shithub: lwext4

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ext4_journal: some reworks to stale metadata protection

--- a/src/ext4_journal.c

+++ b/src/ext4_journal.c

@@ -1157,11 +1157,13 @@

 			ext4_dbg(DEBUG_JBD, "Commit block: %" PRIu32", "

 					    "trans_id: %" PRIu32"\n",

 					    this_block, this_trans_id);

-			/* This is the end of a transaction,

+			/*

+			 * This is the end of a transaction,

 			 * we may now proceed to the next transaction.

 			 */

 			this_trans_id++;

-			info->trans_cnt++;

+			if (action == ACTION_SCAN)

+				info->trans_cnt++;

 			break;

 		case JBD_REVOKE_BLOCK:

 			if (!jbd_verify_meta_csum(jbd_fs, header)) {

@@ -1236,6 +1238,7 @@

 			ext4_get32(&jbd_fs->inode_ref.fs->sb,

 				   features_incompatible);

 		jbd_set32(&jbd_fs->sb, start, 0);

+		jbd_set32(&jbd_fs->sb, sequence, info.last_trans_id);

 		features_incompatible &= ~EXT4_FINCOM_RECOVER;

 		ext4_set32(&jbd_fs->inode_ref.fs->sb,

 			   features_incompatible,

@@ -1267,7 +1270,6 @@

 	uint32_t features_incompatible =

 			ext4_get32(&jbd_fs->inode_ref.fs->sb,

 				   features_incompatible);

-	struct ext4_block block = EXT4_BLOCK_ZERO();

 	features_incompatible |= EXT4_FINCOM_RECOVER;

 	ext4_set32(&jbd_fs->inode_ref.fs->sb,

 			features_incompatible,

@@ -1280,26 +1282,16 @@

 	journal->first = jbd_get32(&jbd_fs->sb, first);

 	journal->start = journal->first;

 	journal->last = journal->first;

-	journal->trans_id = 1;

-	journal->alloc_trans_id = 1;

+	/*

+	 * To invalidate any stale records we need to start from

+	 * the checkpoint transaction ID of the previous journalling session

+	 * plus 1.

+	 */

+	journal->trans_id = jbd_get32(&jbd_fs->sb, sequence) + 1;

+	journal->alloc_trans_id = journal->trans_id;

 	journal->block_size = jbd_get32(&jbd_fs->sb, blocksize);

-	r = jbd_block_get_noread(jbd_fs,

-			 &block,

-			 journal->start);

-	if (r != EOK) {

-		memset(journal, 0, sizeof(struct jbd_journal));

-		return r;

-	}

-	memset(block.data, 0, journal->block_size);

-	ext4_bcache_set_dirty(block.buf);

-	r = jbd_block_set(jbd_fs, &block);

-	if (r != EOK) {

-		memset(journal, 0, sizeof(struct jbd_journal));

-		return r;

-	}

-

 	TAILQ_INIT(&journal->cp_queue);

 	RB_INIT(&journal->block_rec_root);

 	journal->jbd_fs = jbd_fs;

@@ -1773,29 +1765,12 @@

 	int rc;

 	struct ext4_block block;

 	struct jbd_commit_header *header;

-	uint32_t commit_iblock, orig_commit_iblock;

+	uint32_t commit_iblock;

 	struct jbd_journal *journal = trans->journal;

 	commit_iblock = jbd_journal_alloc_block(journal, trans);

-	orig_commit_iblock = commit_iblock;

-	commit_iblock++;

-	wrap(&journal->jbd_fs->sb, commit_iblock);

-	/* To prevent accidental reference to stale journalling metadata. */

-	if (orig_commit_iblock < commit_iblock) {

-		rc = jbd_block_get_noread(journal->jbd_fs, &block, commit_iblock);

-		if (rc != EOK)

-			return rc;

-

-		memset(block.data, 0, journal->block_size);

-		ext4_bcache_set_dirty(block.buf);

-		ext4_bcache_set_flag(block.buf, BC_TMP);

-		rc = jbd_block_set(journal->jbd_fs, &block);

-		if (rc != EOK)

-			return rc;

-	}

-

-	rc = jbd_block_get_noread(journal->jbd_fs, &block, orig_commit_iblock);

+	rc = jbd_block_get_noread(journal->jbd_fs, &block, commit_iblock);

 	if (rc != EOK)

 		return rc;