[Qemu-devel] [PATCH] vvfat: add a label option

[Wolfgang Bumiller <w.bumiller@proxmox.com>]

Till now the vvfat filesystem's label was hardcoded to be
"QEMU VVFAT", now you can pass a file.label=labelname option
to the -drive to change it.

Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
---
 block/vvfat.c        | 25 ++++++++++++++++++++++---
 qapi/block-core.json |  3 ++-
 2 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/block/vvfat.c b/block/vvfat.c
index e803589..d407e37 100644
--- a/block/vvfat.c
+++ b/block/vvfat.c
@@ -322,6 +322,7 @@ typedef struct BDRVVVFATState {
 
     int fat_type; /* 16 or 32 */
     array_t fat,directory,mapping;
+    char volume_label[11];
 
     unsigned int cluster_size;
     unsigned int sectors_per_cluster;
@@ -859,7 +860,7 @@ static int init_directories(BDRVVVFATState* s,
     {
 	direntry_t* entry=array_get_next(&(s->directory));
 	entry->attributes=0x28; /* archive | volume label */
-        memcpy(entry->name, "QEMU VVFAT ", sizeof(entry->name));
+        memcpy(entry->name, s->volume_label, sizeof(entry->name));
     }
 
     /* Now build FAT, and write back information into directory */
@@ -968,7 +969,8 @@ static int init_directories(BDRVVVFATState* s,
     bootsector->u.fat16.signature=0x29;
     bootsector->u.fat16.id=cpu_to_le32(0xfabe1afd);
 
-    memcpy(bootsector->u.fat16.volume_label,"QEMU VVFAT ",11);
+    memcpy(bootsector->u.fat16.volume_label, s->volume_label,
+           sizeof(bootsector->u.fat16.volume_label));
     memcpy(bootsector->fat_type,(s->fat_type==12?"FAT12   ":s->fat_type==16?"FAT16   ":"FAT32   "),8);
     bootsector->magic[0]=0x55; bootsector->magic[1]=0xaa;
 
@@ -1008,6 +1010,11 @@ static QemuOptsList runtime_opts = {
             .help = "Create a floppy rather than a hard disk image",
         },
         {
+            .name = "label",
+            .type = QEMU_OPT_STRING,
+            .help = "Use a partition label other than QEMU VVFAT",
+        },
+        {
             .name = "rw",
             .type = QEMU_OPT_BOOL,
             .help = "Make the image writable",
@@ -1069,7 +1076,7 @@ static int vvfat_open(BlockDriverState *bs, QDict *options, int flags,
     BDRVVVFATState *s = bs->opaque;
     int cyls, heads, secs;
     bool floppy;
-    const char *dirname;
+    const char *dirname, *label;
     QemuOpts *opts;
     Error *local_err = NULL;
     int ret;
@@ -1096,6 +1103,18 @@ static int vvfat_open(BlockDriverState *bs, QDict *options, int flags,
     s->fat_type = qemu_opt_get_number(opts, "fat-type", 0);
     floppy = qemu_opt_get_bool(opts, "floppy", false);
 
+    memset(s->volume_label, ' ', sizeof(s->volume_label));
+    label = qemu_opt_get(opts, "label");
+    if (label) {
+        size_t label_length = strlen(label);
+        if (label_length > 11) {
+            error_setg(errp, "vvfat label cannot be longer than 11 bytes");
+            ret = -EINVAL;
+            goto fail;
+        }
+        memcpy(s->volume_label, label, label_length);
+    }
+
     if (floppy) {
         /* 1.44MB or 2.88MB floppy.  2.88MB can be FAT12 (default) or FAT16. */
         if (!s->fat_type) {
diff --git a/qapi/block-core.json b/qapi/block-core.json
index afa9d3d..2a529b1 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -1453,13 +1453,14 @@
 # @fat-type:    #optional FAT type: 12, 16 or 32
 # @floppy:      #optional whether to export a floppy image (true) or
 #               partitioned hard disk (false; default)
+# @label:       #optional override default label
 # @rw:          #optional whether to allow write operations (default: false)
 #
 # Since: 1.7
 ##
 { 'struct': 'BlockdevOptionsVVFAT',
   'data': { 'dir': 'str', '*fat-type': 'int', '*floppy': 'bool',
-            '*rw': 'bool' } }
+            '*label': 'str', '*rw': 'bool' } }
 
 ##
 # @BlockdevOptionsGenericFormat
-- 
2.1.4