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a0382e2d7e
Coverity complained that oldPartitionLock was possibly dereferenced after having been set to NULL. That actually can't happen, because we'd only use it if (oldFlags & BM_TAG_VALID) is true. But nonetheless Coverity is justified in complaining, because at line 1275 we actually overwrite oldFlags, and then still expect its BM_TAG_VALID bit to be a safe guide to whether to release the oldPartitionLock. Thus, the code would be incorrect if someone else had changed the buffer's BM_TAG_VALID flag meanwhile. That should not happen, since we hold pin on the buffer throughout this sequence, but it's starting to look like a rather shaky chain of logic. And there's no need for such assumptions, because we can simply replace the (oldFlags & BM_TAG_VALID) tests with (oldPartitionLock != NULL), which has identical results and makes it plain to all comers that we don't dereference a null pointer. A small side benefit is that the range of liveness of oldFlags is greatly reduced, possibly allowing the compiler to save a register. This is just cleanup, not an actual bug fix, so there seems no need for a back-patch.