1 files changed, 92 insertions, 0 deletions

diff --git a/include/linux/journal-head.h b/include/linux/journal-head.h
new file mode 100644
index 000000000000..8a62d1e84b9b
--- /dev/null
+++ b/include/linux/journal-head.h
@@ -0,0 +1,92 @@
+/*
+ * include/linux/journal-head.h
+ *
+ * buffer_head fields for JBD
+ *
+ * 27 May 2001 Andrew Morton <akpm@digeo.com>
+ *      Created - pulled out of fs.h
+ */
+
+#ifndef JOURNAL_HEAD_H_INCLUDED
+#define JOURNAL_HEAD_H_INCLUDED
+
+typedef unsigned int            tid_t;          /* Unique transaction ID */
+typedef struct transaction_s    transaction_t;  /* Compound transaction type */
+struct buffer_head;
+
+struct journal_head {
+        /*
+         * Points back to our buffer_head. [jbd_lock_bh_journal_head()]
+         */
+        struct buffer_head *b_bh;
+
+        /*
+         * Reference count - see description in journal.c
+         * [jbd_lock_bh_journal_head()]
+         */
+        int b_jcount;
+
+        /*
+         * Journalling list for this buffer [jbd_lock_bh_state()]
+         */
+        unsigned b_jlist;
+
+        /*
+         * This flag signals the buffer has been modified by
+         * the currently running transaction
+         * [jbd_lock_bh_state()]
+         */
+        unsigned b_modified;
+
+        /*
+         * Copy of the buffer data frozen for writing to the log.
+         * [jbd_lock_bh_state()]
+         */
+        char *b_frozen_data;
+
+        /*
+         * Pointer to a saved copy of the buffer containing no uncommitted
+         * deallocation references, so that allocations can avoid overwriting
+         * uncommitted deletes. [jbd_lock_bh_state()]
+         */
+        char *b_committed_data;
+
+        /*
+         * Pointer to the compound transaction which owns this buffer's
+         * metadata: either the running transaction or the committing
+         * transaction (if there is one).  Only applies to buffers on a
+         * transaction's data or metadata journaling list.
+         * [j_list_lock] [jbd_lock_bh_state()]
+         */
+        transaction_t *b_transaction;
+
+        /*
+         * Pointer to the running compound transaction which is currently
+         * modifying the buffer's metadata, if there was already a transaction
+         * committing it when the new transaction touched it.
+         * [t_list_lock] [jbd_lock_bh_state()]
+         */
+        transaction_t *b_next_transaction;
+
+        /*
+         * Doubly-linked list of buffers on a transaction's data, metadata or
+         * forget queue. [t_list_lock] [jbd_lock_bh_state()]
+         */
+        struct journal_head *b_tnext, *b_tprev;
+
+        /*
+         * Pointer to the compound transaction against which this buffer
+         * is checkpointed.  Only dirty buffers can be checkpointed.
+         * [j_list_lock]
+         */
+        transaction_t *b_cp_transaction;
+
+        /*
+         * Doubly-linked list of buffers still remaining to be flushed
+         * before an old transaction can be checkpointed.
+         * [j_list_lock]
+         */
+        struct journal_head *b_cpnext, *b_cpprev;
+};
+
+#endif          /* JOURNAL_HEAD_H_INCLUDED */