diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index cea813a..391ab55 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3346,11 +3346,15 @@
 {
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
 	struct ext4_super_block *es = sbi->s_es;
+	unsigned def_extra_isize = sizeof(struct ext4_inode) -
+						EXT4_GOOD_OLD_INODE_SIZE;
 
-	/* determine the minimum size of new large inodes, if present */
-	if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE) {
-		sbi->s_want_extra_isize = sizeof(struct ext4_inode) -
-						     EXT4_GOOD_OLD_INODE_SIZE;
+	if (sbi->s_inode_size == EXT4_GOOD_OLD_INODE_SIZE) {
+		sbi->s_want_extra_isize = 0;
+		return;
+	}
+	if (sbi->s_want_extra_isize < 4) {
+		sbi->s_want_extra_isize = def_extra_isize;
 		if (ext4_has_feature_extra_isize(sb)) {
 			if (sbi->s_want_extra_isize <
 			    le16_to_cpu(es->s_want_extra_isize))
@@ -3363,10 +3367,10 @@
 		}
 	}
 	/* Check if enough inode space is available */
-	if (EXT4_GOOD_OLD_INODE_SIZE + sbi->s_want_extra_isize >
-							sbi->s_inode_size) {
-		sbi->s_want_extra_isize = sizeof(struct ext4_inode) -
-						       EXT4_GOOD_OLD_INODE_SIZE;
+	if ((sbi->s_want_extra_isize > sbi->s_inode_size) ||
+	    (EXT4_GOOD_OLD_INODE_SIZE + sbi->s_want_extra_isize >
+							sbi->s_inode_size)) {
+		sbi->s_want_extra_isize = def_extra_isize;
 		ext4_msg(sb, KERN_INFO,
 			 "required extra inode space not available");
 	}