From ec8057f43c44075e02b59078b38b40340220f955 Mon Sep 17 00:00:00 2001
From: Max Reitz <mreitz@redhat.com>
Date: Mon, 18 Jun 2018 17:24:53 +0200
Subject: [PATCH 05/17] qcow2: Repair OFLAG_COPIED when fixing leaks
RH-Author: Max Reitz <mreitz@redhat.com>
Message-id: <20180618172454.27434-2-mreitz@redhat.com>
Patchwork-id: 80785
O-Subject: [RHEL-7.6 qemu-kvm PATCH 1/2] qcow2: Repair OFLAG_COPIED when fixing leaks
Bugzilla: 1527122
RH-Acked-by: John Snow <jsnow@redhat.com>
RH-Acked-by: Kevin Wolf <kwolf@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Repairing OFLAG_COPIED is usually safe because it is done after the
refcounts have been repaired. Therefore, it we did not find anyone else
referencing a data or L2 cluster, it makes no sense to not set
OFLAG_COPIED -- and the other direction (clearing OFLAG_COPIED) is
always safe, anyway, it may just induce leaks.
Furthermore, if OFLAG_COPIED is actually consistent with a wrong (leaky)
refcount, we will decrement the refcount with -r leaks, but OFLAG_COPIED
will then be wrong. qemu-img check should not produce images that are
more corrupted afterwards then they were before.
Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1527085
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 20180509200059.31125-2-mreitz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
(cherry picked from commit 3cce51c919c7b4028cf6676dfcb80a45741b5117)
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
Conflicts:
block/qcow2-refcount.c
Conflicts due to refcounts being fixed to 16 bit downstream, which means
that every instance of the "refcount" variable is an int instead of
uint64_t. This results in contextual conflicts in the corruption
printf()s.
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
block/qcow2-refcount.c | 25 +++++++++++++++++--------
1 file changed, 17 insertions(+), 8 deletions(-)
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
index 848fd31..7a69bcd 100644
--- a/block/qcow2-refcount.c
+++ b/block/qcow2-refcount.c
@@ -1333,6 +1333,19 @@ static int check_oflag_copied(BlockDriverState *bs, BdrvCheckResult *res,
int ret;
int refcount;
int i, j;
+ bool repair;
+
+ if (fix & BDRV_FIX_ERRORS) {
+ /* Always repair */
+ repair = true;
+ } else if (fix & BDRV_FIX_LEAKS) {
+ /* Repair only if that seems safe: This function is always
+ * called after the refcounts have been fixed, so the refcount
+ * is accurate if that repair was successful */
+ repair = !res->check_errors && !res->corruptions && !res->leaks;
+ } else {
+ repair = false;
+ }
for (i = 0; i < s->l1_size; i++) {
uint64_t l1_entry = s->l1_table[i];
@@ -1351,10 +1364,8 @@ static int check_oflag_copied(BlockDriverState *bs, BdrvCheckResult *res,
if ((refcount == 1) != ((l1_entry & QCOW_OFLAG_COPIED) != 0)) {
fprintf(stderr, "%s OFLAG_COPIED L2 cluster: l1_index=%d "
"l1_entry=%" PRIx64 " refcount=%d\n",
- fix & BDRV_FIX_ERRORS ? "Repairing" :
- "ERROR",
- i, l1_entry, refcount);
- if (fix & BDRV_FIX_ERRORS) {
+ repair ? "Repairing" : "ERROR", i, l1_entry, refcount);
+ if (repair) {
s->l1_table[i] = refcount == 1
? l1_entry | QCOW_OFLAG_COPIED
: l1_entry & ~QCOW_OFLAG_COPIED;
@@ -1393,10 +1404,8 @@ static int check_oflag_copied(BlockDriverState *bs, BdrvCheckResult *res,
if ((refcount == 1) != ((l2_entry & QCOW_OFLAG_COPIED) != 0)) {
fprintf(stderr, "%s OFLAG_COPIED data cluster: "
"l2_entry=%" PRIx64 " refcount=%d\n",
- fix & BDRV_FIX_ERRORS ? "Repairing" :
- "ERROR",
- l2_entry, refcount);
- if (fix & BDRV_FIX_ERRORS) {
+ repair ? "Repairing" : "ERROR", l2_entry, refcount);
+ if (repair) {
l2_table[j] = cpu_to_be64(refcount == 1
? l2_entry | QCOW_OFLAG_COPIED
: l2_entry & ~QCOW_OFLAG_COPIED);
--
1.8.3.1