Blame SOURCES/kvm-block-Lock-AioContext-for-drain_end-in-blockdev-reop.patch

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From b21fa5ecd9acf2b91839a2915fb4bb39dac4c803 Mon Sep 17 00:00:00 2001
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From: Kevin Wolf <kwolf@redhat.com>
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Date: Thu, 3 Feb 2022 15:05:33 +0100
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Subject: [PATCH 2/5] block: Lock AioContext for drain_end in blockdev-reopen
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RH-Author: Kevin Wolf <kwolf@redhat.com>
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RH-MergeRequest: 142: block: Lock AioContext for drain_end in blockdev-reopen
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RH-Commit: [1/2] 98de3b5987f88ea6b4b503f623d6c4475574e037
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RH-Bugzilla: 2067118
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RH-Acked-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
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RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
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RH-Acked-by: Hanna Reitz <hreitz@redhat.com>
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bdrv_subtree_drained_end() requires the caller to hold the AioContext
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lock for the drained node. Not doing this for nodes outside of the main
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AioContext leads to crashes when AIO_WAIT_WHILE() needs to wait and
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tries to temporarily release the lock.
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Fixes: 3908b7a8994fa5ef7a89aa58cd5a02fc58141592
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Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2046659
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Reported-by: Qing Wang <qinwang@redhat.com>
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Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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Message-Id: <20220203140534.36522-2-kwolf@redhat.com>
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Reviewed-by: Hanna Reitz <hreitz@redhat.com>
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Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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(cherry picked from commit aba8205be0707b9d108e32254e186ba88107a869)
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Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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---
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 blockdev.c | 11 ++++++++++-
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 1 file changed, 10 insertions(+), 1 deletion(-)
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diff --git a/blockdev.c b/blockdev.c
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index b35072644e..565f6a81fd 100644
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--- a/blockdev.c
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+++ b/blockdev.c
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@@ -3562,6 +3562,7 @@ void qmp_blockdev_reopen(BlockdevOptionsList *reopen_list, Error **errp)
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 {
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     BlockReopenQueue *queue = NULL;
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     GSList *drained = NULL;
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+    GSList *p;
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     /* Add each one of the BDS that we want to reopen to the queue */
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     for (; reopen_list != NULL; reopen_list = reopen_list->next) {
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@@ -3611,7 +3612,15 @@ void qmp_blockdev_reopen(BlockdevOptionsList *reopen_list, Error **errp)
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 fail:
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     bdrv_reopen_queue_free(queue);
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-    g_slist_free_full(drained, (GDestroyNotify) bdrv_subtree_drained_end);
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+    for (p = drained; p; p = p->next) {
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+        BlockDriverState *bs = p->data;
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+        AioContext *ctx = bdrv_get_aio_context(bs);
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+
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+        aio_context_acquire(ctx);
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+        bdrv_subtree_drained_end(bs);
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+        aio_context_release(ctx);
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+    }
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+    g_slist_free(drained);
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 }
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 void qmp_blockdev_del(const char *node_name, Error **errp)
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-- 
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2.27.0
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