xfs: expose errortag knobs via sysfs

Creates a /sys/fs/xfs/$dev/errortag/ directory to control the errortag
values directly.  This enables us to control the randomness values,
rather than having to accept the defaults.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>

fs/xfs/xfs_error.c

@@ -22,6 +22,7 @@
 #include "xfs_trans_resv.h"
 #include "xfs_mount.h"
 #include "xfs_error.h"
+#include "xfs_sysfs.h"
 
 #ifdef DEBUG
 
@@ -56,6 +57,145 @@ static unsigned int xfs_errortag_random_default[] = {
 	XFS_RANDOM_AG_RESV_CRITICAL,
 };
 
+struct xfs_errortag_attr {
+	struct attribute	attr;
+	unsigned int		tag;
+};
+
+static inline struct xfs_errortag_attr *
+to_attr(struct attribute *attr)
+{
+	return container_of(attr, struct xfs_errortag_attr, attr);
+}
+
+static inline struct xfs_mount *
+to_mp(struct kobject *kobject)
+{
+	struct xfs_kobj *kobj = to_kobj(kobject);
+
+	return container_of(kobj, struct xfs_mount, m_errortag_kobj);
+}
+
+STATIC ssize_t
+xfs_errortag_attr_store(
+	struct kobject		*kobject,
+	struct attribute	*attr,
+	const char		*buf,
+	size_t			count)
+{
+	struct xfs_mount	*mp = to_mp(kobject);
+	struct xfs_errortag_attr *xfs_attr = to_attr(attr);
+	int			ret;
+	unsigned int		val;
+
+	if (strcmp(buf, "default") == 0) {
+		val = xfs_errortag_random_default[xfs_attr->tag];
+	} else {
+		ret = kstrtouint(buf, 0, &val);
+		if (ret)
+			return ret;
+	}
+
+	ret = xfs_errortag_set(mp, xfs_attr->tag, val);
+	if (ret)
+		return ret;
+	return count;
+}
+
+STATIC ssize_t
+xfs_errortag_attr_show(
+	struct kobject		*kobject,
+	struct attribute	*attr,
+	char			*buf)
+{
+	struct xfs_mount	*mp = to_mp(kobject);
+	struct xfs_errortag_attr *xfs_attr = to_attr(attr);
+
+	return snprintf(buf, PAGE_SIZE, "%u\n",
+			xfs_errortag_get(mp, xfs_attr->tag));
+}
+
+static const struct sysfs_ops xfs_errortag_sysfs_ops = {
+	.show = xfs_errortag_attr_show,
+	.store = xfs_errortag_attr_store,
+};
+
+#define XFS_ERRORTAG_ATTR_RW(_name, _tag) \
+static struct xfs_errortag_attr xfs_errortag_attr_##_name = {		\
+	.attr = {.name = __stringify(_name),				\
+		 .mode = VERIFY_OCTAL_PERMISSIONS(S_IWUSR | S_IRUGO) },	\
+	.tag	= (_tag),						\
+}
+
+#define XFS_ERRORTAG_ATTR_LIST(_name) &xfs_errortag_attr_##_name.attr
+
+XFS_ERRORTAG_ATTR_RW(noerror,		XFS_ERRTAG_NOERROR);
+XFS_ERRORTAG_ATTR_RW(iflush1,		XFS_ERRTAG_IFLUSH_1);
+XFS_ERRORTAG_ATTR_RW(iflush2,		XFS_ERRTAG_IFLUSH_2);
+XFS_ERRORTAG_ATTR_RW(iflush3,		XFS_ERRTAG_IFLUSH_3);
+XFS_ERRORTAG_ATTR_RW(iflush4,		XFS_ERRTAG_IFLUSH_4);
+XFS_ERRORTAG_ATTR_RW(iflush5,		XFS_ERRTAG_IFLUSH_5);
+XFS_ERRORTAG_ATTR_RW(iflush6,		XFS_ERRTAG_IFLUSH_6);
+XFS_ERRORTAG_ATTR_RW(dareadbuf,		XFS_ERRTAG_DA_READ_BUF);
+XFS_ERRORTAG_ATTR_RW(btree_chk_lblk,	XFS_ERRTAG_BTREE_CHECK_LBLOCK);
+XFS_ERRORTAG_ATTR_RW(btree_chk_sblk,	XFS_ERRTAG_BTREE_CHECK_SBLOCK);
+XFS_ERRORTAG_ATTR_RW(readagf,		XFS_ERRTAG_ALLOC_READ_AGF);
+XFS_ERRORTAG_ATTR_RW(readagi,		XFS_ERRTAG_IALLOC_READ_AGI);
+XFS_ERRORTAG_ATTR_RW(itobp,		XFS_ERRTAG_ITOBP_INOTOBP);
+XFS_ERRORTAG_ATTR_RW(iunlink,		XFS_ERRTAG_IUNLINK);
+XFS_ERRORTAG_ATTR_RW(iunlinkrm,		XFS_ERRTAG_IUNLINK_REMOVE);
+XFS_ERRORTAG_ATTR_RW(dirinovalid,	XFS_ERRTAG_DIR_INO_VALIDATE);
+XFS_ERRORTAG_ATTR_RW(bulkstat,		XFS_ERRTAG_BULKSTAT_READ_CHUNK);
+XFS_ERRORTAG_ATTR_RW(logiodone,		XFS_ERRTAG_IODONE_IOERR);
+XFS_ERRORTAG_ATTR_RW(stratread,		XFS_ERRTAG_STRATREAD_IOERR);
+XFS_ERRORTAG_ATTR_RW(stratcmpl,		XFS_ERRTAG_STRATCMPL_IOERR);
+XFS_ERRORTAG_ATTR_RW(diowrite,		XFS_ERRTAG_DIOWRITE_IOERR);
+XFS_ERRORTAG_ATTR_RW(bmapifmt,		XFS_ERRTAG_BMAPIFORMAT);
+XFS_ERRORTAG_ATTR_RW(free_extent,	XFS_ERRTAG_FREE_EXTENT);
+XFS_ERRORTAG_ATTR_RW(rmap_finish_one,	XFS_ERRTAG_RMAP_FINISH_ONE);
+XFS_ERRORTAG_ATTR_RW(refcount_continue_update,	XFS_ERRTAG_REFCOUNT_CONTINUE_UPDATE);
+XFS_ERRORTAG_ATTR_RW(refcount_finish_one,	XFS_ERRTAG_REFCOUNT_FINISH_ONE);
+XFS_ERRORTAG_ATTR_RW(bmap_finish_one,	XFS_ERRTAG_BMAP_FINISH_ONE);
+XFS_ERRORTAG_ATTR_RW(ag_resv_critical,	XFS_ERRTAG_AG_RESV_CRITICAL);
+
+static struct attribute *xfs_errortag_attrs[] = {
+	XFS_ERRORTAG_ATTR_LIST(noerror),
+	XFS_ERRORTAG_ATTR_LIST(iflush1),
+	XFS_ERRORTAG_ATTR_LIST(iflush2),
+	XFS_ERRORTAG_ATTR_LIST(iflush3),
+	XFS_ERRORTAG_ATTR_LIST(iflush4),
+	XFS_ERRORTAG_ATTR_LIST(iflush5),
+	XFS_ERRORTAG_ATTR_LIST(iflush6),
+	XFS_ERRORTAG_ATTR_LIST(dareadbuf),
+	XFS_ERRORTAG_ATTR_LIST(btree_chk_lblk),
+	XFS_ERRORTAG_ATTR_LIST(btree_chk_sblk),
+	XFS_ERRORTAG_ATTR_LIST(readagf),
+	XFS_ERRORTAG_ATTR_LIST(readagi),
+	XFS_ERRORTAG_ATTR_LIST(itobp),
+	XFS_ERRORTAG_ATTR_LIST(iunlink),
+	XFS_ERRORTAG_ATTR_LIST(iunlinkrm),
+	XFS_ERRORTAG_ATTR_LIST(dirinovalid),
+	XFS_ERRORTAG_ATTR_LIST(bulkstat),
+	XFS_ERRORTAG_ATTR_LIST(logiodone),
+	XFS_ERRORTAG_ATTR_LIST(stratread),
+	XFS_ERRORTAG_ATTR_LIST(stratcmpl),
+	XFS_ERRORTAG_ATTR_LIST(diowrite),
+	XFS_ERRORTAG_ATTR_LIST(bmapifmt),
+	XFS_ERRORTAG_ATTR_LIST(free_extent),
+	XFS_ERRORTAG_ATTR_LIST(rmap_finish_one),
+	XFS_ERRORTAG_ATTR_LIST(refcount_continue_update),
+	XFS_ERRORTAG_ATTR_LIST(refcount_finish_one),
+	XFS_ERRORTAG_ATTR_LIST(bmap_finish_one),
+	XFS_ERRORTAG_ATTR_LIST(ag_resv_critical),
+	NULL,
+};
+
+struct kobj_type xfs_errortag_ktype = {
+	.release = xfs_sysfs_release,
+	.sysfs_ops = &xfs_errortag_sysfs_ops,
+	.default_attrs = xfs_errortag_attrs,
+};
+
 int
 xfs_errortag_init(
 	struct xfs_mount	*mp)
@@ -64,13 +204,16 @@ xfs_errortag_init(
 			KM_SLEEP | KM_MAYFAIL);
 	if (!mp->m_errortag)
 		return -ENOMEM;
-	return 0;
+
+	return xfs_sysfs_init(&mp->m_errortag_kobj, &xfs_errortag_ktype,
+			       &mp->m_kobj, "errortag");
 }
 
 void
 xfs_errortag_del(
 	struct xfs_mount	*mp)
 {
+	xfs_sysfs_del(&mp->m_errortag_kobj);
 	kmem_free(mp->m_errortag);
 }
 
@@ -95,6 +238,17 @@ xfs_errortag_test(
 	return true;
 }
 
+int
+xfs_errortag_get(
+	struct xfs_mount	*mp,
+	unsigned int		error_tag)
+{
+	if (error_tag >= XFS_ERRTAG_MAX)
+		return -EINVAL;
+
+	return mp->m_errortag[error_tag];
+}
+
 int
 xfs_errortag_set(
 	struct xfs_mount	*mp,

fs/xfs/xfs_error.h

@@ -138,6 +138,7 @@ extern bool xfs_errortag_test(struct xfs_mount *mp, const char *expression,
 #define XFS_TEST_ERROR(expr, mp, tag, rf)		\
 	((expr) || xfs_errortag_test((mp), #expr, __FILE__, __LINE__, (tag)))
 
+extern int xfs_errortag_get(struct xfs_mount *mp, unsigned int error_tag);
 extern int xfs_errortag_set(struct xfs_mount *mp, unsigned int error_tag,
 		unsigned int tag_value);
 extern int xfs_errortag_add(struct xfs_mount *mp, unsigned int error_tag);

fs/xfs/xfs_mount.h

@@ -204,6 +204,7 @@ typedef struct xfs_mount {
 	 * error triggers.  1 = always, 2 = half the time, etc.
 	 */
 	unsigned int		*m_errortag;
+	struct xfs_kobj		m_errortag_kobj;
 
 	/*
 	 * DEBUG mode instrumentation to test and/or trigger delayed allocation