jbd2: Make credit checking more strict

Make checking of available credits in jbd2_journal_dirty_metadata() more
strict. There should be always enough credits in the handle to write all
potential revoke descriptors. Also we warn in case there are not enough
credits since this is a bug in the filesystem.

Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20191105164437.32602-22-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index 10fd802..8f11b2d 100644 (file)
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -1477,7 +1477,7 @@ int jbd2_journal_dirty_metadata(handle_t *handle, struct buffer_head *bh)
                 * of the transaction. This needs to be done
                 * once a transaction -bzzz
                 */
-               if (handle->h_total_credits <= 0) {
+               if (WARN_ON_ONCE(jbd2_handle_buffer_credits(handle) <= 0)) {
                        ret = -ENOSPC;
                        goto out_unlock_bh;
                }