[PATCH 4.4 014/113] jbd2: move the clearing of b_modified flag to the journal_unmap_buffer()

Greg Kroah-Hartman
2020-02-27T13:40:53Z

From: zhangyi (F) <yi.zhang@huawei.com>

[ Upstream commit 6a66a7ded12baa6ebbb2e3e82f8cb91382814839 ]

There is no need to delay the clearing of b_modified flag to the
transaction committing time when unmapping the journalled buffer, so
just move it to the journal_unmap_buffer().

Link: https://lore.kernel.org/r/20200213063821.30455-2-yi.zhang@huawei.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/jbd2/commit.c | 43 +++++++++++++++----------------------------
fs/jbd2/transaction.c | 10 ++++++----
2 files changed, 21 insertions(+), 32 deletions(-)

diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index ebbd7d054cabd..3bf86d912b76f 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -987,34 +987,21 @@ void jbd2_journal_commit_transaction(journal_t *journal)
* it. */

/*
- * A buffer which has been freed while still being journaled by
- * a previous transaction.
- */
- if (buffer_freed(bh)) {
- /*
- * If the running transaction is the one containing
- * "add to orphan" operation (b_next_transaction !=
- * NULL), we have to wait for that transaction to
- * commit before we can really get rid of the buffer.
- * So just clear b_modified to not confuse transaction
- * credit accounting and refile the buffer to
- * BJ_Forget of the running transaction. If the just
- * committed transaction contains "add to orphan"
- * operation, we can completely invalidate the buffer
- * now. We are rather through in that since the
- * buffer may be still accessible when blocksize <
- * pagesize and it is attached to the last partial
- * page.
- */
- jh->b_modified = 0;
- if (!jh->b_next_transaction) {
- clear_buffer_freed(bh);
- clear_buffer_jbddirty(bh);
- clear_buffer_mapped(bh);
- clear_buffer_new(bh);
- clear_buffer_req(bh);
- bh->b_bdev = NULL;
- }
+ * A buffer which has been freed while still being journaled
+ * by a previous transaction, refile the buffer to BJ_Forget of
+ * the running transaction. If the just committed transaction
+ * contains "add to orphan" operation, we can completely
+ * invalidate the buffer now. We are rather through in that
+ * since the buffer may be still accessible when blocksize <
+ * pagesize and it is attached to the last partial page.
+ */
+ if (buffer_freed(bh) && !jh->b_next_transaction) {
+ clear_buffer_freed(bh);
+ clear_buffer_jbddirty(bh);
+ clear_buffer_mapped(bh);
+ clear_buffer_new(bh);
+ clear_buffer_req(bh);
+ bh->b_bdev = NULL;
}

if (buffer_jbddirty(bh)) {
diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index c34433432d471..6457023d8fac1 100644
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -2223,14 +2223,16 @@ static int journal_unmap_buffer(journal_t *journal, struct buffer_head *bh,
return -EBUSY;
}
/*
- * OK, buffer won't be reachable after truncate. We just set
- * j_next_transaction to the running transaction (if there is
- * one) and mark buffer as freed so that commit code knows it
- * should clear dirty bits when it is done with the buffer.
+ * OK, buffer won't be reachable after truncate. We just clear
+ * b_modified to not confuse transaction credit accounting, and
+ * set j_next_transaction to the running transaction (if there
+ * is one) and mark buffer as freed so that commit code knows
+ * it should clear dirty bits when it is done with the buffer.
*/
set_buffer_freed(bh);
if (journal->j_running_transaction && buffer_jbddirty(bh))
jh->b_next_transaction = journal->j_running_transaction;
+ jh->b_modified = 0;
jbd2_journal_put_journal_head(jh);
spin_unlock(&journal->j_list_lock);
jbd_unlock_bh_state(bh);
--
2.20.1