]>
Commit | Line | Data |
---|---|---|
f1ec9ffb AD |
1 | From patchwork Thu Oct 1 19:05:28 2015 |
2 | Content-Type: text/plain; charset="utf-8" | |
3 | MIME-Version: 1.0 | |
4 | Content-Transfer-Encoding: 7bit | |
5 | Subject: [PULL, | |
6 | 1/1] block: mirror - fix full sync mode when target does not support | |
7 | zero init | |
8 | From: Jeff Cody <jcody@redhat.com> | |
9 | X-Patchwork-Id: 525278 | |
10 | Message-Id: <1443726328-29484-2-git-send-email-jcody@redhat.com> | |
11 | To: qemu-block@nongnu.org | |
12 | Cc: peter.maydell@linaro.org, jcody@redhat.com, qemu-devel@nongnu.org | |
13 | Date: Thu, 1 Oct 2015 15:05:28 -0400 | |
14 | ||
15 | During mirror, if the target device does not support zero init, a | |
16 | mirror may result in a corrupted image for sync="full" mode. | |
17 | ||
18 | This is due to how the initial dirty bitmap is set up prior to copying | |
19 | data - we did not mark sectors as dirty that are unallocated. This | |
20 | means those unallocated sectors are skipped over on the target, and for | |
21 | a device without zero init, invalid data may reside in those holes. | |
22 | ||
23 | If both of the following conditions are true, then we will explicitly | |
24 | mark all sectors as dirty: | |
25 | ||
26 | 1.) sync = "full" | |
27 | 2.) bdrv_has_zero_init(target) == false | |
28 | ||
29 | If the target does support zero init, but a target image is passed in | |
30 | with data already present (i.e. an "existing" image), it is assumed the | |
31 | data present in the existing image is valid data for those sectors. | |
32 | ||
33 | Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> | |
34 | Message-id: 91ed4bc5bda7e2b09eb508b07c83f4071fe0b3c9.1443705220.git.jcody@redhat.com | |
35 | Signed-off-by: Jeff Cody <jcody@redhat.com> | |
36 | --- | |
37 | block/mirror.c | 4 +++- | |
38 | 1 file changed, 3 insertions(+), 1 deletion(-) | |
39 | ||
40 | diff --git a/block/mirror.c b/block/mirror.c | |
41 | index a258926..87928ab 100644 | |
42 | --- a/block/mirror.c | |
43 | +++ b/block/mirror.c | |
44 | @@ -455,6 +455,8 @@ static void coroutine_fn mirror_run(void *opaque) | |
45 | if (!s->is_none_mode) { | |
46 | /* First part, loop on the sectors and initialize the dirty bitmap. */ | |
47 | BlockDriverState *base = s->base; | |
48 | + bool mark_all_dirty = s->base == NULL && !bdrv_has_zero_init(s->target); | |
49 | + | |
50 | for (sector_num = 0; sector_num < end; ) { | |
51 | /* Just to make sure we are not exceeding int limit. */ | |
52 | int nb_sectors = MIN(INT_MAX >> BDRV_SECTOR_BITS, | |
53 | @@ -477,7 +479,7 @@ static void coroutine_fn mirror_run(void *opaque) | |
54 | } | |
55 | ||
56 | assert(n > 0); | |
57 | - if (ret == 1) { | |
58 | + if (ret == 1 || mark_all_dirty) { | |
59 | bdrv_set_dirty_bitmap(s->dirty_bitmap, sector_num, n); | |
60 | } | |
61 | sector_num += n; |