guest-agent: only enable FSFREEZE when it's supported by the kernel

[qemu.git] / block.c

diff --git a/block.c b/block.c
index effa86fd533a7774fbd35bedd25751e52d18e51e..9549b9eff9f3034fdfae86e239851db459b9c0da 100644 (file)
--- a/block.c
+++ b/block.c
@@ -439,13 +439,7 @@ static int bdrv_open_common(BlockDriverState *bs, const char *filename,
     bs->drv = drv;
     bs->opaque = qemu_mallocz(drv->instance_size);
 
-    /*
-     * Yes, BDRV_O_NOCACHE aka O_DIRECT means we have to present a
-     * write cache to the guest.  We do need the fdatasync to flush
-     * out transactions for block allocations, and we maybe have a
-     * volatile write cache in our backing device to deal with.
-     */
-    if (flags & (BDRV_O_CACHE_WB|BDRV_O_NOCACHE))
+    if (flags & BDRV_O_CACHE_WB)
         bs->enable_write_cache = 1;
 
     /*
@@ -1152,6 +1146,25 @@ int bdrv_truncate(BlockDriverState *bs, int64_t offset)
     return ret;
 }
 
+/**
+ * Length of a allocated file in bytes. Sparse files are counted by actual
+ * allocated space. Return < 0 if error or unknown.
+ */
+int64_t bdrv_get_allocated_file_size(BlockDriverState *bs)
+{
+    BlockDriver *drv = bs->drv;
+    if (!drv) {
+        return -ENOMEDIUM;
+    }
+    if (drv->bdrv_get_allocated_file_size) {
+        return drv->bdrv_get_allocated_file_size(bs);
+    }
+    if (bs->file) {
+        return bdrv_get_allocated_file_size(bs->file);
+    }
+    return -ENOTSUP;
+}
+
 /**
  * Length of a file in bytes. Return < 0 if error or unknown.
  */
@@ -2887,7 +2900,7 @@ int bdrv_img_create(const char *filename, const char *fmt,
                     char *options, uint64_t img_size, int flags)
 {
     QEMUOptionParameter *param = NULL, *create_options = NULL;
-    QEMUOptionParameter *backing_fmt, *backing_file;
+    QEMUOptionParameter *backing_fmt, *backing_file, *size;
     BlockDriverState *bs = NULL;
     BlockDriver *drv, *proto_drv;
     BlockDriver *backing_drv = NULL;
@@ -2970,7 +2983,8 @@ int bdrv_img_create(const char *filename, const char *fmt,
 
     // The size for the image must always be specified, with one exception:
     // If we are using a backing file, we can obtain the size from there
-    if (get_option_parameter(param, BLOCK_OPT_SIZE)->value.n == -1) {
+    size = get_option_parameter(param, BLOCK_OPT_SIZE);
+    if (size && size->value.n == -1) {
         if (backing_file && backing_file->value.s) {
             uint64_t size;
             char buf[32];