block/amend: add 'force' option

'force' option will be used for some unsafe amend operations.

This includes things like erasing last keyslot in luks based formats
(which destroys the data, unless the master key is backed up
by external means), but that _might_ be desired result.

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200608094030.670121-4-mlevitsk@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>

diff --git a/block.c b/block.c
index 6dbcb7e083eab8de30690c06269c3033d41b2e83..144f52e413e919ec58c0e74545da252c50370a46 100644 (file)
--- a/block.c
+++ b/block.c
@@ -6482,6 +6482,7 @@ void bdrv_remove_aio_context_notifier(BlockDriverState *bs,
 
 int bdrv_amend_options(BlockDriverState *bs, QemuOpts *opts,
                        BlockDriverAmendStatusCB *status_cb, void *cb_opaque,
+                       bool force,
                        Error **errp)
 {
     if (!bs->drv) {
@@ -6493,7 +6494,8 @@ int bdrv_amend_options(BlockDriverState *bs, QemuOpts *opts,
                    bs->drv->format_name);
         return -ENOTSUP;
     }
-    return bs->drv->bdrv_amend_options(bs, opts, status_cb, cb_opaque, errp);
+    return bs->drv->bdrv_amend_options(bs, opts, status_cb,
+                                       cb_opaque, force, errp);
 }
 
 /*

diff --git a/block/qcow2.c b/block/qcow2.c
index e20590c3b787cccc188a51ed7a4380c7ec0d9feb..f6c9207312db6596f19141a1e585630edd1d2bd5 100644 (file)
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -5351,6 +5351,7 @@ static void qcow2_amend_helper_cb(BlockDriverState *bs,
 static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts,
                                BlockDriverAmendStatusCB *status_cb,
                                void *cb_opaque,
+                               bool force,
                                Error **errp)
 {
     BDRVQcow2State *s = bs->opaque;

diff --git a/docs/tools/qemu-img.rst b/docs/tools/qemu-img.rst
index 7f0737488adecf641cf6ca2e58ac343b60e6cc19..e33f5575e35d8cc5ca1c8d8ecb6ed69dc1d08d85 100644 (file)
--- a/docs/tools/qemu-img.rst
+++ b/docs/tools/qemu-img.rst
@@ -253,11 +253,14 @@ Command description:
 
 .. program:: qemu-img-commands
 
-.. option:: amend [--object OBJECTDEF] [--image-opts] [-p] [-q] [-f FMT] [-t CACHE] -o OPTIONS FILENAME
+.. option:: amend [--object OBJECTDEF] [--image-opts] [-p] [-q] [-f FMT] [-t CACHE] [--force] -o OPTIONS FILENAME
 
   Amends the image format specific *OPTIONS* for the image file
   *FILENAME*. Not all file formats support this operation.
 
+  --force allows some unsafe operations. Currently for -f luks, it allows to
+  erase the last encryption key, and to overwrite an active encryption key.
+
 .. 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
 
   Run a simple sequential I/O benchmark on the specified image. If ``-w`` is

diff --git a/include/block/block.h b/include/block/block.h
index e8fc8149967ff60b193ea3772c896e4efdc9038f..a2414a58c51ab6b71f9383ec168280efa2733f36 100644 (file)
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -450,6 +450,7 @@ typedef void BlockDriverAmendStatusCB(BlockDriverState *bs, int64_t offset,
                                       int64_t total_work_size, void *opaque);
 int bdrv_amend_options(BlockDriverState *bs_new, QemuOpts *opts,
                        BlockDriverAmendStatusCB *status_cb, void *cb_opaque,
+                       bool force,
                        Error **errp);
 
 /* check if a named node can be replaced when doing drive-mirror */

diff --git a/include/block/block_int.h b/include/block/block_int.h
index 791de6a59c2c0ca7dac10b754ca9f266edf01b07..066b9eaa40809cd16ee04d30ba798a9e57fa575c 100644 (file)
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -440,6 +440,7 @@ struct BlockDriver {
     int (*bdrv_amend_options)(BlockDriverState *bs, QemuOpts *opts,
                               BlockDriverAmendStatusCB *status_cb,
                               void *cb_opaque,
+                              bool force,
                               Error **errp);
 
     void (*bdrv_debug_event)(BlockDriverState *bs, BlkdebugEvent event);

diff --git a/qemu-img-cmds.hx b/qemu-img-cmds.hx
index 10b910b67cf87ee9c0ff1ffad7b43cb2f96424e5..b89c019b76bf34613b19a2cb65a01d148331d94c 100644 (file)
--- a/qemu-img-cmds.hx
+++ b/qemu-img-cmds.hx
@@ -10,9 +10,9 @@ HXCOMM When amending the rST sections, please remember to copy the usage
 HXCOMM over to the per-command sections in docs/tools/qemu-img.rst.
 
 DEF("amend", img_amend,
-    "amend [--object objectdef] [--image-opts] [-p] [-q] [-f fmt] [-t cache] -o options filename")
+    "amend [--object objectdef] [--image-opts] [-p] [-q] [-f fmt] [-t cache] [--force] -o options filename")
 SRST
-.. option:: amend [--object OBJECTDEF] [--image-opts] [-p] [-q] [-f FMT] [-t CACHE] -o OPTIONS FILENAME
+.. option:: amend [--object OBJECTDEF] [--image-opts] [-p] [-q] [-f FMT] [-t CACHE] [--force] -o OPTIONS FILENAME
 ERST
 
 DEF("bench", img_bench,

diff --git a/qemu-img.c b/qemu-img.c
index bdb9f6aa46a3025cd2dae8390ac739e036612b3a..8c26bfafc6f2b666c7c53c5633355171c33f5c83 100644 (file)
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -79,6 +79,7 @@ enum {
     OPTION_DISABLE = 273,
     OPTION_MERGE = 274,
     OPTION_BITMAPS = 275,
+    OPTION_FORCE = 276,
 };
 
 typedef enum OutputFormat {
@@ -4090,6 +4091,7 @@ static int img_amend(int argc, char **argv)
     BlockBackend *blk = NULL;
     BlockDriverState *bs = NULL;
     bool image_opts = false;
+    bool force = false;
 
     cache = BDRV_DEFAULT_CACHE;
     for (;;) {
@@ -4097,6 +4099,7 @@ static int img_amend(int argc, char **argv)
             {"help", no_argument, 0, 'h'},
             {"object", required_argument, 0, OPTION_OBJECT},
             {"image-opts", no_argument, 0, OPTION_IMAGE_OPTS},
+            {"force", no_argument, 0, OPTION_FORCE},
             {0, 0, 0, 0}
         };
         c = getopt_long(argc, argv, ":ho:f:t:pq",
@@ -4144,6 +4147,9 @@ static int img_amend(int argc, char **argv)
         case OPTION_IMAGE_OPTS:
             image_opts = true;
             break;
+        case OPTION_FORCE:
+            force = true;
+            break;
         }
     }
 
@@ -4221,7 +4227,7 @@ static int img_amend(int argc, char **argv)
 
     /* In case the driver does not call amend_status_cb() */
     qemu_progress_print(0.f, 0);
-    ret = bdrv_amend_options(bs, opts, &amend_status_cb, NULL, &err);
+    ret = bdrv_amend_options(bs, opts, &amend_status_cb, NULL, force, &err);
     qemu_progress_print(100.f, 0);
     if (ret < 0) {
         error_report_err(err);