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path: root/lib/sqfs/block_processor/block_processor.c
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2022-11-18libsqfs: Fix an overzealous bounds check in the block processorDavid Oberhollenzer
When (during fragment deduplication) a fragment block is read back from disk and unpacked, it can happen that it is _exactly_ the given block size. The bounds check did '>=' instead of '>' and failed in that case with a "data corruption" error. Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
2021-03-24Fix block processor queue accountingDavid Oberhollenzer
Dequeuing won't work if we have a backlog of 1 or 2 and the blocks are used for internal buffering. Take that into account, similar to the sync code. Also bump the minimum backlog to 3, just to make absolutely sure we cannot run into a dequeue loop trying to allocate a block. Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
2021-03-23block processor: Re-implement exact fragment matchingDavid Oberhollenzer
In the hash-table equals callback, if the hash and size match, do an exact, byte-for-byte comparison of the fragment in question. The fragment can either be in a fragment block that is in-flight (for which we have the in-flight list), in the current, unfinished fragment block, or it can be on disk. In the later case, the fragment block is resolved through the fragment table and read back from disk into a scratch buffer and decompressed. After that, the fragment is checked for byte-for-byte equality with the one we resolved through the hash table. Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
2021-03-23block processor: keep duplicate copies of in-flight fragment blocksDavid Oberhollenzer
If we want full, byte-for byte, verification of fragments during de-duplication we need to check back with the blocks already written to disk, or with the ones that are in flight. The previous, extremely hacky approach simply locked up the thread pool and investigated the queues. For the new approach, we treat the thread pool as completely opaque and don't try to touch it. This commit modifies the block processor to keep duplicate copies of each submitted fragment block around, that are cleaned up once the block is dequeued and written to disk. So instead of touching the thread pool, we can simply investigate the in-fligth-block list and the current block, before resorting to reading back fragment blocks from the file. Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
2021-03-22block processor: simplify backlog accountingDavid Oberhollenzer
Simply count the number of blocks we hand out (malloc'ed or recycled) and decrease the counter when we put blocks back for recycling. The sync() part becomes a little more complicated, because we can get stuck with a backlog of 1 or 2 because we have a fragment or current block buffer in use. We also need to accout for this when creating the processor, because we need to be able to request at least 2 blocks without stalling. Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
2021-03-22Cleanup the block processor file structureDavid Oberhollenzer
A cleaner separation between common code, frontend code and backend code is made. The "is this byte blob zero" function is moved out to libutil (with test case and everything) with a more optimized implementation. Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>