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qcow2-refcount: introduce fix_l2_entry_by_zero()

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Split fix_l2_entry_by_zero() out of check_refcounts_l2() to be
reused in further patch.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20210914122454.141075-5-vsementsov@virtuozzo.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
This commit is contained in:
Vladimir Sementsov-Ogievskiy 2021-09-14 15:24:48 +03:00 committed by Hanna Reitz
parent a6e098462b
commit a2debf6506
1 changed files with 60 additions and 27 deletions
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87
block/qcow2-refcount.c
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@ -1587,6 +1587,54 @@ enum {
CHECK_FRAG_INFO = 0x2, /* update BlockFragInfo counters */
};
/*
* Fix L2 entry by making it QCOW2_CLUSTER_ZERO_PLAIN.
*
* This function decrements res->corruptions on success, so the caller is
* responsible to increment res->corruptions prior to the call.
*
* On failure in-memory @l2_table may be modified.
*/
static int fix_l2_entry_by_zero(BlockDriverState *bs, BdrvCheckResult *res,
uint64_t l2_offset,
uint64_t *l2_table, int l2_index, bool active,
bool *metadata_overlap)
{
BDRVQcow2State *s = bs->opaque;
int ret;
int idx = l2_index * (l2_entry_size(s) / sizeof(uint64_t));
uint64_t l2e_offset = l2_offset + (uint64_t)l2_index * l2_entry_size(s);
int ign = active ? QCOW2_OL_ACTIVE_L2 : QCOW2_OL_INACTIVE_L2;
uint64_t l2_entry = has_subclusters(s) ? 0 : QCOW_OFLAG_ZERO;
set_l2_entry(s, l2_table, l2_index, l2_entry);
ret = qcow2_pre_write_overlap_check(bs, ign, l2e_offset, l2_entry_size(s),
false);
if (metadata_overlap) {
*metadata_overlap = ret < 0;
}
if (ret < 0) {
fprintf(stderr, "ERROR: Overlap check failed\n");
goto fail;
}
ret = bdrv_pwrite_sync(bs->file, l2e_offset, &l2_table[idx],
l2_entry_size(s));
if (ret < 0) {
fprintf(stderr, "ERROR: Failed to overwrite L2 "
"table entry: %s\n", strerror(-ret));
goto fail;
}
res->corruptions--;
res->corruptions_fixed++;
return 0;
fail:
res->check_errors++;
return ret;
}
/*
* Increases the refcount in the given refcount table for the all clusters
* referenced in the L2 table. While doing so, performs some checks on L2
@ -1606,6 +1654,7 @@ static int check_refcounts_l2(BlockDriverState *bs, BdrvCheckResult *res,
int i, ret;
size_t l2_size_bytes = s->l2_size * l2_entry_size(s);
g_autofree uint64_t *l2_table = g_malloc(l2_size_bytes);
bool metadata_overlap;
/* Read L2 table from disk */
ret = bdrv_pread(bs->file, l2_offset, l2_table, l2_size_bytes);
@ -1685,19 +1734,10 @@ static int check_refcounts_l2(BlockDriverState *bs, BdrvCheckResult *res,
fix & BDRV_FIX_ERRORS ? "Repairing" : "ERROR",
offset);
if (fix & BDRV_FIX_ERRORS) {
int idx = i * (l2_entry_size(s) / sizeof(uint64_t));
uint64_t l2e_offset =
l2_offset + (uint64_t)i * l2_entry_size(s);
int ign = active ? QCOW2_OL_ACTIVE_L2 :
QCOW2_OL_INACTIVE_L2;
l2_entry = has_subclusters(s) ? 0 : QCOW_OFLAG_ZERO;
set_l2_entry(s, l2_table, i, l2_entry);
ret = qcow2_pre_write_overlap_check(bs, ign,
l2e_offset, l2_entry_size(s), false);
if (ret < 0) {
fprintf(stderr, "ERROR: Overlap check failed\n");
res->check_errors++;
ret = fix_l2_entry_by_zero(bs, res, l2_offset,
l2_table, i, active,
&metadata_overlap);
if (metadata_overlap) {
/*
* Something is seriously wrong, so abort checking
* this L2 table.
@ -1705,26 +1745,19 @@ static int check_refcounts_l2(BlockDriverState *bs, BdrvCheckResult *res,
return ret;
}
ret = bdrv_pwrite_sync(bs->file, l2e_offset,
&l2_table[idx],
l2_entry_size(s));
if (ret < 0) {
fprintf(stderr, "ERROR: Failed to overwrite L2 "
"table entry: %s\n", strerror(-ret));
res->check_errors++;
/*
* Do not abort, continue checking the rest of this
* L2 table's entries.
*/
} else {
res->corruptions--;
res->corruptions_fixed++;
if (ret == 0) {
/*
* Skip marking the cluster as used
* (it is unused now).
*/
continue;
}
/*
* Failed to fix.
* Do not abort, continue checking the rest of this
* L2 table's entries.
*/
}
} else {
fprintf(stderr, "ERROR offset=%" PRIx64 ": Data cluster is "