diff --git a/block.h b/block.h
index db131a3..5f64380 100644
--- a/block.h
+++ b/block.h
@@ -35,7 +35,7 @@
 #define BDRV_O_NO_BACKING  0x0100 /* don't open the backing file */
 #define BDRV_O_NO_FLUSH    0x0200 /* disable flushing on this disk */
 
-#define BDRV_O_CACHE_MASK  (BDRV_O_NOCACHE | BDRV_O_CACHE_WB)
+#define BDRV_O_CACHE_MASK  (BDRV_O_NOCACHE | BDRV_O_CACHE_WB | BDRV_O_NO_FLUSH)
 
 #define BDRV_SECTOR_BITS   9
 #define BDRV_SECTOR_SIZE   (1ULL << BDRV_SECTOR_BITS)
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index 166922f..f562b16 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -655,7 +655,7 @@
     int ret;
 
     BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE);
-    ret = bdrv_pwrite_sync(bs->file, l2_offset + start_offset,
+    ret = bdrv_pwrite(bs->file, l2_offset + start_offset,
         &l2_table[l2_start_index], len);
     if (ret < 0) {
         return ret;
@@ -718,9 +718,17 @@
         goto err;
     }
 
-    for (i = 0; i < j; i++)
-        qcow2_free_any_clusters(bs,
-            be64_to_cpu(old_cluster[i]) & ~QCOW_OFLAG_COPIED, 1);
+    /*
+     * If this was a COW, we need to decrease the refcount of the old cluster.
+     * Also flush bs->file to get the right order for L2 and refcount update.
+     */
+    if (j != 0) {
+        bdrv_flush(bs->file);
+        for (i = 0; i < j; i++) {
+            qcow2_free_any_clusters(bs,
+                be64_to_cpu(old_cluster[i]) & ~QCOW_OFLAG_COPIED, 1);
+        }
+    }
 
     ret = 0;
 err:
diff --git a/block/raw-posix.c b/block/raw-posix.c
index 72fb8ce..0fce449 100644
--- a/block/raw-posix.c
+++ b/block/raw-posix.c
@@ -1154,9 +1154,6 @@
     int fd, ret;
     int prio = 0;
 
-    if (strstart(filename, "/dev/cd", NULL))
-        prio = 50;
-
     fd = open(filename, O_RDONLY | O_NONBLOCK);
     if (fd < 0) {
         goto out;
diff --git a/block/vvfat.c b/block/vvfat.c
index 365332a..53e57bf 100644
--- a/block/vvfat.c
+++ b/block/vvfat.c
@@ -2665,6 +2665,11 @@
 
 DLOG(checkpoint());
 
+    /* Check if we're operating in read-only mode */
+    if (s->qcow == NULL) {
+        return -EACCES;
+    }
+
     vvfat_close_current_file(s);
 
     /*
@@ -2763,12 +2768,12 @@
 
 static int write_target_commit(BlockDriverState *bs, int64_t sector_num,
 	const uint8_t* buffer, int nb_sectors) {
-    BDRVVVFATState* s = bs->opaque;
+    BDRVVVFATState* s = *((BDRVVVFATState**) bs->opaque);
     return try_commit(s);
 }
 
 static void write_target_close(BlockDriverState *bs) {
-    BDRVVVFATState* s = bs->opaque;
+    BDRVVVFATState* s = *((BDRVVVFATState**) bs->opaque);
     bdrv_delete(s->qcow);
     free(s->qcow_filename);
 }
@@ -2783,6 +2788,7 @@
 {
     BlockDriver *bdrv_qcow;
     QEMUOptionParameter *options;
+    int ret;
     int size = sector2cluster(s, s->sector_count);
     s->used_clusters = calloc(size, 1);
 
@@ -2798,11 +2804,16 @@
 
     if (bdrv_create(bdrv_qcow, s->qcow_filename, options) < 0)
 	return -1;
+
     s->qcow = bdrv_new("");
-    if (s->qcow == NULL ||
-        bdrv_open(s->qcow, s->qcow_filename, BDRV_O_RDWR, bdrv_qcow) < 0)
-    {
-	return -1;
+    if (s->qcow == NULL) {
+        return -1;
+    }
+
+    ret = bdrv_open(s->qcow, s->qcow_filename,
+            BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_NO_FLUSH, bdrv_qcow);
+    if (ret < 0) {
+	return ret;
     }
 
 #ifndef _WIN32
@@ -2811,7 +2822,8 @@
 
     s->bs->backing_hd = calloc(sizeof(BlockDriverState), 1);
     s->bs->backing_hd->drv = &vvfat_write_target;
-    s->bs->backing_hd->opaque = s;
+    s->bs->backing_hd->opaque = qemu_malloc(sizeof(void*));
+    *(void**)s->bs->backing_hd->opaque = s;
 
     return 0;
 }
diff --git a/hw/scsi-disk.c b/hw/scsi-disk.c
index f43f2d09..b64dd31 100644
--- a/hw/scsi-disk.c
+++ b/hw/scsi-disk.c
@@ -485,16 +485,26 @@
     return buflen;
 }
 
-static int mode_sense_page(SCSIRequest *req, int page, uint8_t *p)
+static int mode_sense_page(SCSIRequest *req, int page, uint8_t *p,
+                           int page_control)
 {
     SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, req->dev);
     BlockDriverState *bdrv = s->bs;
     int cylinders, heads, secs;
 
+    /*
+     * If Changeable Values are requested, a mask denoting those mode parameters
+     * that are changeable shall be returned. As we currently don't support
+     * parameter changes via MODE_SELECT all bits are returned set to zero.
+     * The buffer was already menset to zero by the caller of this function.
+     */
     switch (page) {
     case 4: /* Rigid disk device geometry page. */
         p[0] = 4;
         p[1] = 0x16;
+        if (page_control == 1) { /* Changeable Values */
+            return p[1] + 2;
+        }
         /* if a geometry hint is available, use it */
         bdrv_get_geometry_hint(bdrv, &cylinders, &heads, &secs);
         p[2] = (cylinders >> 16) & 0xff;
@@ -519,11 +529,14 @@
         /* Medium rotation rate [rpm], 5400 rpm */
         p[20] = (5400 >> 8) & 0xff;
         p[21] = 5400 & 0xff;
-        return 0x16;
+        return p[1] + 2;
 
     case 5: /* Flexible disk device geometry page. */
         p[0] = 5;
         p[1] = 0x1e;
+        if (page_control == 1) { /* Changeable Values */
+            return p[1] + 2;
+        }
         /* Transfer rate [kbit/s], 5Mbit/s */
         p[2] = 5000 >> 8;
         p[3] = 5000 & 0xff;
@@ -555,21 +568,27 @@
         /* Medium rotation rate [rpm], 5400 rpm */
         p[28] = (5400 >> 8) & 0xff;
         p[29] = 5400 & 0xff;
-        return 0x1e;
+        return p[1] + 2;
 
     case 8: /* Caching page.  */
         p[0] = 8;
         p[1] = 0x12;
+        if (page_control == 1) { /* Changeable Values */
+            return p[1] + 2;
+        }
         if (bdrv_enable_write_cache(s->bs)) {
             p[2] = 4; /* WCE */
         }
-        return 20;
+        return p[1] + 2;
 
     case 0x2a: /* CD Capabilities and Mechanical Status page. */
         if (bdrv_get_type_hint(bdrv) != BDRV_TYPE_CDROM)
             return 0;
         p[0] = 0x2a;
         p[1] = 0x14;
+        if (page_control == 1) { /* Changeable Values */
+            return p[1] + 2;
+        }
         p[2] = 3; // CD-R & CD-RW read
         p[3] = 0; // Writing not supported
         p[4] = 0x7f; /* Audio, composite, digital out,
@@ -593,7 +612,7 @@
         p[19] = (16 * 176) & 0xff;
         p[20] = (16 * 176) >> 8; // 16x write speed current
         p[21] = (16 * 176) & 0xff;
-        return 22;
+        return p[1] + 2;
 
     default:
         return 0;
@@ -604,29 +623,46 @@
 {
     SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, req->dev);
     uint64_t nb_sectors;
-    int page, dbd, buflen;
+    int page, dbd, buflen, page_control;
     uint8_t *p;
+    uint8_t dev_specific_param;
 
     dbd = req->cmd.buf[1]  & 0x8;
     page = req->cmd.buf[2] & 0x3f;
-    DPRINTF("Mode Sense (page %d, len %zd)\n", page, req->cmd.xfer);
+    page_control = (req->cmd.buf[2] & 0xc0) >> 6;
+    DPRINTF("Mode Sense(%d) (page %d, len %d, page_control %d)\n",
+        (req->cmd.buf[0] == MODE_SENSE) ? 6 : 10, page, len, page_control);
     memset(outbuf, 0, req->cmd.xfer);
     p = outbuf;
 
-    p[1] = 0; /* Default media type.  */
-    p[3] = 0; /* Block descriptor length.  */
     if (bdrv_is_read_only(s->bs)) {
-        p[2] = 0x80; /* Readonly.  */
+        dev_specific_param = 0x80; /* Readonly.  */
+    } else {
+        dev_specific_param = 0x00;
     }
-    p += 4;
+
+    if (req->cmd.buf[0] == MODE_SENSE) {
+        p[1] = 0; /* Default media type.  */
+        p[2] = dev_specific_param;
+        p[3] = 0; /* Block descriptor length.  */
+        p += 4;
+    } else { /* MODE_SENSE_10 */
+        p[2] = 0; /* Default media type.  */
+        p[3] = dev_specific_param;
+        p[6] = p[7] = 0; /* Block descriptor length.  */
+        p += 8;
+    }
 
     bdrv_get_geometry(s->bs, &nb_sectors);
-    if ((~dbd) & nb_sectors) {
-        outbuf[3] = 8; /* Block descriptor length  */
+    if (!dbd && nb_sectors) {
+        if (req->cmd.buf[0] == MODE_SENSE) {
+            outbuf[3] = 8; /* Block descriptor length  */
+        } else { /* MODE_SENSE_10 */
+            outbuf[7] = 8; /* Block descriptor length  */
+        }
         nb_sectors /= s->cluster_size;
-        nb_sectors--;
         if (nb_sectors > 0xffffff)
-            nb_sectors = 0xffffff;
+            nb_sectors = 0;
         p[0] = 0; /* media density code */
         p[1] = (nb_sectors >> 16) & 0xff;
         p[2] = (nb_sectors >> 8) & 0xff;
@@ -638,21 +674,37 @@
         p += 8;
     }
 
+    if (page_control == 3) { /* Saved Values */
+        return -1; /* ILLEGAL_REQUEST */
+    }
+
     switch (page) {
     case 0x04:
     case 0x05:
     case 0x08:
     case 0x2a:
-        p += mode_sense_page(req, page, p);
+        p += mode_sense_page(req, page, p, page_control);
         break;
     case 0x3f:
-        p += mode_sense_page(req, 0x08, p);
-        p += mode_sense_page(req, 0x2a, p);
+        p += mode_sense_page(req, 0x08, p, page_control);
+        p += mode_sense_page(req, 0x2a, p, page_control);
         break;
+    default:
+        return -1; /* ILLEGAL_REQUEST */
     }
 
     buflen = p - outbuf;
-    outbuf[0] = buflen - 4;
+    /*
+     * The mode data length field specifies the length in bytes of the
+     * following data that is available to be transferred. The mode data
+     * length does not include itself.
+     */
+    if (req->cmd.buf[0] == MODE_SENSE) {
+        outbuf[0] = buflen - 1;
+    } else { /* MODE_SENSE_10 */
+        outbuf[0] = ((buflen - 2) >> 8) & 0xff;
+        outbuf[1] = (buflen - 2) & 0xff;
+    }
     if (buflen > req->cmd.xfer)
         buflen = req->cmd.xfer;
     return buflen;
diff --git a/qemu-img.c b/qemu-img.c
index d2a978b..4e035e4 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -783,7 +783,8 @@
         goto out;
     }
 
-    out_bs = bdrv_new_open(out_filename, out_fmt, BDRV_O_FLAGS | BDRV_O_RDWR);
+    out_bs = bdrv_new_open(out_filename, out_fmt,
+        BDRV_O_FLAGS | BDRV_O_RDWR | BDRV_O_NO_FLUSH);
     if (!out_bs) {
         ret = -1;
         goto out;