 64-bit, a flag is added in the super block in
order to check if the feature is enabled and the i_version is
incremented in the vfs.

Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: Jean Noel Cordenner <jean-noel.cordenner@bull.net>
Signed-off-by: Kalpak Shah <kalpak@clusterfs.com>

4 files changed, 33 insertions, 6 deletions

diff --git a/fs/afs/dir.c b/fs/afs/dir.c
index 33fe39ad4e03..0cc3597c1197 100644
--- a/fs/afs/dir.c
+++ b/fs/afs/dir.c
@@ -546,11 +546,11 @@ static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry,
         dentry->d_op = &afs_fs_dentry_operations;
 
         d_add(dentry, inode);
-        _leave(" = 0 { vn=%u u=%u } -> { ino=%lu v=%lu }",
+        _leave(" = 0 { vn=%u u=%u } -> { ino=%lu v=%llu }",
                fid.vnode,
                fid.unique,
                dentry->d_inode->i_ino,
-               dentry->d_inode->i_version);
+               (unsigned long long)dentry->d_inode->i_version);
 
         return NULL;
 }
@@ -630,9 +630,10 @@ static int afs_d_revalidate(struct dentry *dentry, struct nameidata *nd)
                  * been deleted and replaced, and the original vnode ID has
                  * been reused */
                 if (fid.unique != vnode->fid.unique) {
-                        _debug("%s: file deleted (uq %u -> %u I:%lu)",
+                        _debug("%s: file deleted (uq %u -> %u I:%llu)",
                                dentry->d_name.name, fid.unique,
-                               vnode->fid.unique, dentry->d_inode->i_version);
+                               vnode->fid.unique,
+                               (unsigned long long)dentry->d_inode->i_version);
                         spin_lock(&vnode->lock);
                         set_bit(AFS_VNODE_DELETED, &vnode->flags);
                         spin_unlock(&vnode->lock);
diff --git a/fs/afs/inode.c b/fs/afs/inode.c
index d196840127c6..84750c8e9f95 100644
--- a/fs/afs/inode.c
+++ b/fs/afs/inode.c
@@ -301,7 +301,8 @@ int afs_getattr(struct vfsmount *mnt, struct dentry *dentry,
 
         inode = dentry->d_inode;
 
-        _enter("{ ino=%lu v=%lu }", inode->i_ino, inode->i_version);
+        _enter("{ ino=%lu v=%llu }", inode->i_ino,
+                (unsigned long long)inode->i_version);
 
         generic_fillattr(inode, stat);
         return 0;
diff --git a/fs/inode.c b/fs/inode.c
index ed35383d0b6c..b48324a94c2b 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1243,6 +1243,23 @@ void touch_atime(struct vfsmount *mnt, struct dentry *dentry)
 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);
+}
+
+/**
  *      file_update_time        -       update mtime and ctime time
  *      @file: file accessed
  *
@@ -1276,6 +1293,11 @@ void file_update_time(struct file *file)
                 sync_it = 1;
         }
 
+        if (IS_I_VERSION(inode)) {
+                inode_inc_iversion(inode);
+                sync_it = 1;
+        }
+
         if (sync_it)
                 mark_inode_dirty_sync(inode);
 }
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 21398a5d688d..9608839552b3 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -124,6 +124,7 @@ extern int dir_notify_enable;
 #define MS_SHARED       (1<<20) /* change to shared */
 #define MS_RELATIME     (1<<21) /* Update atime relative to mtime/ctime. */
 #define MS_KERNMOUNT    (1<<22) /* this is a kern_mount call */
+#define MS_I_VERSION    (1<<23) /* Update inode I_version field */
 #define MS_ACTIVE       (1<<30)
 #define MS_NOUSER       (1<<31)
 
@@ -173,6 +174,7 @@ extern int dir_notify_enable;
                                         ((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)
@@ -599,7 +601,7 @@ struct inode {
         uid_t                   i_uid;
         gid_t                   i_gid;
         dev_t                   i_rdev;
-        unsigned long           i_version;
+        u64                     i_version;
         loff_t                  i_size;
 #ifdef __NEED_I_SIZE_ORDERED
         seqcount_t              i_size_seqcount;
@@ -1394,6 +1396,7 @@ static inline void inode_dec_link_count(struct inode *inode)
         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)
 {