From 6edb01e90071a85edde03f2044d05e07d4257b2e Mon Sep 17 00:00:00 2001 From: Anthony Liguori Date: Mon, 8 Aug 2011 16:13:51 -0700 Subject: [RHEL6 qemu-kvm PATCH 08/19] qed: Images with backing file do not require QED_F_NEED_CHECK RH-Author: Anthony Liguori Message-id: <1312820040-2612-9-git-send-email-aliguori@redhat.com> Patchwork-id: 31103 O-Subject: [RHEL6.2 qemu PATCH 08/17] qed: Images with backing file do not require QED_F_NEED_CHECK Bugzilla: 633380 RH-Acked-by: Kevin Wolf RH-Acked-by: Paolo Bonzini From: Stefan Hajnoczi 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 Signed-off-by: Anthony Liguori Bugzilla: 633380 Signed-off-by: Eduardo Habkost --- block/qed.c | 24 +++++++++++++++++------- 1 files changed, 17 insertions(+), 7 deletions(-) diff --git a/block/qed.c b/block/qed.c index a46f9ef..3273448 100644 --- a/block/qed.c +++ b/block/qed.c @@ -977,6 +977,19 @@ static void qed_aio_write_prefill(void *opaque, int ret) } /** + * 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 * * @acb: Write request @@ -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); } /** -- 1.7.3.2