[PATCH v2 3/6] 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'.  Merge can work either from another
bitmap in the same image, or from a bitmap in 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 bitmap merge.  Likewise, I chose to have --merge
only take a single source rather than following the QMP support for
multiple merges in one go; in part to simplify the command line, and
in part because an offline image can achieve the same effect by
multiple qemu-img bitmap --merge calls.  We can enhance that if needed
in the future (the same way that 'qemu-img convert' has a mode that
concatenates multiple sources into one destination).

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

Signed-off-by: Eric Blake <eblake@redhat.com>
---
 docs/tools/qemu-img.rst |  24 +++++
 qemu-img.c              | 198 ++++++++++++++++++++++++++++++++++++++++
 qemu-img-cmds.hx        |   7 ++
 3 files changed, 229 insertions(+)

diff --git a/docs/tools/qemu-img.rst b/docs/tools/qemu-img.rst
index 7d08c48d308f..4f3b0e2c9ace 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 {--add [-g GRANULARITY] [--disabled] | --remove | --clear | --enable | --disable | --merge SOURCE_BITMAP [-b SOURCE_FILE [-F SOURCE_FMT]]} [--object OBJECTDEF] [--image-opts] [-f FMT] FILENAME BITMAP
+
+  Perform a modification of the persistent bitmap *BITMAP* in the disk
+  image *FILENAME*.  The various modifications are:
+
+  ``--add`` to create *BITMAP*, with additional options ``-g`` to
+  specify a non-default *GRANULARITY*, or whether the bitmap should be
+  ``--disabled`` instead of enabled.
+
+  ``--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*.
+  This defaults to requiring a source bitmap from the same *FILENAME*,
+  but can also be used for cross-image merge by supplying ``-b`` to
+  specify a different *SOURCE_FILE*.
+
+  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 821cbf610e5f..02ebd870faa1 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 {
@@ -4438,6 +4445,197 @@ out:
     return 0;
 }

+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;
+    unsigned long granularity = 0;
+    bool add = false, remove = false, clear = false;
+    bool enable = false, disable = false, add_disabled = false;
+    const char *merge = NULL;
+
+    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},
+            {"disabled", 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':
+            if (qemu_strtosz(optarg, NULL, &granularity)) {
+                error_report("Invalid granularity specified");
+                return 1;
+            }
+            break;
+        case OPTION_ADD:
+            add = true;
+            break;
+        case OPTION_REMOVE:
+            remove = true;
+            break;
+        case OPTION_CLEAR:
+            clear = true;
+            break;
+        case OPTION_ENABLE:
+            enable = true;
+            break;
+        case OPTION_DISABLE:
+            disable = true;
+            break;
+        case OPTION_MERGE:
+            merge = optarg;
+            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 (add && disable) {
+        disable = false;
+        add_disabled = true;
+    }
+    if (add + remove + clear + enable + disable + !!merge != 1) {
+        error_report("Need exactly one mode 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("alternate 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 (add) {
+        qmp_block_dirty_bitmap_add(bs->node_name, bitmap,
+                                   !!granularity, granularity, true, true,
+                                   true, add_disabled, &err);
+    } else if (remove) {
+        qmp_block_dirty_bitmap_remove(bs->node_name, bitmap, &err);
+    } else if (clear) {
+        qmp_block_dirty_bitmap_clear(bs->node_name, bitmap, &err);
+    } else if (enable) {
+        qmp_block_dirty_bitmap_enable(bs->node_name, bitmap, &err);
+    } else if (disable) {
+        qmp_block_dirty_bitmap_disable(bs->node_name, bitmap, &err);
+    } else if (merge) {
+        BlockDirtyBitmapMergeSource *merge_src;
+        BlockDirtyBitmapMergeSourceList *list;
+
+        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;
+        }
+
+        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(merge);
+        list = g_new0(BlockDirtyBitmapMergeSourceList, 1);
+        list->value = merge_src;
+        qmp_block_dirty_bitmap_merge(bs->node_name, bitmap, list, &err);
+        qapi_free_BlockDirtyBitmapMergeSourceList(list);
+    }
+
+    if (err) {
+        error_reportf_err(err, "Bitmap %s operation failed", bitmap);
+        ret = -1;
+        goto out;
+    }
+
+    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 c9c54de1df40..bf0035e226c8 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 {--add [-g granularity] [--disabled] | --remove | --clear | --enable | --disable | --merge source_bitmap [-b source_file [-F source_fmt]]} [--object objectdef] [--image-opts] [-f fmt] filename bitmap")
+SRST
+.. option:: bitmap {--add [-g GRANULARITY] [--disabled] | --remove | --clear | --enable | --disable | --merge SOURCE_BITMAP [-b SOURCE_FILE [-F SOURCE_FMT]]} [--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