btrfs-progs: zoned: check and enable ZONED mode

Introduce function btrfs_check_zoned_mode() to check if ZONED flag is
enabled on the file system and if the file system consists of zoned
devices with equal zone size.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>

kernel-shared/ctree.h

@@ -1213,8 +1213,22 @@ struct btrfs_fs_info {
 	u32 nodesize;
 	u32 sectorsize;
 	u32 stripesize;
+
+	/*
+	 * Zone size > 0 when in ZONED mode, otherwise it's used for a check
+	 * if the mode is enabled
+	 */
+	union {
+		u64 zone_size;
+		u64 zoned;
+	};
 };
 
+static inline bool btrfs_is_zoned(const struct btrfs_fs_info *fs_info)
+{
+	return fs_info->zoned != 0;
+}
+
 /*
  * in ram representation of the tree.  extent_root is used for all allocations
  * and for the extent tree extent_root root.

kernel-shared/disk-io.c

@@ -1325,6 +1325,12 @@ static struct btrfs_fs_info *__open_ctree_fd(int fp, struct open_ctree_flags *oc
 		goto out_chunk;
 	}
 
+	ret = btrfs_check_zoned_mode(fs_info);
+	if (ret) {
+		error("zoned: failed to initialize zoned mode: %d", ret);
+		goto out_chunk;
+	}
+
 	eb = fs_info->chunk_root->node;
 	read_extent_buffer(eb, fs_info->chunk_tree_uuid,
 			   btrfs_header_chunk_tree_uuid(eb),

kernel-shared/zoned.c

@@ -238,3 +238,88 @@ int btrfs_get_zone_info(int fd, const char *file,
 
 	return 0;
 }
+
+int btrfs_check_zoned_mode(struct btrfs_fs_info *fs_info)
+{
+	struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
+	struct btrfs_device *device;
+	u64 zoned_devices = 0;
+	u64 nr_devices = 0;
+	u64 zone_size = 0;
+	const bool incompat_zoned = btrfs_fs_incompat(fs_info, ZONED);
+	int ret = 0;
+
+	/* Count zoned devices */
+	list_for_each_entry(device, &fs_devices->devices, dev_list) {
+		enum btrfs_zoned_model model;
+
+		if (device->fd == -1)
+			continue;
+
+		model = zoned_model(device->name);
+		/*
+		 * A Host-Managed zoned device must be used as a zoned device.
+		 * A Host-Aware zoned device and a non-zoned devices can be
+		 * treated as a zoned device, if ZONED flag is enabled in the
+		 * superblock.
+		 */
+		if (model == ZONED_HOST_MANAGED ||
+		    (model == ZONED_HOST_AWARE && incompat_zoned) ||
+		    (model == ZONED_NONE && incompat_zoned)) {
+			struct btrfs_zoned_device_info *zone_info =
+				device->zone_info;
+
+			zoned_devices++;
+			if (!zone_size) {
+				zone_size = zone_info->zone_size;
+			} else if (zone_info->zone_size != zone_size) {
+				error(
+		"zoned: unequal block device zone sizes: have %llu found %llu",
+				      device->zone_info->zone_size,
+				      zone_size);
+				ret = -EINVAL;
+				goto out;
+			}
+		}
+		nr_devices++;
+	}
+
+	if (!zoned_devices && !incompat_zoned)
+		goto out;
+
+	if (!zoned_devices && incompat_zoned) {
+		/* No zoned block device found on ZONED filesystem */
+		error("zoned: no zoned devices found on a zoned filesystem");
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (zoned_devices && !incompat_zoned) {
+		error("zoned: mode not enabled but zoned device found");
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (zoned_devices != nr_devices) {
+		error("zoned: cannot mix zoned and regular devices");
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/*
+	 * stripe_size is always aligned to BTRFS_STRIPE_LEN in
+	 * __btrfs_alloc_chunk(). Since we want stripe_len == zone_size,
+	 * check the alignment here.
+	 */
+	if (!IS_ALIGNED(zone_size, BTRFS_STRIPE_LEN)) {
+		error("zoned: zone size %llu not aligned to stripe %u",
+		      zone_size, BTRFS_STRIPE_LEN);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	fs_info->zone_size = zone_size;
+
+out:
+	return ret;
+}

kernel-shared/zoned.h

@@ -40,5 +40,6 @@ u64 zone_size(const char *file);
 int btrfs_get_zone_info(int fd, const char *file,
 			struct btrfs_zoned_device_info **zinfo);
 int btrfs_get_dev_zone_info_all_devices(struct btrfs_fs_info *fs_info);
+int btrfs_check_zoned_mode(struct btrfs_fs_info *fs_info);
 
 #endif /* __BTRFS_ZONED_H__ */