commit 44f68235e23ab4bababeafe07d31e07feabb84ba
Author: Gleb Kurtsou <gleb.kurtsou@gmail.com>
Date:   Tue Apr 3 00:02:33 2012 +0300

    tmpfs: Support file system sizes up to 4GB*PAGE_SIZE on 32 bit archs

diff --git a/sys/fs/tmpfs/tmpfs_vfsops.c b/sys/fs/tmpfs/tmpfs_vfsops.c
index 29f2ca4..6b3ecc0 100644
--- a/sys/fs/tmpfs/tmpfs_vfsops.c
+++ b/sys/fs/tmpfs/tmpfs_vfsops.c
@@ -233,17 +233,13 @@ tmpfs_mount(struct mount *mp)
 	 * allowed to use, based on the maximum size the user passed in
 	 * the mount structure.  A value of zero is treated as if the
 	 * maximum available space was requested. */
-	if (size_max < PAGE_SIZE || size_max > SIZE_MAX - PAGE_SIZE)
+	if (size_max < PAGE_SIZE || size_max > UINT64_MAX - PAGE_SIZE ||
+	    (SIZE_MAX < UINT64_MAX && size_max / PAGE_SIZE >= SIZE_MAX))
 		pages = SIZE_MAX;
 	else
 		pages = howmany(size_max, PAGE_SIZE);
 	MPASS(pages > 0);
 
-	if (pages < SIZE_MAX / PAGE_SIZE)
-		size_max = pages * PAGE_SIZE;
-	else
-		size_max = SIZE_MAX;
-
 	if (nodes_max <= 3) {
 		if (pages < INT_MAX / nodes_per_page)
 			nodes_max = pages * nodes_per_page;