xfs: clean up log buffer writes

Don't bother using XFS_bwrite as it doesn't provide much code for
our use case.  Instead opencode it and fold xlog_bdstrat_cb into the
new xlog_bdstrat helper.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>

fs/xfs/linux-2.6/xfs_buf.h

@@ -408,8 +408,6 @@ static inline int XFS_bwrite(xfs_buf_t *bp)
 	return error;
 }
 
-#define XFS_bdstrat(bp) xfs_buf_iorequest(bp)
-
 #define xfs_iowait(bp)	xfs_buf_iowait(bp)
 
 #define xfs_baread(target, rablkno, ralen)  \

fs/xfs/xfs_log.c

@@ -50,7 +50,6 @@ kmem_zone_t	*xfs_log_ticket_zone;
 	  (off) += (bytes);}
 
 /* Local miscellaneous function prototypes */
-STATIC int	 xlog_bdstrat_cb(struct xfs_buf *);
 STATIC int	 xlog_commit_record(xfs_mount_t *mp, xlog_ticket_t *ticket,
 				    xlog_in_core_t **, xfs_lsn_t *);
 STATIC xlog_t *  xlog_alloc_log(xfs_mount_t	*mp,
@@ -987,35 +986,6 @@ xlog_iodone(xfs_buf_t *bp)
 
 }	/* xlog_iodone */
 
-/*
- * The bdstrat callback function for log bufs. This gives us a central
- * place to trap bufs in case we get hit by a log I/O error and need to
- * shutdown. Actually, in practice, even when we didn't get a log error,
- * we transition the iclogs to IOERROR state *after* flushing all existing
- * iclogs to disk. This is because we don't want anymore new transactions to be
- * started or completed afterwards.
- */
-STATIC int
-xlog_bdstrat_cb(struct xfs_buf *bp)
-{
-	xlog_in_core_t *iclog;
-
-	iclog = XFS_BUF_FSPRIVATE(bp, xlog_in_core_t *);
-
-	if ((iclog->ic_state & XLOG_STATE_IOERROR) == 0) {
-	  /* note for irix bstrat will need  struct bdevsw passed
-	   * Fix the following macro if the code ever is merged
-	   */
-	    XFS_bdstrat(bp);
-		return 0;
-	}
-
-	XFS_BUF_ERROR(bp, EIO);
-	XFS_BUF_STALE(bp);
-	xfs_biodone(bp);
-	return XFS_ERROR(EIO);
-}
-
 /*
  * Return size of each in-core log record buffer.
  *
@@ -1158,7 +1128,6 @@ xlog_alloc_log(xfs_mount_t	*mp,
 	if (!bp)
 		goto out_free_log;
 	XFS_BUF_SET_IODONE_FUNC(bp, xlog_iodone);
-	XFS_BUF_SET_BDSTRAT_FUNC(bp, xlog_bdstrat_cb);
 	XFS_BUF_SET_FSPRIVATE2(bp, (unsigned long)1);
 	ASSERT(XFS_BUF_ISBUSY(bp));
 	ASSERT(XFS_BUF_VALUSEMA(bp) <= 0);
@@ -1196,7 +1165,6 @@ xlog_alloc_log(xfs_mount_t	*mp,
 		if (!XFS_BUF_CPSEMA(bp))
 			ASSERT(0);
 		XFS_BUF_SET_IODONE_FUNC(bp, xlog_iodone);
-		XFS_BUF_SET_BDSTRAT_FUNC(bp, xlog_bdstrat_cb);
 		XFS_BUF_SET_FSPRIVATE2(bp, (unsigned long)1);
 		iclog->ic_bp = bp;
 		iclog->ic_data = bp->b_addr;
@@ -1343,6 +1311,37 @@ xlog_grant_push_ail(xfs_mount_t	*mp,
 	    xfs_trans_ail_push(log->l_ailp, threshold_lsn);
 }	/* xlog_grant_push_ail */
 
+/*
+ * The bdstrat callback function for log bufs. This gives us a central
+ * place to trap bufs in case we get hit by a log I/O error and need to
+ * shutdown. Actually, in practice, even when we didn't get a log error,
+ * we transition the iclogs to IOERROR state *after* flushing all existing
+ * iclogs to disk. This is because we don't want anymore new transactions to be
+ * started or completed afterwards.
+ */
+STATIC int
+xlog_bdstrat(
+	struct xfs_buf		*bp)
+{
+	struct xlog_in_core	*iclog;
+
+	iclog = XFS_BUF_FSPRIVATE(bp, xlog_in_core_t *);
+	if (iclog->ic_state & XLOG_STATE_IOERROR) {
+		XFS_BUF_ERROR(bp, EIO);
+		XFS_BUF_STALE(bp);
+		xfs_biodone(bp);
+		/*
+		 * It would seem logical to return EIO here, but we rely on
+		 * the log state machine to propagate I/O errors instead of
+		 * doing it here.
+		 */
+		return 0;
+	}
+
+	bp->b_flags |= _XBF_RUN_QUEUES;
+	xfs_buf_iorequest(bp);
+	return 0;
+}
 
 /*
  * Flush out the in-core log (iclog) to the on-disk log in an asynchronous 
@@ -1462,7 +1461,7 @@ xlog_sync(xlog_t		*log,
 	 */
 	XFS_BUF_WRITE(bp);
 
-	if ((error = XFS_bwrite(bp))) {
+	if ((error = xlog_bdstrat(bp))) {
 		xfs_ioerror_alert("xlog_sync", log->l_mp, bp,
 				  XFS_BUF_ADDR(bp));
 		return error;
@@ -1502,7 +1501,7 @@ xlog_sync(xlog_t		*log,
 		/* account for internal log which doesn't start at block #0 */
 		XFS_BUF_SET_ADDR(bp, XFS_BUF_ADDR(bp) + log->l_logBBstart);
 		XFS_BUF_WRITE(bp);
-		if ((error = XFS_bwrite(bp))) {
+		if ((error = xlog_bdstrat(bp))) {
 			xfs_ioerror_alert("xlog_sync (split)", log->l_mp,
 					  bp, XFS_BUF_ADDR(bp));
 			return error;