blockcommit: Reopen base image as RO after abort

If a blockcommit is aborted the base image remains in RW mode, that leads
to a fail of subsequent live migration.

How to reproduce:
  $ virsh snapshot-create-as vm snp1 --disk-only

  *** write something to the disk inside the guest ***

  $ virsh blockcommit vm vda --active --shallow && virsh blockjob vm vda --abort
  $ lsof /vzt/vm.qcow2
  COMMAND      PID USER   FD   TYPE DEVICE   SIZE/OFF NODE NAME
  qemu-syst 433203 root   45u   REG  253,0 1724776448  133 /vzt/vm.qcow2
  $ cat /proc/433203/fdinfo/45
  pos:    0
  flags:  02140002 <==== The last 2 means RW mode

If the base image is in RW mode at the end of blockcommit and was in RO
mode before blockcommit, reopen the base BDS in RO.

Signed-off-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Message-Id: <20240404091136.129811-1-alexander.ivanov@virtuozzo.com>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
This commit is contained in:
Alexander Ivanov 2024-04-04 11:11:36 +02:00 committed by Vladimir Sementsov-Ogievskiy
parent ad10b4badc
commit 7d99ae59a2

View file

@ -93,6 +93,7 @@ typedef struct MirrorBlockJob {
int64_t active_write_bytes_in_flight;
bool prepared;
bool in_drain;
bool base_ro;
} MirrorBlockJob;
typedef struct MirrorBDSOpaque {
@ -794,6 +795,10 @@ static int mirror_exit_common(Job *job)
bdrv_replace_node(mirror_top_bs, mirror_top_bs->backing->bs, &error_abort);
bdrv_graph_wrunlock();
if (abort && s->base_ro && !bdrv_is_read_only(target_bs)) {
bdrv_reopen_set_read_only(target_bs, true, NULL);
}
bdrv_drained_end(target_bs);
bdrv_unref(target_bs);
@ -1717,6 +1722,7 @@ static BlockJob *mirror_start_job(
bool is_none_mode, BlockDriverState *base,
bool auto_complete, const char *filter_node_name,
bool is_mirror, MirrorCopyMode copy_mode,
bool base_ro,
Error **errp)
{
MirrorBlockJob *s;
@ -1800,6 +1806,7 @@ static BlockJob *mirror_start_job(
bdrv_unref(mirror_top_bs);
s->mirror_top_bs = mirror_top_bs;
s->base_ro = base_ro;
/* No resize for the target either; while the mirror is still running, a
* consistent read isn't necessarily possible. We could possibly allow
@ -2029,7 +2036,7 @@ void mirror_start(const char *job_id, BlockDriverState *bs,
speed, granularity, buf_size, backing_mode, zero_target,
on_source_error, on_target_error, unmap, NULL, NULL,
&mirror_job_driver, is_none_mode, base, false,
filter_node_name, true, copy_mode, errp);
filter_node_name, true, copy_mode, false, errp);
}
BlockJob *commit_active_start(const char *job_id, BlockDriverState *bs,
@ -2058,7 +2065,7 @@ BlockJob *commit_active_start(const char *job_id, BlockDriverState *bs,
on_error, on_error, true, cb, opaque,
&commit_active_job_driver, false, base, auto_complete,
filter_node_name, false, MIRROR_COPY_MODE_BACKGROUND,
errp);
base_read_only, errp);
if (!job) {
goto error_restore_flags;
}