[PATCH 2/4] ext4: fix incorrect tid assumption in __jbd2_log_wait_for_space()

Luis Henriques (SUSE)
2024-07-23T15:44:23Z

Function __jbd2_log_wait_for_space() assumes that '0' is not a valid value
for transaction IDs, which is incorrect. Don't assume that and invoke
jbd2_log_wait_commit() if the journal had a committing transaction instead.

Signed-off-by: Luis Henriques (SUSE) <luis.henriques@linux.dev>
---
fs/jbd2/checkpoint.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c
index 951f78634adf..77bc522e6821 100644
--- a/fs/jbd2/checkpoint.c
+++ b/fs/jbd2/checkpoint.c
@@ -79,9 +79,12 @@ __releases(&journal->j_state_lock)
if (space_left < nblocks) {
int chkpt = journal->j_checkpoint_transactions != NULL;
tid_t tid = 0;
+ bool has_transaction = false;

- if (journal->j_committing_transaction)
+ if (journal->j_committing_transaction) {
tid = journal->j_committing_transaction->t_tid;
+ has_transaction = true;
+ }
spin_unlock(&journal->j_list_lock);
write_unlock(&journal->j_state_lock);
if (chkpt) {
@@ -89,7 +92,7 @@ __releases(&journal->j_state_lock)
} else if (jbd2_cleanup_journal_tail(journal) == 0) {
/* We were able to recover space; yay! */
;
- } else if (tid) {
+ } else if (has_transaction) {
/*
* jbd2_journal_commit_transaction() may want
* to take the checkpoint_mutex if JBD2_FLUSHED