commit: Deal with filters
This includes some permission limiting (for example, we only need to take the RESIZE permission if the base is smaller than the top). Signed-off-by: Max Reitz <mreitz@redhat.com>
This commit is contained in:
parent
2b088c60bb
commit
9a71b9de3f
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@ -2279,10 +2279,13 @@ int blk_commit_all(void)
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while ((blk = blk_all_next(blk)) != NULL) {
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while ((blk = blk_all_next(blk)) != NULL) {
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AioContext *aio_context = blk_get_aio_context(blk);
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AioContext *aio_context = blk_get_aio_context(blk);
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BlockDriverState *unfiltered_bs = bdrv_skip_filters(blk_bs(blk));
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aio_context_acquire(aio_context);
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aio_context_acquire(aio_context);
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if (blk_is_inserted(blk) && blk->root->bs->backing) {
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if (blk_is_inserted(blk) && bdrv_cow_child(unfiltered_bs)) {
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int ret = bdrv_commit(blk->root->bs);
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int ret;
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ret = bdrv_commit(unfiltered_bs);
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if (ret < 0) {
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if (ret < 0) {
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aio_context_release(aio_context);
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aio_context_release(aio_context);
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return ret;
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return ret;
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@ -37,6 +37,7 @@ typedef struct CommitBlockJob {
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BlockBackend *top;
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BlockBackend *top;
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BlockBackend *base;
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BlockBackend *base;
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BlockDriverState *base_bs;
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BlockDriverState *base_bs;
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BlockDriverState *base_overlay;
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BlockdevOnError on_error;
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BlockdevOnError on_error;
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bool base_read_only;
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bool base_read_only;
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bool chain_frozen;
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bool chain_frozen;
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@ -89,7 +90,7 @@ static void commit_abort(Job *job)
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* XXX Can (or should) we somehow keep 'consistent read' blocked even
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* XXX Can (or should) we somehow keep 'consistent read' blocked even
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* after the failed/cancelled commit job is gone? If we already wrote
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* after the failed/cancelled commit job is gone? If we already wrote
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* something to base, the intermediate images aren't valid any more. */
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* something to base, the intermediate images aren't valid any more. */
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bdrv_replace_node(s->commit_top_bs, backing_bs(s->commit_top_bs),
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bdrv_replace_node(s->commit_top_bs, s->commit_top_bs->backing->bs,
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&error_abort);
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&error_abort);
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bdrv_unref(s->commit_top_bs);
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bdrv_unref(s->commit_top_bs);
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@ -153,7 +154,7 @@ static int coroutine_fn commit_run(Job *job, Error **errp)
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break;
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break;
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}
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}
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/* Copy if allocated above the base */
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/* Copy if allocated above the base */
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ret = bdrv_is_allocated_above(blk_bs(s->top), blk_bs(s->base), false,
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ret = bdrv_is_allocated_above(blk_bs(s->top), s->base_overlay, true,
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offset, COMMIT_BUFFER_SIZE, &n);
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offset, COMMIT_BUFFER_SIZE, &n);
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copy = (ret == 1);
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copy = (ret == 1);
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trace_commit_one_iteration(s, offset, n, ret);
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trace_commit_one_iteration(s, offset, n, ret);
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@ -253,15 +254,35 @@ void commit_start(const char *job_id, BlockDriverState *bs,
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CommitBlockJob *s;
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CommitBlockJob *s;
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BlockDriverState *iter;
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BlockDriverState *iter;
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BlockDriverState *commit_top_bs = NULL;
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BlockDriverState *commit_top_bs = NULL;
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BlockDriverState *filtered_base;
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Error *local_err = NULL;
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Error *local_err = NULL;
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int64_t base_size, top_size;
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uint64_t base_perms, iter_shared_perms;
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int ret;
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int ret;
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assert(top != bs);
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assert(top != bs);
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if (top == base) {
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if (bdrv_skip_filters(top) == bdrv_skip_filters(base)) {
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error_setg(errp, "Invalid files for merge: top and base are the same");
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error_setg(errp, "Invalid files for merge: top and base are the same");
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return;
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return;
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}
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}
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base_size = bdrv_getlength(base);
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if (base_size < 0) {
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error_setg_errno(errp, -base_size, "Could not inquire base image size");
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return;
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}
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top_size = bdrv_getlength(top);
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if (top_size < 0) {
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error_setg_errno(errp, -top_size, "Could not inquire top image size");
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return;
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}
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base_perms = BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE;
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if (base_size < top_size) {
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base_perms |= BLK_PERM_RESIZE;
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}
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s = block_job_create(job_id, &commit_job_driver, NULL, bs, 0, BLK_PERM_ALL,
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s = block_job_create(job_id, &commit_job_driver, NULL, bs, 0, BLK_PERM_ALL,
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speed, creation_flags, NULL, NULL, errp);
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speed, creation_flags, NULL, NULL, errp);
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if (!s) {
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if (!s) {
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@ -301,17 +322,43 @@ void commit_start(const char *job_id, BlockDriverState *bs,
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s->commit_top_bs = commit_top_bs;
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s->commit_top_bs = commit_top_bs;
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/* Block all nodes between top and base, because they will
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/*
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* disappear from the chain after this operation. */
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* Block all nodes between top and base, because they will
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assert(bdrv_chain_contains(top, base));
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* disappear from the chain after this operation.
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for (iter = top; iter != base; iter = backing_bs(iter)) {
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* Note that this assumes that the user is fine with removing all
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/* XXX BLK_PERM_WRITE needs to be allowed so we don't block ourselves
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* nodes (including R/W filters) between top and base. Assuring
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* this is the responsibility of the interface (i.e. whoever calls
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* commit_start()).
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*/
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s->base_overlay = bdrv_find_overlay(top, base);
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assert(s->base_overlay);
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/*
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* The topmost node with
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* bdrv_skip_filters(filtered_base) == bdrv_skip_filters(base)
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*/
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filtered_base = bdrv_cow_bs(s->base_overlay);
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assert(bdrv_skip_filters(filtered_base) == bdrv_skip_filters(base));
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/*
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* XXX BLK_PERM_WRITE needs to be allowed so we don't block ourselves
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* at s->base (if writes are blocked for a node, they are also blocked
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* at s->base (if writes are blocked for a node, they are also blocked
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* for its backing file). The other options would be a second filter
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* for its backing file). The other options would be a second filter
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* driver above s->base. */
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* driver above s->base.
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*/
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iter_shared_perms = BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE;
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for (iter = top; iter != base; iter = bdrv_filter_or_cow_bs(iter)) {
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if (iter == filtered_base) {
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/*
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* From here on, all nodes are filters on the base. This
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* allows us to share BLK_PERM_CONSISTENT_READ.
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*/
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iter_shared_perms |= BLK_PERM_CONSISTENT_READ;
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}
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ret = block_job_add_bdrv(&s->common, "intermediate node", iter, 0,
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ret = block_job_add_bdrv(&s->common, "intermediate node", iter, 0,
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BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE,
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iter_shared_perms, errp);
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errp);
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if (ret < 0) {
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if (ret < 0) {
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goto fail;
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goto fail;
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}
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}
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@ -328,9 +375,7 @@ void commit_start(const char *job_id, BlockDriverState *bs,
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}
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}
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s->base = blk_new(s->common.job.aio_context,
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s->base = blk_new(s->common.job.aio_context,
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BLK_PERM_CONSISTENT_READ
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base_perms,
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| BLK_PERM_WRITE
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| BLK_PERM_RESIZE,
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BLK_PERM_CONSISTENT_READ
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BLK_PERM_CONSISTENT_READ
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| BLK_PERM_GRAPH_MOD
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| BLK_PERM_GRAPH_MOD
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| BLK_PERM_WRITE_UNCHANGED);
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| BLK_PERM_WRITE_UNCHANGED);
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@ -398,19 +443,22 @@ int bdrv_commit(BlockDriverState *bs)
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if (!drv)
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if (!drv)
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return -ENOMEDIUM;
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return -ENOMEDIUM;
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if (!bs->backing) {
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backing_file_bs = bdrv_cow_bs(bs);
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if (!backing_file_bs) {
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return -ENOTSUP;
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return -ENOTSUP;
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}
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}
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if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_COMMIT_SOURCE, NULL) ||
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if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_COMMIT_SOURCE, NULL) ||
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bdrv_op_is_blocked(bs->backing->bs, BLOCK_OP_TYPE_COMMIT_TARGET, NULL)) {
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bdrv_op_is_blocked(backing_file_bs, BLOCK_OP_TYPE_COMMIT_TARGET, NULL))
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{
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return -EBUSY;
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return -EBUSY;
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}
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}
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ro = bs->backing->bs->read_only;
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ro = backing_file_bs->read_only;
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if (ro) {
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if (ro) {
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if (bdrv_reopen_set_read_only(bs->backing->bs, false, NULL)) {
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if (bdrv_reopen_set_read_only(backing_file_bs, false, NULL)) {
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return -EACCES;
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return -EACCES;
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}
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}
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}
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}
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@ -428,8 +476,6 @@ int bdrv_commit(BlockDriverState *bs)
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}
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}
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/* Insert commit_top block node above backing, so we can write to it */
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/* Insert commit_top block node above backing, so we can write to it */
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backing_file_bs = backing_bs(bs);
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commit_top_bs = bdrv_new_open_driver(&bdrv_commit_top, NULL, BDRV_O_RDWR,
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commit_top_bs = bdrv_new_open_driver(&bdrv_commit_top, NULL, BDRV_O_RDWR,
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&local_err);
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&local_err);
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if (commit_top_bs == NULL) {
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if (commit_top_bs == NULL) {
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@ -515,7 +561,7 @@ ro_cleanup:
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qemu_vfree(buf);
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qemu_vfree(buf);
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blk_unref(backing);
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blk_unref(backing);
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if (backing_file_bs) {
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if (bdrv_cow_bs(bs) != backing_file_bs) {
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bdrv_set_backing_hd(bs, backing_file_bs, &error_abort);
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bdrv_set_backing_hd(bs, backing_file_bs, &error_abort);
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}
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}
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bdrv_unref(commit_top_bs);
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bdrv_unref(commit_top_bs);
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@ -523,7 +569,7 @@ ro_cleanup:
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if (ro) {
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if (ro) {
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/* ignoring error return here */
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/* ignoring error return here */
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bdrv_reopen_set_read_only(bs->backing->bs, true, NULL);
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bdrv_reopen_set_read_only(backing_file_bs, true, NULL);
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}
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}
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return ret;
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return ret;
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@ -217,7 +217,7 @@ void hmp_commit(Monitor *mon, const QDict *qdict)
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return;
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return;
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}
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}
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bs = blk_bs(blk);
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bs = bdrv_skip_implicit_filters(blk_bs(blk));
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aio_context = bdrv_get_aio_context(bs);
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aio_context = bdrv_get_aio_context(bs);
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aio_context_acquire(aio_context);
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aio_context_acquire(aio_context);
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@ -2703,7 +2703,9 @@ void qmp_block_commit(bool has_job_id, const char *job_id, const char *device,
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assert(bdrv_get_aio_context(base_bs) == aio_context);
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assert(bdrv_get_aio_context(base_bs) == aio_context);
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for (iter = top_bs; iter != backing_bs(base_bs); iter = backing_bs(iter)) {
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for (iter = top_bs; iter != bdrv_filter_or_cow_bs(base_bs);
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iter = bdrv_filter_or_cow_bs(iter))
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{
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if (bdrv_op_is_blocked(iter, BLOCK_OP_TYPE_COMMIT_TARGET, errp)) {
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if (bdrv_op_is_blocked(iter, BLOCK_OP_TYPE_COMMIT_TARGET, errp)) {
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goto out;
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goto out;
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}
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}
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