Commit f47aa3eb authored by Kemeng Shi's avatar Kemeng Shi Committed by Theodore Ts'o
Browse files

jbd2: move escape handle to futher improve jbd2_journal_write_metadata_buffer 



Move escape handle to futher improve code readability and remove some
repeat check.

Signed-off-by: default avatarKemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Reviewed-by: default avatarZhang Yi <yi.zhang@huawei.com>
Link: https://patch.msgid.link/20240801013815.2393869-7-shikemeng@huaweicloud.com


Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent 7c48e7d5

fs/jbd2/journal.c

+24 −25
Original line number Diff line number Diff line
@@ -281,6 +281,16 @@ static void journal_kill_thread(journal_t *journal) 
	write_unlock(&journal->j_state_lock);

}



static inline bool jbd2_data_needs_escaping(char *data)

{

	return *((__be32 *)data) == cpu_to_be32(JBD2_MAGIC_NUMBER);

}



static inline void jbd2_data_do_escape(char *data)

{

	*((unsigned int *)data) = 0;

}



/*

 * jbd2_journal_write_metadata_buffer: write a metadata buffer to the journal.

 *
@@ -319,7 +329,6 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction, 
				  sector_t blocknr)

{

	int do_escape = 0;

	char *mapped_data;

	struct buffer_head *new_bh;

	struct folio *new_folio;

	unsigned int new_offset;
@@ -350,8 +359,13 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction, 
	if (jh_in->b_frozen_data) {

		new_folio = virt_to_folio(jh_in->b_frozen_data);

		new_offset = offset_in_folio(new_folio, jh_in->b_frozen_data);

		mapped_data = jh_in->b_frozen_data;

		do_escape = jbd2_data_needs_escaping(jh_in->b_frozen_data);

		if (do_escape)

			jbd2_data_do_escape(jh_in->b_frozen_data);

	} else {

		char *tmp;

		char *mapped_data;



		new_folio = bh_in->b_folio;

		new_offset = offset_in_folio(new_folio, bh_in->b_data);

		mapped_data = kmap_local_folio(new_folio, new_offset);
@@ -363,21 +377,13 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction, 
		 */

		jbd2_buffer_frozen_trigger(jh_in, mapped_data,

					   jh_in->b_triggers);

	}



	/*

	 * Check for escaping

	 */

	if (*((__be32 *)mapped_data) == cpu_to_be32(JBD2_MAGIC_NUMBER))

		do_escape = 1;

	if (!jh_in->b_frozen_data)

		do_escape = jbd2_data_needs_escaping(mapped_data);

		kunmap_local(mapped_data);



		/*

		 * Do we need to do a data copy?

		 */

	if (do_escape && !jh_in->b_frozen_data) {

		char *tmp;

		if (!do_escape)

			goto escape_done;



		spin_unlock(&jh_in->b_state_lock);

		tmp = jbd2_alloc(bh_in->b_size, GFP_NOFS);
@@ -404,17 +410,10 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction, 
copy_done:

		new_folio = virt_to_folio(jh_in->b_frozen_data);

		new_offset = offset_in_folio(new_folio, jh_in->b_frozen_data);

		jbd2_data_do_escape(jh_in->b_frozen_data);

	}



	/*

	 * Did we need to do an escaping?  Now we've done all the

	 * copying, we can finally do so.

	 * b_frozen_data is from jbd2_alloc() which always provides an

	 * address from the direct kernels mapping.

	 */

	if (do_escape)

		*((unsigned int *)jh_in->b_frozen_data) = 0;



escape_done:

	folio_set_bh(new_bh, new_folio, new_offset);

	new_bh->b_size = bh_in->b_size;

	new_bh->b_bdev = journal->j_dev;