From 0d09c7970063ecdabdc2841ffa32e1cf3e032336 Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Fri, 28 Jan 2011 17:11:59 +0000 Subject: [PATCH] qed: Images with backing file do not require QED_F_NEED_CHECK The consistency check on open is necessary in order to fix inconsistent table offsets left as a result of a crash mid-operation. Images with a backing file actually flush before updating table offsets and are therefore guaranteed to be consistent. Do not mark these images dirty. Signed-off-by: Stefan Hajnoczi Signed-off-by: Kevin Wolf --- block/qed.c | 24 +++++++++++++++++------- 1 file changed, 17 insertions(+), 7 deletions(-) diff --git a/block/qed.c b/block/qed.c index a46f9ef419..32734486c5 100644 --- a/block/qed.c +++ b/block/qed.c @@ -976,6 +976,19 @@ static void qed_aio_write_prefill(void *opaque, int ret) qed_aio_write_postfill, acb); } +/** + * Check if the QED_F_NEED_CHECK bit should be set during allocating write + */ +static bool qed_should_set_need_check(BDRVQEDState *s) +{ + /* The flush before L2 update path ensures consistency */ + if (s->bs->backing_hd) { + return false; + } + + return !(s->header.features & QED_F_NEED_CHECK); +} + /** * Write new data cluster * @@ -1001,15 +1014,12 @@ static void qed_aio_write_alloc(QEDAIOCB *acb, size_t len) acb->cur_cluster = qed_alloc_clusters(s, acb->cur_nclusters); qemu_iovec_copy(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len); - /* Write new cluster if the image is already marked dirty */ - if (s->header.features & QED_F_NEED_CHECK) { + if (qed_should_set_need_check(s)) { + s->header.features |= QED_F_NEED_CHECK; + qed_write_header(s, qed_aio_write_prefill, acb); + } else { qed_aio_write_prefill(acb, 0); - return; } - - /* Mark the image dirty before writing the new cluster */ - s->header.features |= QED_F_NEED_CHECK; - qed_write_header(s, qed_aio_write_prefill, acb); } /**