The code doesn't seem to be working correctly.
(1)
+ for (block_num = 0; block_num <= nblocks;
block_num++)
should be
+ for (block_num = firstDelBlock[fork_num];
block_num < nblocks; block_num++)
because:
* You only want to invalidate blocks >= firstDelBlock[fork_num], don't you?
* The relation's block number ranges from 0 to nblocks - 1.
(2)
+ INIT_BUFFERTAG(newTag, rnode.node,
forkNum[fork_num],
+
firstDelBlock[block_num]);
Replace firstDelBlock[fork_num] with block_num, because you want to process the
current block of per-block loop. Your code accesses memory out of the bounds
of the array, and doesn't invalidate any buffer.
(3)
+ if
(RelFileNodeEquals(bufHdr->tag.rnode, rnode.node) &&
+ bufHdr->tag.forkNum ==
forkNum[fork_num] &&
+ bufHdr->tag.blockNum >=
firstDelBlock[block_num])
+ InvalidateBuffer(bufHdr);
/* releases spinlock */
+ else
+ UnlockBufHdr(bufHdr, buf_state);
Replace
bufHdr->tag.blockNum >= firstDelBlock[fork_num]
with
bufHdr->tag.blockNum == block_num
because you want to check if the found buffer is for the current block of the
loop.
(4)
+ /*
+ * We've invalidated the nblocks already. Scan
the shared buffers
+ * for each fork.
+ */
+ if (block_num > nblocks)
+ {
+
DropRelFileNodeBuffersOfFork(rnode.node, forkNum[fork_num],
+
firstDelBlock[fork_num]);
+ }
This part is unnecessary. This invalidates all buffers that (2) failed to
process, so the regression test succeeds.
Regards
Takayuki Tsunakawa
