From 8ad4202bf61bc1d124ff26016cfe17cb261cc392 Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Mon, 18 Aug 2014 16:07:12 +0100 Subject: [PATCH] block: acquire AioContext in do_drive_del() Make drive_del safe for dataplane where another thread may be running the BlockDriverState's AioContext. Note the assumption that AioContext's lifetime exceeds DriveInfo and BlockDriverState. We release AioContext after DriveInfo and BlockDriverState are potentially freed. This is clearly safe with the global AioContext but also with -object iothread and implicit iothreads created by -device virtio-blk-pci,x-data-plane=on (their lifetime is tied to DeviceState, not BlockDriverState). Signed-off-by: Stefan Hajnoczi --- blockdev.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/blockdev.c b/blockdev.c index eeb414efc0..e37b068e9e 100644 --- a/blockdev.c +++ b/blockdev.c @@ -1757,6 +1757,7 @@ int do_drive_del(Monitor *mon, const QDict *qdict, QObject **ret_data) { const char *id = qdict_get_str(qdict, "id"); BlockDriverState *bs; + AioContext *aio_context; Error *local_err = NULL; bs = bdrv_find(id); @@ -1764,9 +1765,14 @@ int do_drive_del(Monitor *mon, const QDict *qdict, QObject **ret_data) error_report("Device '%s' not found", id); return -1; } + + aio_context = bdrv_get_aio_context(bs); + aio_context_acquire(aio_context); + if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_DRIVE_DEL, &local_err)) { error_report("%s", error_get_pretty(local_err)); error_free(local_err); + aio_context_release(aio_context); return -1; } @@ -1790,6 +1796,7 @@ int do_drive_del(Monitor *mon, const QDict *qdict, QObject **ret_data) drive_del(drive_get_by_blockdev(bs)); } + aio_context_release(aio_context); return 0; }