md: add new helpers for sync_action

The new helpers will get current sync_action of the array, will be used
in later patches to make code cleaner.
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20240611132251.1967786-4-yukuai1@huaweicloud.com

drivers/md/md.c

@@ -69,6 +69,16 @@
 #include "md-bitmap.h"
 #include "md-cluster.h"
 
+static const char *action_name[NR_SYNC_ACTIONS] = {
+	[ACTION_RESYNC]		= "resync",
+	[ACTION_RECOVER]	= "recover",
+	[ACTION_CHECK]		= "check",
+	[ACTION_REPAIR]		= "repair",
+	[ACTION_RESHAPE]	= "reshape",
+	[ACTION_FROZEN]		= "frozen",
+	[ACTION_IDLE]		= "idle",
+};
+
 /* pers_list is a list of registered personalities protected by pers_lock. */
 static LIST_HEAD(pers_list);
 static DEFINE_SPINLOCK(pers_lock);
@@ -4868,6 +4878,75 @@ metadata_store(struct mddev *mddev, const char *buf, size_t len)
 static struct md_sysfs_entry md_metadata =
 __ATTR_PREALLOC(metadata_version, S_IRUGO|S_IWUSR, metadata_show, metadata_store);
 
+enum sync_action md_sync_action(struct mddev *mddev)
+{
+	unsigned long recovery = mddev->recovery;
+
+	/*
+	 * frozen has the highest priority, means running sync_thread will be
+	 * stopped immediately, and no new sync_thread can start.
+	 */
+	if (test_bit(MD_RECOVERY_FROZEN, &recovery))
+		return ACTION_FROZEN;
+
+	/*
+	 * read-only array can't register sync_thread, and it can only
+	 * add/remove spares.
+	 */
+	if (!md_is_rdwr(mddev))
+		return ACTION_IDLE;
+
+	/*
+	 * idle means no sync_thread is running, and no new sync_thread is
+	 * requested.
+	 */
+	if (!test_bit(MD_RECOVERY_RUNNING, &recovery) &&
+	    !test_bit(MD_RECOVERY_NEEDED, &recovery))
+		return ACTION_IDLE;
+
+	if (test_bit(MD_RECOVERY_RESHAPE, &recovery) ||
+	    mddev->reshape_position != MaxSector)
+		return ACTION_RESHAPE;
+
+	if (test_bit(MD_RECOVERY_RECOVER, &recovery))
+		return ACTION_RECOVER;
+
+	if (test_bit(MD_RECOVERY_SYNC, &recovery)) {
+		/*
+		 * MD_RECOVERY_CHECK must be paired with
+		 * MD_RECOVERY_REQUESTED.
+		 */
+		if (test_bit(MD_RECOVERY_CHECK, &recovery))
+			return ACTION_CHECK;
+		if (test_bit(MD_RECOVERY_REQUESTED, &recovery))
+			return ACTION_REPAIR;
+		return ACTION_RESYNC;
+	}
+
+	/*
+	 * MD_RECOVERY_NEEDED or MD_RECOVERY_RUNNING is set, however, no
+	 * sync_action is specified.
+	 */
+	return ACTION_IDLE;
+}
+
+enum sync_action md_sync_action_by_name(const char *page)
+{
+	enum sync_action action;
+
+	for (action = 0; action < NR_SYNC_ACTIONS; ++action) {
+		if (cmd_match(page, action_name[action]))
+			return action;
+	}
+
+	return NR_SYNC_ACTIONS;
+}
+
+const char *md_sync_action_name(enum sync_action action)
+{
+	return action_name[action];
+}
+
 static ssize_t
 action_show(struct mddev *mddev, char *page)
 {

drivers/md/md.h

@@ -864,6 +864,9 @@ extern void md_unregister_thread(struct mddev *mddev, struct md_thread __rcu **t
 extern void md_wakeup_thread(struct md_thread __rcu *thread);
 extern void md_check_recovery(struct mddev *mddev);
 extern void md_reap_sync_thread(struct mddev *mddev);
+extern enum sync_action md_sync_action(struct mddev *mddev);
+extern enum sync_action md_sync_action_by_name(const char *page);
+extern const char *md_sync_action_name(enum sync_action action);
 extern void md_write_start(struct mddev *mddev, struct bio *bi);
 extern void md_write_inc(struct mddev *mddev, struct bio *bi);
 extern void md_write_end(struct mddev *mddev);