static void replay_journal()

in dm-integrity.c [2899:3057]

• 134 lines of code
• 32 McCabe index (conditional complexity)

static void replay_journal(struct dm_integrity_c *ic)
{
	unsigned i, j;
	bool used_commit_ids[N_COMMIT_IDS];
	unsigned max_commit_id_sections[N_COMMIT_IDS];
	unsigned write_start, write_sections;
	unsigned continue_section;
	bool journal_empty;
	unsigned char unused, last_used, want_commit_seq;

	if (ic->mode == 'R')
		return;

	if (ic->journal_uptodate)
		return;

	last_used = 0;
	write_start = 0;

	if (!ic->just_formatted) {
		DEBUG_print("reading journal\n");
		rw_journal(ic, REQ_OP_READ, 0, 0, ic->journal_sections, NULL);
		if (ic->journal_io)
			DEBUG_bytes(lowmem_page_address(ic->journal_io[0].page), 64, "read journal");
		if (ic->journal_io) {
			struct journal_completion crypt_comp;
			crypt_comp.ic = ic;
			init_completion(&crypt_comp.comp);
			crypt_comp.in_flight = (atomic_t)ATOMIC_INIT(0);
			encrypt_journal(ic, false, 0, ic->journal_sections, &crypt_comp);
			wait_for_completion(&crypt_comp.comp);
		}
		DEBUG_bytes(lowmem_page_address(ic->journal[0].page), 64, "decrypted journal");
	}

	if (dm_integrity_failed(ic))
		goto clear_journal;

	journal_empty = true;
	memset(used_commit_ids, 0, sizeof used_commit_ids);
	memset(max_commit_id_sections, 0, sizeof max_commit_id_sections);
	for (i = 0; i < ic->journal_sections; i++) {
		for (j = 0; j < ic->journal_section_sectors; j++) {
			int k;
			struct journal_sector *js = access_journal(ic, i, j);
			k = find_commit_seq(ic, i, j, js->commit_id);
			if (k < 0)
				goto clear_journal;
			used_commit_ids[k] = true;
			max_commit_id_sections[k] = i;
		}
		if (journal_empty) {
			for (j = 0; j < ic->journal_section_entries; j++) {
				struct journal_entry *je = access_journal_entry(ic, i, j);
				if (!journal_entry_is_unused(je)) {
					journal_empty = false;
					break;
				}
			}
		}
	}

	if (!used_commit_ids[N_COMMIT_IDS - 1]) {
		unused = N_COMMIT_IDS - 1;
		while (unused && !used_commit_ids[unused - 1])
			unused--;
	} else {
		for (unused = 0; unused < N_COMMIT_IDS; unused++)
			if (!used_commit_ids[unused])
				break;
		if (unused == N_COMMIT_IDS) {
			dm_integrity_io_error(ic, "journal commit ids", -EIO);
			goto clear_journal;
		}
	}
	DEBUG_print("first unused commit seq %d [%d,%d,%d,%d]\n",
		    unused, used_commit_ids[0], used_commit_ids[1],
		    used_commit_ids[2], used_commit_ids[3]);

	last_used = prev_commit_seq(unused);
	want_commit_seq = prev_commit_seq(last_used);

	if (!used_commit_ids[want_commit_seq] && used_commit_ids[prev_commit_seq(want_commit_seq)])
		journal_empty = true;

	write_start = max_commit_id_sections[last_used] + 1;
	if (unlikely(write_start >= ic->journal_sections))
		want_commit_seq = next_commit_seq(want_commit_seq);
	wraparound_section(ic, &write_start);

	i = write_start;
	for (write_sections = 0; write_sections < ic->journal_sections; write_sections++) {
		for (j = 0; j < ic->journal_section_sectors; j++) {
			struct journal_sector *js = access_journal(ic, i, j);

			if (js->commit_id != dm_integrity_commit_id(ic, i, j, want_commit_seq)) {
				/*
				 * This could be caused by crash during writing.
				 * We won't replay the inconsistent part of the
				 * journal.
				 */
				DEBUG_print("commit id mismatch at position (%u, %u): %d != %d\n",
					    i, j, find_commit_seq(ic, i, j, js->commit_id), want_commit_seq);
				goto brk;
			}
		}
		i++;
		if (unlikely(i >= ic->journal_sections))
			want_commit_seq = next_commit_seq(want_commit_seq);
		wraparound_section(ic, &i);
	}
brk:

	if (!journal_empty) {
		DEBUG_print("replaying %u sections, starting at %u, commit seq %d\n",
			    write_sections, write_start, want_commit_seq);
		do_journal_write(ic, write_start, write_sections, true);
	}

	if (write_sections == ic->journal_sections && (ic->mode == 'J' || journal_empty)) {
		continue_section = write_start;
		ic->commit_seq = want_commit_seq;
		DEBUG_print("continuing from section %u, commit seq %d\n", write_start, ic->commit_seq);
	} else {
		unsigned s;
		unsigned char erase_seq;
clear_journal:
		DEBUG_print("clearing journal\n");

		erase_seq = prev_commit_seq(prev_commit_seq(last_used));
		s = write_start;
		init_journal(ic, s, 1, erase_seq);
		s++;
		wraparound_section(ic, &s);
		if (ic->journal_sections >= 2) {
			init_journal(ic, s, ic->journal_sections - 2, erase_seq);
			s += ic->journal_sections - 2;
			wraparound_section(ic, &s);
			init_journal(ic, s, 1, erase_seq);
		}

		continue_section = 0;
		ic->commit_seq = next_commit_seq(erase_seq);
	}

	ic->committed_section = continue_section;
	ic->n_committed_sections = 0;

	ic->uncommitted_section = continue_section;
	ic->n_uncommitted_sections = 0;

	ic->free_section = continue_section;
	ic->free_section_entry = 0;
	ic->free_sectors = ic->journal_entries;

	ic->journal_tree_root = RB_ROOT;
	for (i = 0; i < ic->journal_entries; i++)
		init_journal_node(&ic->journal_tree[i]);
}