[PATCH 6.1 096/194] md: introduce md_ro_state

11 Dec 2023

6.1-stable review patch.  If anyone has any objections, please let me know.
------------------
From: Ye Bin yebin10@huawei.com
[ Upstream commit f97a5528b21eb175d90dce2df9960c8d08e1be82 ]
Introduce md_ro_state for mddev->ro, so it is easy to understand.
Signed-off-by: Ye Bin yebin10@huawei.com
Signed-off-by: Song Liu song@kernel.org
Stable-dep-of: c9f7cb5b2bc9 ("md: don't leave 'MD_RECOVERY_FROZEN' in error path of md_set_readonly()")
Signed-off-by: Sasha Levin sashal@kernel.org
---
 drivers/md/md.c | 152 ++++++++++++++++++++++++++----------------------
 1 file changed, 82 insertions(+), 70 deletions(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 20f67edae95d0..246af78c05dd1 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -93,6 +93,18 @@ static int remove_and_add_spares(struct mddev *mddev,
    			 struct md_rdev *this);
 static void mddev_detach(struct mddev *mddev);
+enum md_ro_state {
+	MD_RDWR,
+	MD_RDONLY,
+	MD_AUTO_READ,
+	MD_MAX_STATE
+};
+
+static bool md_is_rdwr(struct mddev *mddev)
+{
+	return (mddev->ro == MD_RDWR);
+}
+
 /*
  * Default number of read corrections we'll attempt on an rdev
  * before ejecting it from the array. We divide the read error
@@ -444,7 +456,7 @@ static void md_submit_bio(struct bio *bio)
    if (!bio)
    	return;
-	if (mddev->ro == 1 && unlikely(rw == WRITE)) {
+	if (mddev->ro == MD_RDONLY && unlikely(rw == WRITE)) {
    	if (bio_sectors(bio) != 0)
    		bio->bi_status = BLK_STS_IOERR;
    	bio_endio(bio);
@@ -2643,7 +2655,7 @@ void md_update_sb(struct mddev *mddev, int force_change)
    int any_badblocks_changed = 0;
    int ret = -1;
-	if (mddev->ro) {
+	if (!md_is_rdwr(mddev)) {
    	if (force_change)
    		set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
    	return;
@@ -3909,7 +3921,7 @@ level_store(struct mddev *mddev, const char *buf, size_t len)
    	goto out_unlock;
    }
    rv = -EROFS;
-	if (mddev->ro)
+	if (!md_is_rdwr(mddev))
    	goto out_unlock;
/* request to change the personality.  Need to ensure:
@@ -4115,7 +4127,7 @@ layout_store(struct mddev *mddev, const char *buf, size_t len)
    if (mddev->pers) {
    	if (mddev->pers->check_reshape == NULL)
    		err = -EBUSY;
-		else if (mddev->ro)
+		else if (!md_is_rdwr(mddev))
    		err = -EROFS;
    	else {
    		mddev->new_layout = n;
@@ -4224,7 +4236,7 @@ chunk_size_store(struct mddev *mddev, const char *buf, size_t len)
    if (mddev->pers) {
    	if (mddev->pers->check_reshape == NULL)
    		err = -EBUSY;
-		else if (mddev->ro)
+		else if (!md_is_rdwr(mddev))
    		err = -EROFS;
    	else {
    		mddev->new_chunk_sectors = n >> 9;
@@ -4347,13 +4359,13 @@ array_state_show(struct mddev *mddev, char *page)
if (mddev->pers && !test_bit(MD_NOT_READY, &mddev->flags)) {
    	switch(mddev->ro) {
-		case 1:
+		case MD_RDONLY:
    		st = readonly;
    		break;
-		case 2:
+		case MD_AUTO_READ:
    		st = read_auto;
    		break;
-		case 0:
+		case MD_RDWR:
    		spin_lock(&mddev->lock);
    		if (test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags))
    			st = write_pending;
@@ -4389,7 +4401,8 @@ array_state_store(struct mddev *mddev, const char *buf, size_t len)
    int err = 0;
    enum array_state st = match_word(buf, array_states);
-	if (mddev->pers && (st == active || st == clean) && mddev->ro != 1) {
+	if (mddev->pers && (st == active || st == clean) &&
+	    mddev->ro != MD_RDONLY) {
    	/* don't take reconfig_mutex when toggling between
    	 * clean and active
    	 */
@@ -4433,23 +4446,23 @@ array_state_store(struct mddev *mddev, const char *buf, size_t len)
    	if (mddev->pers)
    		err = md_set_readonly(mddev, NULL);
    	else {
-			mddev->ro = 1;
+			mddev->ro = MD_RDONLY;
    		set_disk_ro(mddev->gendisk, 1);
    		err = do_md_run(mddev);
    	}
    	break;
    case read_auto:
    	if (mddev->pers) {
-			if (mddev->ro == 0)
+			if (md_is_rdwr(mddev))
    			err = md_set_readonly(mddev, NULL);
-			else if (mddev->ro == 1)
+			else if (mddev->ro == MD_RDONLY)
    			err = restart_array(mddev);
    		if (err == 0) {
-				mddev->ro = 2;
+				mddev->ro = MD_AUTO_READ;
    			set_disk_ro(mddev->gendisk, 0);
    		}
    	} else {
-			mddev->ro = 2;
+			mddev->ro = MD_AUTO_READ;
    		err = do_md_run(mddev);
    	}
    	break;
@@ -4474,7 +4487,7 @@ array_state_store(struct mddev *mddev, const char *buf, size_t len)
    		wake_up(&mddev->sb_wait);
    		err = 0;
    	} else {
-			mddev->ro = 0;
+			mddev->ro = MD_RDWR;
    		set_disk_ro(mddev->gendisk, 0);
    		err = do_md_run(mddev);
    	}
@@ -4775,7 +4788,7 @@ action_show(struct mddev *mddev, char *page)
    if (test_bit(MD_RECOVERY_FROZEN, &recovery))
    	type = "frozen";
    else if (test_bit(MD_RECOVERY_RUNNING, &recovery) ||
-	    (!mddev->ro && test_bit(MD_RECOVERY_NEEDED, &recovery))) {
+	    (md_is_rdwr(mddev) && test_bit(MD_RECOVERY_NEEDED, &recovery))) {
    	if (test_bit(MD_RECOVERY_RESHAPE, &recovery))
    		type = "reshape";
    	else if (test_bit(MD_RECOVERY_SYNC, &recovery)) {
@@ -4861,11 +4874,11 @@ action_store(struct mddev *mddev, const char *page, size_t len)
    	set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
    	set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
    }
-	if (mddev->ro == 2) {
+	if (mddev->ro == MD_AUTO_READ) {
    	/* A write to sync_action is enough to justify
    	 * canceling read-auto mode
    	 */
-		mddev->ro = 0;
+		mddev->ro = MD_RDWR;
    	md_wakeup_thread(mddev->sync_thread);
    }
    set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
@@ -5093,8 +5106,7 @@ max_sync_store(struct mddev *mddev, const char *buf, size_t len)
    		goto out_unlock;
err = -EBUSY;
-		if (max < mddev->resync_max &&
-		    mddev->ro == 0 &&
+		if (max < mddev->resync_max && md_is_rdwr(mddev) &&
    	    test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
    		goto out_unlock;
@@ -5829,8 +5841,8 @@ int md_run(struct mddev *mddev)
    		continue;
    	sync_blockdev(rdev->bdev);
    	invalidate_bdev(rdev->bdev);
-		if (mddev->ro != 1 && rdev_read_only(rdev)) {
-			mddev->ro = 1;
+		if (mddev->ro != MD_RDONLY && rdev_read_only(rdev)) {
+			mddev->ro = MD_RDONLY;
    		if (mddev->gendisk)
    			set_disk_ro(mddev->gendisk, 1);
    	}
@@ -5938,8 +5950,8 @@ int md_run(struct mddev *mddev)
mddev->ok_start_degraded = start_dirty_degraded;
-	if (start_readonly && mddev->ro == 0)
-		mddev->ro = 2; /* read-only, but switch on first write */
+	if (start_readonly && md_is_rdwr(mddev))
+		mddev->ro = MD_AUTO_READ; /* read-only, but switch on first write */
err = pers->run(mddev);
    if (err)
@@ -6017,8 +6029,8 @@ int md_run(struct mddev *mddev)
    	mddev->sysfs_action = sysfs_get_dirent_safe(mddev->kobj.sd, "sync_action");
    	mddev->sysfs_completed = sysfs_get_dirent_safe(mddev->kobj.sd, "sync_completed");
    	mddev->sysfs_degraded = sysfs_get_dirent_safe(mddev->kobj.sd, "degraded");
-	} else if (mddev->ro == 2) /* auto-readonly not meaningful */
-		mddev->ro = 0;
+	} else if (mddev->ro == MD_AUTO_READ)
+		mddev->ro = MD_RDWR;
atomic_set(&mddev->max_corr_read_errors,
    	   MD_DEFAULT_MAX_CORRECTED_READ_ERRORS);
@@ -6036,7 +6048,7 @@ int md_run(struct mddev *mddev)
    	if (rdev->raid_disk >= 0)
    		sysfs_link_rdev(mddev, rdev); /* failure here is OK */
-	if (mddev->degraded && !mddev->ro)
+	if (mddev->degraded && md_is_rdwr(mddev))
    	/* This ensures that recovering status is reported immediately
    	 * via sysfs - until a lack of spares is confirmed.
    	 */
@@ -6128,7 +6140,7 @@ static int restart_array(struct mddev *mddev)
    	return -ENXIO;
    if (!mddev->pers)
    	return -EINVAL;
-	if (!mddev->ro)
+	if (md_is_rdwr(mddev))
    	return -EBUSY;
rcu_read_lock();
@@ -6147,7 +6159,7 @@ static int restart_array(struct mddev *mddev)
    	return -EROFS;
mddev->safemode = 0;
-	mddev->ro = 0;
+	mddev->ro = MD_RDWR;
    set_disk_ro(disk, 0);
    pr_debug("md: %s switched to read-write mode.\n", mdname(mddev));
    /* Kick recovery or resync if necessary */
@@ -6174,7 +6186,7 @@ static void md_clean(struct mddev *mddev)
    mddev->clevel[0] = 0;
    mddev->flags = 0;
    mddev->sb_flags = 0;
-	mddev->ro = 0;
+	mddev->ro = MD_RDWR;
    mddev->metadata_type[0] = 0;
    mddev->chunk_sectors = 0;
    mddev->ctime = mddev->utime = 0;
@@ -6226,7 +6238,7 @@ static void __md_stop_writes(struct mddev *mddev)
    }
    md_bitmap_flush(mddev);
-	if (mddev->ro == 0 &&
+	if (md_is_rdwr(mddev) &&
        ((!mddev->in_sync && !mddev_is_clustered(mddev)) ||
         mddev->sb_flags)) {
    	/* mark array as shutdown cleanly */
@@ -6340,9 +6352,9 @@ static int md_set_readonly(struct mddev *mddev, struct block_device *bdev)
    	__md_stop_writes(mddev);
err  = -ENXIO;
-		if (mddev->ro==1)
+		if (mddev->ro == MD_RDONLY)
    		goto out;
-		mddev->ro = 1;
+		mddev->ro = MD_RDONLY;
    	set_disk_ro(mddev->gendisk, 1);
    	clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
    	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
@@ -6399,7 +6411,7 @@ static int do_md_stop(struct mddev *mddev, int mode,
    	return -EBUSY;
    }
    if (mddev->pers) {
-		if (mddev->ro)
+		if (!md_is_rdwr(mddev))
    		set_disk_ro(disk, 0);
__md_stop_writes(mddev);
@@ -6416,8 +6428,8 @@ static int do_md_stop(struct mddev *mddev, int mode,
    	mutex_unlock(&mddev->open_mutex);
    	mddev->changed = 1;
-		if (mddev->ro)
-			mddev->ro = 0;
+		if (!md_is_rdwr(mddev))
+			mddev->ro = MD_RDWR;
    } else
    	mutex_unlock(&mddev->open_mutex);
    /*
@@ -7232,7 +7244,7 @@ static int update_size(struct mddev *mddev, sector_t num_sectors)
    if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
        mddev->sync_thread)
    	return -EBUSY;
-	if (mddev->ro)
+	if (!md_is_rdwr(mddev))
    	return -EROFS;
rdev_for_each(rdev, mddev) {
@@ -7262,7 +7274,7 @@ static int update_raid_disks(struct mddev *mddev, int raid_disks)
    /* change the number of raid disks */
    if (mddev->pers->check_reshape == NULL)
    	return -EINVAL;
-	if (mddev->ro)
+	if (!md_is_rdwr(mddev))
    	return -EROFS;
    if (raid_disks <= 0 ||
        (mddev->max_disks && raid_disks >= mddev->max_disks))
@@ -7686,26 +7698,25 @@ static int md_ioctl(struct block_device *bdev, fmode_t mode,
     * The remaining ioctls are changing the state of the
     * superblock, so we do not allow them on read-only arrays.
     */
-	if (mddev->ro && mddev->pers) {
-		if (mddev->ro == 2) {
-			mddev->ro = 0;
-			sysfs_notify_dirent_safe(mddev->sysfs_state);
-			set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
-			/* mddev_unlock will wake thread */
-			/* If a device failed while we were read-only, we
-			 * need to make sure the metadata is updated now.
-			 */
-			if (test_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags)) {
-				mddev_unlock(mddev);
-				wait_event(mddev->sb_wait,
-					   !test_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags) &&
-					   !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags));
-				mddev_lock_nointr(mddev);
-			}
-		} else {
+	if (!md_is_rdwr(mddev) && mddev->pers) {
+		if (mddev->ro != MD_AUTO_READ) {
    		err = -EROFS;
    		goto unlock;
    	}
+		mddev->ro = MD_RDWR;
+		sysfs_notify_dirent_safe(mddev->sysfs_state);
+		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
+		/* mddev_unlock will wake thread */
+		/* If a device failed while we were read-only, we
+		 * need to make sure the metadata is updated now.
+		 */
+		if (test_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags)) {
+			mddev_unlock(mddev);
+			wait_event(mddev->sb_wait,
+				   !test_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags) &&
+				   !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags));
+			mddev_lock_nointr(mddev);
+		}
    }
switch (cmd) {
@@ -7791,11 +7802,11 @@ static int md_set_read_only(struct block_device *bdev, bool ro)
     * Transitioning to read-auto need only happen for arrays that call
     * md_write_start and which are not ready for writes yet.
     */
-	if (!ro && mddev->ro == 1 && mddev->pers) {
+	if (!ro && mddev->ro == MD_RDONLY && mddev->pers) {
    	err = restart_array(mddev);
    	if (err)
    		goto out_unlock;
-		mddev->ro = 2;
+		mddev->ro = MD_AUTO_READ;
    }
out_unlock:
@@ -8269,9 +8280,9 @@ static int md_seq_show(struct seq_file *seq, void *v)
    	seq_printf(seq, "%s : %sactive", mdname(mddev),
    					mddev->pers ? "" : "in");
    	if (mddev->pers) {
-			if (mddev->ro==1)
+			if (mddev->ro == MD_RDONLY)
    			seq_printf(seq, " (read-only)");
-			if (mddev->ro==2)
+			if (mddev->ro == MD_AUTO_READ)
    			seq_printf(seq, " (auto-read-only)");
    		seq_printf(seq, " %s", mddev->pers->name);
    	}
@@ -8530,10 +8541,10 @@ bool md_write_start(struct mddev *mddev, struct bio *bi)
    if (bio_data_dir(bi) != WRITE)
    	return true;
-	BUG_ON(mddev->ro == 1);
-	if (mddev->ro == 2) {
+	BUG_ON(mddev->ro == MD_RDONLY);
+	if (mddev->ro == MD_AUTO_READ) {
    	/* need to switch to read/write */
-		mddev->ro = 0;
+		mddev->ro = MD_RDWR;
    	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
    	md_wakeup_thread(mddev->thread);
    	md_wakeup_thread(mddev->sync_thread);
@@ -8584,7 +8595,7 @@ void md_write_inc(struct mddev *mddev, struct bio *bi)
 {
    if (bio_data_dir(bi) != WRITE)
    	return;
-	WARN_ON_ONCE(mddev->in_sync || mddev->ro);
+	WARN_ON_ONCE(mddev->in_sync || !md_is_rdwr(mddev));
    percpu_ref_get(&mddev->writes_pending);
 }
 EXPORT_SYMBOL(md_write_inc);
@@ -8690,7 +8701,7 @@ void md_allow_write(struct mddev *mddev)
 {
    if (!mddev->pers)
    	return;
-	if (mddev->ro)
+	if (!md_is_rdwr(mddev))
    	return;
    if (!mddev->pers->sync_request)
    	return;
@@ -8738,7 +8749,7 @@ void md_do_sync(struct md_thread *thread)
    if (test_bit(MD_RECOVERY_DONE, &mddev->recovery) ||
        test_bit(MD_RECOVERY_WAIT, &mddev->recovery))
    	return;
-	if (mddev->ro) {/* never try to sync a read-only array */
+	if (!md_is_rdwr(mddev)) {/* never try to sync a read-only array */
    	set_bit(MD_RECOVERY_INTR, &mddev->recovery);
    	return;
    }
@@ -9207,9 +9218,9 @@ static int remove_and_add_spares(struct mddev *mddev,
    	if (test_bit(Faulty, &rdev->flags))
    		continue;
    	if (!test_bit(Journal, &rdev->flags)) {
-			if (mddev->ro &&
-			    ! (rdev->saved_raid_disk >= 0 &&
-			       !test_bit(Bitmap_sync, &rdev->flags)))
+			if (!md_is_rdwr(mddev) &&
+			    !(rdev->saved_raid_disk >= 0 &&
+			      !test_bit(Bitmap_sync, &rdev->flags)))
    			continue;
rdev->recovery_offset = 0;
@@ -9307,7 +9318,8 @@ void md_check_recovery(struct mddev *mddev)
    	flush_signals(current);
    }
-	if (mddev->ro && !test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))
+	if (!md_is_rdwr(mddev) &&
+	    !test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))
    	return;
    if ( ! (
    	(mddev->sb_flags & ~ (1<<MD_SB_CHANGE_PENDING)) ||
@@ -9326,7 +9338,7 @@ void md_check_recovery(struct mddev *mddev)
    	if (!mddev->external && mddev->safemode == 1)
    		mddev->safemode = 0;
-		if (mddev->ro) {
+		if (!md_is_rdwr(mddev)) {
    		struct md_rdev *rdev;
    		if (!mddev->external && mddev->in_sync)
    			/* 'Blocked' flag not needed as failed devices
-- 
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[PATCH 6.1 096/194] md: introduce md_ro_state