[PATCH v2 2/5] vvfat: move fat_type check prior to size setup

[Clément Chigot]

This allows to handle the default FAT size in a single place and make the
following part taking care only about size parameters. It will be later
moved away in a specific function.

The selection of floppy size was a bit unusual:
 - fat-type undefined: a FAT 12 2880 Kib disk (default)
 - fat-type=16: a FAT 16 2880 Kib disk
 - fat-type=12: a FAT 12 1440 Kib disk

Now, that fat-type undefined means fat-type=12, it's no longer possible
to make that size distinction. Therefore, it's being changed for the
following:
 - fat-type=12: a FAT 12 1440 Kib disk (default)
 - fat-type=16: a FAT 16 2880 Kib dis

This has been choosen for two reasons: keep fat-type=12 the default and
creates a more usual size for it: 1440 Kib.

The possibility to create a FAT 12 2880 Kib floppy will be added back
later, through the fat-size parameter.

Side note to mention that s->sectors_per_cluster assignments are
removed because they are overidden a few line further.

Signed-off-by: Clément Chigot <chi...@adacore.com>
---
 block/vvfat.c | 48 ++++++++++++++++++++++++------------------------
 1 file changed, 24 insertions(+), 24 deletions(-)

diff --git a/block/vvfat.c b/block/vvfat.c
index de6031db98..d8c8d44f16 100644
--- a/block/vvfat.c
+++ b/block/vvfat.c
@@ -1192,45 +1192,45 @@ static int vvfat_open(BlockDriverState *bs, QDict 
*options, int flags,
         memcpy(s->volume_label, "QEMU VVFAT", 10);
     }
 
-    if (floppy) {
-        /* 1.44MB or 2.88MB floppy.  2.88MB can be FAT12 (default) or FAT16. */
-        if (!s->fat_type) {
+    /* Verify FAT type  */
+    switch (s->fat_type) {
+    case 32:
+        warn_report("FAT32 has not been tested. You are welcome to do so!");
+        break;
+    case 16:
+    case 12:
+        break;
+    case 0:
+        /* Set a default type */
+        if (floppy) {
             s->fat_type = 12;
-            secs = 36;
-            s->sectors_per_cluster = 2;
         } else {
-            secs = s->fat_type == 12 ? 18 : 36;
-            s->sectors_per_cluster = 1;
+            s->fat_type = 16;
         }
+        break;
+    default:
+        error_setg(errp, "Valid FAT types are only 12, 16 and 32");
+        ret = -EINVAL;
+        goto fail;
+    }
+
+
+    if (floppy) {
+        /* Choose floppy size. 1440 KiB for FAT 12, 2880 KiB for FAT-16 */
+        secs = s->fat_type == 12 ? 18 : 36;
         cyls = 80;
         heads = 2;
     } else {
-        /* 32MB or 504MB disk*/
-        if (!s->fat_type) {
-            s->fat_type = 16;
-        }
         /* Reserver space for MBR */
         if (qemu_opt_get_bool(opts, "partitioned", true)) {
             s->offset_to_bootsector = 0x3f;
         }
+        /* 32MB or 504MB disk*/
         cyls = s->fat_type == 12 ? 64 : 1024;
         heads = 16;
         secs = 63;
     }
 
-    switch (s->fat_type) {
-    case 32:
-        warn_report("FAT32 has not been tested. You are welcome to do so!");
-        break;
-    case 16:
-    case 12:
-        break;
-    default:
-        error_setg(errp, "Valid FAT types are only 12, 16 and 32");
-        ret = -EINVAL;
-        goto fail;
-    }
-
 
     s->bs = bs;
 
-- 
2.43.0