Btrfs: check for a null fs root when writing to the backup root log
During log replay, can commit the transaction before the fs_root
pointers are setup, so we have to make sure they are not null before
trying to use them.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index e532892..e53a5bb 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1754,11 +1754,18 @@
btrfs_set_backup_extent_root_level(root_backup,
btrfs_header_level(info->extent_root->node));
- btrfs_set_backup_fs_root(root_backup, info->fs_root->node->start);
- btrfs_set_backup_fs_root_gen(root_backup,
+ /*
+ * we might commit during log recovery, which happens before we set
+ * the fs_root. Make sure it is valid before we fill it in.
+ */
+ if (info->fs_root && info->fs_root->node) {
+ btrfs_set_backup_fs_root(root_backup,
+ info->fs_root->node->start);
+ btrfs_set_backup_fs_root_gen(root_backup,
btrfs_header_generation(info->fs_root->node));
- btrfs_set_backup_fs_root_level(root_backup,
+ btrfs_set_backup_fs_root_level(root_backup,
btrfs_header_level(info->fs_root->node));
+ }
btrfs_set_backup_dev_root(root_backup, info->dev_root->node->start);
btrfs_set_backup_dev_root_gen(root_backup,