xfs: convert log flags to an operational state field

log->l_flags doesn't actually contain "flags" as such, it contains
operational state information that can change at runtime. For the
shutdown state, this at least should be an atomic bit because
it is read without holding locks in many places and so using atomic
bitops for the state field modifications makes sense.

This allows us to use things like test_and_set_bit() on state
changes (e.g. setting XLOG_TAIL_WARN) to avoid races in setting the
state when we aren't holding locks.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>

1 files changed, 23 insertions, 11 deletions

diff --git a/fs/xfs/xfs_log_priv.h b/fs/xfs/xfs_log_priv.h
index 88b1136e475e..86ddd0f9cecf 100644
--- a/fs/xfs/xfs_log_priv.h
+++ b/fs/xfs/xfs_log_priv.h
@@ -12,15 +12,6 @@ struct xlog_ticket;
 struct xfs_mount;
 
 /*
- * Flags for log structure
- */
-#define XLOG_ACTIVE_RECOVERY	0x2	/* in the middle of recovery */
-#define	XLOG_RECOVERY_NEEDED	0x4	/* log was recovered */
-#define XLOG_IO_ERROR		0x8	/* log hit an I/O error, and being
-					   shutdown */
-#define XLOG_TAIL_WARN		0x10	/* log tail verify warning issued */
-
-/*
  * get client id from packed copy.
  *
  * this hack is here because the xlog_pack code copies four bytes
@@ -405,7 +396,7 @@ struct xlog {
 	struct xfs_buftarg	*l_targ;        /* buftarg of log */
 	struct workqueue_struct	*l_ioend_workqueue; /* for I/O completions */
 	struct delayed_work	l_work;		/* background flush work */
-	uint			l_flags;
+	long			l_opstate;	/* operational state */
 	uint			l_quotaoffs_flag; /* XFS_DQ_*, for QUOTAOFFs */
 	struct list_head	*l_buf_cancel_table;
 	int			l_iclog_hsize;  /* size of iclog header */
@@ -462,10 +453,31 @@ struct xlog {
 #define XLOG_BUF_CANCEL_BUCKET(log, blkno) \
 	((log)->l_buf_cancel_table + ((uint64_t)blkno % XLOG_BC_TABLE_SIZE))
 
+/*
+ * Bits for operational state
+ */
+#define XLOG_ACTIVE_RECOVERY	0	/* in the middle of recovery */
+#define XLOG_RECOVERY_NEEDED	1	/* log was recovered */
+#define XLOG_IO_ERROR		2	/* log hit an I/O error, and being
+				   shutdown */
+#define XLOG_TAIL_WARN		3	/* log tail verify warning issued */
+
+static inline bool
+xlog_recovery_needed(struct xlog *log)
+{
+	return test_bit(XLOG_RECOVERY_NEEDED, &log->l_opstate);
+}
+
+static inline bool
+xlog_in_recovery(struct xlog *log)
+{
+	return test_bit(XLOG_ACTIVE_RECOVERY, &log->l_opstate);
+}
+
 static inline bool
 xlog_is_shutdown(struct xlog *log)
 {
-	return (log->l_flags & XLOG_IO_ERROR);
+	return test_bit(XLOG_IO_ERROR, &log->l_opstate);
 }
 
 /* common routines */