[PATCH v4 6/9] qemu-img: Add bitmap sub-command

[Eric Blake <eblake@redhat.com>]

Include actions for --add, --remove, --clear, --enable, --disable, and
--merge (note that --clear is a bit of fluff, because the same can be
accomplished by removing a bitmap and then adding a new one in its
place, but it matches what QMP commands exist).  Listing is omitted,
because it does not require a bitmap name and because it was already
possible with 'qemu-img info'.  A single command line can play one or
more bitmap commands in sequence on the same bitmap name (although all
added bitmaps share the same granularity, and and all merged bitmaps
come from the same source file).  Merge defaults to other bitmaps in
the primary image, but can also be told to merge bitmaps from a
distinct image.

While this supports --image-opts for the file being modified, I did
not think it worth the extra complexity to support that for the source
file in a cross-file merges.  Likewise, I chose to have --merge only
take a single source rather than following the QMP support for
multiple merges in one go (although you can still use more than one
--merge in the command line); in part because qemu-img is offline and
therefore atomicity is not an issue.

Upcoming patches will add iotest coverage of these commands while
also testing other features.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
---
 docs/tools/qemu-img.rst |  24 ++++
 qemu-img.c              | 254 ++++++++++++++++++++++++++++++++++++++++
 qemu-img-cmds.hx        |   7 ++
 3 files changed, 285 insertions(+)

diff --git a/docs/tools/qemu-img.rst b/docs/tools/qemu-img.rst
index 7d08c48d308f..219483cec279 100644
--- a/docs/tools/qemu-img.rst
+++ b/docs/tools/qemu-img.rst
@@ -281,6 +281,30 @@ Command description:
   For write tests, by default a buffer filled with zeros is written. This can be
   overridden with a pattern byte specified by *PATTERN*.

+.. option:: bitmap (--merge SOURCE | --add | --remove | --clear | --enable | --disable)... [-b SOURCE_FILE [-F SOURCE_FMT]] [-g GRANULARITY] [--object OBJECTDEF] [--image-opts | -f FMT] FILENAME BITMAP
+
+  Perform one or more modifications of the persistent bitmap *BITMAP*
+  in the disk image *FILENAME*.  The various modifications are:
+
+  ``--add`` to create *BITMAP*, enabled to record future edits.
+
+  ``--remove`` to remove *BITMAP*.
+
+  ``--clear`` to clear *BITMAP*.
+
+  ``--enable`` to change *BITMAP* to start recording future edits.
+
+  ``--disable`` to change *BITMAP* to stop recording future edits.
+
+  ``--merge`` to merge the contents of *SOURCE_BITMAP* into *BITMAP*.
+
+  Additional options include ``-g`` which sets a non-default
+  *GRANULARITY* for ``--add``, and ``-b`` and ``-F`` which select an
+  alternative source file for all *SOURCE* bitmaps used by
+  ``--merge``.
+
+  To see what bitmaps are present in an image, use ``qemu-img info``.
+
 .. option:: check [--object OBJECTDEF] [--image-opts] [-q] [-f FMT] [--output=OFMT] [-r [leaks | all]] [-T SRC_CACHE] [-U] FILENAME

   Perform a consistency check on the disk image *FILENAME*. The command can
diff --git a/qemu-img.c b/qemu-img.c
index b6e8af9202a5..8c99e68ba8aa 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -28,6 +28,7 @@
 #include "qemu-common.h"
 #include "qemu-version.h"
 #include "qapi/error.h"
+#include "qapi/qapi-commands-block-core.h"
 #include "qapi/qapi-visit-block-core.h"
 #include "qapi/qobject-output-visitor.h"
 #include "qapi/qmp/qjson.h"
@@ -71,6 +72,12 @@ enum {
     OPTION_SHRINK = 266,
     OPTION_SALVAGE = 267,
     OPTION_TARGET_IS_ZERO = 268,
+    OPTION_ADD = 269,
+    OPTION_REMOVE = 270,
+    OPTION_CLEAR = 271,
+    OPTION_ENABLE = 272,
+    OPTION_DISABLE = 273,
+    OPTION_MERGE = 274,
 };

 typedef enum OutputFormat {
@@ -169,6 +176,14 @@ static void QEMU_NORETURN help(void)
            "  '-n' skips the target volume creation (useful if the volume is created\n"
            "       prior to running qemu-img)\n"
            "\n"
+           "Parameters to bitmap subcommand:\n"
+           "  'bitmap' is the name of the bitmap to manipulate, through one or more\n"
+           "       actions from '--add', '--remove', '--clear', '--enable', '--disable',\n"
+           "       or '--merge source'\n"
+           "  '-g granularity' sets the granularity for '--add' actions\n"
+           "  '-b source' and '-F src_fmt' tell '--merge' actions to find the source\n"
+           "       bitmaps from an alternative file\n"
+           "\n"
            "Parameters to check subcommand:\n"
            "  '-r' tries to repair any inconsistencies that are found during the check.\n"
            "       '-r leaks' repairs only cluster leaks, whereas '-r all' fixes all\n"
@@ -4461,6 +4476,245 @@ out:
     return 0;
 }

+enum ImgBitmapAct {
+    BITMAP_ADD,
+    BITMAP_REMOVE,
+    BITMAP_CLEAR,
+    BITMAP_ENABLE,
+    BITMAP_DISABLE,
+    BITMAP_MERGE,
+};
+typedef struct ImgBitmapAction {
+    enum ImgBitmapAct act;
+    const char *src; /* only used for merge */
+    QSIMPLEQ_ENTRY(ImgBitmapAction) next;
+} ImgBitmapAction;
+
+static int img_bitmap(int argc, char **argv)
+{
+    Error *err = NULL;
+    int c, ret = -1;
+    QemuOpts *opts = NULL;
+    const char *fmt = NULL, *src_fmt = NULL, *src_filename = NULL;
+    const char *filename, *bitmap;
+    BlockBackend *blk = NULL, *src = NULL;
+    BlockDriverState *bs = NULL, *src_bs = NULL;
+    bool image_opts = false;
+    int64_t granularity = 0;
+    bool add = false, merge = false;
+    QSIMPLEQ_HEAD(, ImgBitmapAction) actions;
+    ImgBitmapAction *act, *act_next;
+    const char *op;
+
+    QSIMPLEQ_INIT(&actions);
+
+    for (;;) {
+        static const struct option long_options[] = {
+            {"help", no_argument, 0, 'h'},
+            {"object", required_argument, 0, OPTION_OBJECT},
+            {"image-opts", no_argument, 0, OPTION_IMAGE_OPTS},
+            {"add", no_argument, 0, OPTION_ADD},
+            {"remove", no_argument, 0, OPTION_REMOVE},
+            {"clear", no_argument, 0, OPTION_CLEAR},
+            {"enable", no_argument, 0, OPTION_ENABLE},
+            {"disable", no_argument, 0, OPTION_DISABLE},
+            {"merge", required_argument, 0, OPTION_MERGE},
+            {"granularity", required_argument, 0, 'g'},
+            {"source-file", required_argument, 0, 'b'},
+            {"source-format", required_argument, 0, 'F'},
+            {0, 0, 0, 0}
+        };
+        c = getopt_long(argc, argv, ":b:f:F:g:h", long_options, NULL);
+        if (c == -1) {
+            break;
+        }
+
+        switch (c) {
+        case ':':
+            missing_argument(argv[optind - 1]);
+            break;
+        case '?':
+            unrecognized_option(argv[optind - 1]);
+            break;
+        case 'h':
+            help();
+            break;
+        case 'b':
+            src_filename = optarg;
+            break;
+        case 'f':
+            fmt = optarg;
+            break;
+        case 'F':
+            src_fmt = optarg;
+            break;
+        case 'g':
+            granularity = cvtnum(optarg);
+            if (granularity < 0) {
+                error_report("Invalid granularity specified");
+                return 1;
+            }
+            break;
+        case OPTION_ADD:
+            act = g_new0(ImgBitmapAction, 1);
+            act->act = BITMAP_ADD;
+            QSIMPLEQ_INSERT_TAIL(&actions, act, next);
+            add = true;
+            break;
+        case OPTION_REMOVE:
+            act = g_new0(ImgBitmapAction, 1);
+            act->act = BITMAP_REMOVE;
+            QSIMPLEQ_INSERT_TAIL(&actions, act, next);
+            break;
+        case OPTION_CLEAR:
+            act = g_new0(ImgBitmapAction, 1);
+            act->act = BITMAP_CLEAR;
+            QSIMPLEQ_INSERT_TAIL(&actions, act, next);
+            break;
+        case OPTION_ENABLE:
+            act = g_new0(ImgBitmapAction, 1);
+            act->act = BITMAP_ENABLE;
+            QSIMPLEQ_INSERT_TAIL(&actions, act, next);
+            break;
+        case OPTION_DISABLE:
+            act = g_new0(ImgBitmapAction, 1);
+            act->act = BITMAP_DISABLE;
+            QSIMPLEQ_INSERT_TAIL(&actions, act, next);
+            break;
+        case OPTION_MERGE:
+            act = g_new0(ImgBitmapAction, 1);
+            act->act = BITMAP_MERGE;
+            act->src = optarg;
+            QSIMPLEQ_INSERT_TAIL(&actions, act, next);
+            merge = true;
+            break;
+        case OPTION_OBJECT:
+            opts = qemu_opts_parse_noisily(&qemu_object_opts, optarg, true);
+            if (!opts) {
+                goto out;
+            }
+            break;
+        case OPTION_IMAGE_OPTS:
+            image_opts = true;
+            break;
+        }
+    }
+
+    if (qemu_opts_foreach(&qemu_object_opts,
+                          user_creatable_add_opts_foreach,
+                          qemu_img_object_print_help, &error_fatal)) {
+        goto out;
+    }
+
+    if (QSIMPLEQ_EMPTY(&actions)) {
+        error_report("Need at least one of --add, --remove, --clear, "
+                     "--enable, --disable, or --merge");
+        goto out;
+    }
+
+    if (granularity && !add) {
+        error_report("granularity only supported with --add");
+        goto out;
+    }
+    if (src_fmt && !src_filename) {
+        error_report("-F only supported with -b");
+        goto out;
+    }
+    if (src_filename && !merge) {
+        error_report("Merge bitmap source file only supported with "
+                     "--merge");
+        goto out;
+    }
+
+    if (optind != argc - 2) {
+        error_report("Expecting filename and bitmap name");
+        goto out;
+    }
+
+    filename = argv[optind];
+    bitmap = argv[optind + 1];
+
+    blk = img_open(image_opts, filename, fmt, BDRV_O_RDWR, false, false,
+                   false);
+    if (!blk) {
+        goto out;
+    }
+    bs = blk_bs(blk);
+    if (src_filename) {
+        src = img_open(NULL, src_filename, src_fmt, 0, false, false,
+                       false);
+        if (!src) {
+            goto out;
+        }
+        src_bs = blk_bs(src);
+    } else {
+        src_bs = bs;
+    }
+
+    QSIMPLEQ_FOREACH_SAFE(act, &actions, next, act_next) {
+        switch (act->act) {
+        case BITMAP_ADD:
+            qmp_block_dirty_bitmap_add(bs->node_name, bitmap,
+                                       !!granularity, granularity, true, true,
+                                       false, false, &err);
+            op = "add";
+            break;
+        case BITMAP_REMOVE:
+            qmp_block_dirty_bitmap_remove(bs->node_name, bitmap, &err);
+            op = "remove";
+            break;
+        case BITMAP_CLEAR:
+            qmp_block_dirty_bitmap_clear(bs->node_name, bitmap, &err);
+            op = "clear";
+            break;
+        case BITMAP_ENABLE:
+            qmp_block_dirty_bitmap_enable(bs->node_name, bitmap, &err);
+            op = "enable";
+            break;
+        case BITMAP_DISABLE:
+            qmp_block_dirty_bitmap_disable(bs->node_name, bitmap, &err);
+            op = "disable";
+            break;
+        case BITMAP_MERGE: {
+            BlockDirtyBitmapMergeSource *merge_src;
+            BlockDirtyBitmapMergeSourceList *list;
+
+            merge_src = g_new0(BlockDirtyBitmapMergeSource, 1);
+            merge_src->type = QTYPE_QDICT;
+            merge_src->u.external.node = g_strdup(src_bs->node_name);
+            merge_src->u.external.name = g_strdup(act->src);
+            list = g_new0(BlockDirtyBitmapMergeSourceList, 1);
+            list->value = merge_src;
+            qmp_block_dirty_bitmap_merge(bs->node_name, bitmap, list, &err);
+            qapi_free_BlockDirtyBitmapMergeSourceList(list);
+            op = "merge";
+            break;
+        }
+        default:
+            g_assert_not_reached();
+        }
+
+        if (err) {
+            error_reportf_err(err, "Operation %s on bitmap %s failed",
+                              op, bitmap);
+            ret = -1;
+            goto out;
+        }
+        g_free(act);
+    }
+
+    ret = 0;
+
+ out:
+    blk_unref(src);
+    blk_unref(blk);
+    qemu_opts_del(opts);
+    if (ret) {
+        return 1;
+    }
+    return 0;
+}
+
 #define C_BS      01
 #define C_COUNT   02
 #define C_IF      04
diff --git a/qemu-img-cmds.hx b/qemu-img-cmds.hx
index e0886437b1f2..011688245668 100644
--- a/qemu-img-cmds.hx
+++ b/qemu-img-cmds.hx
@@ -20,6 +20,13 @@ DEF("bench", img_bench,
 SRST
 .. option:: bench [-c COUNT] [-d DEPTH] [-f FMT] [--flush-interval=FLUSH_INTERVAL] [-i AIO] [-n] [--no-drain] [-o OFFSET] [--pattern=PATTERN] [-q] [-s BUFFER_SIZE] [-S STEP_SIZE] [-t CACHE] [-w] [-U] FILENAME
 ERST
+
+DEF("bitmap", img_bitmap,
+    "bitmap (--merge SOURCE | --add | --remove | --clear | --enable | --disable)... [-b source_file [-F source_fmt]] [-g granularity] [--object objectdef] [--image-opts | -f fmt] filename bitmap")
+SRST
+.. option:: bitmap (--merge SOURCE | --add | --remove | --clear | --enable | --disable)... [-b SOURCE_FILE [-F SOURCE_FMT]] [-g GRANULARITY] [--object OBJECTDEF] [--image-opts | -f FMT] FILENAME BITMAP
+ERST
+
 DEF("check", img_check,
     "check [--object objectdef] [--image-opts] [-q] [-f fmt] [--output=ofmt] [-r [leaks | all]] [-T src_cache] [-U] filename")
 SRST
-- 
2.26.2