Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/fs/xfs/xfs_sysfs.c b/fs/xfs/xfs_sysfs.c
index cd6a994..f1bc88f 100644
--- a/fs/xfs/xfs_sysfs.c
+++ b/fs/xfs/xfs_sysfs.c
@@ -10,9 +10,7 @@
 #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"
 #include "xfs_mount.h"
 
 struct xfs_sysfs_attr {
@@ -65,19 +63,6 @@
 	.store = xfs_sysfs_object_store,
 };
 
-/*
- * xfs_mount kobject. The mp kobject also serves as the per-mount parent object
- * that is identified by the fsname under sysfs.
- */
-
-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_kobj);
-}
-
 static struct attribute *xfs_mp_attrs[] = {
 	NULL,
 };
@@ -183,10 +168,74 @@
 }
 XFS_SYSFS_ATTR_RW(mount_delay);
 
+static ssize_t
+always_cow_store(
+	struct kobject	*kobject,
+	const char	*buf,
+	size_t		count)
+{
+	ssize_t		ret;
+
+	ret = kstrtobool(buf, &xfs_globals.always_cow);
+	if (ret < 0)
+		return ret;
+	return count;
+}
+
+static ssize_t
+always_cow_show(
+	struct kobject	*kobject,
+	char		*buf)
+{
+	return snprintf(buf, PAGE_SIZE, "%d\n", xfs_globals.always_cow);
+}
+XFS_SYSFS_ATTR_RW(always_cow);
+
+#ifdef DEBUG
+/*
+ * Override how many threads the parallel work queue is allowed to create.
+ * This has to be a debug-only global (instead of an errortag) because one of
+ * the main users of parallel workqueues is mount time quotacheck.
+ */
+STATIC ssize_t
+pwork_threads_store(
+	struct kobject	*kobject,
+	const char	*buf,
+	size_t		count)
+{
+	int		ret;
+	int		val;
+
+	ret = kstrtoint(buf, 0, &val);
+	if (ret)
+		return ret;
+
+	if (val < -1 || val > num_possible_cpus())
+		return -EINVAL;
+
+	xfs_globals.pwork_threads = val;
+
+	return count;
+}
+
+STATIC ssize_t
+pwork_threads_show(
+	struct kobject	*kobject,
+	char		*buf)
+{
+	return snprintf(buf, PAGE_SIZE, "%d\n", xfs_globals.pwork_threads);
+}
+XFS_SYSFS_ATTR_RW(pwork_threads);
+#endif /* DEBUG */
+
 static struct attribute *xfs_dbg_attrs[] = {
 	ATTR_LIST(bug_on_assert),
 	ATTR_LIST(log_recovery_delay),
 	ATTR_LIST(mount_delay),
+	ATTR_LIST(always_cow),
+#ifdef DEBUG
+	ATTR_LIST(pwork_threads),
+#endif
 	NULL,
 };