aboutsummaryrefslogtreecommitdiff
path: root/blockdev.c
diff options
context:
space:
mode:
authorStefan Hajnoczi <stefanha@redhat.com>2014-11-21 10:48:59 +0000
committerKevin Wolf <kwolf@redhat.com>2014-12-10 10:31:13 +0100
commit5d6e96efb81f94f39a50110e8178584fb1817f66 (patch)
treefc4be81c502861345c5cf0de9065e64ff833fcd9 /blockdev.c
parent73f1f7564d58963fc692334bcf0c529e1e3536fb (diff)
blockdev: acquire AioContext in QMP 'transaction' actions
The transaction QMP command performs operations atomically on a group of drives. This command needs to acquire AioContext in order to work safely when virtio-blk dataplane IOThreads are accessing drives. The transactional nature of the command means that actions are split into prepare, commit, abort, and clean functions. Acquire the AioContext in prepare and don't release it until one of the other functions is called. This prevents the IOThread from running the AioContext before the transaction has completed. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 1416566940-4430-4-git-send-email-stefanha@redhat.com Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'blockdev.c')
-rw-r--r--blockdev.c52
1 files changed, 51 insertions, 1 deletions
diff --git a/blockdev.c b/blockdev.c
index b58ce303a5..ea59c39c15 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1207,6 +1207,7 @@ struct BlkTransactionState {
typedef struct InternalSnapshotState {
BlkTransactionState common;
BlockDriverState *bs;
+ AioContext *aio_context;
QEMUSnapshotInfo sn;
} InternalSnapshotState;
@@ -1240,6 +1241,10 @@ static void internal_snapshot_prepare(BlkTransactionState *common,
return;
}
+ /* AioContext is released in .clean() */
+ state->aio_context = bdrv_get_aio_context(bs);
+ aio_context_acquire(state->aio_context);
+
if (!bdrv_is_inserted(bs)) {
error_set(errp, QERR_DEVICE_HAS_NO_MEDIUM, device);
return;
@@ -1317,11 +1322,22 @@ static void internal_snapshot_abort(BlkTransactionState *common)
}
}
+static void internal_snapshot_clean(BlkTransactionState *common)
+{
+ InternalSnapshotState *state = DO_UPCAST(InternalSnapshotState,
+ common, common);
+
+ if (state->aio_context) {
+ aio_context_release(state->aio_context);
+ }
+}
+
/* external snapshot private data */
typedef struct ExternalSnapshotState {
BlkTransactionState common;
BlockDriverState *old_bs;
BlockDriverState *new_bs;
+ AioContext *aio_context;
} ExternalSnapshotState;
static void external_snapshot_prepare(BlkTransactionState *common,
@@ -1388,6 +1404,10 @@ static void external_snapshot_prepare(BlkTransactionState *common,
return;
}
+ /* Acquire AioContext now so any threads operating on old_bs stop */
+ state->aio_context = bdrv_get_aio_context(state->old_bs);
+ aio_context_acquire(state->aio_context);
+
if (!bdrv_is_inserted(state->old_bs)) {
error_set(errp, QERR_DEVICE_HAS_NO_MEDIUM, device);
return;
@@ -1446,6 +1466,8 @@ static void external_snapshot_commit(BlkTransactionState *common)
ExternalSnapshotState *state =
DO_UPCAST(ExternalSnapshotState, common, common);
+ bdrv_set_aio_context(state->new_bs, state->aio_context);
+
/* This removes our old bs and adds the new bs */
bdrv_append(state->new_bs, state->old_bs);
/* We don't need (or want) to use the transactional
@@ -1453,6 +1475,8 @@ static void external_snapshot_commit(BlkTransactionState *common)
* don't want to abort all of them if one of them fails the reopen */
bdrv_reopen(state->new_bs, state->new_bs->open_flags & ~BDRV_O_RDWR,
NULL);
+
+ aio_context_release(state->aio_context);
}
static void external_snapshot_abort(BlkTransactionState *common)
@@ -1462,23 +1486,38 @@ static void external_snapshot_abort(BlkTransactionState *common)
if (state->new_bs) {
bdrv_unref(state->new_bs);
}
+ if (state->aio_context) {
+ aio_context_release(state->aio_context);
+ }
}
typedef struct DriveBackupState {
BlkTransactionState common;
BlockDriverState *bs;
+ AioContext *aio_context;
BlockJob *job;
} DriveBackupState;
static void drive_backup_prepare(BlkTransactionState *common, Error **errp)
{
DriveBackupState *state = DO_UPCAST(DriveBackupState, common, common);
+ BlockDriverState *bs;
DriveBackup *backup;
Error *local_err = NULL;
assert(common->action->kind == TRANSACTION_ACTION_KIND_DRIVE_BACKUP);
backup = common->action->drive_backup;
+ bs = bdrv_find(backup->device);
+ if (!bs) {
+ error_set(errp, QERR_DEVICE_NOT_FOUND, backup->device);
+ return;
+ }
+
+ /* AioContext is released in .clean() */
+ state->aio_context = bdrv_get_aio_context(bs);
+ aio_context_acquire(state->aio_context);
+
qmp_drive_backup(backup->device, backup->target,
backup->has_format, backup->format,
backup->sync,
@@ -1492,7 +1531,7 @@ static void drive_backup_prepare(BlkTransactionState *common, Error **errp)
return;
}
- state->bs = bdrv_find(backup->device);
+ state->bs = bs;
state->job = state->bs->job;
}
@@ -1507,6 +1546,15 @@ static void drive_backup_abort(BlkTransactionState *common)
}
}
+static void drive_backup_clean(BlkTransactionState *common)
+{
+ DriveBackupState *state = DO_UPCAST(DriveBackupState, common, common);
+
+ if (state->aio_context) {
+ aio_context_release(state->aio_context);
+ }
+}
+
static void abort_prepare(BlkTransactionState *common, Error **errp)
{
error_setg(errp, "Transaction aborted using Abort action");
@@ -1528,6 +1576,7 @@ static const BdrvActionOps actions[] = {
.instance_size = sizeof(DriveBackupState),
.prepare = drive_backup_prepare,
.abort = drive_backup_abort,
+ .clean = drive_backup_clean,
},
[TRANSACTION_ACTION_KIND_ABORT] = {
.instance_size = sizeof(BlkTransactionState),
@@ -1538,6 +1587,7 @@ static const BdrvActionOps actions[] = {
.instance_size = sizeof(InternalSnapshotState),
.prepare = internal_snapshot_prepare,
.abort = internal_snapshot_abort,
+ .clean = internal_snapshot_clean,
},
};