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authorKevin Wolf <kwolf@redhat.com>2023-05-25 14:47:07 +0200
committerKevin Wolf <kwolf@redhat.com>2023-05-30 17:21:23 +0200
commitaa269ff888d70158fe0c26ed17814046bdc19bd5 (patch)
tree163e0772a46d4f46622c1fae63e9963dd8cfd06c /block.c
parent2626d27f50f3c993936db04bc6e92d553e1dc914 (diff)
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qcow2: Fix open with 'file' in iothread
qcow2_open() doesn't work correctly when opening the 'file' child moves bs to an iothread, for several reasons: - It uses BDRV_POLL_WHILE() to wait for the qcow2_open_entry() coroutine, which involves dropping the AioContext lock for bs when it is not in the main context - but we don't hold it, so this crashes. - It runs the qcow2_open_entry() coroutine in the current thread instead of the new AioContext of bs. - qcow2_open_entry() doesn't notify the main loop when it's done. This patches fixes these issues around delegating work to a coroutine. Temporarily dropping the main AioContext lock is not necessary because we know we run in the main thread. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20230525124713.401149-7-kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'block.c')
-rw-r--r--block.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/block.c b/block.c
index be9ae36..178ece2 100644
--- a/block.c
+++ b/block.c
@@ -3646,6 +3646,9 @@ done:
* BlockdevRef.
*
* The BlockdevRef will be removed from the options QDict.
+ *
+ * @parent can move to a different AioContext in this function. Callers must
+ * make sure that their AioContext locking is still correct after this.
*/
BdrvChild *bdrv_open_child(const char *filename,
QDict *options, const char *bdref_key,
@@ -3670,6 +3673,9 @@ BdrvChild *bdrv_open_child(const char *filename,
/*
* Wrapper on bdrv_open_child() for most popular case: open primary child of bs.
+ *
+ * @parent can move to a different AioContext in this function. Callers must
+ * make sure that their AioContext locking is still correct after this.
*/
int bdrv_open_file_child(const char *filename,
QDict *options, const char *bdref_key,