udf: fix default mode and dmode options handling

On x86 (and several other archs) mode_t is defined as "unsigned short"
and comparing unsigned shorts to negative ints is broken (because short
is promoted to int and then compared). Fix it.
Reported-and-tested-by: Laurent Riffard <laurent.riffard@free.fr>
Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>

fs/udf/inode.c

@@ -1223,10 +1223,10 @@ static void udf_fill_inode(struct inode *inode, struct buffer_head *bh)
 	iinfo->i_lenExtents = inode->i_size;
 
 	if (fe->icbTag.fileType != ICBTAG_FILE_TYPE_DIRECTORY &&
-			sbi->s_fmode != -1)
+			sbi->s_fmode != UDF_INVALID_MODE)
 		inode->i_mode = sbi->s_fmode;
 	else if (fe->icbTag.fileType == ICBTAG_FILE_TYPE_DIRECTORY &&
-			sbi->s_dmode != -1)
+			sbi->s_dmode != UDF_INVALID_MODE)
 		inode->i_mode = sbi->s_dmode;
 	else
 		inode->i_mode = udf_convert_permissions(fe);

fs/udf/super.c

@@ -284,9 +284,9 @@ static int udf_show_options(struct seq_file *seq, struct vfsmount *mnt)
 		seq_printf(seq, ",gid=%u", sbi->s_gid);
 	if (sbi->s_umask != 0)
 		seq_printf(seq, ",umask=%o", sbi->s_umask);
-	if (sbi->s_fmode != -1)
+	if (sbi->s_fmode != UDF_INVALID_MODE)
 		seq_printf(seq, ",mode=%o", sbi->s_fmode);
-	if (sbi->s_dmode != -1)
+	if (sbi->s_dmode != UDF_INVALID_MODE)
 		seq_printf(seq, ",dmode=%o", sbi->s_dmode);
 	if (UDF_QUERY_FLAG(sb, UDF_FLAG_SESSION_SET))
 		seq_printf(seq, ",session=%u", sbi->s_session);
@@ -1892,8 +1892,8 @@ static int udf_fill_super(struct super_block *sb, void *options, int silent)
 	uopt.uid = -1;
 	uopt.gid = -1;
 	uopt.umask = 0;
-	uopt.fmode = -1;
-	uopt.dmode = -1;
+	uopt.fmode = UDF_INVALID_MODE;
+	uopt.dmode = UDF_INVALID_MODE;
 
 	sbi = kzalloc(sizeof(struct udf_sb_info), GFP_KERNEL);
 	if (!sbi)

fs/udf/udf_sb.h

@@ -48,6 +48,8 @@
 #define UDF_SPARABLE_MAP15		0x1522U
 #define UDF_METADATA_MAP25		0x2511U
 
+#define UDF_INVALID_MODE		((mode_t)-1)
+
 #pragma pack(1) /* XXX(hch): Why?  This file just defines in-core structures */
 
 struct udf_meta_data {