From 27eb6c097c132bf9fc49d73554b0160293b630cd Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Tue, 11 Mar 2014 15:15:03 +0100 Subject: qcow2: Don't write with BDRV_O_INCOMING qcow2_open() causes writes when repairing an image with the dirty flag set and when clearing autoclear flags. It shouldn't do this when another qemu instance is still actively working on this image file. One effect of the bug is that images may have a cleared dirty flag while the migration source host still has it in use with lazy refcounts enabled, so refcounts are not accurate and the dirty flag must remain set. Signed-off-by: Kevin Wolf Reviewed-by: Eric Blake Signed-off-by: Stefan Hajnoczi --- block/qcow2.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) (limited to 'block') diff --git a/block/qcow2.c b/block/qcow2.c index ec23cc47e4..945c9d6334 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -644,7 +644,7 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags, } /* Clear unknown autoclear feature bits */ - if (!bs->read_only && s->autoclear_features != 0) { + if (!bs->read_only && !(flags & BDRV_O_INCOMING) && s->autoclear_features) { s->autoclear_features = 0; ret = qcow2_update_header(bs); if (ret < 0) { @@ -657,7 +657,7 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags, qemu_co_mutex_init(&s->lock); /* Repair image if dirty */ - if (!(flags & BDRV_O_CHECK) && !bs->read_only && + if (!(flags & (BDRV_O_CHECK | BDRV_O_INCOMING)) && !bs->read_only && (s->incompatible_features & QCOW2_INCOMPAT_DIRTY)) { BdrvCheckResult result = {0}; @@ -1137,10 +1137,12 @@ static void qcow2_close(BlockDriverState *bs) /* else pre-write overlap checks in cache_destroy may crash */ s->l1_table = NULL; - qcow2_cache_flush(bs, s->l2_table_cache); - qcow2_cache_flush(bs, s->refcount_block_cache); + if (!(bs->open_flags & BDRV_O_INCOMING)) { + qcow2_cache_flush(bs, s->l2_table_cache); + qcow2_cache_flush(bs, s->refcount_block_cache); - qcow2_mark_clean(bs); + qcow2_mark_clean(bs); + } qcow2_cache_destroy(bs, s->l2_table_cache); qcow2_cache_destroy(bs, s->refcount_block_cache); -- cgit v1.2.1