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-rw-r--r--block/stream.c63
-rw-r--r--blockdev.c4
-rw-r--r--qapi/block-core.json13
3 files changed, 59 insertions, 21 deletions
diff --git a/block/stream.c b/block/stream.c
index 310ccbaa4c..8ce6729a33 100644
--- a/block/stream.c
+++ b/block/stream.c
@@ -31,7 +31,8 @@ enum {
typedef struct StreamBlockJob {
BlockJob common;
- BlockDriverState *bottom;
+ BlockDriverState *base_overlay; /* COW overlay (stream from this) */
+ BlockDriverState *above_base; /* Node directly above the base */
BlockdevOnError on_error;
char *backing_file_str;
bool bs_read_only;
@@ -53,7 +54,7 @@ static void stream_abort(Job *job)
if (s->chain_frozen) {
BlockJob *bjob = &s->common;
- bdrv_unfreeze_backing_chain(blk_bs(bjob->blk), s->bottom);
+ bdrv_unfreeze_backing_chain(blk_bs(bjob->blk), s->above_base);
}
}
@@ -62,14 +63,15 @@ static int stream_prepare(Job *job)
StreamBlockJob *s = container_of(job, StreamBlockJob, common.job);
BlockJob *bjob = &s->common;
BlockDriverState *bs = blk_bs(bjob->blk);
- BlockDriverState *base = backing_bs(s->bottom);
+ BlockDriverState *unfiltered_bs = bdrv_skip_filters(bs);
+ BlockDriverState *base = bdrv_filter_or_cow_bs(s->above_base);
Error *local_err = NULL;
int ret = 0;
- bdrv_unfreeze_backing_chain(bs, s->bottom);
+ bdrv_unfreeze_backing_chain(bs, s->above_base);
s->chain_frozen = false;
- if (bs->backing) {
+ if (bdrv_cow_child(unfiltered_bs)) {
const char *base_id = NULL, *base_fmt = NULL;
if (base) {
base_id = s->backing_file_str;
@@ -77,8 +79,8 @@ static int stream_prepare(Job *job)
base_fmt = base->drv->format_name;
}
}
- bdrv_set_backing_hd(bs, base, &local_err);
- ret = bdrv_change_backing_file(bs, base_id, base_fmt, false);
+ bdrv_set_backing_hd(unfiltered_bs, base, &local_err);
+ ret = bdrv_change_backing_file(unfiltered_bs, base_id, base_fmt, false);
if (local_err) {
error_report_err(local_err);
return -EPERM;
@@ -109,14 +111,15 @@ static int coroutine_fn stream_run(Job *job, Error **errp)
StreamBlockJob *s = container_of(job, StreamBlockJob, common.job);
BlockBackend *blk = s->common.blk;
BlockDriverState *bs = blk_bs(blk);
- bool enable_cor = !backing_bs(s->bottom);
+ BlockDriverState *unfiltered_bs = bdrv_skip_filters(bs);
+ bool enable_cor = !bdrv_cow_child(s->base_overlay);
int64_t len;
int64_t offset = 0;
uint64_t delay_ns = 0;
int error = 0;
int64_t n = 0; /* bytes */
- if (bs == s->bottom) {
+ if (unfiltered_bs == s->base_overlay) {
/* Nothing to stream */
return 0;
}
@@ -150,13 +153,14 @@ static int coroutine_fn stream_run(Job *job, Error **errp)
copy = false;
- ret = bdrv_is_allocated(bs, offset, STREAM_CHUNK, &n);
+ ret = bdrv_is_allocated(unfiltered_bs, offset, STREAM_CHUNK, &n);
if (ret == 1) {
/* Allocated in the top, no need to copy. */
} else if (ret >= 0) {
/* Copy if allocated in the intermediate images. Limit to the
* known-unallocated area [offset, offset+n*BDRV_SECTOR_SIZE). */
- ret = bdrv_is_allocated_above(backing_bs(bs), s->bottom, true,
+ ret = bdrv_is_allocated_above(bdrv_cow_bs(unfiltered_bs),
+ s->base_overlay, true,
offset, n, &n);
/* Finish early if end of backing file has been reached */
if (ret == 0 && n == 0) {
@@ -223,9 +227,29 @@ void stream_start(const char *job_id, BlockDriverState *bs,
BlockDriverState *iter;
bool bs_read_only;
int basic_flags = BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED;
- BlockDriverState *bottom = bdrv_find_overlay(bs, base);
+ BlockDriverState *base_overlay = bdrv_find_overlay(bs, base);
+ BlockDriverState *above_base;
- if (bdrv_freeze_backing_chain(bs, bottom, errp) < 0) {
+ if (!base_overlay) {
+ error_setg(errp, "'%s' is not in the backing chain of '%s'",
+ base->node_name, bs->node_name);
+ return;
+ }
+
+ /*
+ * Find the node directly above @base. @base_overlay is a COW overlay, so
+ * it must have a bdrv_cow_child(), but it is the immediate overlay of
+ * @base, so between the two there can only be filters.
+ */
+ above_base = base_overlay;
+ if (bdrv_cow_bs(above_base) != base) {
+ above_base = bdrv_cow_bs(above_base);
+ while (bdrv_filter_bs(above_base) != base) {
+ above_base = bdrv_filter_bs(above_base);
+ }
+ }
+
+ if (bdrv_freeze_backing_chain(bs, above_base, errp) < 0) {
return;
}
@@ -255,14 +279,19 @@ void stream_start(const char *job_id, BlockDriverState *bs,
* and resizes. Reassign the base node pointer because the backing BS of the
* bottom node might change after the call to bdrv_reopen_set_read_only()
* due to parallel block jobs running.
+ * above_base node might change after the call to
+ * bdrv_reopen_set_read_only() due to parallel block jobs running.
*/
- base = backing_bs(bottom);
- for (iter = backing_bs(bs); iter && iter != base; iter = backing_bs(iter)) {
+ base = bdrv_filter_or_cow_bs(above_base);
+ for (iter = bdrv_filter_or_cow_bs(bs); iter != base;
+ iter = bdrv_filter_or_cow_bs(iter))
+ {
block_job_add_bdrv(&s->common, "intermediate node", iter, 0,
basic_flags, &error_abort);
}
- s->bottom = bottom;
+ s->base_overlay = base_overlay;
+ s->above_base = above_base;
s->backing_file_str = g_strdup(backing_file_str);
s->bs_read_only = bs_read_only;
s->chain_frozen = true;
@@ -276,5 +305,5 @@ fail:
if (bs_read_only) {
bdrv_reopen_set_read_only(bs, true, NULL);
}
- bdrv_unfreeze_backing_chain(bs, bottom);
+ bdrv_unfreeze_backing_chain(bs, above_base);
}
diff --git a/blockdev.c b/blockdev.c
index 3848a9c8ab..862aa1b9aa 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -2528,7 +2528,9 @@ void qmp_block_stream(bool has_job_id, const char *job_id, const char *device,
}
/* Check for op blockers in the whole chain between bs and base */
- for (iter = bs; iter && iter != base_bs; iter = backing_bs(iter)) {
+ for (iter = bs; iter && iter != base_bs;
+ iter = bdrv_filter_or_cow_bs(iter))
+ {
if (bdrv_op_is_blocked(iter, BLOCK_OP_TYPE_STREAM, errp)) {
goto out;
}
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 55b58ba892..b04df13bea 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -2484,13 +2484,20 @@
# of 'device'.
#
# If a base file is specified then sectors are not copied from that base file and
-# its backing chain. When streaming completes the image file will have the base
-# file as its backing file. This can be used to stream a subset of the backing
-# file chain instead of flattening the entire image.
+# its backing chain. This can be used to stream a subset of the backing file
+# chain instead of flattening the entire image.
+# When streaming completes the image file will have the base file as its backing
+# file, unless that node was changed while the job was running. In that case,
+# base's parent's backing (or filtered, whichever exists) child (i.e., base at
+# the beginning of the job) will be the new backing file.
#
# On successful completion the image file is updated to drop the backing file
# and the BLOCK_JOB_COMPLETED event is emitted.
#
+# In case @device is a filter node, block-stream modifies the first non-filter
+# overlay node below it to point to the new backing node instead of modifying
+# @device itself.
+#
# @job-id: identifier for the newly-created block job. If
# omitted, the device name will be used. (Since 2.7)
#
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-23 11:35:58 +0000