jbd2: use a weaker annotation in journal handling

jbd2 journal handling code doesn't want jbd2_might_wait_for_commit()
to be placed between start_this_handle() and stop_this_handle().  So it
marks the region with rwsem_acquire_read() and rwsem_release().

However, the annotation is too strong for that purpose.  We don't have
to use more than try lock annotation for that.

rwsem_acquire_read() implies:

   1. might be a waiter on contention of the lock.
   2. enter to the critical section of the lock.

All we need in here is to act 2, not 1.  So trylock version of
annotation is sufficient for that purpose.  Now that dept partially
relies on lockdep annotaions, dept interpets rwsem_acquire_read() as a
potential wait and might report a deadlock by the wait.

Replace it with trylock version of annotation.

Signed-off-by: Byungchul Park <byungchul@sk.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: stable@kernel.org
Message-ID: <20251024073940.1063-1-byungchul@sk.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index 3e510564de6ee85a20dcecf0a87cfdcda0a9f36d..3a866fc87e7ac7d3a32d6274b587b6977914a49c 100644 (file)
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -441,7 +441,7 @@ static int start_this_handle(journal_t *journal, handle_t *handle,
        read_unlock(&journal->j_state_lock);
        current->journal_info = handle;
 
-       rwsem_acquire_read(&journal->j_trans_commit_map, 0, 0, _THIS_IP_);
+       rwsem_acquire_read(&journal->j_trans_commit_map, 0, 1, _THIS_IP_);
        jbd2_journal_free_transaction(new_transaction);
        /*
         * Ensure that no allocations done while the transaction is open are