10:59 p.m.
Since 'block-export-add' is new to 5.2, we can still tweak the
interface; there, allowing 'bitmaps':['str'] is nicer than
'bitmap':'str'. This wires up the qapi and qemu-nbd changes to permit
passing multiple bitmaps as distinct metadata contexts that the NBD
client may request, but the actual support for more than one will
require a further patch to the server.
Note that there are no changes made to the existing deprecated
'nbd-server-add' command; this required splitting the QAPI type
BlockExportOptionsNbd, which fortunately does not affect QMP
introspection.
Signed-off-by: Eric Blake <eblake(a)redhat.com>
Message-Id: <20201027050556.269064-5-eblake(a)redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov(a)virtuozzo.com>
Reviewed-by: Peter Krempa <pkrempa(a)redhat.com>
---
docs/system/deprecated.rst | 3 ++-
qapi/block-export.json | 41 +++++++++++++++++++++++++++-----------
blockdev-nbd.c | 6 +++++-
nbd/server.c | 19 ++++++++++++------
qemu-nbd.c | 18 ++++++++---------
5 files changed, 58 insertions(+), 29 deletions(-)
diff --git a/docs/system/deprecated.rst b/docs/system/deprecated.rst
index 0ebce37a1919..32a0e620dbb9 100644
--- a/docs/system/deprecated.rst
+++ b/docs/system/deprecated.rst
@@ -257,7 +257,8 @@ the 'wait' field, which is only applicable to sockets in
server mode
''''''''''''''''''''''''''''''''''''''''''''''''''''''''
Use the more generic commands ``block-export-add`` and ``block-export-del``
-instead.
+instead. As part of this deprecation, where ``nbd-server-add`` used a
+single ``bitmap``, the new ``block-export-add`` uses a list of ``bitmaps``.
Human Monitor Protocol (HMP) commands
-------------------------------------
diff --git a/qapi/block-export.json b/qapi/block-export.json
index 480c497690b0..c4125f4d2104 100644
--- a/qapi/block-export.json
+++ b/qapi/block-export.json
@@ -63,10 +63,10 @@
'*max-connections': 'uint32' } }
##
-# @BlockExportOptionsNbd:
+# @BlockExportOptionsNbdBase:
#
-# An NBD block export (options shared between nbd-server-add and the NBD branch
-# of block-export-add).
+# An NBD block export (common options shared between nbd-server-add and
+# the NBD branch of block-export-add).
#
# @name: Export name. If unspecified, the @device parameter is used as the
# export name. (Since 2.12)
@@ -74,15 +74,27 @@
# @description: Free-form description of the export, up to 4096 bytes.
# (Since 5.0)
#
-# @bitmap: Also export the dirty bitmap reachable from @device, so the
-# NBD client can use NBD_OPT_SET_META_CONTEXT with
-# "qemu:dirty-bitmap:NAME" to inspect the bitmap. (since 4.0)
-#
# Since: 5.0
##
+{ 'struct': 'BlockExportOptionsNbdBase',
+ 'data': { '*name': 'str', '*description': 'str'
} }
+
+##
+# @BlockExportOptionsNbd:
+#
+# An NBD block export (distinct options used in the NBD branch of
+# block-export-add).
+#
+# @bitmaps: Also export each of the named dirty bitmaps reachable from
+# @device, so the NBD client can use NBD_OPT_SET_META_CONTEXT with
+# the metadata context name "qemu:dirty-bitmap:BITMAP" to inspect
+# each bitmap.
+#
+# Since: 5.2
+##
{ 'struct': 'BlockExportOptionsNbd',
- 'data': { '*name': 'str', '*description':
'str',
- '*bitmap': 'str' } }
+ 'base': 'BlockExportOptionsNbdBase',
+ 'data': { '*bitmaps': ['str'] } }
##
# @BlockExportOptionsVhostUserBlk:
@@ -106,19 +118,24 @@
##
# @NbdServerAddOptions:
#
-# An NBD block export.
+# An NBD block export, per legacy nbd-server-add command.
#
# @device: The device name or node name of the node to be exported
#
# @writable: Whether clients should be able to write to the device via the
# NBD connection (default false).
#
+# @bitmap: Also export a single dirty bitmap reachable from @device, so the
+# NBD client can use NBD_OPT_SET_META_CONTEXT with the metadata
+# context name "qemu:dirty-bitmap:BITMAP" to inspect the bitmap
+# (since 4.0).
+#
# Since: 5.0
##
{ 'struct': 'NbdServerAddOptions',
- 'base': 'BlockExportOptionsNbd',
+ 'base': 'BlockExportOptionsNbdBase',
'data': { 'device': 'str',
- '*writable': 'bool' } }
+ '*writable': 'bool', '*bitmap': 'str' } }
##
# @nbd-server-add:
diff --git a/blockdev-nbd.c b/blockdev-nbd.c
index cee9134b12eb..d8443d235b73 100644
--- a/blockdev-nbd.c
+++ b/blockdev-nbd.c
@@ -209,8 +209,12 @@ void qmp_nbd_server_add(NbdServerAddOptions *arg, Error **errp)
.has_writable = arg->has_writable,
.writable = arg->writable,
};
- QAPI_CLONE_MEMBERS(BlockExportOptionsNbd, &export_opts->u.nbd,
+ QAPI_CLONE_MEMBERS(BlockExportOptionsNbdBase, &export_opts->u.nbd,
qapi_NbdServerAddOptions_base(arg));
+ if (arg->has_bitmap) {
+ export_opts->u.nbd.has_bitmaps = true;
+ QAPI_LIST_PREPEND(export_opts->u.nbd.bitmaps, g_strdup(arg->bitmap));
+ }
/*
* nbd-server-add doesn't complain when a read-only device should be
diff --git a/nbd/server.c b/nbd/server.c
index 08b621f70a3a..8d01662b4511 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -1474,6 +1474,7 @@ static int nbd_export_create(BlockExport *blk_exp,
BlockExportOptions *exp_args,
uint64_t perm, shared_perm;
bool readonly = !exp_args->writable;
bool shared = !exp_args->writable;
+ strList *bitmaps;
int ret;
assert(exp_args->type == BLOCK_EXPORT_TYPE_NBD);
@@ -1533,12 +1534,18 @@ static int nbd_export_create(BlockExport *blk_exp,
BlockExportOptions *exp_args,
}
exp->size = QEMU_ALIGN_DOWN(size, BDRV_SECTOR_SIZE);
- if (arg->bitmap) {
+ /* XXX Allow more than one bitmap */
+ if (arg->bitmaps && arg->bitmaps->next) {
+ error_setg(errp, "multiple bitmaps per export not supported yet");
+ return -EOPNOTSUPP;
+ }
+ for (bitmaps = arg->bitmaps; bitmaps; bitmaps = bitmaps->next) {
+ const char *bitmap = bitmaps->value;
BlockDriverState *bs = blk_bs(blk);
BdrvDirtyBitmap *bm = NULL;
while (bs) {
- bm = bdrv_find_dirty_bitmap(bs, arg->bitmap);
+ bm = bdrv_find_dirty_bitmap(bs, bitmap);
if (bm != NULL) {
break;
}
@@ -1548,7 +1555,7 @@ static int nbd_export_create(BlockExport *blk_exp,
BlockExportOptions *exp_args,
if (bm == NULL) {
ret = -ENOENT;
- error_setg(errp, "Bitmap '%s' is not found",
arg->bitmap);
+ error_setg(errp, "Bitmap '%s' is not found", bitmap);
goto fail;
}
@@ -1562,15 +1569,15 @@ static int nbd_export_create(BlockExport *blk_exp,
BlockExportOptions *exp_args,
ret = -EINVAL;
error_setg(errp,
"Enabled bitmap '%s' incompatible with readonly
export",
- arg->bitmap);
+ bitmap);
goto fail;
}
bdrv_dirty_bitmap_set_busy(bm, true);
exp->export_bitmap = bm;
- assert(strlen(arg->bitmap) <= BDRV_BITMAP_MAX_NAME_SIZE);
+ assert(strlen(bitmap) <= BDRV_BITMAP_MAX_NAME_SIZE);
exp->export_bitmap_context =
g_strdup_printf("qemu:dirty-bitmap:%s",
- arg->bitmap);
+ bitmap);
assert(strlen(exp->export_bitmap_context) < NBD_MAX_STRING_SIZE);
}
diff --git a/qemu-nbd.c b/qemu-nbd.c
index a0701cdf369d..74e73a74657b 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -574,7 +574,7 @@ int main(int argc, char **argv)
QDict *options = NULL;
const char *export_name = NULL; /* defaults to "" later for server mode */
const char *export_description = NULL;
- const char *bitmap = NULL;
+ strList *bitmaps = NULL;
const char *tlscredsid = NULL;
bool imageOpts = false;
bool writethrough = true;
@@ -690,7 +690,7 @@ int main(int argc, char **argv)
flags &= ~BDRV_O_RDWR;
break;
case 'B':
- bitmap = optarg;
+ QAPI_LIST_PREPEND(bitmaps, g_strdup(optarg));
break;
case 'k':
sockpath = optarg;
@@ -786,7 +786,7 @@ int main(int argc, char **argv)
exit(EXIT_FAILURE);
}
if (export_name || export_description || dev_offset ||
- device || disconnect || fmt || sn_id_or_name || bitmap ||
+ device || disconnect || fmt || sn_id_or_name || bitmaps ||
seen_aio || seen_discard || seen_cache) {
error_report("List mode is incompatible with per-device
settings");
exit(EXIT_FAILURE);
@@ -1067,12 +1067,12 @@ int main(int argc, char **argv)
.has_writable = true,
.writable = !readonly,
.u.nbd = {
- .has_name = true,
- .name = g_strdup(export_name),
- .has_description = !!export_description,
- .description = g_strdup(export_description),
- .has_bitmap = !!bitmap,
- .bitmap = g_strdup(bitmap),
+ .has_name = true,
+ .name = g_strdup(export_name),
+ .has_description = !!export_description,
+ .description = g_strdup(export_description),
+ .has_bitmaps = !!bitmaps,
+ .bitmaps = bitmaps,
},
};
blk_exp_add(export_opts, &error_fatal);
--
2.29.0