block: Add driver callback to get cluster informationblock_qcow2_cluster_info

Signed-off-by: Manuel Bentele <development@manuel-bentele.de>

9 files changed, 129 insertions, 0 deletions

diff --git a/block.c b/block.c
index a18f052374..e73b262871 100644
--- a/block.c
+++ b/block.c
@@ -6304,6 +6304,23 @@ BlockStatsSpecific *bdrv_get_specific_stats(BlockDriverState *bs)
     return drv->bdrv_get_specific_stats(bs);
 }
 
+#ifdef CONFIG_BDRV_CLUSTER_INFO
+int bdrv_get_cluster_info(BlockDriverState *bs, uint64_t offset)
+{
+    BlockDriver *drv = bs->drv;
+
+    if (!drv) {
+        return -ENOMEDIUM;
+    }
+
+    if (drv->bdrv_get_cluster_info) {
+        return drv->bdrv_get_cluster_info(bs, offset);
+    }
+
+    return -ENOTSUP;
+}
+#endif
+
 void bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event)
 {
     IO_CODE();
diff --git a/block/qcow2.c b/block/qcow2.c
index 4d6666d3ff..a97f7b431a 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -5925,6 +5925,42 @@ void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset,
     s->signaled_corruption = true;
 }
 
+#ifdef CONFIG_BDRV_CLUSTER_INFO
+int qcow2_get_cluster_info(BlockDriverState *bs, uint64_t offset)
+{
+    BDRVQcow2State *s = bs->opaque;
+    uint64_t host_offset;
+    uint64_t coffset;
+    unsigned int bytes;
+    QCow2SubclusterType type;
+    int ret = 0, csize, nb_csectors;
+
+    /* only get information for one byte */
+    bytes = 1;
+
+    ret = qcow2_get_host_offset(bs, offset, &bytes, &host_offset, &type);
+    if (ret < 0) {
+        return ret;
+    }
+
+    printf("cluster type: %s\n", qcow2_get_subcluster_name(type));
+    printf("cluster offset host: %ld\n", host_offset);
+    printf("cluster offset guest: %ld\n", offset);
+    printf("cluster offset in-cluster: %ld\n", offset_into_cluster(s, offset));
+
+    if (type == QCOW2_SUBCLUSTER_COMPRESSED) {
+        qcow2_parse_compressed_l2_entry(bs, host_offset, &coffset, &csize);
+        nb_csectors = ((host_offset >> s->csize_shift) & s->csize_mask) + 1;
+
+        printf("cluster compressed offset: %ld\n", coffset);
+        printf("cluster compressed sectors: %d\n", nb_csectors);
+        printf("cluster compressed size: %d\n", csize);
+    }
+
+    return ret;
+}
+#endif
+
 #define QCOW_COMMON_OPTIONS                                         \
     {                                                               \
         .name = BLOCK_OPT_SIZE,                                     \
@@ -6108,6 +6144,10 @@ BlockDriver bdrv_qcow2 = {
     .bdrv_co_can_store_new_dirty_bitmap = qcow2_co_can_store_new_dirty_bitmap,
     .bdrv_co_remove_persistent_dirty_bitmap =
             qcow2_co_remove_persistent_dirty_bitmap,
+
+#ifdef CONFIG_BDRV_CLUSTER_INFO
+    .bdrv_get_cluster_info = qcow2_get_cluster_info,
+#endif
 };
 
 static void bdrv_qcow2_init(void)
diff --git a/block/qcow2.h b/block/qcow2.h
index 2285f18a73..ac30e48ee6 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -793,6 +793,24 @@ QCow2SubclusterType qcow2_get_subcluster_type(BlockDriverState *bs,
     }
 }
 
+#ifdef CONFIG_BDRV_CLUSTER_INFO
+static inline const char *qcow2_get_subcluster_name(
+    const QCow2SubclusterType type)
+{
+    static const char *subcluster_names[] = {
+        "QCOW2_SUBCLUSTER_UNALLOCATED_PLAIN",
+        "QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC",
+        "QCOW2_SUBCLUSTER_ZERO_PLAIN",
+        "QCOW2_SUBCLUSTER_ZERO_ALLOC",
+        "QCOW2_SUBCLUSTER_NORMAL",
+        "QCOW2_SUBCLUSTER_COMPRESSED",
+        "QCOW2_SUBCLUSTER_INVALID"
+    };
+
+    return subcluster_names[type];
+}
+#endif
+
 static inline bool qcow2_cluster_is_allocated(QCow2ClusterType type)
 {
     return (type == QCOW2_CLUSTER_COMPRESSED || type == QCOW2_CLUSTER_NORMAL ||
@@ -840,6 +858,10 @@ void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset,
                              int64_t size, const char *message_format, ...)
                              G_GNUC_PRINTF(5, 6);
 
+#ifdef CONFIG_BDRV_CLUSTER_INFO
+int qcow2_get_cluster_info(BlockDriverState *bs, uint64_t offset);
+#endif
+
 int qcow2_validate_table(BlockDriverState *bs, uint64_t offset,
                          uint64_t entries, size_t entry_len,
                          int64_t max_size_bytes, const char *table_name,
diff --git a/include/block/block-io.h b/include/block/block-io.h
index b099d7db45..8866258282 100644
--- a/include/block/block-io.h
+++ b/include/block/block-io.h
@@ -126,6 +126,9 @@ int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi);
 ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs,
                                           Error **errp);
 BlockStatsSpecific *bdrv_get_specific_stats(BlockDriverState *bs);
+#ifdef CONFIG_BDRV_CLUSTER_INFO
+    int bdrv_get_cluster_info(BlockDriverState *bs, uint64_t offset);
+#endif
 void bdrv_round_to_clusters(BlockDriverState *bs,
                             int64_t offset, int64_t bytes,
                             int64_t *cluster_offset,
diff --git a/include/block/block_int-common.h b/include/block/block_int-common.h
index 31ae91e56e..2546500ab0 100644
--- a/include/block/block_int-common.h
+++ b/include/block/block_int-common.h
@@ -638,6 +638,14 @@ struct BlockDriver {
     int coroutine_fn (*bdrv_co_pdiscard_snapshot)(BlockDriverState *bs,
         int64_t offset, int64_t bytes);
 
+#ifdef CONFIG_BDRV_CLUSTER_INFO
+    /*
+     * Returns information about the mapping between the guest cluster
+     * and the host cluster for a specific guest block address.
+     */
+    int (*bdrv_get_cluster_info)(BlockDriverState *bs, uint64_t offset);
+#endif
+
     /*
      * Invalidate any cached meta-data.
      */
diff --git a/meson.build b/meson.build
index 5c6b5a1c75..1b671e04ff 100644
--- a/meson.build
+++ b/meson.build
@@ -1821,6 +1821,7 @@ endif
 config_host_data.set('CONFIG_MODULE_UPGRADES', get_option('module_upgrades'))
 
 config_host_data.set('CONFIG_ATTR', libattr.found())
+config_host_data.set('CONFIG_BDRV_CLUSTER_INFO', get_option('block_drv_cluster_info'))
 config_host_data.set('CONFIG_BDRV_WHITELIST_TOOLS', get_option('block_drv_whitelist_in_tools'))
 config_host_data.set('CONFIG_BRLAPI', brlapi.found())
 config_host_data.set('CONFIG_COCOA', cocoa.found())
@@ -3854,6 +3855,7 @@ summary_info += {'coroutine pool':    have_coroutine_pool}
 if have_block
   summary_info += {'Block whitelist (rw)': get_option('block_drv_rw_whitelist')}
   summary_info += {'Block whitelist (ro)': get_option('block_drv_ro_whitelist')}
+  summary_info += {'Block cluster info support': get_option('block_drv_cluster_info')}
   summary_info += {'Use block whitelist in tools': get_option('block_drv_whitelist_in_tools')}
   summary_info += {'VirtFS support':    have_virtfs}
   summary_info += {'build virtiofs daemon': have_virtiofsd}
diff --git a/meson_options.txt b/meson_options.txt
index 4b749ca549..ea5b11c596 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -27,6 +27,8 @@ option('block_drv_rw_whitelist', type : 'string', value : '',
        description: 'set block driver read-write whitelist (by default affects only QEMU, not tools like qemu-img)')
 option('block_drv_ro_whitelist', type : 'string', value : '',
        description: 'set block driver read-only whitelist (by default affects only QEMU, not tools like qemu-img)')
+option('block_drv_cluster_info', type: 'boolean', value: false,
+       description: 'block driver cluster info support')
 option('interp_prefix', type : 'string', value : '/usr/gnemul/qemu-%M',
        description: 'where to find shared libraries etc., use %M for cpu name')
 option('fuzzing_engine', type : 'string', value : '',
diff --git a/qemu-io-cmds.c b/qemu-io-cmds.c
index 952dc940f1..c288c2ab30 100644
--- a/qemu-io-cmds.c
+++ b/qemu-io-cmds.c
@@ -2405,6 +2405,34 @@ static const cmdinfo_t sleep_cmd = {
        .oneline        = "waits for the given value in milliseconds",
 };
 
+#ifdef CONFIG_BDRV_CLUSTER_INFO
+static int cluster_info_f(BlockBackend *blk, int argc, char **argv)
+{
+    BlockDriverState *bs = blk_bs(blk);
+    char *endptr;
+    long offset;
+
+    offset = strtol(argv[1], &endptr, 0);
+    if (offset < 0 || *endptr != '\0' ||
+        offset > (bs->total_sectors * BDRV_SECTOR_SIZE)) {
+        printf("%s is not a valid number\n", argv[1]);
+        return -EINVAL;
+    }
+
+    return bdrv_get_cluster_info(bs, offset);
+}
+
+static const cmdinfo_t cluster_info_cmd = {
+       .name           = "cluster_info",
+       .argmin         = 1,
+       .argmax         = 1,
+       .cfunc          = cluster_info_f,
+       .args           = "offset",
+       .oneline        = "returns information about the mapping between guest \
+                          and host cluster type for a specific guest address",
+};
+#endif
+
 static void help_oneline(const char *cmd, const cmdinfo_t *ct)
 {
     printf("%s ", cmd);
@@ -2517,5 +2545,8 @@ static void __attribute((constructor)) init_qemuio_commands(void)
     qemuio_add_command(&wait_break_cmd);
     qemuio_add_command(&abort_cmd);
     qemuio_add_command(&sleep_cmd);
+#ifdef CONFIG_BDRV_CLUSTER_INFO
+    qemuio_add_command(&cluster_info_cmd);
+#endif
     qemuio_add_command(&sigraise_cmd);
 }
diff --git a/scripts/meson-buildoptions.sh b/scripts/meson-buildoptions.sh
index aa6e30ea91..ff0764b866 100644
--- a/scripts/meson-buildoptions.sh
+++ b/scripts/meson-buildoptions.sh
@@ -13,6 +13,8 @@ meson_options_help() {
   printf "%s\n" '  --disable-install-blobs  install provided firmware blobs'
   printf "%s\n" '  --docdir=VALUE           Base directory for documentation installation'
   printf "%s\n" '                           (can be empty) [share/doc]'
+  printf "%s\n" '  --enable-block-drv-cluster-info'
+  printf "%s\n" '                           block driver cluster info support'
   printf "%s\n" '  --enable-block-drv-whitelist-in-tools'
   printf "%s\n" '                           use block whitelist also in tools instead of only'
   printf "%s\n" '                           QEMU'
@@ -204,6 +206,8 @@ _meson_option_parse() {
     --disable-blkio) printf "%s" -Dblkio=disabled ;;
     --block-drv-ro-whitelist=*) quote_sh "-Dblock_drv_ro_whitelist=$2" ;;
     --block-drv-rw-whitelist=*) quote_sh "-Dblock_drv_rw_whitelist=$2" ;;
+    --enable-block-drv-cluster-info) printf "%s" -Dblock_drv_cluster_info=true ;;
+    --disable-block-drv-cluster-info) printf "%s" -Dblock_drv_cluster_info=false ;;
     --enable-block-drv-whitelist-in-tools) printf "%s" -Dblock_drv_whitelist_in_tools=true ;;
     --disable-block-drv-whitelist-in-tools) printf "%s" -Dblock_drv_whitelist_in_tools=false ;;
     --enable-bochs) printf "%s" -Dbochs=enabled ;;