[Qemu-devel] [PATCH 7/8] qemu: command line option for dirty bitmaps

[Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>]

From: Vladimir Sementsov-Ogievskiy <vsementsov@parallels.com>

The patch adds the following command line option:

-dirty-bitmap [option1=val1][,option2=val2]...
    Available options are:
    name         The name for the bitmap (necessary).

    file         The file to load the bitmap from.

    file_id      When specified with 'file' option, then this file will
                 be available through this id for other -dirty-bitmap
                 options when specified without 'file' option, then it
                 is a reference to 'file', specified with another
                 -dirty-bitmap option, and it will be used to load the
                 bitmap from.

    drive        The drive to bind the bitmap to. It should be specified
                 as 'id' suboption of one of -drive options. If nor
                 'file' neither 'file_id' are specified, then the bitmap
                 will be loaded from that drive (internal dirty bitmap).

    granularity  The granularity for the bitmap. Not necessary, the
                 default value may be used.

    enabled      on|off. Default is 'on'. Disabled bitmaps are not
                 changing regardless of writes to corresponding drive.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 blockdev.c                |  38 ++++++++++++++++++
 include/sysemu/blockdev.h |   1 +
 include/sysemu/sysemu.h   |   1 +
 qemu-options.hx           |  37 +++++++++++++++++
 vl.c                      | 100 ++++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 177 insertions(+)

diff --git a/blockdev.c b/blockdev.c
index 5eaf77e..2a74395 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -176,6 +176,11 @@ QemuOpts *drive_def(const char *optstr)
     return qemu_opts_parse(qemu_find_opts("drive"), optstr, 0);
 }
 
+QemuOpts *dirty_bitmap_def(const char *optstr)
+{
+    return qemu_opts_parse(qemu_find_opts("dirty-bitmap"), optstr, 0);
+}
+
 QemuOpts *drive_add(BlockInterfaceType type, int index, const char *file,
                     const char *optstr)
 {
@@ -3093,6 +3098,39 @@ BlockJobInfoList *qmp_query_block_jobs(Error **errp)
     return head;
 }
 
+QemuOptsList qemu_dirty_bitmap_opts = {
+    .name = "dirty-bitmap",
+    .head = QTAILQ_HEAD_INITIALIZER(qemu_dirty_bitmap_opts.head),
+    .desc = {
+        {
+            .name = "name",
+            .type = QEMU_OPT_STRING,
+            .help = "Name of the dirty bitmap",
+        },{
+            .name = "file",
+            .type = QEMU_OPT_STRING,
+            .help = "file name to load the bitmap from",
+        },{
+            .name = "file_id",
+            .type = QEMU_OPT_STRING,
+            .help = "node name to load the bitmap from (or to set id for"
+                    " for file, opened by previous option)",
+        },{
+            .name = "drive",
+            .type = QEMU_OPT_STRING,
+            .help = "drive id to bind the bitmap to",
+        },{
+            .name = "granularity",
+            .type = QEMU_OPT_NUMBER,
+            .help = "granularity",
+        },{
+            .name = "enabled",
+            .type = QEMU_OPT_BOOL,
+            .help = "enabled flag (default is 'on')",
+        }
+    }
+};
+
 QemuOptsList qemu_common_drive_opts = {
     .name = "drive",
     .head = QTAILQ_HEAD_INITIALIZER(qemu_common_drive_opts.head),
diff --git a/include/sysemu/blockdev.h b/include/sysemu/blockdev.h
index 7ca59b5..5b101b8 100644
--- a/include/sysemu/blockdev.h
+++ b/include/sysemu/blockdev.h
@@ -57,6 +57,7 @@ int drive_get_max_devs(BlockInterfaceType type);
 DriveInfo *drive_get_next(BlockInterfaceType type);
 
 QemuOpts *drive_def(const char *optstr);
+QemuOpts *dirty_bitmap_def(const char *optstr);
 QemuOpts *drive_add(BlockInterfaceType type, int index, const char *file,
                     const char *optstr);
 DriveInfo *drive_new(QemuOpts *arg, BlockInterfaceType block_default_type);
diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h
index 8a52934..681a8f3 100644
--- a/include/sysemu/sysemu.h
+++ b/include/sysemu/sysemu.h
@@ -207,6 +207,7 @@ bool usb_enabled(void);
 
 extern QemuOptsList qemu_legacy_drive_opts;
 extern QemuOptsList qemu_common_drive_opts;
+extern QemuOptsList qemu_dirty_bitmap_opts;
 extern QemuOptsList qemu_drive_opts;
 extern QemuOptsList qemu_chardev_opts;
 extern QemuOptsList qemu_device_opts;
diff --git a/qemu-options.hx b/qemu-options.hx
index ec356f6..5e93122 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -614,6 +614,43 @@ qemu-system-i386 -hda a -hdb b
 @end example
 ETEXI
 
+DEF("dirty-bitmap", HAS_ARG, QEMU_OPTION_dirty_bitmap,
+    "-dirty-bitmap name=name[,file=file][,file_id=file_id][,drive=@var{id}]\n"
+    "              [,granularity=granularity][,enabled=on|off]\n",
+    QEMU_ARCH_ALL)
+STEXI
+@item -dirty-bitmap @var{option}[,@var{option}[,@var{option}[,...]]]
+@findex -dirty-bitmap
+
+Define a dirty-bitmap. Valid options are:
+
+@table @option
+@item name=@var{name}
+The name of the bitmap. Should be unique per @var{file}/@var{drive} and per
+@var{for_drive}.
+@item file=@var{file}
+The separate qcow2 file for loading the bitmap @var{name} from it.
+@item file_id=@var{file_id}
+When specified with @var{file} option, then this @var{file} will be available
+through this @var{file_id} for other @option{-dirty-bitmap} options.
+When specified without @var{file} option, then it is a reference to @var{file},
+specified with another @option{-dirty-bitmap} option, and it will be used to
+load the bitmap from.
+@item drive=@var{drive}
+The drive to bind the bitmap to. It should be specified as @var{id} suboption
+of one of @option{-drive} options.
+If nor @var{file} neither @var{file_id} are specified, then the bitmap will be
+loaded from that drive (internal dirty bitmap).
+@item granularity=@var{granularity}
+Granularity (in bytes) for created dirty bitmap. If the bitmap is already
+exists in specified @var{file}/@var{file_id}/@var{device} it's granularity will
+not be changed but only checked (an error will be generated if this check
+fails).
+@item enabled=@var{enabled}
+Enabled flag for the bitmap. By default the bitmap will be enabled.
+@end table
+ETEXI
+
 DEF("mtdblock", HAS_ARG, QEMU_OPTION_mtdblock,
     "-mtdblock file  use 'file' as on-board Flash memory image\n",
     QEMU_ARCH_ALL)
diff --git a/vl.c b/vl.c
index 83871f5..fb16d0c 100644
--- a/vl.c
+++ b/vl.c
@@ -1091,6 +1091,95 @@ static int cleanup_add_fd(QemuOpts *opts, void *opaque)
 #define MTD_OPTS ""
 #define SD_OPTS ""
 
+static int dirty_bitmap_func(QemuOpts *opts, void *opaque)
+{
+    Error *local_err = NULL;
+    Error **errp = &local_err;
+    BlockDriverState *file_bs = NULL, *for_bs = NULL;
+    BdrvDirtyBitmap *bitmap = NULL;
+
+    const char *name = qemu_opt_get(opts, "name");
+    const char *drive = qemu_opt_get(opts, "drive");
+    const char *file = qemu_opt_get(opts, "file");
+    const char *file_id = qemu_opt_get(opts, "file_id");
+
+    uint64_t granularity = qemu_opt_get_number(opts, "granularity", 0);
+    bool enabled = qemu_opt_get_bool(opts, "enabled", true);
+
+    if (name == NULL) {
+        error_setg(errp, "'name' option is necessary");
+        goto fail;
+    }
+
+    if (drive == NULL) {
+        error_setg(errp, "'drive' option is necessary");
+        goto fail;
+    }
+
+    for_bs = bdrv_lookup_bs(drive, NULL, errp);
+    if (for_bs == NULL) {
+        goto fail;
+    }
+
+    if (file != NULL) {
+        QDict *options = NULL;
+        if (file_id != NULL) {
+            options = qdict_new();
+            qdict_put(options, "node-name", qstring_from_str(file_id));
+        }
+
+        bdrv_open(&file_bs, file, NULL, options, 0, NULL, errp);
+        if (options) {
+            QDECREF(options);
+        }
+        if (file_bs == NULL) {
+            goto fail;
+        }
+    } else if (file_id != NULL) {
+        file_bs = bdrv_find_node(file_id);
+        if (file_bs == NULL) {
+            error_setg(errp, "node '%s' is not found", drive);
+            goto fail;
+        }
+    } else {
+        file_bs = for_bs;
+    }
+
+    if (granularity == 0) {
+        granularity = bdrv_get_default_bitmap_granularity(for_bs);
+    }
+
+    bitmap = bdrv_load_dirty_bitmap(for_bs, file_bs, granularity, name,
+                                    errp);
+    if (*errp != NULL) {
+        goto fail;
+    }
+
+    if (bitmap == NULL) {
+        /* bitmap is not found in file_bs */
+        bitmap = bdrv_create_dirty_bitmap(for_bs, granularity, name, errp);
+        if (!bitmap) {
+            goto fail;
+        }
+    }
+
+    bdrv_dirty_bitmap_set_file(bitmap, file_bs);
+
+    if (!enabled) {
+        bdrv_disable_dirty_bitmap(bitmap);
+    }
+
+    return 0;
+
+fail:
+    error_report("-dirty-bitmap: %s", error_get_pretty(local_err));
+    error_free(local_err);
+    if (file_bs != NULL) {
+        bdrv_close(file_bs);
+    }
+    return -1;
+}
+
 static int drive_init_func(QemuOpts *opts, void *opaque)
 {
     BlockInterfaceType *block_default_type = opaque;
@@ -2790,6 +2879,7 @@ int main(int argc, char **argv, char **envp)
     module_call_init(MODULE_INIT_QOM);
 
     qemu_add_opts(&qemu_drive_opts);
+    qemu_add_opts(&qemu_dirty_bitmap_opts);
     qemu_add_drive_opts(&qemu_legacy_drive_opts);
     qemu_add_drive_opts(&qemu_common_drive_opts);
     qemu_add_drive_opts(&qemu_drive_opts);
@@ -2918,6 +3008,11 @@ int main(int argc, char **argv, char **envp)
                     exit(1);
                 }
                 break;
+            case QEMU_OPTION_dirty_bitmap:
+                if (dirty_bitmap_def(optarg) == NULL) {
+                    exit(1);
+                }
+                break;
             case QEMU_OPTION_set:
                 if (qemu_set_option(optarg) != 0)
                     exit(1);
@@ -4198,6 +4293,11 @@ int main(int argc, char **argv, char **envp)
 
     parse_numa_opts(machine_class);
 
+    if (qemu_opts_foreach(qemu_find_opts("dirty-bitmap"), dirty_bitmap_func,
+                          NULL, 1) != 0) {
+        exit(1);
+    }
+
     if (qemu_opts_foreach(qemu_find_opts("mon"), mon_init_func, NULL, 1) != 0) {
         exit(1);
     }
-- 
1.9.1