gfs2: Update file times after grabbing glock

In gfs2_page_mkwrite, grab the inode glock in EX mode before calling
file_update_time: grabbing the lock may result in a call to
gfs2_dinode_in, which will reset the file times to their on-disk state.
Signed-off-by: NAndreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: NBob Peterson <rpeterso@redhat.com>

fs/gfs2/file.c

@@ -395,9 +395,6 @@ static int gfs2_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 
 	sb_start_pagefault(inode->i_sb);
 
-	/* Update file times before taking page lock */
-	file_update_time(vma->vm_file);
-
 	ret = gfs2_rsqa_alloc(ip);
 	if (ret)
 		goto out;
@@ -409,6 +406,9 @@ static int gfs2_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 	if (ret)
 		goto out_uninit;
 
+	/* Update file times before taking page lock */
+	file_update_time(vma->vm_file);
+
 	set_bit(GLF_DIRTY, &ip->i_gl->gl_flags);
 	set_bit(GIF_SW_PAGED, &ip->i_flags);