From 13ac133e5fbde2559899dc3717b2a2c20ce9aeb1 Mon Sep 17 00:00:00 2001

From: John Snow <jsnow@redhat.com>

Date: Wed, 27 Mar 2019 17:22:32 +0100

Subject: [PATCH 093/163] nbd: Merge nbd_export_bitmap into nbd_export_new

RH-Author: John Snow <jsnow@redhat.com>

Message-id: <20190327172308.31077-20-jsnow@redhat.com>

Patchwork-id: 85190

O-Subject: [RHEL-7.7 qemu-kvm-rhev PATCH 19/55] nbd: Merge nbd_export_bitmap into nbd_export_new

Bugzilla: 1691009

RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>

RH-Acked-by: Max Reitz <mreitz@redhat.com>

RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>

From: Eric Blake <eblake@redhat.com>

We only have one caller that wants to export a bitmap name,

which it does right after creation of the export. But there is

still a brief window of time where an NBD client could see the

export but not the dirty bitmap, which a robust client would

have to interpret as meaning the entire image should be treated

as dirty.  Better is to eliminate the window entirely, by

inlining nbd_export_bitmap() into nbd_export_new(), and refusing

to create the bitmap in the first place if the requested bitmap

can't be located.

We also no longer need logic for setting a different bitmap

name compared to the bitmap being exported.

Signed-off-by: Eric Blake <eblake@redhat.com>

Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

Message-Id: <20190111194720.15671-8-eblake@redhat.com>

(cherry picked from commit 678ba275c77b5b12f3bc9bb369a1b824fc9f679f)

Signed-off-by: John Snow <jsnow@redhat.com>

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>

---

 blockdev-nbd.c      | 11 +------

 include/block/nbd.h |  9 ++----

 nbd/server.c        | 87 ++++++++++++++++++++++++-----------------------------

 qemu-nbd.c          |  5 +--

 4 files changed, 47 insertions(+), 65 deletions(-)

diff --git a/blockdev-nbd.c b/blockdev-nbd.c

index cd86b38..c76d541 100644

--- a/blockdev-nbd.c

+++ b/blockdev-nbd.c

@@ -175,7 +175,7 @@ void qmp_nbd_server_add(const char *device, bool has_name, const char *name,

         writable = false;

     }

-    exp = nbd_export_new(bs, 0, -1, name, NULL,

+    exp = nbd_export_new(bs, 0, -1, name, NULL, bitmap,

                          writable ? 0 : NBD_FLAG_READ_ONLY,

                          NULL, false, on_eject_blk, errp);

     if (!exp) {

@@ -186,15 +186,6 @@ void qmp_nbd_server_add(const char *device, bool has_name, const char *name,

      * our only way of accessing it is through nbd_export_find(), so we can drop

      * the strong reference that is @exp. */

     nbd_export_put(exp);

-

-    if (has_bitmap) {

-        Error *err = NULL;

-        nbd_export_bitmap(exp, bitmap, bitmap, &err;;

-        if (err) {

-            error_propagate(errp, err);

-            nbd_export_remove(exp, NBD_SERVER_REMOVE_MODE_HARD, NULL);

-        }

-    }

 }

 void qmp_nbd_server_remove(const char *name,

diff --git a/include/block/nbd.h b/include/block/nbd.h

index 2f9a2ae..1971b55 100644

--- a/include/block/nbd.h

+++ b/include/block/nbd.h

@@ -296,9 +296,9 @@ typedef struct NBDClient NBDClient;

 NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, off_t size,

                           const char *name, const char *description,

-                          uint16_t nbdflags, void (*close)(NBDExport *),

-                          bool writethrough, BlockBackend *on_eject_blk,

-                          Error **errp);

+                          const char *bitmap, uint16_t nbdflags,

+                          void (*close)(NBDExport *), bool writethrough,

+                          BlockBackend *on_eject_blk, Error **errp);

 void nbd_export_close(NBDExport *exp);

 void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error **errp);

 void nbd_export_get(NBDExport *exp);

@@ -319,9 +319,6 @@ void nbd_client_put(NBDClient *client);

 void nbd_server_start(SocketAddress *addr, const char *tls_creds,

                       Error **errp);

-void nbd_export_bitmap(NBDExport *exp, const char *bitmap,

-                       const char *bitmap_export_name, Error **errp);

-

 /* nbd_read

  * Reads @size bytes from @ioc. Returns 0 on success.

  */

diff --git a/nbd/server.c b/nbd/server.c

index 6c02b57..6b13601 100644

--- a/nbd/server.c

+++ b/nbd/server.c

@@ -1457,9 +1457,9 @@ static void nbd_eject_notifier(Notifier *n, void *data)

 NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, off_t size,

                           const char *name, const char *description,

-                          uint16_t nbdflags, void (*close)(NBDExport *),

-                          bool writethrough, BlockBackend *on_eject_blk,

-                          Error **errp)

+                          const char *bitmap, uint16_t nbdflags,

+                          void (*close)(NBDExport *), bool writethrough,

+                          BlockBackend *on_eject_blk, Error **errp)

 {

     AioContext *ctx;

     BlockBackend *blk;

@@ -1507,6 +1507,43 @@ NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, off_t size,

     }

     exp->size -= exp->size % BDRV_SECTOR_SIZE;

+    if (bitmap) {

+        BdrvDirtyBitmap *bm = NULL;

+        BlockDriverState *bs = blk_bs(blk);

+

+        while (true) {

+            bm = bdrv_find_dirty_bitmap(bs, bitmap);

+            if (bm != NULL || bs->backing == NULL) {

+                break;

+            }

+

+            bs = bs->backing->bs;

+        }

+

+        if (bm == NULL) {

+            error_setg(errp, "Bitmap '%s' is not found", bitmap);

+            goto fail;

+        }

+

+        if ((nbdflags & NBD_FLAG_READ_ONLY) && bdrv_is_writable(bs) &&

+            bdrv_dirty_bitmap_enabled(bm)) {

+            error_setg(errp,

+                       "Enabled bitmap '%s' incompatible with readonly export",

+                       bitmap);

+            goto fail;

+        }

+

+        if (bdrv_dirty_bitmap_user_locked(bm)) {

+            error_setg(errp, "Bitmap '%s' is in use", bitmap);

+            goto fail;

+        }

+

+        bdrv_dirty_bitmap_set_qmp_locked(bm, true);

+        exp->export_bitmap = bm;

+        exp->export_bitmap_context = g_strdup_printf("qemu:dirty-bitmap:%s",

+                                                     bitmap);

+    }

+

     exp->close = close;

     exp->ctx = blk_get_aio_context(blk);

     blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp);

@@ -2424,47 +2461,3 @@ void nbd_client_new(QIOChannelSocket *sioc,

     co = qemu_coroutine_create(nbd_co_client_start, client);

     qemu_coroutine_enter(co);

 }

-

-void nbd_export_bitmap(NBDExport *exp, const char *bitmap,

-                       const char *bitmap_export_name, Error **errp)

-{

-    BdrvDirtyBitmap *bm = NULL;

-    BlockDriverState *bs = blk_bs(exp->blk);

-

-    if (exp->export_bitmap) {

-        error_setg(errp, "Export bitmap is already set");

-        return;

-    }

-

-    while (true) {

-        bm = bdrv_find_dirty_bitmap(bs, bitmap);

-        if (bm != NULL || bs->backing == NULL) {

-            break;

-        }

-

-        bs = bs->backing->bs;

-    }

-

-    if (bm == NULL) {

-        error_setg(errp, "Bitmap '%s' is not found", bitmap);

-        return;

-    }

-

-    if ((exp->nbdflags & NBD_FLAG_READ_ONLY) && bdrv_is_writable(bs) &&

-        bdrv_dirty_bitmap_enabled(bm)) {

-        error_setg(errp,

-                   "Enabled bitmap '%s' incompatible with readonly export",

-                   bitmap);

-        return;

-    }

-

-    if (bdrv_dirty_bitmap_user_locked(bm)) {

-        error_setg(errp, "Bitmap '%s' is in use", bitmap);

-        return;

-    }

-

-    bdrv_dirty_bitmap_set_qmp_locked(bm, true);

-    exp->export_bitmap = bm;

-    exp->export_bitmap_context =

-            g_strdup_printf("qemu:dirty-bitmap:%s", bitmap_export_name);

-}

diff --git a/qemu-nbd.c b/qemu-nbd.c

index c85aee4..ac4c958 100644

--- a/qemu-nbd.c

+++ b/qemu-nbd.c

@@ -1018,8 +1018,9 @@ int main(int argc, char **argv)

     }

     export = nbd_export_new(bs, dev_offset, fd_size, export_name,

-                            export_description, nbdflags, nbd_export_closed,

-                            writethrough, NULL, &error_fatal);

+                            export_description, NULL, nbdflags,

+                            nbd_export_closed, writethrough, NULL,

+                            &error_fatal);

     if (device) {

 #if HAVE_NBD_DEVICE

-- 

1.8.3.1