In start_this_handle() the caller does not have a handle ref pinning the
transaction open, and so the call to log_start_commit() is racy because some
other CPU could take the transaction into commit state independently.
Fix that by holding j_state_lock (which pins j_running_transaction) across
the log_start_commit() call.
25-akpm/fs/jbd/journal.c | 2 +-
25-akpm/fs/jbd/transaction.c | 6 +++---
25-akpm/include/linux/jbd.h | 1 +
3 files changed, 5 insertions(+), 4 deletions(-)
diff -puN fs/jbd/transaction.c~jbd-580-log_start_commit-race-fix fs/jbd/transaction.c
--- 25/fs/jbd/transaction.c~jbd-580-log_start_commit-race-fix Thu Jun 5 15:14:37 2003
+++ 25-akpm/fs/jbd/transaction.c Thu Jun 5 15:14:37 2003
@@ -171,12 +171,12 @@ repeat:
*/
DEFINE_WAIT(wait);
- spin_unlock(&transaction->t_handle_lock);
- spin_unlock(&journal->j_state_lock);
jbd_debug(2, "Handle %p starting new commit...\n", handle);
+ spin_unlock(&transaction->t_handle_lock);
prepare_to_wait(&journal->j_wait_transaction_locked, &wait,
TASK_UNINTERRUPTIBLE);
- log_start_commit(journal, transaction);
+ __log_start_commit(journal, transaction);
+ spin_unlock(&journal->j_state_lock);
schedule();
finish_wait(&journal->j_wait_transaction_locked, &wait);
goto repeat;
diff -puN fs/jbd/journal.c~jbd-580-log_start_commit-race-fix fs/jbd/journal.c
--- 25/fs/jbd/journal.c~jbd-580-log_start_commit-race-fix Thu Jun 5 15:14:37 2003
+++ 25-akpm/fs/jbd/journal.c Thu Jun 5 15:14:37 2003
@@ -442,7 +442,7 @@ int __log_space_left(journal_t *journal)
/*
* Called under j_state_lock.
*/
-static tid_t __log_start_commit(journal_t *journal, transaction_t *transaction)
+tid_t __log_start_commit(journal_t *journal, transaction_t *transaction)
{
tid_t target = journal->j_commit_request;
diff -puN include/linux/jbd.h~jbd-580-log_start_commit-race-fix include/linux/jbd.h
--- 25/include/linux/jbd.h~jbd-580-log_start_commit-race-fix Thu Jun 5 15:14:37 2003
+++ 25-akpm/include/linux/jbd.h Thu Jun 5 15:14:37 2003
@@ -991,6 +991,7 @@ extern void journal_switch_revoke_table(
int __log_space_left(journal_t *); /* Called with journal locked */
extern tid_t log_start_commit (journal_t *, transaction_t *);
+extern tid_t __log_start_commit(journal_t *, transaction_t *);
extern int log_wait_commit (journal_t *, tid_t);
extern int log_do_checkpoint (journal_t *, int);
_