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由 Eric Blake 提交于
This one's nasty. Ever since we fixed virHashForEach to prevent nested hash iterations for safety reasons (commit fba550f6), virDomainSnapshotDelete with VIR_DOMAIN_SNAPSHOT_DELETE_CHILDREN has been broken for qemu: it deletes children, while leaving grandchildren intact but pointing to a no-longer-present parent. But even before then, the code would often appear to succeed to clean up grandchildren, but risked memory corruption if you have a large and deep hierarchy of snapshots. For acting on just children, a single virHashForEach is sufficient. But for acting on an entire subtree, it requires iteration; and since we declared recursion as invalid, we have to switch to a while loop. Doing this correctly requires quite a bit of overhaul, so I added a new helper function to isolate the algorithm from the actions, so that callers do not have to reinvent the iteration. Note that this _still_ does not handle CHILDREN correctly if one of the children is the current snapshot; that will be next. * src/conf/domain_conf.h (_virDomainSnapshotDef): Add mark. (virDomainSnapshotForEachDescendant): New prototype. * src/libvirt_private.syms (domain_conf.h): Export it. * src/conf/domain_conf.c (virDomainSnapshotMarkDescendant) (virDomainSnapshotActOnDescendant) (virDomainSnapshotForEachDescendant): New functions. * src/qemu/qemu_driver.c (qemuDomainSnapshotDiscardChildren): Replace... (qemuDomainSnapshotDiscardDescenent): ...with callback that doesn't nest hash traversal. (qemuDomainSnapshotDelete): Use new function.
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