diff --git a/block/qcow2.c b/block/qcow2.c
index 7949d15fc6..01c39c56c0 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -777,29 +777,35 @@ static void read_cache_sizes(BlockDriverState *bs, QemuOpts *opts,
                              uint64_t *refcount_cache_size, Error **errp)
 {
     BDRVQcow2State *s = bs->opaque;
-    uint64_t combined_cache_size;
+    uint64_t combined_cache_size, l2_cache_max_setting;
     bool l2_cache_size_set, refcount_cache_size_set, combined_cache_size_set;
     int min_refcount_cache = MIN_REFCOUNT_CACHE_SIZE * s->cluster_size;
+    uint64_t virtual_disk_size = bs->total_sectors * BDRV_SECTOR_SIZE;
+    uint64_t max_l2_cache = virtual_disk_size / (s->cluster_size / 8);
 
     combined_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_CACHE_SIZE);
     l2_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_L2_CACHE_SIZE);
     refcount_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_REFCOUNT_CACHE_SIZE);
 
     combined_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_CACHE_SIZE, 0);
-    *l2_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_L2_CACHE_SIZE, 0);
+    l2_cache_max_setting = qemu_opt_get_size(opts, QCOW2_OPT_L2_CACHE_SIZE,
+                                             DEFAULT_L2_CACHE_MAX_SIZE);
     *refcount_cache_size = qemu_opt_get_size(opts,
                                              QCOW2_OPT_REFCOUNT_CACHE_SIZE, 0);
 
     *l2_cache_entry_size = qemu_opt_get_size(
         opts, QCOW2_OPT_L2_CACHE_ENTRY_SIZE, s->cluster_size);
 
+    *l2_cache_size = MIN(max_l2_cache, l2_cache_max_setting);
+
     if (combined_cache_size_set) {
         if (l2_cache_size_set && refcount_cache_size_set) {
             error_setg(errp, QCOW2_OPT_CACHE_SIZE ", " QCOW2_OPT_L2_CACHE_SIZE
                        " and " QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not be set "
                        "at the same time");
             return;
-        } else if (*l2_cache_size > combined_cache_size) {
+        } else if (l2_cache_size_set &&
+                   (l2_cache_max_setting > combined_cache_size)) {
             error_setg(errp, QCOW2_OPT_L2_CACHE_SIZE " may not exceed "
                        QCOW2_OPT_CACHE_SIZE);
             return;
@@ -814,9 +820,6 @@ static void read_cache_sizes(BlockDriverState *bs, QemuOpts *opts,
         } else if (refcount_cache_size_set) {
             *l2_cache_size = combined_cache_size - *refcount_cache_size;
         } else {
-            uint64_t virtual_disk_size = bs->total_sectors * BDRV_SECTOR_SIZE;
-            uint64_t max_l2_cache = virtual_disk_size / (s->cluster_size / 8);
-
             /* Assign as much memory as possible to the L2 cache, and
              * use the remainder for the refcount cache */
             if (combined_cache_size >= max_l2_cache + min_refcount_cache) {
@@ -828,12 +831,6 @@ static void read_cache_sizes(BlockDriverState *bs, QemuOpts *opts,
                 *l2_cache_size = combined_cache_size - *refcount_cache_size;
             }
         }
-    } else {
-        if (!l2_cache_size_set) {
-            *l2_cache_size = MAX(DEFAULT_L2_CACHE_SIZE,
-                                 (uint64_t)DEFAULT_L2_CACHE_CLUSTERS
-                                 * s->cluster_size);
-        }
     }
     /* l2_cache_size and refcount_cache_size are ensured to have at least
      * their minimum values in qcow2_update_options_prepare() */
diff --git a/block/qcow2.h b/block/qcow2.h
index a8d6f757b1..2f8c1fd15c 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -74,9 +74,7 @@
 /* Must be at least 4 to cover all cases of refcount table growth */
 #define MIN_REFCOUNT_CACHE_SIZE 4 /* clusters */
 
-/* Whichever is more */
-#define DEFAULT_L2_CACHE_CLUSTERS 8 /* clusters */
-#define DEFAULT_L2_CACHE_SIZE S_1MiB
+#define DEFAULT_L2_CACHE_MAX_SIZE S_1MiB
 
 #define DEFAULT_CLUSTER_SIZE S_64KiB
 
diff --git a/docs/qcow2-cache.txt b/docs/qcow2-cache.txt
index 013991e21c..c84cd69cc7 100644
--- a/docs/qcow2-cache.txt
+++ b/docs/qcow2-cache.txt
@@ -124,8 +124,12 @@ There are a few things that need to be taken into account:
  - Both caches must have a size that is a multiple of the cluster size
    (or the cache entry size: see "Using smaller cache sizes" below).
 
- - The default L2 cache size is 8 clusters or 1MB (whichever is more),
-   and the minimum is 2 clusters (or 2 cache entries, see below).
+ - The maximum L2 cache size is 1 MB by default (enough for full coverage
+   of 8 GB images, with the default cluster size). This value can be
+   modified using the "l2-cache-size" option. QEMU will not use more memory
+   than needed to hold all of the image's L2 tables, regardless of this max.
+   value. The minimal L2 cache size is 2 clusters (or 2 cache entries, see
+   below).
 
  - The default (and minimum) refcount cache size is 4 clusters.
 
@@ -183,9 +187,10 @@ Some things to take into account:
    always uses the cluster size as the entry size.
 
  - If the L2 cache is big enough to hold all of the image's L2 tables
-   (as explained in the "Choosing the right cache sizes" section
-   earlier in this document) then none of this is necessary and you
-   can omit the "l2-cache-entry-size" parameter altogether.
+   (as explained in the "Choosing the right cache sizes" and "How to
+   configure the cache sizes" sections in this document) then none of
+   this is necessary and you can omit the "l2-cache-entry-size"
+   parameter altogether.
 
 
 Reducing the memory usage
diff --git a/qemu-options.hx b/qemu-options.hx
index ab1a3b240e..f9fe43a4dc 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -746,9 +746,9 @@ The maximum total size of the L2 table and refcount block caches in bytes
 
 @item l2-cache-size
 The maximum size of the L2 table cache in bytes
-(default: if cache-size is not defined - 1048576 bytes or 8 clusters, whichever
-is larger; otherwise, as large as possible or needed within the cache-size,
-while permitting the requested or the minimal refcount cache size)
+(default: if cache-size is not specified - 1M; otherwise, as large as possible
+within the cache-size, while permitting the requested or the minimal refcount
+cache size)
 
 @item refcount-cache-size
 The maximum size of the refcount block cache in bytes
diff --git a/tests/qemu-iotests/137 b/tests/qemu-iotests/137
index 87965625d8..19e8597306 100755
--- a/tests/qemu-iotests/137
+++ b/tests/qemu-iotests/137
@@ -109,7 +109,6 @@ $QEMU_IO \
     -c "reopen -o cache-size=1M,l2-cache-size=64k,refcount-cache-size=64k" \
     -c "reopen -o cache-size=1M,l2-cache-size=2M" \
     -c "reopen -o cache-size=1M,refcount-cache-size=2M" \
-    -c "reopen -o l2-cache-size=256T" \
     -c "reopen -o l2-cache-entry-size=33k" \
     -c "reopen -o l2-cache-entry-size=128k" \
     -c "reopen -o refcount-cache-size=256T" \
@@ -119,6 +118,13 @@ $QEMU_IO \
     -c "reopen -o cache-clean-interval=-1" \
     "$TEST_IMG" | _filter_qemu_io
 
+IMGOPTS="cluster_size=256k" _make_test_img 32P
+$QEMU_IO \
+    -c "reopen -o l2-cache-entry-size=512,l2-cache-size=1T" \
+    "$TEST_IMG" | _filter_qemu_io
+
+_make_test_img 64M
+
 echo
 echo === Test transaction semantics ===
 echo
diff --git a/tests/qemu-iotests/137.out b/tests/qemu-iotests/137.out
index 6a2ffc71fd..2c080b72f3 100644
--- a/tests/qemu-iotests/137.out
+++ b/tests/qemu-iotests/137.out
@@ -19,7 +19,6 @@ Parameter 'lazy-refcounts' expects 'on' or 'off'
 cache-size, l2-cache-size and refcount-cache-size may not be set at the same time
 l2-cache-size may not exceed cache-size
 refcount-cache-size may not exceed cache-size
-L2 cache size too big
 L2 cache entry size must be a power of two between 512 and the cluster size (65536)
 L2 cache entry size must be a power of two between 512 and the cluster size (65536)
 Refcount cache size too big
@@ -27,6 +26,9 @@ Conflicting values for qcow2 options 'overlap-check' ('constant') and 'overlap-c
 Unsupported value 'blubb' for qcow2 option 'overlap-check'. Allowed are any of the following: none, constant, cached, all
 Unsupported value 'blubb' for qcow2 option 'overlap-check'. Allowed are any of the following: none, constant, cached, all
 Cache clean interval too big
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=36028797018963968
+L2 cache size too big
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864
 
 === Test transaction semantics ===
 
