| Message ID | 20200617091031.6558-1-lczerner@redhat.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | jbd2: make sure jh have b_transaction set in refile/unlink_buffer | expand |
On Wed 17-06-20 11:10:31, Lukas Czerner wrote: > Callers of __jbd2_journal_unfile_buffer() and > __jbd2_journal_refile_buffer() assume that the b_transaction is set. In > fact if it's not, we can end up with journal_head refcounting errors > leading to crash much later that might be very hard to track down. Add > asserts to make sure that is the case. > > We also make sure that b_next_transaction is NULL in > __jbd2_journal_unfile_buffer() since the callers expect that as well and > we should not get into that stage in this state anyway, leading to > problems later on if we do. > > Tested with fstests. > > Signed-off-by: Lukas Czerner <lczerner@redhat.com> Thanks! The patch looks good to me. You can add: Reviewed-by: Jan Kara <jack@suse.cz> Honza > --- > fs/jbd2/transaction.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c > index e91aad3637a2..e65e0aca2826 100644 > --- a/fs/jbd2/transaction.c > +++ b/fs/jbd2/transaction.c > @@ -2026,6 +2026,9 @@ static void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh) > */ > static void __jbd2_journal_unfile_buffer(struct journal_head *jh) > { > + J_ASSERT_JH(jh, jh->b_transaction != NULL); > + J_ASSERT_JH(jh, jh->b_next_transaction == NULL); > + > __jbd2_journal_temp_unlink_buffer(jh); > jh->b_transaction = NULL; > } > @@ -2572,6 +2575,13 @@ bool __jbd2_journal_refile_buffer(struct journal_head *jh) > > was_dirty = test_clear_buffer_jbddirty(bh); > __jbd2_journal_temp_unlink_buffer(jh); > + > + /* > + * b_transaction must be set, otherwise the new b_transaction won't > + * be holding jh reference > + */ > + J_ASSERT_JH(jh, jh->b_transaction != NULL); > + > /* > * We set b_transaction here because b_next_transaction will inherit > * our jh reference and thus __jbd2_journal_file_buffer() must not > -- > 2.21.3 >
diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c index e91aad3637a2..e65e0aca2826 100644 --- a/fs/jbd2/transaction.c +++ b/fs/jbd2/transaction.c @@ -2026,6 +2026,9 @@ static void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh) */ static void __jbd2_journal_unfile_buffer(struct journal_head *jh) { + J_ASSERT_JH(jh, jh->b_transaction != NULL); + J_ASSERT_JH(jh, jh->b_next_transaction == NULL); + __jbd2_journal_temp_unlink_buffer(jh); jh->b_transaction = NULL; } @@ -2572,6 +2575,13 @@ bool __jbd2_journal_refile_buffer(struct journal_head *jh) was_dirty = test_clear_buffer_jbddirty(bh); __jbd2_journal_temp_unlink_buffer(jh); + + /* + * b_transaction must be set, otherwise the new b_transaction won't + * be holding jh reference + */ + J_ASSERT_JH(jh, jh->b_transaction != NULL); + /* * We set b_transaction here because b_next_transaction will inherit * our jh reference and thus __jbd2_journal_file_buffer() must not
Callers of __jbd2_journal_unfile_buffer() and __jbd2_journal_refile_buffer() assume that the b_transaction is set. In fact if it's not, we can end up with journal_head refcounting errors leading to crash much later that might be very hard to track down. Add asserts to make sure that is the case. We also make sure that b_next_transaction is NULL in __jbd2_journal_unfile_buffer() since the callers expect that as well and we should not get into that stage in this state anyway, leading to problems later on if we do. Tested with fstests. Signed-off-by: Lukas Czerner <lczerner@redhat.com> --- fs/jbd2/transaction.c | 10 ++++++++++ 1 file changed, 10 insertions(+)