Suggest valid cluster size if user specified too small value.

git-svn-id: http://exfat.googlecode.com/svn/trunk@279 60bc1c72-a15a-11de-b98f-4500b42dc123

diff --git a/mkfs/main.c b/mkfs/main.c
index 1f78b44..e7daf34 100644 (file)
--- a/mkfs/main.c
+++ b/mkfs/main.c
@@ -49,6 +49,23 @@ struct exfat_structure
        int (*write_data)(struct exfat_dev*, off_t);
 };
 
+static int get_spc_bits(int sector_bits, int user_defined, off_t volume_size)
+{
+       int i;
+
+       if (user_defined != -1)
+               return user_defined;
+
+       if (volume_size < 256ull * 1024 * 1024)
+               return MAX(0, 12 - sector_bits);        /* 4 KB */
+       if (volume_size < 32ull * 1024 * 1024 * 1024)
+               return MAX(0, 15 - sector_bits);        /* 32 KB */
+
+       for (i = 17; ; i++)                                             /* 128 KB or more */
+               if (DIV_ROUND_UP(volume_size, 1 << i) <= EXFAT_LAST_DATA_CLUSTER)
+                       return MAX(0, i - sector_bits);
+}
+
 static int init_sb(off_t volume_size, int sector_bits, int spc_bits,
                uint32_t volume_serial, int first_sector)
 {
@@ -63,9 +80,10 @@ static int init_sb(off_t volume_size, int sector_bits, int spc_bits,
                exfat_humanize_bytes(1 << sector_bits << spc_bits, &chb);
                exfat_humanize_bytes(volume_size, &vhb);
                exfat_error("cluster size %"PRIu64" %s is too small for "
-                               "%"PRIu64" %s volume",
+                               "%"PRIu64" %s volume, try -s %d",
                                chb.value, chb.unit,
-                               vhb.value, vhb.unit);
+                               vhb.value, vhb.unit,
+                               1 << get_spc_bits(sector_bits, -1, volume_size));
                return 1;
        }
 
@@ -247,23 +265,6 @@ static int write_structures(struct exfat_dev* dev)
        return 0;
 }
 
-static int get_spc_bits(int sector_bits, int user_defined, off_t volume_size)
-{
-       int i;
-
-       if (user_defined != -1)
-               return user_defined;
-
-       if (volume_size < 256ull * 1024 * 1024)
-               return MAX(0, 12 - sector_bits);        /* 4 KB */
-       if (volume_size < 32ull * 1024 * 1024 * 1024)
-               return MAX(0, 15 - sector_bits);        /* 32 KB */
-
-       for (i = 17; ; i++)                                             /* 128 KB or more */
-               if (DIV_ROUND_UP(volume_size, 1 << i) <= EXFAT_LAST_DATA_CLUSTER)
-                       return MAX(0, i - sector_bits);
-}
-
 static int set_volume_label(const char* volume_label)
 {
        le16_t tmp[EXFAT_ENAME_MAX + 1];