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| author | Stefan Hajnoczi <stefanha@redhat.com> | 2016-03-08 10:11:16 +0000 |
|---|---|---|
| committer | Stefan Hajnoczi <stefanha@redhat.com> | 2016-03-17 09:50:14 +0000 |
| commit | 1f3ddfcb258e6e0562467a9644daad3f28597da8 (patch) | |
| tree | f6cfc2b655d997660b63add838cc64f24124cc65 | |
| parent | 147dfab747dd1720cb6350b6b746ca84e15f9a24 (diff) | |
| download | focaccia-qemu-1f3ddfcb258e6e0562467a9644daad3f28597da8.tar.gz focaccia-qemu-1f3ddfcb258e6e0562467a9644daad3f28597da8.zip | |
Revert "qed: Implement .bdrv_drain"
This reverts commit df9a681dc9ad41c9cdeb9ecc5d060ba9abd27e01. Note that commit df9a681dc9ad41c9cdeb9ecc5d060ba9abd27e01 included some unrelated hunks, possibly due to a merge failure or an overlooked squash. This only reverts the qed .bdrv_drain() implementation. The qed .bdrv_drain() implementation is unsafe and can lead to a double request completion. Paolo Bonzini reports: "The problem is that bdrv_qed_drain calls qed_plug_allocating_write_reqs unconditionally, but this is not correct if an allocating write is queued. In this case, qed_unplug_allocating_write_reqs will restart the allocating write and possibly cause it to complete. The aiocb however is still in use for the L2/L1 table writes, and will then be completed again as soon as the table writes are stable." For QEMU 2.6 we can simply revert this commit. A full solution for the qed need check timer may be added if the bdrv_drain() implementation is extended. Reported-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Message-id: 1457431876-8475-1-git-send-email-stefanha@redhat.com
| -rw-r--r-- | block/qed.c | 13 |
1 files changed, 0 insertions, 13 deletions
diff --git a/block/qed.c b/block/qed.c index 8de7dd0832..5a58856ecd 100644 --- a/block/qed.c +++ b/block/qed.c @@ -377,18 +377,6 @@ static void bdrv_qed_attach_aio_context(BlockDriverState *bs, } } -static void bdrv_qed_drain(BlockDriverState *bs) -{ - BDRVQEDState *s = bs->opaque; - - /* Cancel timer and start doing I/O that were meant to happen as if it - * fired, that way we get bdrv_drain() taking care of the ongoing requests - * correctly. */ - qed_cancel_need_check_timer(s); - qed_plug_allocating_write_reqs(s); - bdrv_aio_flush(s->bs, qed_clear_need_check, s); -} - static int bdrv_qed_open(BlockDriverState *bs, QDict *options, int flags, Error **errp) { @@ -1694,7 +1682,6 @@ static BlockDriver bdrv_qed = { .bdrv_check = bdrv_qed_check, .bdrv_detach_aio_context = bdrv_qed_detach_aio_context, .bdrv_attach_aio_context = bdrv_qed_attach_aio_context, - .bdrv_drain = bdrv_qed_drain, }; static void bdrv_qed_init(void) |