xfs: introduce metadata IO error class

Now we have the basic infrastructure, add the first error class so
we can build up the infrastructure in a meaningful way. Add the
metadata async write IO error class and sysfs entry, and introduce a
default configuration that matches the existing "retry forever"
behavior for async write metadata buffers.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

fs/xfs/xfs_mount.h

@@ -44,9 +44,11 @@ enum {
  * Error numbers define the errors that are configurable.
  */
 enum {
+	XFS_ERR_METADATA,
 	XFS_ERR_CLASS_MAX,
 };
 enum {
+	XFS_ERR_DEFAULT,
 	XFS_ERR_ERRNO_MAX,
 };
 
@@ -146,6 +148,7 @@ typedef struct xfs_mount {
 						/* low free space thresholds */
 	struct xfs_kobj		m_kobj;
 	struct xfs_kobj		m_error_kobj;
+	struct xfs_kobj		m_error_meta_kobj;
 	struct xfs_error_cfg	m_error_cfg[XFS_ERR_CLASS_MAX][XFS_ERR_ERRNO_MAX];
 	struct xstats		m_stats;	/* per-fs stats */
 

fs/xfs/xfs_sysfs.c

@@ -399,17 +399,51 @@ int
 xfs_error_sysfs_init(
 	struct xfs_mount	*mp)
 {
+	struct xfs_error_cfg	*cfg;
 	int			error;
 
 	/* .../xfs/<dev>/error/ */
 	error = xfs_sysfs_init(&mp->m_error_kobj, &xfs_error_ktype,
 				&mp->m_kobj, "error");
+	if (error)
+		return error;
+
+	/* .../xfs/<dev>/error/metadata/ */
+	error = xfs_sysfs_init(&mp->m_error_meta_kobj, &xfs_error_ktype,
+				&mp->m_error_kobj, "metadata");
+	if (error)
+		goto out_error;
+
+	cfg = &mp->m_error_cfg[XFS_ERR_METADATA][XFS_ERR_DEFAULT];
+	error = xfs_sysfs_init(&cfg->kobj, &xfs_error_cfg_ktype,
+				&mp->m_error_meta_kobj, "default");
+	if (error)
+		goto out_error_meta;
+	cfg->max_retries = -1;
+
+	return 0;
+
+out_error_meta:
+	xfs_sysfs_del(&mp->m_error_meta_kobj);
+out_error:
+	xfs_sysfs_del(&mp->m_error_kobj);
 	return error;
 }
 
 void
 xfs_error_sysfs_del(
 	struct xfs_mount	*mp)
 {
+	struct xfs_error_cfg	*cfg;
+	int			i, j;
+
+	for (i = 0; i < XFS_ERR_CLASS_MAX; i++) {
+		for (j = 0; j < XFS_ERR_ERRNO_MAX; j++) {
+			cfg = &mp->m_error_cfg[i][j];
+
+			xfs_sysfs_del(&cfg->kobj);
+		}
+	}
+	xfs_sysfs_del(&mp->m_error_meta_kobj);
 	xfs_sysfs_del(&mp->m_error_kobj);
 }