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qcow2: External file I/O

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This changes the qcow2 implementation to direct all guest data I/O to
s->data_file rather than bs->file, while metadata I/O still uses
bs->file. At the moment, this is still always the same, but soon we'll
add options to set s->data_file to an external data file.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Kevin Wolf 2019-01-15 20:39:06 +01:00
parent 37be14036b
commit 966b000f49
7 changed files with 122 additions and 37 deletions
Download patch file Download diff file Expand all files Collapse all files

39
block/qcow2-refcount.c
View file

@ -1156,8 +1156,20 @@ void qcow2_free_any_clusters(BlockDriverState *bs, uint64_t l2_entry,
int nb_clusters, enum qcow2_discard_type type)
{
BDRVQcow2State *s = bs->opaque;
QCow2ClusterType ctype = qcow2_get_cluster_type(bs, l2_entry);
switch (qcow2_get_cluster_type(bs, l2_entry)) {
if (has_data_file(bs)) {
if (s->discard_passthrough[type] &&
(ctype == QCOW2_CLUSTER_NORMAL ||
ctype == QCOW2_CLUSTER_ZERO_ALLOC))
{
bdrv_pdiscard(s->data_file, l2_entry & L2E_OFFSET_MASK,
nb_clusters << s->cluster_bits);
}
return;
}
switch (ctype) {
case QCOW2_CLUSTER_COMPRESSED:
{
int nb_csectors;
@ -1649,7 +1661,7 @@ static int check_refcounts_l2(BlockDriverState *bs, BdrvCheckResult *res,
l2_table[i] = cpu_to_be64(l2_entry);
ret = qcow2_pre_write_overlap_check(bs,
QCOW2_OL_ACTIVE_L2 | QCOW2_OL_INACTIVE_L2,
l2e_offset, sizeof(uint64_t));
l2e_offset, sizeof(uint64_t), false);
if (ret < 0) {
fprintf(stderr, "ERROR: Overlap check failed\n");
res->check_errors++;
@ -1898,7 +1910,8 @@ static int check_oflag_copied(BlockDriverState *bs, BdrvCheckResult *res,
if (l2_dirty) {
ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_ACTIVE_L2,
l2_offset, s->cluster_size);
l2_offset, s->cluster_size,
false);
if (ret < 0) {
fprintf(stderr, "ERROR: Could not write L2 table; metadata "
"overlap check failed: %s\n", strerror(-ret));
@ -2366,7 +2379,7 @@ write_refblocks:
}
ret = qcow2_pre_write_overlap_check(bs, 0, refblock_offset,
s->cluster_size);
s->cluster_size, false);
if (ret < 0) {
fprintf(stderr, "ERROR writing refblock: %s\n", strerror(-ret));
goto fail;
@ -2417,7 +2430,8 @@ write_refblocks:
}
ret = qcow2_pre_write_overlap_check(bs, 0, reftable_offset,
reftable_size * sizeof(uint64_t));
reftable_size * sizeof(uint64_t),
false);
if (ret < 0) {
fprintf(stderr, "ERROR writing reftable: %s\n", strerror(-ret));
goto fail;
@ -2751,10 +2765,15 @@ QEMU_BUILD_BUG_ON(QCOW2_OL_MAX_BITNR != ARRAY_SIZE(metadata_ol_names));
* overlaps; or a negative value (-errno) on error.
*/
int qcow2_pre_write_overlap_check(BlockDriverState *bs, int ign, int64_t offset,
int64_t size)
int64_t size, bool data_file)
{
int ret = qcow2_check_metadata_overlap(bs, ign, offset, size);
int ret;
if (data_file && has_data_file(bs)) {
return 0;
}
ret = qcow2_check_metadata_overlap(bs, ign, offset, size);
if (ret < 0) {
return ret;
} else if (ret > 0) {
@ -2855,7 +2874,8 @@ static int flush_refblock(BlockDriverState *bs, uint64_t **reftable,
if (reftable_index < *reftable_size && (*reftable)[reftable_index]) {
offset = (*reftable)[reftable_index];
ret = qcow2_pre_write_overlap_check(bs, 0, offset, s->cluster_size);
ret = qcow2_pre_write_overlap_check(bs, 0, offset, s->cluster_size,
false);
if (ret < 0) {
error_setg_errno(errp, -ret, "Overlap check failed");
return ret;
@ -3121,7 +3141,8 @@ int qcow2_change_refcount_order(BlockDriverState *bs, int refcount_order,
/* Write the new reftable */
ret = qcow2_pre_write_overlap_check(bs, 0, new_reftable_offset,
new_reftable_size * sizeof(uint64_t));
new_reftable_size * sizeof(uint64_t),
false);
if (ret < 0) {
error_setg_errno(errp, -ret, "Overlap check failed");
goto done;