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| author | Fam Zheng <famz@redhat.com> | 2017-05-03 00:35:53 +0800 |
|---|---|---|
| committer | Michael Roth <mdroth@linux.vnet.ibm.com> | 2017-07-31 17:11:50 -0500 |
| commit | d2fcb92b18f735b7ea623ea649f3aedcacf48677 (patch) | |
| tree | f3bdc5f32dff424d04e2736d29d8c17637befc17 /blockdev.c | |
| parent | e59084b5b2daa22427d3dc4e1fd241f69910615e (diff) | |
| download | qemu-d2fcb92b18f735b7ea623ea649f3aedcacf48677.tar.gz | |
block: Reuse bs as backing hd for drive-backup sync=none
Opening the backing image for the second time is bad, especially here
when it is also in use as the active image as the source. The
drive-backup job itself doesn't read from target->backing for COW,
instead it gets data from the write notifier, so it's not a big problem.
However, exporting the target to NBD etc. won't work, because of the
likely stale metadata cache.
Use BDRV_O_NO_BACKING in this case and manually set up the backing
BdrvChild.
Cc: qemu-stable@nongnu.org
Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit fc0932fdcfc3e5cafa3641e361b681c07f639812)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Diffstat (limited to 'blockdev.c')
| -rw-r--r-- | blockdev.c | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/blockdev.c b/blockdev.c index e2f9c1e877..841200ee3e 100644 --- a/blockdev.c +++ b/blockdev.c @@ -3170,6 +3170,7 @@ static BlockJob *do_drive_backup(DriveBackup *backup, BlockJobTxn *txn, Error *local_err = NULL; int flags; int64_t size; + bool set_backing_hd = false; if (!backup->has_speed) { backup->speed = 0; @@ -3220,6 +3221,8 @@ static BlockJob *do_drive_backup(DriveBackup *backup, BlockJobTxn *txn, } if (backup->sync == MIRROR_SYNC_MODE_NONE) { source = bs; + flags |= BDRV_O_NO_BACKING; + set_backing_hd = true; } size = bdrv_getlength(bs); @@ -3246,7 +3249,9 @@ static BlockJob *do_drive_backup(DriveBackup *backup, BlockJobTxn *txn, } if (backup->format) { - options = qdict_new(); + if (!options) { + options = qdict_new(); + } qdict_put_str(options, "driver", backup->format); } @@ -3257,6 +3262,14 @@ static BlockJob *do_drive_backup(DriveBackup *backup, BlockJobTxn *txn, bdrv_set_aio_context(target_bs, aio_context); + if (set_backing_hd) { + bdrv_set_backing_hd(target_bs, source, &local_err); + if (local_err) { + bdrv_unref(target_bs); + goto out; + } + } + if (backup->has_bitmap) { bmap = bdrv_find_dirty_bitmap(bs, backup->bitmap); if (!bmap) { |