xfs: move di_changecount to VFS inode

We can store the di_changecount in the i_version field of the VFS
inode and remove another 8 bytes from the xfs_icdinode.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>

fs/xfs/libxfs/xfs_inode_buf.c

@@ -251,7 +251,7 @@ xfs_inode_from_disk(
 	to->di_flags	= be16_to_cpu(from->di_flags);
 
 	if (to->di_version == 3) {
-		to->di_changecount = be64_to_cpu(from->di_changecount);
+		inode->i_version = be64_to_cpu(from->di_changecount);
 		to->di_crtime.t_sec = be32_to_cpu(from->di_crtime.t_sec);
 		to->di_crtime.t_nsec = be32_to_cpu(from->di_crtime.t_nsec);
 		to->di_flags2 = be64_to_cpu(from->di_flags2);
@@ -300,7 +300,7 @@ xfs_inode_to_disk(
 	to->di_flags = cpu_to_be16(from->di_flags);
 
 	if (from->di_version == 3) {
-		to->di_changecount = cpu_to_be64(from->di_changecount);
+		to->di_changecount = cpu_to_be64(inode->i_version);
 		to->di_crtime.t_sec = cpu_to_be32(from->di_crtime.t_sec);
 		to->di_crtime.t_nsec = cpu_to_be32(from->di_crtime.t_nsec);
 		to->di_flags2 = cpu_to_be64(from->di_flags2);

fs/xfs/libxfs/xfs_inode_buf.h

@@ -47,7 +47,6 @@ struct xfs_icdinode {
 	__uint16_t	di_dmstate;	/* DMIG state info */
 	__uint16_t	di_flags;	/* random flags, XFS_DIFLAG_... */
 
-	__uint64_t	di_changecount;	/* number of attribute changes */
 	__uint64_t	di_flags2;	/* more random flags */
 
 	xfs_ictimestamp_t di_crtime;	/* time created */

fs/xfs/xfs_icache.c

@@ -138,9 +138,9 @@ xfs_inode_free(
  * When we recycle a reclaimable inode, we need to re-initialise the VFS inode
  * part of the structure. This is made more complex by the fact we store
  * information about the on-disk values in the VFS inode and so we can't just
- * overwrite it's values unconditionally. Hence we save the parameters we
+ * overwrite the values unconditionally. Hence we save the parameters we
  * need to retain across reinitialisation, and rewrite them into the VFS inode
- * after resetting it's state even if resetting fails.
+ * after reinitialisation even if it fails.
  */
 static int
 xfs_reinit_inode(
@@ -150,11 +150,13 @@ xfs_reinit_inode(
 	int		error;
 	uint32_t	nlink = inode->i_nlink;
 	uint32_t	generation = inode->i_generation;
+	uint64_t	version = inode->i_version;
 
 	error = inode_init_always(mp->m_super, inode);
 
 	set_nlink(inode, nlink);
 	inode->i_generation = generation;
+	inode->i_version = version;
 	return error;
 }
 

fs/xfs/xfs_inode.c

@@ -841,7 +841,7 @@ xfs_ialloc(
 	ip->i_d.di_flags = 0;
 
 	if (ip->i_d.di_version == 3) {
-		ip->i_d.di_changecount = 1;
+		inode->i_version = 1;
 		ip->i_d.di_flags2 = 0;
 		ip->i_d.di_crtime.t_sec = (__int32_t)tv.tv_sec;
 		ip->i_d.di_crtime.t_nsec = (__int32_t)tv.tv_nsec;

fs/xfs/xfs_inode_item.c

@@ -364,7 +364,7 @@ xfs_inode_to_log_dinode(
 	to->di_flags = from->di_flags;
 
 	if (from->di_version == 3) {
-		to->di_changecount = from->di_changecount;
+		to->di_changecount = inode->i_version;
 		to->di_crtime.t_sec = from->di_crtime.t_sec;
 		to->di_crtime.t_nsec = from->di_crtime.t_nsec;
 		to->di_flags2 = from->di_flags2;

fs/xfs/xfs_trans_inode.c

@@ -117,7 +117,7 @@ xfs_trans_log_inode(
 	 */
 	if (!(ip->i_itemp->ili_item.li_desc->lid_flags & XFS_LID_DIRTY) &&
 	    IS_I_VERSION(VFS_I(ip))) {
-		ip->i_d.di_changecount = ++VFS_I(ip)->i_version;
+		VFS_I(ip)->i_version++;
 		flags |= XFS_ILOG_CORE;
 	}