shithub: lwext4

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ext4_journal: code logic changes on jbd_trans_add_block.

Now jbd_trans_add_block should be called before making any
modications on the buffer.

--- a/lwext4/ext4.c

+++ b/lwext4/ext4.c

@@ -2551,8 +2551,6 @@

 			if (r != EOK)

 				goto out;

-			ext4_bcache_set_dirty(block.buf);

-

 			struct jbd_trans *t = jbd_journal_new_trans(journal);

 			if (!t) {

 				ext4_block_set(mp->fs.bdev, &block);

@@ -2570,6 +2568,7 @@

 					r = ENOMEM;

 					goto out;

 				}

+				ext4_bcache_set_dirty(block.buf);

 				break;

 			case 1:

 				r = jbd_trans_revoke_block(t, rand_block);

--- a/lwext4/ext4_journal.c

+++ b/lwext4/ext4_journal.c

@@ -1049,7 +1049,8 @@

 			  int res,

 			  void *arg);

-/**@brief  Add block to a transaction

+/**@brief  Add block to a transaction and gain

+ *         access to it before making any modications.

  * @param  trans transaction

  * @param  block block descriptor

  * @return standard error code*/

@@ -1057,11 +1058,17 @@

 			struct ext4_block *block)

 {

 	struct jbd_buf *buf;

-	/* We do not need to add those unmodified buffer to

-	 * a transaction. */

-	if (!ext4_bcache_test_flag(block->buf, BC_DIRTY))

-		return EOK;

+	struct ext4_fs *fs =

+		trans->journal->jbd_fs->inode_ref.fs;

+	/* If the buffer has already been modified, we should

+	 * flush dirty data in this buffer to disk.*/

+	if (ext4_bcache_test_flag(block->buf, BC_DIRTY)) {

+		/* XXX: i don't want to know whether the call

+		 * succeeds or not. */

+		ext4_block_flush_buf(fs->bdev, block->buf);

+	}

+

 	buf = calloc(1, sizeof(struct jbd_buf));

 	if (!buf)

 		return ENOMEM;

@@ -1170,12 +1177,22 @@

 	uint32_t desc_iblock = 0;

 	uint32_t data_iblock = 0;

 	char *tag_start = NULL, *tag_ptr = NULL;

-	struct jbd_buf *jbd_buf;

+	struct jbd_buf *jbd_buf, *tmp;

 	struct ext4_block desc_block, data_block;

+	struct ext4_fs *fs = journal->jbd_fs->inode_ref.fs;

-	LIST_FOREACH(jbd_buf, &trans->buf_list, buf_node) {

+	LIST_FOREACH_SAFE(jbd_buf, &trans->buf_list, buf_node, tmp) {

 		struct tag_info tag_info;

 		bool uuid_exist = false;

+		if (!ext4_bcache_test_flag(jbd_buf->block.buf,

+					   BC_DIRTY)) {

+			/* The buffer has not been modified, just release

+			 * that jbd_buf. */

+			ext4_block_set(fs->bdev, &jbd_buf->block);

+			LIST_REMOVE(jbd_buf, buf_node);

+			free(jbd_buf);

+			continue;

+		}

 again:

 		if (!desc_iblock) {

 			struct jbd_bhdr *bhdr;

@@ -1430,6 +1447,15 @@

 	rc = jbd_journal_prepare_revoke(journal, trans);

 	if (rc != EOK)

 		goto Finish;

+

+	if (LIST_EMPTY(&trans->buf_list) &&

+	    LIST_EMPTY(&trans->revoke_list)) {

+		/* Since there are no entries in both buffer list

+		 * and revoke entry list, we do not consider trans as

+		 * complete transaction and just return EOK.*/

+		jbd_journal_free_trans(journal, trans, false);

+		goto Finish;

+	}

 	rc = jbd_trans_write_commit_block(trans);

 	if (rc != EOK)