xfs: configurable error behavior via sysfs

We need to be able to change the way XFS behaviours in error
conditions depending on the type of underlying storage. This is
necessary for handling non-traditional block devices with extended
error cases, such as thin provisioned devices that can return ENOSPC
as an IO error.

Introduce the basic sysfs infrastructure needed to define and
configure error behaviours. This is done to be generic enough to
extend to configuring behaviour in other error conditions, such as
ENOMEM, which also has different desired behaviours according to
machine configuration.

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>

diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index 536a0ee9cd5af1fbbc89960a597eb7158b676771..677c3e0da472b9e1755bedd63e37232426df1275 100644 (file)
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -690,10 +690,15 @@ xfs_mountfs(
        if (error)
                goto out_remove_sysfs;
 
-       error = xfs_uuid_mount(mp);
+       error = xfs_error_sysfs_init(mp);
        if (error)
                goto out_del_stats;
 
+
+       error = xfs_uuid_mount(mp);
+       if (error)
+               goto out_remove_error_sysfs;
+
        /*
         * Set the minimum read and write sizes
         */
@@ -968,6 +973,8 @@ xfs_mountfs(
        xfs_da_unmount(mp);
  out_remove_uuid:
        xfs_uuid_unmount(mp);
+ out_remove_error_sysfs:
+       xfs_error_sysfs_del(mp);
  out_del_stats:
        xfs_sysfs_del(&mp->m_stats.xs_kobj);
  out_remove_sysfs:
@@ -1056,6 +1063,7 @@ xfs_unmountfs(
 #endif
        xfs_free_perag(mp);
 
+       xfs_error_sysfs_del(mp);
        xfs_sysfs_del(&mp->m_stats.xs_kobj);
        xfs_sysfs_del(&mp->m_kobj);
 }

diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index bac6b3435591b6725ea2b4a6115fd7bf89db8c15..d639795b0310a6344b11f5c2e9af17c2a40e4346 100644 (file)
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -37,6 +37,24 @@ enum {
        XFS_LOWSP_MAX,
 };
 
+/*
+ * Error Configuration
+ *
+ * Error classes define the subsystem the configuration belongs to.
+ * Error numbers define the errors that are configurable.
+ */
+enum {
+       XFS_ERR_CLASS_MAX,
+};
+enum {
+       XFS_ERR_ERRNO_MAX,
+};
+
+struct xfs_error_cfg {
+       struct xfs_kobj kobj;
+       int             max_retries;
+};
+
 typedef struct xfs_mount {
        struct super_block      *m_super;
        xfs_tid_t               m_tid;          /* next unused tid for fs */
@@ -127,6 +145,8 @@ typedef struct xfs_mount {
        int64_t                 m_low_space[XFS_LOWSP_MAX];
                                                /* low free space thresholds */
        struct xfs_kobj         m_kobj;
+       struct xfs_kobj         m_error_kobj;
+       struct xfs_error_cfg    m_error_cfg[XFS_ERR_CLASS_MAX][XFS_ERR_ERRNO_MAX];
        struct xstats           m_stats;        /* per-fs stats */
 
        struct workqueue_struct *m_buf_workqueue;

diff --git a/fs/xfs/xfs_sysfs.c b/fs/xfs/xfs_sysfs.c
index 6ced4f1434948d3757077c732a93d6fac88ea0cc..74e39407124250d602b30e674e655c7edb58cbf3 100644 (file)
--- a/fs/xfs/xfs_sysfs.c
+++ b/fs/xfs/xfs_sysfs.c
@@ -17,10 +17,11 @@
  */
 
 #include "xfs.h"
-#include "xfs_sysfs.h"
+#include "xfs_shared.h"
 #include "xfs_format.h"
 #include "xfs_log_format.h"
 #include "xfs_trans_resv.h"
+#include "xfs_sysfs.h"
 #include "xfs_log.h"
 #include "xfs_log_priv.h"
 #include "xfs_stats.h"
@@ -362,3 +363,53 @@ struct kobj_type xfs_log_ktype = {
        .sysfs_ops = &xfs_sysfs_ops,
        .default_attrs = xfs_log_attrs,
 };
+
+/*
+ * Metadata IO error configuration
+ *
+ * The sysfs structure here is:
+ *     ...xfs/<dev>/error/<class>/<errno>/<error_attrs>
+ *
+ * where <class> allows us to discriminate between data IO and metadata IO,
+ * and any other future type of IO (e.g. special inode or directory error
+ * handling) we care to support.
+ */
+static struct attribute *xfs_error_attrs[] = {
+       NULL,
+};
+
+static inline struct xfs_error_cfg *
+to_error_cfg(struct kobject *kobject)
+{
+       struct xfs_kobj *kobj = to_kobj(kobject);
+       return container_of(kobj, struct xfs_error_cfg, kobj);
+}
+
+struct kobj_type xfs_error_cfg_ktype = {
+       .release = xfs_sysfs_release,
+       .sysfs_ops = &xfs_sysfs_ops,
+       .default_attrs = xfs_error_attrs,
+};
+
+struct kobj_type xfs_error_ktype = {
+       .release = xfs_sysfs_release,
+};
+
+int
+xfs_error_sysfs_init(
+       struct xfs_mount        *mp)
+{
+       int                     error;
+
+       /* .../xfs/<dev>/error/ */
+       error = xfs_sysfs_init(&mp->m_error_kobj, &xfs_error_ktype,
+                               &mp->m_kobj, "error");
+       return error;
+}
+
+void
+xfs_error_sysfs_del(
+       struct xfs_mount        *mp)
+{
+       xfs_sysfs_del(&mp->m_error_kobj);
+}

diff --git a/fs/xfs/xfs_sysfs.h b/fs/xfs/xfs_sysfs.h
index be692e59938db7e8cba4ca4186b1a8f90928887c..d04637181ef21709715d6320bf0569e3d715740a 100644 (file)
--- a/fs/xfs/xfs_sysfs.h
+++ b/fs/xfs/xfs_sysfs.h
@@ -58,4 +58,7 @@ xfs_sysfs_del(
        wait_for_completion(&kobj->complete);
 }
 
+int    xfs_error_sysfs_init(struct xfs_mount *mp);
+void   xfs_error_sysfs_del(struct xfs_mount *mp);
+
 #endif /* __XFS_SYSFS_H__ */