jbd2: allocate transaction from separate slab cache

There is normally only a handful of these active at any one time, but
putting them in a separate slab cache makes debugging memory
corruption problems easier.  Manish Katiyar also wanted this make it
easier to test memory failure scenarios in the jbd2 layer.

Cc: Manish Katiyar <mkatiyar@gmail.com>
Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 5 insertions, 0 deletions

diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index 5557baefed60..46eef77e6ab8 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -1020,6 +1020,11 @@ jbd2_journal_write_metadata_buffer(transaction_t	  *transaction,
 /* Transaction locking */
 extern void             __wait_on_journal (journal_t *);
 
+/* Transaction cache support */
+extern void jbd2_journal_destroy_transaction_cache(void);
+extern int  jbd2_journal_init_transaction_cache(void);
+extern void jbd2_journal_free_transaction(transaction_t *);
+
 /*
  * Journal locking.
  *