Btrfs: Add code to support file creation time

This patch adds a new member to the 'struct btrfs_inode' structure to hold
the file creation time.

Signed-off-by: chandan <chandanrmail@gmail.com>
[refreshed, removed btrfs_inode_otime]
Signed-off-by: David Sterba <dsterba@suse.cz>

Signed-off-by: Chris Mason <clm@fb.com>
diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c
index 116eb4b..82f0c7c 100644
--- a/fs/btrfs/delayed-inode.c
+++ b/fs/btrfs/delayed-inode.c
@@ -1769,6 +1769,11 @@
 				     inode->i_ctime.tv_sec);
 	btrfs_set_stack_timespec_nsec(&inode_item->ctime,
 				      inode->i_ctime.tv_nsec);
+
+	btrfs_set_stack_timespec_sec(&inode_item->otime,
+				     BTRFS_I(inode)->i_otime.tv_sec);
+	btrfs_set_stack_timespec_nsec(&inode_item->otime,
+				     BTRFS_I(inode)->i_otime.tv_nsec);
 }
 
 int btrfs_fill_inode(struct inode *inode, u32 *rdev)
@@ -1810,6 +1815,11 @@
 	inode->i_ctime.tv_sec = btrfs_stack_timespec_sec(&inode_item->ctime);
 	inode->i_ctime.tv_nsec = btrfs_stack_timespec_nsec(&inode_item->ctime);
 
+	BTRFS_I(inode)->i_otime.tv_sec =
+		btrfs_stack_timespec_sec(&inode_item->otime);
+	BTRFS_I(inode)->i_otime.tv_nsec =
+		btrfs_stack_timespec_nsec(&inode_item->otime);
+
 	inode->i_generation = BTRFS_I(inode)->generation;
 	BTRFS_I(inode)->index_cnt = (u64)-1;