[EXT4 set 4][PATCH 5/5] i_version: noversion mount option to disable inode version updates

[Mingming Cao <cmm@us.ibm.com>]

Add a "noversion" mount option to disable inode version updates.

Signed-off-by: Andreas Dilger <adilger@clusterfs.com>
Signed-off-by: Kalpak Shah <kalpak@clusterfs.com>

Index: linux-2.6.21/fs/ext4/super.c
===================================================================
--- linux-2.6.21.orig/fs/ext4/super.c
+++ linux-2.6.21/fs/ext4/super.c
@@ -725,7 +725,7 @@ enum {
 	Opt_usrjquota, Opt_grpjquota, Opt_offusrjquota, Opt_offgrpjquota,
 	Opt_jqfmt_vfsold, Opt_jqfmt_vfsv0, Opt_quota, Opt_noquota,
 	Opt_ignore, Opt_barrier, Opt_err, Opt_resize, Opt_usrquota,
-	Opt_grpquota, Opt_extents, Opt_noextents,
+	Opt_grpquota, Opt_extents, Opt_noextents, Opt_noversion,
 };

 static match_table_t tokens = {
@@ -777,6 +777,7 @@ static match_table_t tokens = {
 	{Opt_barrier, "barrier=%u"},
 	{Opt_extents, "extents"},
 	{Opt_noextents, "noextents"},
+	{Opt_noversion, "noversion"},
 	{Opt_err, NULL},
 	{Opt_resize, "resize"},
 };
@@ -1115,6 +1116,9 @@ clear_qf_name:
 		case Opt_noextents:
 			clear_opt (sbi->s_mount_opt, EXTENTS);
 			break;
+		case Opt_noversion:
+			set_opt(sbi->s_mount_opt, NOVERSION);
+			break;
 		default:
 			printk (KERN_ERR
 				"EXT4-fs: Unrecognized mount option \"%s\" "
Index: linux-2.6.21/include/linux/ext4_fs.h
===================================================================
--- linux-2.6.21.orig/include/linux/ext4_fs.h
+++ linux-2.6.21/include/linux/ext4_fs.h
@@ -473,6 +473,7 @@ do {									       \
 #define EXT4_MOUNT_USRQUOTA		0x100000 /* "old" user quota */
 #define EXT4_MOUNT_GRPQUOTA		0x200000 /* "old" group quota */
 #define EXT4_MOUNT_EXTENTS		0x400000 /* Extents support */
+#define EXT4_MOUNT_NOVERSION		0x800000 /* No inode version updates */

 /* Compatibility, for having both ext2_fs.h and ext4_fs.h included at once */
 #ifndef _LINUX_EXT2_FS_H
Index: linux-2.6.21/fs/ext4/inode.c
===================================================================
--- linux-2.6.21.orig/fs/ext4/inode.c
+++ linux-2.6.21/fs/ext4/inode.c
@@ -3082,7 +3082,9 @@ int ext4_mark_iloc_dirty(handle_t *handl
 {
 	int err = 0;

-	inode->i_version++;
+	if (!test_opt(inode->i_sb, NOVERSION))
+		inode->i_version++;
+
 	/* the do_update_inode consumes one bh->b_count */
 	get_bh(iloc->bh);