Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / include / linux / journal-head.h

diff --git a/kernel/include/linux/journal-head.h b/kernel/include/linux/journal-head.h
new file mode 100644 (file)
index 0000000..98cd41b
--- /dev/null
+++ b/kernel/include/linux/journal-head.h
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+/*
+ * include/linux/journal-head.h
+ *
+ * buffer_head fields for JBD
+ *
+ * 27 May 2001 Andrew Morton
+ *     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()]
+        * NOTE: We *cannot* combine this with b_modified into a bitfield
+        * as gcc would then (which the C standard allows but which is
+        * very unuseful) make 64-bit accesses to the bitfield and clobber
+        * b_jcount if its update races with bitfield modification.
+        */
+       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()]
+        * Either of these locks is enough for reading, both are needed for
+        * changes.
+        */
+       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;
+
+       /* Trigger type */
+       struct jbd2_buffer_trigger_type *b_triggers;
+
+       /* Trigger type for the committing transaction's frozen data */
+       struct jbd2_buffer_trigger_type *b_frozen_triggers;
+};
+
+#endif         /* JOURNAL_HEAD_H_INCLUDED */