1 files changed, 27 insertions, 6 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index c1d127decc8d..18bc678ae4e6 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -542,7 +542,7 @@ static int csum_dirty_buffer(struct btrfs_fs_info *fs_info, struct page *page)
 	if (WARN_ON(!PageUptodate(page)))
 		return -EUCLEAN;
 
-	ASSERT(memcmp_extent_buffer(eb, fs_info->fsid,
+	ASSERT(memcmp_extent_buffer(eb, fs_info->metadata_fsid,
 			btrfs_header_fsid(), BTRFS_FSID_SIZE) == 0);
 
 	return csum_tree_block(fs_info, eb, 0);
@@ -557,7 +557,20 @@ static int check_tree_block_fsid(struct btrfs_fs_info *fs_info,
 
 	read_extent_buffer(eb, fsid, btrfs_header_fsid(), BTRFS_FSID_SIZE);
 	while (fs_devices) {
-		if (!memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE)) {
+		u8 *metadata_uuid;
+
+		/*
+		 * Checking the incompat flag is only valid for the current
+		 * fs. For seed devices it's forbidden to have their uuid
+		 * changed so reading ->fsid in this case is fine
+		 */
+		if (fs_devices == fs_info->fs_devices &&
+		    btrfs_fs_incompat(fs_info, METADATA_UUID))
+			metadata_uuid = fs_devices->metadata_uuid;
+		else
+			metadata_uuid = fs_devices->fsid;
+
+		if (!memcmp(fsid, metadata_uuid, BTRFS_FSID_SIZE)) {
 			ret = 0;
 			break;
 		}
@@ -2443,10 +2456,11 @@ static int validate_super(struct btrfs_fs_info *fs_info,
 		ret = -EINVAL;
 	}
 
-	if (memcmp(fs_info->fsid, sb->dev_item.fsid, BTRFS_FSID_SIZE) != 0) {
+	if (memcmp(fs_info->metadata_fsid, sb->dev_item.fsid,
+		   BTRFS_FSID_SIZE) != 0) {
 		btrfs_err(fs_info,
-			   "dev_item UUID does not match fsid: %pU != %pU",
-			   fs_info->fsid, sb->dev_item.fsid);
+			"dev_item UUID does not match metadata fsid: %pU != %pU",
+			fs_info->metadata_fsid, sb->dev_item.fsid);
 		ret = -EINVAL;
 	}
 
@@ -2790,6 +2804,12 @@ int open_ctree(struct super_block *sb,
 	brelse(bh);
 
 	memcpy(fs_info->fsid, fs_info->super_copy->fsid, BTRFS_FSID_SIZE);
+	if (btrfs_fs_incompat(fs_info, METADATA_UUID)) {
+		memcpy(fs_info->metadata_fsid,
+		       fs_info->super_copy->metadata_uuid, BTRFS_FSID_SIZE);
+	} else {
+		memcpy(fs_info->metadata_fsid, fs_info->fsid, BTRFS_FSID_SIZE);
+	}
 
 	ret = btrfs_validate_mount_super(fs_info);
 	if (ret) {
@@ -3728,7 +3748,8 @@ int write_all_supers(struct btrfs_fs_info *fs_info, int max_mirrors)
 		btrfs_set_stack_device_io_width(dev_item, dev->io_width);
 		btrfs_set_stack_device_sector_size(dev_item, dev->sector_size);
 		memcpy(dev_item->uuid, dev->uuid, BTRFS_UUID_SIZE);
-		memcpy(dev_item->fsid, dev->fs_devices->fsid, BTRFS_FSID_SIZE);
+		memcpy(dev_item->fsid, dev->fs_devices->metadata_uuid,
+		       BTRFS_FSID_SIZE);
 
 		flags = btrfs_super_flags(sb);
 		btrfs_set_super_flags(sb, flags | BTRFS_HEADER_FLAG_WRITTEN);