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Allow situations where the journal contains a big_write(v1) after delete(v2) and v1 < v2

Fixes a crash in the following scenario:
- client issues a delete request (object version is at least 2)
- OSD has time to flush it to the metadata, but doesn't have time to move the journal start pointer on disk
- client overwrites the same object and it gets the version number 1 again
- OSD is restarted and sees delete(v=2), big_write(v=1) in the journal
- dirty_db sequence gets broken and OSD crashes with assert("Writes and deletes shouldn't happen at the same time")
Vitaliy Filippov 2 years ago
parent
commit
089f138e0c
  1. 39
      blockstore_init.cpp
  2. 5
      blockstore_write.cpp

39
blockstore_init.cpp

@ -562,6 +562,45 @@ int blockstore_init_journal::handle_journal_part(void *buf, uint64_t done_pos, u
je->big_write.oid.inode, je->big_write.oid.stripe, je->big_write.version, je->big_write.location
);
#endif
auto dirty_it = bs->dirty_db.upper_bound((obj_ver_id){
.oid = je->big_write.oid,
.version = UINT64_MAX,
});
if (dirty_it != bs->dirty_db.begin() && bs->dirty_db.size() > 0)
{
dirty_it--;
if (dirty_it->first.oid == je->big_write.oid &&
(dirty_it->second.state & BS_ST_TYPE_MASK) == BS_ST_DELETE)
{
// It is allowed to overwrite a deleted object with a
// version number less than deletion version number,
// because the presence of a BIG_WRITE entry means that
// the data for it is already on disk.
// Purge all dirty and clean entries for this object.
auto dirty_end = dirty_it;
dirty_end++;
while (1)
{
if (dirty_it == bs->dirty_db.begin())
{
break;
}
dirty_it--;
if (dirty_it->first.oid != je->big_write.oid)
{
dirty_it++;
break;
}
}
bs->erase_dirty(dirty_it, dirty_end, UINT64_MAX);
auto clean_it = bs->clean_db.find(je->big_write.oid);
if (clean_it != bs->clean_db.end())
{
bs->data_alloc->set(clean_it->second.location >> bs->block_order, false);
bs->clean_db.erase(clean_it);
}
}
}
auto clean_it = bs->clean_db.find(je->big_write.oid);
if (clean_it == bs->clean_db.end() ||
clean_it->second.version < je->big_write.version)

5
blockstore_write.cpp

@ -492,7 +492,10 @@ int blockstore_impl_t::dequeue_del(blockstore_op_t *op)
prepare_journal_sector_write(journal, journal.cur_sector, sqe, cb);
PRIV(op)->min_flushed_journal_sector = PRIV(op)->max_flushed_journal_sector = 1 + journal.cur_sector;
PRIV(op)->pending_ops++;
// Remember small write as unsynced
}
else
{
// Remember delete as unsynced
unsynced_small_writes.push_back((obj_ver_id){
.oid = op->oid,
.version = op->version,

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