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authorKevin Wolf <kwolf@redhat.com>2019-01-15 20:39:06 +0100
committerKevin Wolf <kwolf@redhat.com>2019-03-08 12:26:46 +0100
commit966b000f49c3f44d2853d691f6bbc2a4e1f2d0b0 (patch)
tree43a2112e2da560e5b36ccc779c9069e38639aded
parent37be14036b1a7ae066f76d3296bbd37b0c697637 (diff)
qcow2: External file I/O
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>
-rw-r--r--block/qcow2-bitmap.c7
-rw-r--r--block/qcow2-cache.c6
-rw-r--r--block/qcow2-cluster.c46
-rw-r--r--block/qcow2-refcount.c39
-rw-r--r--block/qcow2-snapshot.c7
-rw-r--r--block/qcow2.c52
-rw-r--r--block/qcow2.h2
7 files changed, 122 insertions, 37 deletions
diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c
index 3ee524da4b..9d968bdcda 100644
--- a/block/qcow2-bitmap.c
+++ b/block/qcow2-bitmap.c
@@ -778,7 +778,8 @@ static int bitmap_list_store(BlockDriverState *bs, Qcow2BitmapList *bm_list,
* directory in-place (actually, turn-off the extension), which is checked
* in qcow2_check_metadata_overlap() */
ret = qcow2_pre_write_overlap_check(
- bs, in_place ? QCOW2_OL_BITMAP_DIRECTORY : 0, dir_offset, dir_size);
+ bs, in_place ? QCOW2_OL_BITMAP_DIRECTORY : 0, dir_offset, dir_size,
+ false);
if (ret < 0) {
goto fail;
}
@@ -1224,7 +1225,7 @@ static uint64_t *store_bitmap_data(BlockDriverState *bs,
memset(buf + write_size, 0, s->cluster_size - write_size);
}
- ret = qcow2_pre_write_overlap_check(bs, 0, off, s->cluster_size);
+ ret = qcow2_pre_write_overlap_check(bs, 0, off, s->cluster_size, false);
if (ret < 0) {
error_setg_errno(errp, -ret, "Qcow2 overlap check failed");
goto fail;
@@ -1292,7 +1293,7 @@ static int store_bitmap(BlockDriverState *bs, Qcow2Bitmap *bm, Error **errp)
}
ret = qcow2_pre_write_overlap_check(bs, 0, tb_offset,
- tb_size * sizeof(tb[0]));
+ tb_size * sizeof(tb[0]), false);
if (ret < 0) {
error_setg_errno(errp, -ret, "Qcow2 overlap check failed");
goto fail;
diff --git a/block/qcow2-cache.c b/block/qcow2-cache.c
index d9dafa31e5..df02e7b20a 100644
--- a/block/qcow2-cache.c
+++ b/block/qcow2-cache.c
@@ -205,13 +205,13 @@ static int qcow2_cache_entry_flush(BlockDriverState *bs, Qcow2Cache *c, int i)
if (c == s->refcount_block_cache) {
ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_REFCOUNT_BLOCK,
- c->entries[i].offset, c->table_size);
+ c->entries[i].offset, c->table_size, false);
} else if (c == s->l2_table_cache) {
ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_ACTIVE_L2,
- c->entries[i].offset, c->table_size);
+ c->entries[i].offset, c->table_size, false);
} else {
ret = qcow2_pre_write_overlap_check(bs, 0,
- c->entries[i].offset, c->table_size);
+ c->entries[i].offset, c->table_size, false);
}
if (ret < 0) {
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index 8c4b4005ff..7579f5a5ae 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -153,7 +153,7 @@ int qcow2_grow_l1_table(BlockDriverState *bs, uint64_t min_size,
/* the L1 position has not yet been updated, so these clusters must
* indeed be completely free */
ret = qcow2_pre_write_overlap_check(bs, 0, new_l1_table_offset,
- new_l1_size2);
+ new_l1_size2, false);
if (ret < 0) {
goto fail;
}
@@ -238,7 +238,7 @@ int qcow2_write_l1_entry(BlockDriverState *bs, int l1_index)
}
ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_ACTIVE_L1,
- s->l1_table_offset + 8 * l1_start_index, sizeof(buf));
+ s->l1_table_offset + 8 * l1_start_index, sizeof(buf), false);
if (ret < 0) {
return ret;
}
@@ -490,6 +490,7 @@ static int coroutine_fn do_perform_cow_write(BlockDriverState *bs,
unsigned offset_in_cluster,
QEMUIOVector *qiov)
{
+ BDRVQcow2State *s = bs->opaque;
int ret;
if (qiov->size == 0) {
@@ -497,13 +498,13 @@ static int coroutine_fn do_perform_cow_write(BlockDriverState *bs,
}
ret = qcow2_pre_write_overlap_check(bs, 0,
- cluster_offset + offset_in_cluster, qiov->size);
+ cluster_offset + offset_in_cluster, qiov->size, true);
if (ret < 0) {
return ret;
}
BLKDBG_EVENT(bs->file, BLKDBG_COW_WRITE);
- ret = bdrv_co_pwritev(bs->file, cluster_offset + offset_in_cluster,
+ ret = bdrv_co_pwritev(s->data_file, cluster_offset + offset_in_cluster,
qiov->size, qiov, 0);
if (ret < 0) {
return ret;
@@ -607,6 +608,14 @@ int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset,
}
switch (type) {
case QCOW2_CLUSTER_COMPRESSED:
+ if (has_data_file(bs)) {
+ qcow2_signal_corruption(bs, true, -1, -1, "Compressed cluster "
+ "entry found in image with external data "
+ "file (L2 offset: %#" PRIx64 ", L2 index: "
+ "%#x)", l2_offset, l2_index);
+ ret = -EIO;
+ goto fail;
+ }
/* Compressed clusters can only be processed one by one */
c = 1;
*cluster_offset &= L2E_COMPRESSED_OFFSET_SIZE_MASK;
@@ -633,6 +642,17 @@ int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset,
ret = -EIO;
goto fail;
}
+ if (has_data_file(bs) && *cluster_offset != offset - offset_in_cluster)
+ {
+ qcow2_signal_corruption(bs, true, -1, -1,
+ "External data file host cluster offset %#"
+ PRIx64 " does not match guest cluster "
+ "offset: %#" PRIx64
+ ", L2 index: %#x)", *cluster_offset,
+ offset - offset_in_cluster, l2_index);
+ ret = -EIO;
+ goto fail;
+ }
break;
default:
abort();
@@ -753,6 +773,10 @@ int qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
int64_t cluster_offset;
int nb_csectors;
+ if (has_data_file(bs)) {
+ return 0;
+ }
+
ret = get_cluster_table(bs, offset, &l2_slice, &l2_index);
if (ret < 0) {
return ret;
@@ -1243,6 +1267,13 @@ static int do_alloc_cluster_offset(BlockDriverState *bs, uint64_t guest_offset,
trace_qcow2_do_alloc_clusters_offset(qemu_coroutine_self(), guest_offset,
*host_offset, *nb_clusters);
+ if (has_data_file(bs)) {
+ assert(*host_offset == INV_OFFSET ||
+ *host_offset == start_of_cluster(s, guest_offset));
+ *host_offset = start_of_cluster(s, guest_offset);
+ return 0;
+ }
+
/* Allocate new clusters */
trace_qcow2_cluster_alloc_phys(qemu_coroutine_self());
if (*host_offset == INV_OFFSET) {
@@ -1919,7 +1950,7 @@ static int expand_zero_clusters_in_l1(BlockDriverState *bs, uint64_t *l1_table,
}
ret = qcow2_pre_write_overlap_check(bs, 0, offset,
- s->cluster_size);
+ s->cluster_size, true);
if (ret < 0) {
if (cluster_type == QCOW2_CLUSTER_ZERO_PLAIN) {
qcow2_free_clusters(bs, offset, s->cluster_size,
@@ -1928,7 +1959,8 @@ static int expand_zero_clusters_in_l1(BlockDriverState *bs, uint64_t *l1_table,
goto fail;
}
- ret = bdrv_pwrite_zeroes(bs->file, offset, s->cluster_size, 0);
+ ret = bdrv_pwrite_zeroes(s->data_file, offset,
+ s->cluster_size, 0);
if (ret < 0) {
if (cluster_type == QCOW2_CLUSTER_ZERO_PLAIN) {
qcow2_free_clusters(bs, offset, s->cluster_size,
@@ -1955,7 +1987,7 @@ static int expand_zero_clusters_in_l1(BlockDriverState *bs, uint64_t *l1_table,
if (l2_dirty) {
ret = qcow2_pre_write_overlap_check(
bs, QCOW2_OL_INACTIVE_L2 | QCOW2_OL_ACTIVE_L2,
- slice_offset, slice_size2);
+ slice_offset, slice_size2, false);
if (ret < 0) {
goto fail;
}
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
index 05e7974d7e..df73580e5d 100644
--- a/block/qcow2-refcount.c
+++ b/block/qcow2-refcount.c
@@ -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;
diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c
index 20e8472191..5ae3407f68 100644
--- a/block/qcow2-snapshot.c
+++ b/block/qcow2-snapshot.c
@@ -184,7 +184,7 @@ static int qcow2_write_snapshots(BlockDriverState *bs)
/* The snapshot list position has not yet been updated, so these clusters
* must indeed be completely free */
- ret = qcow2_pre_write_overlap_check(bs, 0, offset, snapshots_size);
+ ret = qcow2_pre_write_overlap_check(bs, 0, offset, snapshots_size, false);
if (ret < 0) {
goto fail;
}
@@ -389,7 +389,7 @@ int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
}
ret = qcow2_pre_write_overlap_check(bs, 0, sn->l1_table_offset,
- s->l1_size * sizeof(uint64_t));
+ s->l1_size * sizeof(uint64_t), false);
if (ret < 0) {
goto fail;
}
@@ -528,7 +528,8 @@ int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id)
}
ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_ACTIVE_L1,
- s->l1_table_offset, cur_l1_bytes);
+ s->l1_table_offset, cur_l1_bytes,
+ false);
if (ret < 0) {
goto fail;
}
diff --git a/block/qcow2.c b/block/qcow2.c
index 8d1f667e91..f048763e10 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -140,7 +140,7 @@ static ssize_t qcow2_crypto_hdr_init_func(QCryptoBlock *block, size_t headerlen,
/* Zero fill remaining space in cluster so it has predictable
* content in case of future spec changes */
clusterlen = size_to_clusters(s, headerlen) * s->cluster_size;
- assert(qcow2_pre_write_overlap_check(bs, 0, ret, clusterlen) == 0);
+ assert(qcow2_pre_write_overlap_check(bs, 0, ret, clusterlen, false) == 0);
ret = bdrv_pwrite_zeroes(bs->file,
ret + headerlen,
clusterlen - headerlen, 0);
@@ -1965,7 +1965,7 @@ static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset,
*/
if (!cluster_data) {
cluster_data =
- qemu_try_blockalign(bs->file->bs,
+ qemu_try_blockalign(s->data_file->bs,
QCOW_MAX_CRYPT_CLUSTERS
* s->cluster_size);
if (cluster_data == NULL) {
@@ -1981,7 +1981,7 @@ static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset,
BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
qemu_co_mutex_unlock(&s->lock);
- ret = bdrv_co_preadv(bs->file,
+ ret = bdrv_co_preadv(s->data_file,
cluster_offset + offset_in_cluster,
cur_bytes, &hd_qiov, 0);
qemu_co_mutex_lock(&s->lock);
@@ -2140,7 +2140,7 @@ static coroutine_fn int qcow2_co_pwritev(BlockDriverState *bs, uint64_t offset,
}
ret = qcow2_pre_write_overlap_check(bs, 0,
- cluster_offset + offset_in_cluster, cur_bytes);
+ cluster_offset + offset_in_cluster, cur_bytes, true);
if (ret < 0) {
goto fail;
}
@@ -2154,7 +2154,7 @@ static coroutine_fn int qcow2_co_pwritev(BlockDriverState *bs, uint64_t offset,
BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
trace_qcow2_writev_data(qemu_coroutine_self(),
cluster_offset + offset_in_cluster);
- ret = bdrv_co_pwritev(bs->file,
+ ret = bdrv_co_pwritev(s->data_file,
cluster_offset + offset_in_cluster,
cur_bytes, &hd_qiov, 0);
qemu_co_mutex_lock(&s->lock);
@@ -3356,7 +3356,7 @@ qcow2_co_copy_range_from(BlockDriverState *bs,
goto out;
case QCOW2_CLUSTER_NORMAL:
- child = bs->file;
+ child = s->data_file;
copy_offset += offset_into_cluster(s, src_offset);
if ((copy_offset & 511) != 0) {
ret = -EIO;
@@ -3426,14 +3426,14 @@ qcow2_co_copy_range_to(BlockDriverState *bs,
assert((cluster_offset & 511) == 0);
ret = qcow2_pre_write_overlap_check(bs, 0,
- cluster_offset + offset_in_cluster, cur_bytes);
+ cluster_offset + offset_in_cluster, cur_bytes, true);
if (ret < 0) {
goto fail;
}
qemu_co_mutex_unlock(&s->lock);
ret = bdrv_co_copy_range_to(src, src_offset,
- bs->file,
+ s->data_file,
cluster_offset + offset_in_cluster,
cur_bytes, read_flags, write_flags);
qemu_co_mutex_lock(&s->lock);
@@ -3588,6 +3588,17 @@ static int coroutine_fn qcow2_co_truncate(BlockDriverState *bs, int64_t offset,
int64_t old_file_size, new_file_size;
uint64_t nb_new_data_clusters, nb_new_l2_tables;
+ /* With a data file, preallocation means just allocating the metadata
+ * and forwarding the truncate request to the data file */
+ if (has_data_file(bs)) {
+ ret = preallocate_co(bs, old_length, offset);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "Preallocation failed");
+ goto fail;
+ }
+ break;
+ }
+
old_file_size = bdrv_getlength(bs->file->bs);
if (old_file_size < 0) {
error_setg_errno(errp, -old_file_size,
@@ -3696,6 +3707,16 @@ static int coroutine_fn qcow2_co_truncate(BlockDriverState *bs, int64_t offset,
bs->total_sectors = offset / BDRV_SECTOR_SIZE;
+ if (has_data_file(bs)) {
+ if (prealloc == PREALLOC_MODE_METADATA) {
+ prealloc = PREALLOC_MODE_OFF;
+ }
+ ret = bdrv_co_truncate(s->data_file, offset, prealloc, errp);
+ if (ret < 0) {
+ goto fail;
+ }
+ }
+
/* write updated header.size */
offset = cpu_to_be64(offset);
ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, size),
@@ -3898,6 +3919,10 @@ qcow2_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset,
uint8_t *buf, *out_buf;
uint64_t cluster_offset;
+ if (has_data_file(bs)) {
+ return -ENOTSUP;
+ }
+
if (bytes == 0) {
/* align end of file to a sector boundary to ease reading with
sector based I/Os */
@@ -3949,7 +3974,7 @@ qcow2_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset,
goto fail;
}
- ret = qcow2_pre_write_overlap_check(bs, 0, cluster_offset, out_len);
+ ret = qcow2_pre_write_overlap_check(bs, 0, cluster_offset, out_len, true);
qemu_co_mutex_unlock(&s->lock);
if (ret < 0) {
goto fail;
@@ -3957,8 +3982,8 @@ qcow2_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset,
qemu_iovec_init_buf(&hd_qiov, out_buf, out_len);
- BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED);
- ret = bdrv_co_pwritev(bs->file, cluster_offset, out_len, &hd_qiov, 0);
+ BLKDBG_EVENT(s->data_file, BLKDBG_WRITE_COMPRESSED);
+ ret = bdrv_co_pwritev(s->data_file, cluster_offset, out_len, &hd_qiov, 0);
if (ret < 0) {
goto fail;
}
@@ -4547,6 +4572,11 @@ static int qcow2_downgrade(BlockDriverState *bs, int target_version,
return -ENOTSUP;
}
+ if (has_data_file(bs)) {
+ error_setg(errp, "Cannot downgrade an image with a data file");
+ return -ENOTSUP;
+ }
+
/* clear incompatible features */
if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) {
ret = qcow2_mark_clean(bs);
diff --git a/block/qcow2.h b/block/qcow2.h
index fad6abf602..aac7fc4348 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -622,7 +622,7 @@ void qcow2_process_discards(BlockDriverState *bs, int ret);
int qcow2_check_metadata_overlap(BlockDriverState *bs, int ign, int64_t offset,
int64_t size);
int qcow2_pre_write_overlap_check(BlockDriverState *bs, int ign, int64_t offset,
- int64_t size);
+ int64_t size, bool data_file);
int qcow2_inc_refcounts_imrt(BlockDriverState *bs, BdrvCheckResult *res,
void **refcount_table,
int64_t *refcount_table_size,