fat: Fix stat->f_namelen

I found that the length of a file name when created cannot exceed 255
characters, yet, pathconf(), via statfs(), returns the maximum as 260.
Signed-off-by: NKevin Dankwardt <k@kcomputing.com>
Signed-off-by: NOGAWA Hirofumi <hirofumi@mail.parknet.co.jp>

fs/fat/inode.c

@@ -558,7 +558,7 @@ static int fat_statfs(struct dentry *dentry, struct kstatfs *buf)
 	buf->f_bavail = sbi->free_clusters;
 	buf->f_fsid.val[0] = (u32)id;
 	buf->f_fsid.val[1] = (u32)(id >> 32);
-	buf->f_namelen = sbi->options.isvfat ? 260 : 12;
+	buf->f_namelen = sbi->options.isvfat ? FAT_LFN_LEN : 12;
 
 	return 0;
 }

fs/fat/namei_vfat.c

@@ -502,14 +502,14 @@ xlate_to_uni(const unsigned char *name, int len, unsigned char *outname,
 		*outlen = utf8s_to_utf16s(name, len, (wchar_t *)outname);
 		if (*outlen < 0)
 			return *outlen;
-		else if (*outlen > 255)
+		else if (*outlen > FAT_LFN_LEN)
 			return -ENAMETOOLONG;
 
 		op = &outname[*outlen * sizeof(wchar_t)];
 	} else {
 		if (nls) {
 			for (i = 0, ip = name, op = outname, *outlen = 0;
-			     i < len && *outlen <= 255;
+			     i < len && *outlen <= FAT_LFN_LEN;
 			     *outlen += 1)
 			{
 				if (escape && (*ip == ':')) {
@@ -549,7 +549,7 @@ xlate_to_uni(const unsigned char *name, int len, unsigned char *outname,
 				return -ENAMETOOLONG;
 		} else {
 			for (i = 0, ip = name, op = outname, *outlen = 0;
-			     i < len && *outlen <= 255;
+			     i < len && *outlen <= FAT_LFN_LEN;
 			     i++, *outlen += 1)
 			{
 				*op++ = *ip++;

include/linux/msdos_fs.h

@@ -15,6 +15,7 @@
 #define MSDOS_DPB_BITS	4		/* log2(MSDOS_DPB) */
 #define MSDOS_DPS	(SECTOR_SIZE / sizeof(struct msdos_dir_entry))
 #define MSDOS_DPS_BITS	4		/* log2(MSDOS_DPS) */
+#define MSDOS_LONGNAME	256		/* maximum name length */
 #define CF_LE_W(v)	le16_to_cpu(v)
 #define CF_LE_L(v)	le32_to_cpu(v)
 #define CT_LE_W(v)	cpu_to_le16(v)
@@ -47,8 +48,8 @@
 #define DELETED_FLAG	0xe5	/* marks file as deleted when in name[0] */
 #define IS_FREE(n)	(!*(n) || *(n) == DELETED_FLAG)
 
+#define FAT_LFN_LEN	255	/* maximum long name length */
 #define MSDOS_NAME	11	/* maximum name length */
-#define MSDOS_LONGNAME	256	/* maximum name length */
 #define MSDOS_SLOTS	21	/* max # of slots for short and long names */
 #define MSDOS_DOT	".          "	/* ".", padded to MSDOS_NAME chars */
 #define MSDOS_DOTDOT	"..         "	/* "..", padded to MSDOS_NAME chars */